Cultivating Questions Concerning the Bioextensive Market Garden
by Anne and Eric Nordell of Trout Run, PA
Problem Solving Reduced Tillage Systems
In the Winter 2004 SFJ we cultivated a question about raising heat-loving crops in a high residue system. In this issue, we would like to address two other challenges specific to low-till vegetable production – weeds and slugs – before concluding this series of CQ installments on alternative tillage.
Fearing that the topic of low-till weeds and mulch-loving slugs may not be of general interest, we have made an extra effort to select material on this esoteric subject which demonstrates the problem solving skills necessary for the success of any sustainable farm system. We begin this column by looking at our own problem solving efforts to reduce the population of cool season weeds and high moisture mollusks in the bioextensive market garden, and how we have integrated the resulting cultural practices into the new and improved version of our cover crop/tillage rotation.
We continue the troubleshooting theme with a special guest contribution from Mark Cain who describes so well the challenges of adapting reduced tillage to diversified market gardening. Located in the Ozarks of Arkansas, slugs and cool soil are not a problem at Dripping Springs Garden. However, increasing labor requirements for hand weeding and planting have lead Mark to question the commercial liability of a permanent no till system. We couldn’t agree more with his conclusion that a “cultivation rotation” may be a more practical and sustainable way to grow a diverse mix of vegetables, flowers and herbs than locking the farm into one system of tillage.
The following photo essay on Triple Mulch Vegetables looks at some of the new problem solving changes we have made in our cultivation rotation, and sets the stage for The No Till Dilemma. This collection of excerpts takes the topic of reduced-tillage troubleshooting to the next level by touting the benefits and challenges of going 100% no-till without using herbicides.
It seems only fitting to conclude this Spring CQ column on problem solving with a first hand account of horse and ox farmers in Brazil who have developed a no-till cover crop system that makes it possible for them to compete in the commodity grain market with large-scale tractor farmers. Similar to our own minimum-till/cover crop experience, the animal-traction farmers of Catarina have discovered that instead of increasing weed problems, no-tilling grains into cover crop mulches has dramatically reduced weed pressure. We just wish that Roland Bunch’s amazing eyewitness report also described how these innovative no-till pioneers keep the population of residue seeking slugs in check.
They Shoot Slugs, Don’t They?
It seemed like it had been raining almost nonstop for two months and the slugs were taking over the market garden. First, the telltale holes in the leafy greens. But now, the slime balls were gnawing away at the roots of the spinach and Rainbow Chard, and had completely chewed off the tops of two rows of young carrots.
Feeling depressed, and like I had to do something, I stopped at The Beverage Barn on the way home from restaurant deliveries. When I walked in the door, the men lounging around the dimly lit store went silent and gave me the cold stare. Asked what I wanted, I said I desperately needed a case of beer. Asked what kind, I explained that I needed a cheap brand for trapping slugs. Something that holds a good head because slugs are not attracted to beer that has gone flat.
The owner looked at me like I was nuts. “Lady,” he drawled with disgust, “the people who come in here, they shoot slugs!”
– related by Anne in the very wet Spring of 1998
Slugs have always been a challenge for growing succulent market garden crops in our cool, moist climate. Even during the first years on the farm when we practiced exclusively clean tillage, slugs would move into the vegetable fields from the surrounding grass sod during extended periods of wet weather.
After a number of years of experimenting with reduced tillage, slug numbers seemed to increase. More specifically, slug damage showed up first in the middle of our cropped fields rather than starting at the field edges. Apparently, the moisture-conserving mulch of cover crop residues in our minimum-till vegetables provided better year-round habitat for the mucousy mollusks than the permanent grass in the adjoining roadways, hayfields and pasture.
A quick review of the literature on slug control sent to us by Abby Seaman (IPM specialist at the Geneva, NY Experiment Station) and Dr. Aref Abdul-Baki (at ARSUSDA in Beltsville, MD – see the last issue) reinforced the idea that our moisture conserving practices would favor the buildup of slug populations. Cover crops, reduced tillage, and coarse, high-residue seedbeds were cited again and again throughout this exhaustive collection of research reports as cropping practices that would encourage the slugs to setup housekeeping.
Not surprisingly, the literature recommended finely-pulverized, residue-free seedbeds as the best way to deter slugs from horticultural crops. The last ten years of research also contained several references to fall plowing and leaving the soil bare overwinter in order to freeze-out the mollusks during their egg-laying season. Neither of these recommended practices fit our image of sustainable soil stewardship or our requirements for dryland market gardening.
Although the literature cites some success in Europe using certain strains of nematodes to reduce slug populations in conservation tillage systems, these biological controls are not presently cleared for use in the U.S. One research report claimed that a caffeine-based spray shows potential as a slug deterrent. But The Boss put her foot down on experimenting with this stimulant – she might be willing to share her case of cheap beer with the slugs, but not her precious stash of fair trade, organic coffee.
As for the traditional gardening method of trapping slugs, we have found that bait baths made from beer or other yeasty concoctions are cost prohibitive and ineffective for field applications. They also attract carabid beetles, one of the few slug predators. Making slug barriers with diatomaceous earth has also proved too expensive, time consuming and ineffective, especially in rainy conditions that favor the slugs. At present, there are no OMRI- approved commercial slug baits for certified organic production. Even the poison pellets used by conventional no-till farmers are not 100% effective.
The cultural methods we have come up with to reduce slug pressure are not 100% effective either. However, they seem to hold enough promise for us to continue with high residue vegetable production while waiting for a natural balance to develop between the mulch-loving slugs and their predators.
As a short term deterrent, we have had moderate success interseeding slug-prone crops with an even more appetizing living mulch. For example, interseeding ridge-till carrots with a single-row of string beans in the pathways seems to distract the slugs and improve the stand of carrots.
The slug’s evident preference for legumes has also encouraged us to rethink our fallow year cover crop sequence preceding EARLY ridge-till vegetables. Instead of planting a winterkilled cover crop of oats and peas on the ridges in August for planting into early the next spring, we now plant the slug-loving peas with the preceding spring cover crop of barley as described in the last column. This minor change in the fallow year cover-cropping scheme moves the shallow incorporation of the small grain and legume to the warmer, drier months of summer when decomposition proceeds relatively quickly and the slugs are less likely to be active. Following the summer-tilled barley and peas with a pure stand of oats on the ridges should not be as attractive to the slugs as our usual oat-pea combination when planting the ridges the next spring in cool, wet conditions.
We have also been experimenting with a little spring tillage at the beginning of the fallow year in order to disrupt the slugs during their prime time for feeding and breeding. A brief early season fallow for slug reduction fits in nicely with establishing the spring barley-and-pea cover crop in the revised fallow year sequence leading up to early ridge-till crops. It also complements the fallow management changes we have made preparing for MIDSEASON crops, planting Italian ryegrass and clover in June to discourage the tarnished plant bug as described in Grass-fed Potatoes in the Spring 2002 SFJ. Both of these spring-till fallow scenarios seem like a more earth-friendly way to setback slug regeneration than fall plowing and leaving the soil exposed to the elements over the winter.
However, the most effective and soil protective method we have found so far for actually eliminating slugs the fallow year before production is to graze our small flocks of layers right on the fallow cover crops. The hens quickly develop an appetite for fresh escargot, scratching through the cover crop residues and any loose soil looking for the slugs as well as grubs, maggots, worms and other bugs. Given the choice, the birds actually seem to prefer scratching through the moisture-conserving cover crop residues in the fallow fields than grazing green grass during dry conditions. Apparently, the cover crop mulch shelters a larger number of tasty ground-dwelling insects than the dry sod.
We use this phenomenon to our advantage, fencing the layers into the fallow fields of mulch-tilled cover crops during the dry months of summer. In the process of scratching through the coarse, carbonaceous residues searching for bugs, the birds add their high nitrogen droppings to the sheet composting process and shred the residues into small pieces so that very little additional tillage is required before planting the fall cover crops.
Then, in September, when conditions are more typically moist and cool, we pasture the hens on one of the fallow lands seeded down to Italian ryegrass and clover in June. This fast growing forage produces a lot of good grazing for the birds in the fall and serves as trap crop for the slugs. Even after a couple of months of intensive henpecking, this tough biennial sod provides plenty of soil protection overwinter. In our minds, free ranging birds on green grass seems like a more sustainable approach to slug management than fall plowing and frozen bare soil.
This past year really put our slug control program to the test. Not only was 2003 the third wettest year on record in our area, but most of the 53” of precipitation fell in small frequent showers spread out over almost the whole growing season, creating the continuously wet soil conditions so favorable to high-moisture mollusks. Nevertheless, slug damage was remarkably low in the 2003 crop fields where we had grazed the layers during the preceding 2002 fallow year. For example, we were rewarded with a near perfect carrot stand in Field 4 where the cover crops had been chicken-tilled the previous summer. There were also noticeably fewer slug holes in the onion tops in this field than in the alliums in Field 6 which had not received the chicken treatment in 2002.
Likewise, slug damage was minimal in the 2003 midsummer plantings of lettuce, carrots and brassicas in Field 10 where the skim plowed ryegrass sod had been grazed by the hens the previous fall. By contrast, slug damage was intense for a few weeks in the same crops planted around the same dates in Field 8 which had not received the benefit of the birds during the previous fallow year.
Of course, by the end of this extra-wet season, slugs were widespread in the bioextensive market garden, even in fields that had been chicken-tilled in 2002. However, overall slug damage was so minimal that 2003 turned out to be one of our best production years ever, encouraging us to continue with our moisture conserving, high-residue system for growing dryland vegetables.
Outwitting Cool Season Weeds
Slugs are primarily a problem in areas that experience extended periods of cool, moist weather. Weeds, on the other hand, are well adapted to all growing regions. They are usually cited as the main obstacle to growing minimum-till vegetables without chemicals due to the difficulty of using mechanical weed control in high residue.
Our experience has been just the opposite. We actually started experimenting with reduced tillage as part of our bio-extensive approach to weed management. As described in some of our earliest articles (see “Weedfree Onions” and “A Few Long Furrows” in the Spring ’93 and Fall ’96 SFJ’s), we preceded each cash crop with a fallow year sequence of cover crops and summer tillage to eliminate perennial rhizomonous weeds and to deplete the soil surface of viable annual weed seeds. In order to prevent bringing up new weed seeds to the surface to germinate during the following production year, we limited the depth of pre-plant tillage to the top two-tothree inches of the soil.
We shallowly mulch-tilled winterkilled cover crops before planting EARLY cash crops, and skim plowed overwintering cover crops before planting LATE crops. Using these forms of reduced tillage to start the production year not only minimized the exposure of new weed seeds on the surface to germinate, but also seemed to prevent flushes of weeds by creating favorable conditions for decomposition and by providing a slow-and-steady release of nutrients and energy in the soil.
Using these two types of pre-plant minimum tillage in conjunction with a fallow year of cover cropping proved so effective at reducing weed pressure over the years that we were tempted to reduce tillage even further by adapting ridge-tillage to vegetable production. Rather than increasing the weed challenge, we found this one-pass tillage system provided some significant weed management advantages over both traditional clean-till seedbeds and the mulch-tillage practices we had been using before the EARLIEST planted cash crops in the market garden.
For instance, winter weeds like chickweed and henbit are not easy to kill with tillage during the typically wet, cool conditions of spring. More often than not, these cool season weeds are simply transplanted to a new spot by mechanically manipulating the wet soil, and then reestablish themselves before the cash crop has a chance to get started.
The beauty of the ridge-till system is that any of these cold hardy weeds growing on the ridgetops will be moved into the pathways during the ridge-tilling process. (To visualize this, see the Ridge-till/No-till photo essay in the Winter 2004 issue of SFJ.) The result is a weed free planting zone which gives the crop a major head start on these winter weeds and their offspring. Meanwhile, the chickweed, henbit and other cool season weeds knocked off the ridgetops into the ridge-till pathways can be cultivated aggressively once the soil has dried out sufficiently for effective weed-killing.
Even with the persistently wet conditions we faced last year, ridge-tillage provided just the right amount and type of soil disturbance to dramatically reduce early season weed pressure. For instance, the Labor and Sales Chart in the last column documented that we spent ten to twenty minutes per 380’ row to hand weed the 2004 crops of ridge-till potatoes, onions, peas and spinach in Field 6. This modest labor expenditure was almost entirely for removing a second generation of chickweed that sprouted at the ends of the field – we did not want to let this prolific weed creeping in from the headlands to set seed.
The Labor and Sales Chart also recorded that only two cultivations and no further hand weeding were necessary to maintain weed free conditions in these ridge-till crops thanks to the preceding fallow year management which had virtually eliminated the presence of warm weather weeds. This fallow year/ridge-tillage combination has consistently provided full season weed control for the EARLIEST planted cash crops over the past seven years that we have been using this system.
By contrast, the 2003 Labor and Sales Chart indicated that we had devoted from one-half to one-and-a-half hour per row to remove the cool season weeds that might go to seed in onions, leeks and garlic planted on the no-till ridges in Field 6. Although the constantly moist soil certainly increased the germination of these types of weeds on the undisturbed ridgetops compared to previous years, the consistently higher hand weeding requirements of this no-till system made us think that we really needed to adapt the preceding fallow year management to reduce the weed seed bank of cool season weeds. If we could lower this seed pool to the same degree as the heat loving weeds, then we could take advantage of the moisture-soil-and-crop enhancing benefits of the no-till ridge system without any more hand weeding than ridge-tillage.
With that objective in mind, we have begun experimenting with a brief period of spring tillage at the beginning of the fallow year before no-tilling the ridges. Shifting the bare fallow period from summer to spring to target cool season weeds also coincides nicely with two of the new cultural practices for reducing slug pressure in minimum-till vegetables.
The NEON Weed Study
We have used some of the preliminary results of the NEON project in recent CQ installments to help fill in the gaps in our long winded narrative on the pros and cons of alternative tillage techniques. One of the goals of this ambitious, multi-disciplinary research project is to create a fairly accurate picture of organic crop management in the Northeast by tracking selected crops on eleven focal farms. Although the mix of focal crops is different on each farm, they have been evaluated using the same parameters: insect scouting, disease monitoring, yield checks, economic analysis, nutrient budgets, and weed counts. Given that weed management is often considered a major obstacle to chemical-free farming, the NEON weed study may be of particular interest to farmers considering the transition to organics. Look for the publication date of the focal farm case studies at the NEON website: www.neon.cornell.edu or contact Anu Rangarajan, Cornell University, 121 Plant Science Bldg., Ithaca, NY 14850.
We have included some of the results of the NEON weed study for our farm in this column to provide an unbiased record of the weed pressure in our minimum-till vegetables during two very different growing seasons. The shaded bars in the weed density charts represent weed counts for the five focal crops in the dry, hot conditions of 2002. The unshaded bars refer to the predominantly cool, wet 2003 growing season. Research coordinator, Steve Vanek, conducted the weed counts shortly before harvest. The data was then analyzed and summarized by Chuck Mohler, a weed ecologist at Cornell who has a lot of experience and interest in organic weed management.
A few points of clarification may make these easy-to-understand charts even more meaningful. Three of the focal crops monitored – lettuce, onions and carrots – involved several different varieties planted in different fields at different dates using different cover crop/tillage combinations. For example, the 2002 “onions” found in the charts represents mulch-tilled sweet onions (Candy transplants) set out in May and no-tilled and mulched-tilled storage onions (Stuttgart sets) planted in April, including a few rows on the south side of Field 9 where it seemed like a whole hayfield of dandelions blew in! The 2002 and 2003 “carrots” are also a composite crop, representing three different plantings of fall carrots in three different fields with three different types of cover crop/tillage techniques.
We should also point out that the weed density charts focus on just the top four weeds for each focal crop. (The total number of different weeds ranged from just two in the 2002 composite crop of carrots and the three plantings of 2003 Two Star and New Red Fire lettuce, to seven types of weeds in the 2002 onions.) We think that unusual variety of weed species recorded in our vegetable fields accurately reflects the strengths and weaknesses of our fallow year/reduced tillage approach to weed control. Note the conspicuous absence of typical market garden weeds like lambsquarter, pigweed, galinsoga, purslane, and other warm season annuals associated with high fertility, intensively cultivated soils. Instead, our dominant weeds tend to be cool season species more commonly found on undisturbed land such as pastures and old hayfields.
The presence of these oddball weeds might be due to the reduction in tillage and the fact that these kinds of weeds could blow in, or be carried in on equipment or the horses’ feet, from the field lanes and hayfields surrounding the market garden. Chuck Mohler also speculates that these uncompetitive weeds may be observed in our fields simply because there is so little competition from more aggressive weeds commonly found in cultivated soils.
At first glance, some of the numbers for these unusual market garden weeds seem pretty high – over 2700 mousear chickweed seedlings per acre in the 2003 no-till garlic and more than 35,000 dandelions per acre in the 2002 onions! However, a quick look at the dry biomass graph shows that even these seemingly high weed counts amounted to extremely low biomass and little competition to either crop as they approached harvest. Researcher notes accompanying the raw data indicated that “weed biomass and abundance was too low to have affected yields” in both cases. As for the other focal crops, weed pressure was considered “negligible.”
The weed study also monitored the maturity of the weeds present at harvest time, a real concern for us given our weed management objective of reducing the weed seed bank in the soil by preventing weeds from going to seed. The raw data shows that all of the weeds found in the sample areas were in the “vegetative” state shortly before harvest. That is, they posed little threat of making viable seed before post-harvest cleanup and planting the fall cover crop.
If nothing else, we hope that the weed charts help to complete the whole picture of the reduced tillage crops featured in recent CQ columns. The weed density and biomass numbers document weed pressure for the 2002 no-till garlic and mulch-tilled carrots highlighted in the enterprise budgets found in the Summer 2003 SFJ as well as the 2003 Stuttgart onions that played a prominent role in the Ridge-Till/No-Till Trial in the Winter 2004 issue of SFJ. And the sweet onions and carrots referred to in this issue’s photo essay on Triple Mulch Vegetables are also included in the composite crop data in the NEON weed charts.
This photo (above) of the bio-extensive market garden, taken in early November of 2003, showcases the new-and-improved fallow year cover crop rotation and how it matches a handful of reduced tillage techniques with six different planting windows.
- In the foreground, a lush stand of Italian ryegrass and clover in Field 1 prepares the land for grass-fed potatoes and other MIDSEASON crops to be planted in 2004.
- Knee-high oats on the ridges in Field 3 will dieback overwinter, ready for no-tilling and ridge-tilling the EARLIEST TRANSPLANTED and DIRECT SEEDED vegetables in 2004.
- The thigh-high oats, peas and millet in Field 5 will also winterkill, in this case conditioning this flat field for EARLY mulch-tilled TRANSPLANTS and MIDSUMMER DIRECT SEEDINGS as illustrated in the Triple-Mulch Vegetables photo essay.
- The poly-covered Conestoga Coop just barely visible in Field 7 provides nighttime protection for our small flocks of layers deslugging the Italian ryegrass and clover planted here in late June. This short-term sod will be skim plowed early in 2004 just like Field 1, preserving the winter moisture for MIDSUMMER TRANSPLANTS and LATE DIRECT SEEDED produce.
Fine-tuning the Cover Crop/Tillage Rotation
We include in this column the 2003 Crop Map and Field Notes just to show how our new cultural practices for reducing cool season weeds and mulch-loving slugs have been integrated into the overall rotation. For example, the Field Notes provide the details of the new fallow year options we are experimenting with, such as a spring fallow, chicken tillage, and changing the growing period of the pea cover crop to the drier part of the season.
Although the basic bio-extensive alternation between cash crops and fallow lands remains intact, the 2003 Crop Map and Field Notes also document a radical departure from our original system of rotating the cash crops between those planted EARLY and those planted LATE. Instead of relying on just two large planting windows for our diverse mix of vegetables, we now distinguish between EARLY, MIDSEASON and LATE plantings. For the purpose of moisture conservation, residue management, and seedbed preparation, we also find it advantageous to differentiate between DIRECT SEEDED and TRANSPLANTED cash crops. The result of making these finer distinctions is a half dozen possible planting combinations – ranging from EARLY DIRECT SEEDED to LATE TRANSPLANTED vegetables. Consequently, we now use a handful of cover crop/tillage combinations to provide the best field conditions for each of these planting windows.
For simplicity’s sake, we have tried to indicate the clockwise movement of the cover crop/tillage rotation around the market garden by highlighting on the Crop Map the fall cover crops in the fallow lands. The Field Notes show how each cover crop/tillage combo meshes with a specific planting window. What may not be evident at first glance is how this fine-tuned version of the cover crop/tillage rotation enhances planting flexibility in two significant ways:
*First, a diversity of cover crop/tillage options pretty much guarantees that there will be suitable conditions for planting all season long.
*Second, the rotation does not restrict the selection or placement of cash crops making it easy to adapt to changes in the weather or customer preferences.
Of course, we first check our cropping records to make sure we have not planted the same plant family in the same location during the previous four years. We take this simple precaution to prevent the buildup of diseases and insects associated with a particular crop family.
This process is somewhat simplified in our case by the fact that a fallow year of cover crops separates each cash crop. Consequently, we only need to check our records for the field two years earlier to guarantee that the same plant family is not planted in the same area for the whole four year sanitation period.
For example, in 2003 we needed to expand our planting of leeks and sweet onions to keep up with increasing demand at the farmers market. We did this by putting out fifty percent more plants, and by planting about a third of the crop extra-early to spread out the fresh market harvest. Thanks to the no-till ridges in Fields 2 and 6 we were able to get these extra-early sweet onions and leeks in the ground on time despite the wet weather. A precautionary look at our 2001 cropping records confirmed that we had not planted alliums in either of these notill areas during the last four years.
We set out the main portion of the sweet onions and leeks in the middle of Field 4 at our usual mid-May planting date. Not only was this mulch-tilled field in good shape for transplanting bare-rooted starts at this time, but this section of Field 4 had been planted to three very different plant families – namely, peas, carrots and spinach – during the most recent cash crop year in 2001. We decided not to grow this expanded planting of alliums on the north or south sides of this field in 2003 because our records indicated that we had planted garlic and storage onions in these areas two years previous. Instead, we devoted the sides of Field 4 to carrots and strawberries as shown in the Triple Mulch photo essay.
We hope that this allium example illustrates how easy it is for us to adapt to changes in the weather and marketplace by using a bare minimum of record keeping in conjunction with a handful of cover crop/tillage options. More importantly, this sort of short-term planting flexibility does not interfere with our long-term management objectives, like enhancing moisture retention or reducing the populations of low-till weeds and slugs. To the contrary, the bio-extensive nature of the cover crop/tillage rotation keeps these proactive cultural practices on track by separating each cash crop with a fallow year devoted entirely to holistic problem solving.
2003 FIELD NOTES
field 3 & 9
2003 FALLOW before the EARLIEST transplanted and direct seeded crops: plow interseeded rye or vetch and plant barley and field peas end of April; mulch-till or chicken-till mid-July; apply compost and plant oats on ridges late August
objectives: reduce dandelions, spring weeds and slugs; enhance soil fertility and tilth before early planted minimum-till crops
2004 CROP no-till ridges with transplants or sets in April; ridge-till direct seeded crops in April and early May; mulch no-till pathways with wheat straw; interseed ridge-till crops with hairy vetch or insectiary mix of oats and buckwheat; fall cover crop of rye and spelt
field 5 & 9
2003 FALLOW before EARLY transplants and MIDSEASON direct seeded crops: mow rye and spelt cover crop two times, then mulch- till or chicken-till early July; plant oats, peas and Japanese Millet early August; apply compost in October or November
objectives: reduce slugs and summer weeds; fiberize soil surface to improve moisture retention for early and midseason crops
2004 CROP mulch-till winterkilled oats, peas and millet before May transplanted crops and late May and June direct seeded crops; interseed with rye or hairy vetch
field 1 & 7
2003 FALLOW before MIDSEASON transplants and LATE direct seeded crops: plow or chicken-till interseeded rye and vetch in April and May; plant Italian ryegrass and clover end of June; pasture layers, or apply compost, in September-October
objectives: reduce chickweed and slugs; improve soil structure; minimize tarnished plant bug and leafhopper damage to adjacent crops
2004 CROP skim plow grass-legume sod in early April to conserve moisture for June transplants and July direct seeded crops; interseed with rye; fall cover of rye
field 3 & CS
2003 FALLOW before LATE transplanted and direct seeded crops: mow rye two times, then mulch-till or chicken-till early July; plant ridged rye or rye and vetch early August
objectives: reduce slugs and summer weeds; fiberize soil surface to improve moisture retention for late season crops
2004 CROP apply compost and mulch-till ridged rye late April or rye and vetch mid-May; for July and August transplants and August direct seeded crops; interseed with rye
NO-TILL, MULCH-BASED MARKET GARDENING
by Mark Cain, Dripping Springs Gardens, Huntsville, AR. Spring 1997
“Synergistic” agriculture is a term that has been applied by permaculturist Emilia Hazelip to her method of no-till gardening inspired by the work of Japanese farmer-scientist Masanobu Fukuoka. Author of The One-Straw Revolution, Fukuoka has been applying his unique no-till approach in his rice fields and orchards for almost 50 years.
Ms. Hazelip defines synergistic agriculture as consisting of four fundamental principles:
- Continuous fertilization of the soil by a permanent organic cover (mulch).
- Growing crops in association with complementary plants—edible legumes and companion plants integrated in with crop plants.
- No plowing or any other type of tilling the soil after initial bed-digging; the soil “works itself.”
- The soil remains aerated and in good tilth as long as we minimize compaction.
Hazelip’s procedure when creating her no-till gardens is to begin by setting up a raised-bed system which is then kept continually mulched. Plant residues are always returned to the bed to allow the soil life to recycle the organic matter back into the soil’s digestive system. Non-noxious weeds are also laid back on the soil surface to decay, as long as no seeds have been allowed to mature. Fertility maintenance is accomplished by growing edible legumes either in association or in rotation with crop plants, as well as providing for the continuous breakdown of organic matter at the surface of the bed.
What we have been working with is 2-1/2 acres of raised beds on a gravelly, silt-loam soil; we are raising cut flowers and vegetables for the Fayetteville (Arkansas) Farmers’ Market. Our general procedure in the past was to prepare our beds by tilling and adding amendments, laying down drip irrigation lines, then mulching over with straw or clean hay. We then open holes for the transplants along the water lines, transplanting through the mulch. By doing so we avoid subsequent cultivation for the remainder of the summer, although some hand pulling of weeds is necessary around planting sites. This general method has been applicable and desirable for most species we grow, as it moderates soil temperature, reduces irrigation, reduces labor in weed control, and adds valuable organic material to the beds. Our clean-up procedure was to mow down plant residues, till in the residues and remaining mulch, and cover-crop with a legume/grass combination for the winter. In spring we would till again to incorporate the green manure, re-shape beds, re-mulch, and plant the new season’s crops.
We began shifting the management of a portion of the garden toward the no-till approach in the spring of 1995 (after attending a 2-day presentation of Hazelip’s at the Meadowcreek Project in Fox, AR). These beds were prepared as usual, fitted with irrigation lines, mulched, and planted. Thereafter, we have paid special care not to compact the soil, especially when wet, by confining all traffic to the walkways. Any weeds which make it through the mulch layer are pulled and placed on top of the litter to decompose unless they have gone to seed (too late!) and must be removed to the compost pile. The thing to keep in mind is that we are essentially sheet-mulching the beds with a permanent cover of continually decomposing organic matter which serves as weed barrier and fertilizer. One must also check the rate of decay of the litter layer, and add mulch whenever necessary to keep the soil covered – as soon as soil is exposed, weeds are sure to germinate! For years we have used fescue hay as a top-mulch for beds, with decent results, but it was obvious in 1996 that wheat straw may be a better buy even though more expensive. By the end of the summer, the hay layer that was 6” thick in May had decomposed to nil, but straw was at least 50% persistent. We have also brought in a good supply of dock and assorted pasture weeds to the garden over the years with the fescue hay, most of which have not been problematic with annual tillage. Now with the untilled beds, it is important not to make any investments we don’t want interest on!
As stated above, we primarily use transplants — over 10,000 annually — to stock the raised beds, but some crops require direct-sowing: carrots and most vegetable root crops; corn, beans, cereals; bulbous items like gladioli, onions, garlic; and assorted plants which resent transplanting like larkspur, nigella, and poppies. Large-seeded crops like corn, beans, and sunflowers may be sown in furrows and broadcast over with mulch which is not too thick (approx. 2”) and they will germinate through the litter layer. We follow the same procedure for the bulbous plants, but can mulch more deeply (4-6”). Wheat, oats, etc., can be broadcast on bed surface and covered with a thin layer of mulch—enough to protect the seed from birds but thin enough to allow emergence (1” or less).
Small-seeded items are challenging. Although some no-till references will advise to simply pull back the mulch and open a line for sowing, our experiments with carrots and spinach sown this way have been disappointing, as the straw mulch tends to sift back over the line and adversely affect germination. For the time being we are sowing in furrows on beds where mulch has been removed, and surface-cultivate after germination. Mulch can be re-applied after plants are tall enough.
During the summer we try to have all beds in production continuously, which requires changing out crops. For instance, spring greens beds will be planted to summer flowers, over-wintering garlic gives way to beans or fall crops, etc. How to do this if we eliminate tillage in-between crops? In 1996 we used several relay-cropping techniques, some of which worked well. Cosmos and ageratum were interplanted with maturing spring lettuces in early May by removing some lettuces for salad mix and filling spaces with the flower transplants. After the lettuces were all harvested, the beds filled in completely with the second crop. Broccoli intercrops effectively with lettuce when both are planted at the same time in early spring: the lettuce matures and is harvested just about the time the broccoli needs the room to expand. Some combinations we would likely not use again were: peppers interplanted with maturing lettuce (lettuce expansion slowed down early pepper growth); sweet potatoes with early flower crops of cornflower, nigella and larkspur (again, dense shade slowed the early growth of this heat-lover).
When an entire bed is harvested and a change of crop is desired, we matched the succession crop to the type of harvest that had occurred. For instance, garlic and early potatoes both necessitate spading out the crop, leaving a worked bed that is ready to accept direct-sown seeds (late beans, corn, etc.). We simply raked the harvested beds smooth and sowed as soon as possible, then re-covered with mulch to conserve moisture and avoid weed germination. For crops that are harvested by cutting at the soil surface (lettuce, spinach, etc.), we simply stocked the emptied bed with new transplants.
As stated earlier, all plant residues are kept on the beds for future fertilizer in this no-till system. In the case of a spent snapdragon crop, in early August the plants were cut at the soil line and allowed to lay on top of the mulch. A fresh layer of mulch was added to keep the residues moist for decomposition, and two weeks later fall Chinese cabbage transplants were planted in the same bed, with excellent subsequent growth— and no tillage required. This general procedure of cutting down spent plants and remulching is the autumn maintenance regime—eliminating the removal of hoses, tillage, sowing cover crop/re-tilling again in the spring, re-shaping, etc.
This past season we were caught in several rainy periods during the prime spring planting period, needing to move plants out of the greenhouse. And, taking a leap of faith, many beds that in the past would have been tilled in preparation for the crop were simply mulched and planted. This was only attempted where a good residual mulch had prevented the emergence of spring weeds, and tilth was judged acceptable for transplanting. The growth of these crops was excellent, and weed germination noticeably less than where beds were tilled and mulched.
Our main concern over time will be the maintenance of friability and fertility under a permanent cover. Hazelip has suggested the broadcasting of turnip, mangel, or daikon over beds in the fall, and subsequently allowing the roots formed to decompose over the winter, feeding the soil organisms. Edible legumes such as peas, beans, and cowpeas should be rotated through the beds either alone or in combination with other crop plants. Friability can be assisted by constructing beds which are fairly high to begin with (up to 18”), protecting them from compaction, and always preserving the litter layer to prevent baking, leaching, erosion. Over time, the topsoil formed by the decomposing mulch layer should increase in depth.
These are just a few preliminary investigations into a whole new way of growing crops and managing the soil. For further information on no-till techniques:
“The Synergistic Garden,” 30 minute video with Emilia Hazelip, available from LAS ENCANTADAS, B.P. 217, F-11300 Limoux, France.
Ruth Stout, How To Have A Green Thumb Without An Aching Back: A New Method of Mulch Gardening, Simon and Schuster, 1978. A classic, now out-of-print, but available in many libraries.
Masanobu Fukuoka, The Natural Way of Farming: The Theory and Practice of Green Philosophy, Japan Publications 1985. This second English publication of Fukuoka’s contains the most nuts-and-bolts information, but also see his other two books for inspiration and encouragement: The One-Straw Revolution: Introduction to Natural Farming, Rodale Press, 1978 and The Road Back to Nature: Regaining the Paradise Lost, Japan Publications.
CHALLENGES TO NO-TILL MARKET GARDENING
by Mark Cain, Dripping Springs Gardens, Huntsville, AR. Spring 2003
I want to start by saying that I do believe Fukuoka’s statement that “the crops of nature have nothing to do with money.” But we are market gardeners, and intervene as benignly as we know how to in Nature’s doings to harvest crops as dependably as possible. The scale of market gardening makes it impossible, for instance, to handweed large areas if they are ‘out of control’ for planting; the backyard gardener can spend more time on smaller areas with less mechanization. A fellow I met back in 1981 had spent about 6 months on Fukuoka’s farm, and said that one morning he came across this guru of no-till planting peas in a conventional way—making furrows, planting in rows, etc. When the astonished student asked him why he wasn’t simply broadcasting the peas in the ‘do-nothing’ way, Fukuoka simply said, “If you want peas, plant them this way.” I hear that Shunryu Suzuki once summarized Zen as “not always so.” Certainly this applies to the art of gardening as well.
In any case, the first challenge we faced in implementing no-till beds was the direct-sowing of seeds. Typically, we may need to seed a 4’ x 60’-100’ bed with something like turnips, carrots, and the like, and will usually put 4 rows per bed. This requires taking the mulch off of the bed, and having soil friable enough to make shallow furrows to seed into. Our soil here does not remain of loose tilth over time, even without traffic or tillage but with mulch protection. This was an unexpected discovery— if our soil is “working itself,” it certainly is not working itself into a fluff! It settles, becomes stiff, and can become difficult to make furrows in or even transplant into without a lot of effort (I am speaking here of beds which are left untilled for 2-3 years). I think a lot of this is due to our soil type—a gravelly loam-to-clay soil that would double as a rough concrete mix if you added some cement! We are able to see the worm channels that penetrate the untilled soil over time, and water capillary action is no doubt better as well, but nevertheless, the soil becomes hard here. I realized that soil type might have a lot to do with lack of friability over time in no-till beds after seeing a no-till garden in Nicaragua last winter. The soil at this project was very sandy and loose, and stayed that way as long as traffic was kept off of it. To direct seed, they are able to remove the mulch, work up the surface shallowly with small hand tools, and plant onions and the like. These direct-seeded crops are kept cultivated with hand tools until they are large enough to be mulched, or the canopy of plants itself forms a ‘living mulch’.
In our work with cut flowers here, we often have to plant large numbers of bulbs (gladiolus, daffodils, lilies), and simply cannot make a hole for each individual plant in an untilled bed. A four hundred square foot bed, for example, requires 800 gladiolus bulbs; garlic is the same. So, we till and make furrows and poke the bulbs or quickly trowel them into loose soil, then cover, put down drip-tape, and mulch over. We are no longer trying to mulch over direct-sown beans, corn, grains, etc., because too often there may be a weed problem that is much easier to take care of by hand-cultivation with a stirrup hoe rather than by hand weeding. Our annual crop of dry beans for soups is cultivated once then mulched for the duration of the season. Our corn last year was planted by preparing beds, mulching them then opening holes in two lines down the beds and poking two seeds into each opening, thinned eventually to one per hole. The corn grew wonderfully tall, but eventually blew over. Corn is usually hilled (loose soil pulled up around the roots to cover the anchor roots) to prevent this, in the same way that potatoes or peanuts are. Growers must experiment for themselves to see if they can do away with these time-honored (and often valuable) techniques—that require moving soil around.
Emilia Hazelip’s film, “The Synergistic Garden,” shows her opening holes in the mulch, sprinkling a bit of wood ash, poking in a few bean seeds here and there, and covering lightly. Although this also works, you can see why we cannot always implement this type of procedure on even our small-farm scale. Transplants are a natural for mulched raised beds, and we use them wherever possible. But most root crops, bulbs, and a scattering of plants that resent transplanting we sow into furrows made in unmulched beds. And for good results, these beds need to have good tilth (friability). It seems we lose this over time in untilled beds here—fastest in soils with low organic matter and higher clay content. In these cases we will loosen the soil to prepare a seedbed by: (for smaller areas) forking over with garden forks and ‘tilthing’; (for larger areas) tilling with a rear-tine rotary tiller, or spading with a tractor spader. Today, for instance, I was getting beds ready for spring onions. These are so small and are planted so closely, that it is not practical to transplant through mulch when we have so many to plant—we will plant about 6000 in four 100’ x 4’ beds with five rows per bed and 4” apart in the row. So these beds will be tilled before furrows are made and onions planted. When the first generation of weeds is still under ½ to 1” tall, we’ll cultivate the bed shallowly with scuffle hoes. When the onions are large enough to not get lost in the mulch, we’ll mulch the area between the rows with straw. After the onions are pulled, late summer transplants can go in the same beds with no intervening tillage.
[A case should be made for “rotational cultivation” in which the succession of crops around the market garden would bring cultivation to each area every second year or so.]
TEMPERATURE AND MOISTURE
In the spring and the fall here, it really seems to work better not to use mulch on some crops. The soil stays as much as 10 degrees cooler under mulch that has been on all winter, and the soil cannot re-radiate the daytime heat at night if it is covered. We’ve seen this in tomato transplants in early May (we can have light frosts until the first week of May): a group of un-mulched plants was unaffected by light frost, but where a bit of mulch was around a plant, they were damaged by the cold air, isolated from the ground’s warmth. Another year, we lost several large beds of tomatoes, snapdragons, and asters that were transplanted into over-wintered mulched beds, and drowned when we had an unusually wet period. Cool-season items that can be transplanted, like lettuces and cabbage, can often be transplanted into mulched beds with better weed control than on unmulched ground, and I think they do pretty well because they tolerate cooler soils. But I don’t like putting out tomatoes, peppers, sweet potatoes, etc., into the cold soil underneath a mulch that has been on all winter. Instead, now we cultivate the beds for these (tiller or spader) and re-mulch before planting.
I was very disappointed a couple of years ago to see what appeared to be fertility decreasing in a no-till bed. This bed had been initially tilled, fertilized, and shaped, and planted to tulips in the fall. The next spring, after the tulip bloom, we interplanted cosmos, which grew well throughout the season, and after frost (following Hazelip’s technique of retaining all biomass in the bed where it grew), cut off the cosmos, put it down on top of the beds, and mulched over the residue. The following spring, holes were made in the mulch and ageratum transplanted. But the ageratum never took off and grew strongly like it usually does. It took perhaps twice as long to reach maturity as normal—and appeared to be due to lack of (what we take for) normal fertility. I realize that this is simply anecdotal evidence, but my impression is that the wheat straw that we’ve been using just isn’t breaking down into a nice rich humus very fast, leaving us with less fertility in the soil itself after several crops. (Our general experience has been that second-year crop growth in no-till beds with no additional fertilization has been good.) Perhaps one should vary the mulch by using some faster-decomposing materials underneath a protective layer of straw? We compensated in some cases by broadcasting chicken litter over the summer’s mulch layer in the fall before covering with a fresh layer of straw. (I had read about Ruth Stout’s doing the same with soybean meal, and Fukuoka’s broadcasting of chicken litter “for high yields” over the decomposing straw of a previously harvested grain crop.)
As for the self-fertility of the soil, I think this is an open question. Of course enhanced microbial life, good earthworm environment, mulch decay, etc., will all lead to enhanced fertility, but whether this level of fertility is adequate for horticultural crops over time—that depends. So many factors are at play: current level of soil fertility and organic matter content; how many crops per year are taken from the same area; water availability; growth rate and size of vegetable desired; temperature; etc. Emilia suggested using legumes in rotation with other crops to enhance fertility, and perhaps this can be done in the home garden by using mixed plantings which include edible legumes. In our situation, it is not practical to mix plantings like this, and difficult to introduce enough legumes into the rotations, unless these are winter green manure crops, which are of necessity, spaded or tilled in.
Weeds are the bane of no-till, and this is why most conservation tillage in commercial farming relies heavily on herbicides. We’ve noticed that the beds that remain the cleanest after an initial crop (that was transplanted through mulch) are those that had dense foliage crops that kept the ground shaded and difficult for weed volunteers to emerge. If we are able to keep the stray weeds pulled during the summer, these beds are good candidates for re-mulching in the fall and another transplanted crop set out through the mulch the second year. But often winter weeds that are low-spreading will emerge here and there through the mulch during the winter; if there are enough of them, we must cultivate in order to use the beds because hand weeding takes too long.
I think cultivation (whether shallow hoeing with stirrup hoe or tillage), as an organic form of weed control, is very important when properly used. We have tried many times to control weed infiltration with heavier applications of mulch, but this can make the soil too wet or cold, or make transplanting awkward (small plants can be lost in the mulch).
A FINAL NOTE
For backyard or homestead garden situations, I think many of Emilia’s Synergistic Ag techniques can be implemented, and each individual gardener must make adjustments as needed for climate, crop, etc. Market gardeners will probably identify with some of the problems of scale we’ve encountered trying to use no-till beds, and I’m having to temper my initial enthusiasm with the stark facts I encounter in the garden. When we use the Fukuoka method and ask ourselves the question, “what do I not have to do,” and the answer comes that we do have to till, we do it with care. We try to keep the soil covered whenever possible with a mulch layer which acts as sheet compost, weed suppressant, and conserves water. And if we need to apply some fertilizer supplement (organic of course) here and there, we do. But his is beginning to sound like regular old organic gardening…not the self-fertile, never tilled synergistic garden that Hazelip has envisioned.
When Fukuoka was asked by an organic farmer friend of mine what relevance his methods might have to a 400 acre corn and soybean farm in the American Midwest, Fukuoka replied, “First you have to cut your head off!” And most of us would have to do just that, to live a life of Lao Tzu farming, scattering vegetable pellets here and there beneath our un-pruned orchard trees and scything the season’s grain twice a year. What has made it possible for us on our farm to remain in the deep countryside has been producing organically grown crops to sell at a local farmers’ market. For me, hearing Fukuoka’s words in the back of my mind while I am at the work of planting crops creates a creative friction where philosophy hits the reality of weeds, crop failures, and the occasional unexpected success. One of Fukuoka’s Japanese students came to join a group of us living in the mountains of northern California in the early eighties. After he’d looked around at our little gardens next to our yurts and tipis, I asked him what he thought about the gardens. He replied, “Like children’s toys. If you want to grow food, start with grains.” And even though our subsequent trials with rice never yielded much (scarce water supplies and abundant deer), his words stuck with me. I would consider it a shame if well-meaning folks, inspired by Fukuoka’s books, get bogged down in a strict no-till approach, and end up having “toy” gardens that are a kind of philosophical game but do not produce the most basic foods (potatoes and sweet potatoes are a good place to start).
It may be that the road to no-till is paved with tillage…
At the end of the last CQ installment, we fantasized about using three kinds of mulch to grow heat-loving crops in a reduced tillage system. The following Reality Photo Essay details the triple-mulch system we have actually used over the past eight years for growing spring planted crops like sweet onions and leeks.
Unlike the virtual triple-mulch plan for hastening the maturity of warm season plants, our time proven system for long season alliums relies entirely on mulch materials that can be produced right in the field. The photos of Field 4 this past year also document a few new twists on our fallow year practices to increase cover crop biomass, minimize tillage, reduce slug pressure, enhance moisture management, and prevent cool season weeds from going to seed.
Increasing Organic Matter with a Rye-and-Spelt Mixture
1. Preparation for EARLY TRANSPLANTED crops and MIDSEASON DIRECT SEEDED vegetables typically begins in the spring of the preceding fallow year with a cover crop of rye. In recent years we have discovered that we can enhance the biomass production and weed suppression of the overwintering rye simply by mixing in a good bit of spelt seed. When planted in September, this cover crop combination establishes quickly and provides excellent ground cover and weed competition overwinter. The next spring the rye begins growing rapidly almost two weeks earlier than the spelt, producing the bulk of the biomass at the first clipping you see here. At this stage the rye averages 30” high and is just beginning to head out while the slow starting spelt, only 6-8” tall, is hiding in the understory.
2. At the second clipping of this cover crop mix a month later, mid-June, the spelt really dominates, significantly increasing the amount of organic matter compared to the regrowth of a pure stand of rye. The thicker and heavier regrowth from this ryeand- spelt combination also provides a lot more late spring weed suppression of cool season weeds that germinate in the undisturbed soil overwinter or are blown in from the surrounding hayfields.
According to NEON research conducted on our farm this past year, two cuttings of rye alone produced close to 2.8 tons of dry biomass, approximately the same tonnage and C:N ratio of a mature stand of grass hay. Based on several year’s observation, we would guess that the rye-and-spelt mix has the potential to increase above ground biomass by another 1-2,000 lbs. in the same growing window, not to mention the underground organic matter contribution from an additional root system.
Chicken-Tillage And The Summer Fowl-O
3. Before fencing in the layers to de-slug the cover crop, we usually disc the fallow field in order to chop up the long stem rye-and-spelt residues and to kill the cool season weeds suppressed by the cover crop biomass before they have a chance to set seed. However, this past year the soil was so wet in these heavily mulched fallow lands that we tried pasturing the birds right on the untilled clippings of rye and spelt. The birds pecked back the cool season weeds breaking through the decomposing cover crop mulch sufficiently to prevent them from going to seed. And within a few weeks time, the layers had shredded the three-to-four foot long rye-and-spelt stalks into small enough pieces so that when we finally received a break in the weather, we could lightly till the field with the team and seed the second cover crop of this fallow year sequence.
4. In addition to protecting the soil, building up organic matter, and preserving moisture, the cover crop mulch also serves as a trap crop for slugs. This high moisture habitat keeps the slugs on the surface where they are easy picking for the hens. As we rely more and more on reduced tillage and cover crop mulches to preserve moisture for growing unirrigated vegetables, the focus of the summer fallow has shifted from controlling warm weather weeds to a “summer fowl-o” for reducing the number of mulch-loving mollusks. Using chicken-tillage to depopulate the slugs the fallow year before production also complies with the federal organic standards prohibiting the application of fresh animal manure within 90-120 days of harvesting crops for human consumption.
Holding in Moisture with 2 ½ tons of Dry Biomass
5. After the summer fowl-o in 2002, we seeded down Field 4 to a mix of oats and Canadian field peas the second week of August. For the sake of comparison, we planted the south edge of Field 4 to an experimental mix of sorghum-sudan grass and field peas a couple of weeks earlier.
Unfortunately, we did not capture the fall cover crops in Field 4 on film, so we have substituted with this image of oats, peas and millet in Field 5 taken the first week of November in 2003, just a few days before this mature cover was killed by a hard freeze. According to NEON research coordinator, Steve Vanek, the headed-out oats and early-bloom peas, planted August 9, had produced almost 2 ½ tons of dry biomass at this point – plenty of coarse organic matter to protect the soil and preserve moisture over the winter and into the next spring and summer.
(Note the low-growing cover crop of rye and spelt in the foreground, planted after the harvest of the no-till and ridge-till crops in Field 6 this past year. This overwintering cover crop mix prepares Field 6 for the 2004 fallow year sequence of double-cut biomass production, chicken-tillage, and a fall cover of oats, peas and millet – repeating virtually the same fallow year cycle as Field 5 in 2003, and Field 4 in 2002 as the cover crop/tillage rotation works its way clockwise around the bio-extensive market garden.)
6. Back to Field 4 in the Spring of 2003, getting ready for EARLY TRANSPLANTED vegetables. One of the advantages of using a really mature winterkilled cover crop for this planting window, is that its extensive, soil structuring root system is almost completely decomposed by the time the ground thaws in the spring, making it easy to prepare a shallow seedbed with limited tillage. However, it is necessary to chop up the tangly mat of oat stalks and pea vines into smaller pieces before shallowly mulch-tilling the soil and forming the planting beds.
Usually, we chop up the residues with a disc, but in 2003 we tried out this custom-built tool shown above in Field 4. For lack of a better term, we call it the Residue Cutter because its sole purpose is to…
7. and 8. …cut the cover crop residues into small pieces. The series of plow coulters attached to a disc axle did an excellent job of slicing the mulch of oats and peas into 6” pieces. This one-of-a-kind implement was made for us by the Groffdale Machine Shop featured in the Winter 2003 CQ column.
In these photos we are trying out the residue cutter on the winterkilled sorghum-sudan grass and field peas planted along the south side of Field 4 the end of July. With the two of us standing on the implement’s platform to provide adequate weight, it cut through the coarse material easily, and it did the job without smearing or compacting the soil like a disc tends to do in wet conditions.
9. After chopping up the winterkilled residues, we then shallowly work the soil with the ridger and the spring tooth harrow before forming the planting beds with the wide tractor sweeps on the old riding cultivator, the same setup shown in this 1993 photo. Mulch-tilling the earth just a couple of inches deep dries out and warms up the seedbed adequately for early spring planting while maintaining a sufficient mulch of cover crop residues on the surface to minimize runoff and slow down evaporation.
10. Despite all the rain we received in the spring of 2003, the soil surface remained porous and crumbly between the mulch-tilled strawberries planted the end of April along the south side of Field 4. We depend on the cover crop residues to buffer the land from heavy rainfall, and we rely on the earthworms feeding on the coarse litter to aggregate and open up the wet soil with their worm holes and castings.
We asked NEON researcher, Steve Vanek, to document with his digital camera the way the nightcrawlers had clumped the coarse sorghum-sudan grass residues into these small straw huts covering their burrows. Uncovering their thatched huts, we could see the fresh organic matter being pulled deep into their worm holes, incorporating the cover crop without any work on our part, In fact, limiting tillage to the top few inches has increased the nightcrawler population to the extent that we are almost alarmed at how quickly a couple of tons of cover crop biomass can disappear!
Cultivating for Moisture, Fallowing for Weeds
11. Once the cover crop mulch begins to breakdown – or disappears into the nightcrawler holes – then we rely on the cultivator to create an earth mulch to hold in soil moisture. For more details on the fine points of cultivating the surface of the soil to preserve precipitation, see “Trashed Out Onions” (Vol. 18 No. 3, Summer 1994, SFJ) and “Cover Cropping for Moisture” (Vol. 24 No. 2, Spring 2000, SFJ). In a nutshell, the idea is to get into the fields with cultivator after each packing rain to loosen the soil around the plants and reestablish a mulch of cultivated earth to slow down evaporation.
12. This shot shows Field 4 the beginning of July. The leeks and sweet onions in the middle of the field were transplanted into the mulch-tilled oats-and-peas in Mid- May, then cultivated a couple of times between heavy rains before seeding down the pathways with a single row of hairy vetch the middle of June. To the left of the alliums are four rows of carrots direct seeded June 24 after the bulk of the winterkilled cover crop residues had decomposed, producing a fine and fibrous seedbed. (We use the scare-eye balloons to deter flocking birds from eating the succulent carrot seedlings.)
To the right of the sweet onions and leeks are four rows of strawberries transplanted into the mulch-tilled sorghum-sudan grass the last week of April. Next to the new berry patch you can see chicken-tilled rye and spelt in Field 5, preparing this fallow field for the winterkilled cover of oats, peas and millet shown in photo #5.
13. We assume that pasturing the chickens in Field 4 during the summer of 2002 is the reason that slug damage was so minimal in the 2003 cash crops despite all the rain. For instance, we saw very few slug holes in the leaves of the alliums in Field 4 compared to the no-till and ridge-till onions in Field 6 which had not received the chicken treatment. Likewise, we were rewarded with almost a perfect stand of carrots along the north side of Field 4, a crop which is usually very susceptible to being thinned out by the slugs in wet weather.
The 2002 fallow year management also reduced weed pressure in Field 4 to such low levels that we could establish the living mulch of vetch in the pathways just one month after planting the alliums. The records we kept for the NEON project showed that we devoted seven minutes per 380’ row on June 24 to remove a smattering of cool season weeds before they could go to seed. We also spent twelve minutes a row on August 2 to handweed blown-in dandelions and encroaching chickweed at the ends of the field. No handweeding was necessary for the carrots which were planted a month later than the sweet onions and leeks, after dandelion season was over and a generation or two of cool season weeds had already germinated.
Sidedressing with Vetch
14. Within a week or two of the fresh market harvest of the onions, the single-row interseeding of hairy vetch had produced a mat of live vines protecting almost 80% of the soil from the 2003 rains. The beauty of using this living mulch system for long-term crops like the spring planted alliums, is the carpet of vetch vines minimizes run-off and erosion but does not appear to compete with the cash crop for either moisture or nutrients. We assume this is simply due to the fact that the root system of the single-row interseeding is concentrated in the middle of the pathways, a good sixteen inches away from the crop.
15. The single row of vetch in the pathways seems to help with moisture management in both wet and dry weather. For example, the living mulch of ground hugging vetch shaded the soil between these four rows of leeks in Field 12 during a hot, dry stretch in 2001. (See the Summer 2002 SFJ for more details.) The main drawback with this field-grown mulching system is that eventually the vetch vines begin to climb up the leeks, reducing air circulation and interfering with harvest. In this situation, we use disc hillers on the cultivator to slice through the vetch vines on either side of the row as illustrated in this photo.
16. Using the cultivator to trim back the vetch results in a mulch of dead vines over the row while maintaining a green carpet of live vetch in the pathways to protect the soil from heavy rain. Trimming back the living mulch at this point in the season also seems to provide some extra nitrogen just when the sizing-up leeks really need it. At least, that is how we explain why the leek leaves take on an extra deep green color two-to-three weeks after pruning this leguminous interseeding. For this reason, we now refer to this single-row living mulch system as “sidedressing with vetch.”
Looking back over the whole season, we have used three different types of field-produced mulch for the spring planted alliums. First, we depend on a cover crop mulch of oats and peas to hold in the winter accumulation of moisture for the critical establishment period of these barerooted transplants. Then, when the cover crop residues break down, we rely on the cultivator to create an earth mulch to slow down evaporation. Finally, once these long-term alliums are well established, we seed down the pathways to a living mulch of hairy vetch to shade the soil, prevent erosion and provide some late season nitrogen. Although triple-mulch vegetables still require a little shallow tillage during the fallow year and the cropping season, we think this lowinput system provides many of the benefits of a 100% no-till approach but without the need for toxic chemicals or lots of hand weeding.
THE NO-TILL DILEMMA
How to Preserve Organic Matter, Moisture and Mycorrhizae without Using Toxic Chemicals
A Longtime Organic Grower Makes a Plea for No-Till
Nature, if left to her choice, never allows bare, exposed soil. She prefers a continuous cover of diverse plants that are good for food, forage and thousands of other uses. If we overgraze, or somehow destroy the good plants, she puts in its place a lesser plant, until there is nothing growing except hard-to-control bitter, poisonous, and thorny plants. Nature is determined to protect her soil – the foundation of the whole environment. That is why she designed weeds, cactus, mesquites and junipers. These so-called pest plants are actually pioneer plants. Give them enough time – it could take centuries – and they will restore the soil to perfection…
The most imminent problem we have today is posed by water shortages. Even though the annual rainfall has averaged the same for the past 125 years, because of population growth, urban sprawl, technology, and higher standards of living, water demands are continually going up, while the supply seems to be dwindling fast. We need to concentrate on water conservation. The next wars could very well be fought over water.
Conservation tillage, low- and no-till farming have been proven to be the most efficient and best methods for catching and storing fresh water. This is the most natural practice for the farmer. Think about it: nature never turns the soil over. Plowing, or any soil tillage, causes the soil to lose moisture and exposes it to the damaging sun rays, destroying billions of exposed microbes and fine root hairs. These small life forms then quickly oxidize to form CO2, which escapes to the already-overloaded atmosphere.
Conservation tillage is the best water-saving practice that mankind has. Even the organic farmers that still plow could gain soil organic content faster and save the air from CO2 pollution if they practiced no-till.
Strip-till, ridge-till and mulch-till are all methods of conservation tillage. No-till disturbs the soil the least. It is the best method to keep the carbon in the soil and increases the soil organic content the fastest without hauling in organic matter from an outside source…
In conventional till you are always plowing weed seeds in deep or bringing them up from underground, leaving behind a continuous supply of weed seeds to sprout. Notill keeps all the weed seeds on the top of the soil, where you can eventually get rid of them – or, if you wish, you can let them grow for added mulch material.
One drawback to the no-till method, however, is the use of herbicides in the early phases and then periodically years later. Glysophate is the herbicide most widely used. If not used correctly – i.e. without a mist inhibitor or in the wrong weather conditions or at the wrong time of day – it can drift to other locations, causing crop damage. It is toxic if inhaled or comes in contact with the skin. All of this can be prevented when handled properly, but, as organic, sustainable and holistic management enthusiasts, can we approve?
When the question, “Which is more damaging to the mycorrhizae, deep tillage or herbicide?” was asked of a wellknown mycorrhizae specialist, he explained that tillage kills the host plant and tears the beneficial mycorrhizae to pieces, destroying it before it gets a chance to make spores (seed). With herbicides (glysophate), the host plant is killed. As soon as the plant stops sending energy to the root, that is the signal for the mycorrhizae to quickly make seed so it can regrow and live on the next plant…
- Malcolm Beck, Holistic Resourse Management, May 2002 ACRES-USA Austin, TX
Organic Matter and Water-holding Capacity
Arkansas soil scientists report that for every 1% of organic matter content, the soil can hold 16,500 gallons of plant-available water per acre down to one foot deep. That is roughly 1.5 quarts of water per cubic-foot of soil for each percent of organic matter. Table 1 shows the relationship of organic matter to water-holding capacity.
In addition to holding water, organic matter also improves aggregation. As soil organic matter breaks down, large amounts of glues and slimes – the cementing agents of aggregation – are produced by microbes in the decomposition process. A good demonstration of this is provided in Table 2. The increasing manure rate in Table 2 led to improved infiltration through the increase in soil aggregation.
The most apparent benefit of maintaining ground cover on soil is erosion resistance. However, ground cover is also associated with drought proofing. This has been well demonstrated by a research team at Indiana using variable applications of straw. Higher applications resulted in higher water infiltration rates, up to 2.5 tons of straw per acre (Table 3).
Surface cover also reduces water evaporation from soil. In a Kentucky study, surface evaporation was five times less under no-till (which leaves a surface mulch) than with conventional tillage over the May to September season (Table 4). Because less water was lost to evaporation, more water was available for plants.
Tillage systems and equipment have enormous impacts on water infiltration, storage, and plant efficiency. These include mechanical stress on soil aggregates, effects on soil microorganisms, and the tendency to create hardpans. Of most importance to drought-proofing, however, is the extent to which a surface cover is maintained.
Table 5 shows three different tillage methods and how they affect water entry into the soil. Notice the direct relationship between tillage types, ground cover, and water infiltration. No-till has more than three times the water infiltration of moldboard-plowed soil. Additionally, the no-till field would have higher aggregation from the organic matter decomposing on-site.
- Preston Sullivan, Drought Resistant Soil, free ATTRA publication
Managing Cover Crops and Weeds through Mechanical Suppression
Cover crops are an integral component of conservation tillage cropping systems. A typical system is fall establishment of a winter cover crop, followed by herbicide kill prior to spring planting. The killed residue that results is essentially an organic mulch grown in place.
While herbicides are commonly used to manage cover crops, non-chemical alternatives do exist, though they are less widely known. In keeping with ATTRA’s mandate to transfer technology on low-chemical-input farming methods, and to support the information needs of farmers who want to reduce their use of herbicides or raise certified organic crops, emphasis is placed on non-chemical weed suppression.
In addition, while the organic mulch that results from the cover crops – whether killed by chemical or mechanical means – can provide fairly good weed suppression for the first 30-45 days after kill-down, there will always be additional weeds that sprout through the mulch; therefore, follow-up weed control methods are important.
Non-chemical methods of cover crop suppression that can be integrated with no-till vegetable production include: strip tillage, mowing, rolling and crimping (also known as roll chopping), undercutting, and thermal weed control (flame, steam, infra-red). Based on extensive research and field experience, growers looking into no-till vegetable production can proceed with a high degree of confidence that strip tillage, mowing, roll chopping and undercutting are solid performers…
To handle follow-up weed control for weeds emerging through the killed mulch, supplemental weed control options include: high-residue cultivators, weeder geese, chicken tractors, hand hoeing and spot-spray steam weed control.
High-residue cultivators are widely used in agronomic no-till production, and would be an affordable option on larger-scale no-till vegetable farms raising sweet corn, green beans, and related row crops. Weeder geese, chicken tractors, and hand hoeing also have a proven track record, but are geared to smaller-scale market farming. Spot-spray steam weed control is a technique the author feels has good potential as an appropriate technology in association with organic no-till mulch. While commercial steam equipment is available to control vegetation it is extremely expensive and targeted to other market segments (e.g. Aqua Heat for large-scale orchards, Waipuna for municipal parks and non-croplands). Thus, steam needs an infusion of on-farm technology development. Infra-red thermal weeding equipment, on the other hand, looks affordable and practical. Trials in association with organic no-till mulches are needed to ascertain how well it actually works. A companion ATTRA publication, Flame Weeding for Vegetables, provides essential details and equipment suppliers for flame and infra-red weeding systems.
- Steve Diver, No-Till Vegetable Production: Non-Chemical Methods of Cover Crop and Weed Control, ATTRA Web page: www.attra.ncat.org
ANIMAL POWERED NO-TILL IN SOUTH AMERICA
Resource Note and Technical Tip: Rob Flory, ox drover and intern director at Howell Living Museum Farm in Titusville, NJ, sent us this inspiring report about EPAGRI. The excerpts from the firsthand account by Roland Bunch document the substantial economic and environmental gains realized by small-scale, animal powered farmers in Brazil who have pioneered and refined a no-till/cover crop system for grain production.
Unfortunately, the photos in this report were not clear enough to reproduce here, so we suggest Roland Bunch’s account with several images of farmers in Paraguay and other parts of South America using similar tools and techniques. A slide presentation by Seth Dabney, Managing Cover Crops and Green Manures, (https://www.ars.usda.gov/ARSUserFiles/64080530/Projects/CoverCrops/managingcovercropsandgreenmanure.pdf), was recommended to us by Steve Diver at ATTRA. This virtual slide presentation also includes research supporting some of the advantages of using cover crop mulches already mentioned in this column, such as reduced runoff and erosion, increased soil quality and moisture retention, and greater soil inoculation of mycorrhizae boosting early crop growth.
The website also points out a drawback to planting directly into cover crop mulches not addressed so far in this column. During the first few weeks of decomposition, the cover crop mulch can produce sufficient heat, fermentation and allelopathy to severely compromise the crop. One solution is to delay planting the no-till crop for three to four weeks until after the initial phase of decomposition subsides. However, this delay coincides with the emergence of the first weeds breaking through the cover mulch, giving the weeds the advantage.
A more practical solution pointed out in Seth Dabney’s slide presentation is to use a row cleaner on the planter to move the cover crop residues away from the planting zone. This simple modification gives the crop a 3-4 week head start on the weeds by making it possible to no-till the crop immediately after roll-killing the cover crop and without suffering the consequences of the decay process. – Eric Nordell
The Technology and Its Results In Santa Catarina, Brazil
Although EPAGRI is involved in sanitation, infrastructure and post-harvest operations, in addition to agriculture, I will concentrate here on its work in soil conservation and recuperation, because this is the area in which EPAGRI’s work is, as far as I know, not only highly original, but at the very cutting edge of these issues worldwide. (Similar work on green manures/cover crops is also very advanced in the states of Rio Grande do Sol and Parana, but in those states, most of the work has been done on large-scale, tractor-based farms rather than the small- to medium-sized, animal traction-based farms that dominate the work in Santa Catarina.)
The technologies being used by EPAGRI include the more or less traditional contour grass barriers (for which they have a series of species, including the very popular dwarf Kinggrass) and orienting of crop rows according to the contour, but by far the most important part of their work, and by far the most popular with the farmers, are the green manure/cover crops. (These plants are used to fertilize and condition the soil. Nevertheless, they are usually applied to the soil surface rather than buried. Thus, they are not handled as “green manures” in the traditional sense. At the same time, they are valued for their soil cover, both as “green mulches” while they are growing and as dead mulches after being cut, but they do more, much more for the soil than just cover it. I will, therefore, refer to them here as gm/cc’s.)…
Although a few gm/cc’s are then ploughed under, the vast majority of farmers use a traditional animal-drawn tool revived by EPAGRI called a rolo-faca (knife-roller?) which knocks over and cuts up the gm/cc. leaving it on the surface. Then, with other animal-drawn instruments, they clear a narrow furrow of the resulting mulch and plant their next crop. The resulting mulch greatly reduces or simplifies weeding operations, and provides sufficient organic matter to noticeably increase soil fertility each year.
Furthermore, farmers who have used any of these systems for more than five or six years are, in the majority, no longer ploughing. That is, after five or six years, with heavy applications of in situ-produced organic matter, these farmers are evolving from a minimum tillage system to a no-till system, much like Fukuoka’s One-Straw Revolution. Seeds of the succeeding crop are merely hand-drilled into the soil, with no tilling necessary. Some farmers’ animal-drawn ploughs are rusting in abandonment. Yet, even without ploughing, farmers are achieving yields of 3 to 5 T/Ha. of corn (zea mays) without chemical fertilizer, and as many as 7 to 8 T/Ha. with fertilizer. Physically, the soil is very dark or black in color, spongy to the step, moist, and full of earthworms.
I have visited more than 140 agricultural development programs in some 30 nations over the last 26 years. I can honestly say I have never seen any single agricultural program that had such a major sustainable impact on 3,000 to 4,000 families (and this program’s coverage is more than double that). Furthermore, it is based on technologies largely unknown elsewhere. I cannot say I ever spent a week during which I learned as much about agricultural development as I did this one…
Probably the most important single result of the Brazilian work is that, by eliminating the need for both most of the weeding and all of the ploughing, this work may well be showing us the most feasible way for small farmers to compete in this Neoliberal world of falling national barriers to trade. During the last 40 years, the resource- poor farmer was always at a major, almost insurmountable disadvantage when he or she had to compete with the larger, well-capitalized farmers: he/she was unable to carry out the really heavy and expensive labors of ploughing and weeding as cheaply as the mechanized farmers. Now, however, we are beginning to see the answer to this major problem. It lies not in the mechanization of these jobs (through tractors, microtractors, or even animal traction), none of which he/she has much of a chance to succeed at. It very likely lies in the elimination of these jobs, through the heavy use of mulches (to control weeds) and of no-till systems.
- Roland Bunch, EPAGRI’S WORK IN THE STATE OF SANTA CATARINA, BRAZIL: Major New Possibilities for Resource-Poor Farmers