Cultivating Questions

Concerning the Bio-Extensive Market Garden

by Anne and Eric Nordell of Trout Run, PA

Farmers of Forty Centuries

My name is John Arbuckle. We help run an organic CSA/Farmer’s Market on the eastern shore of Maryland. Your work with cover crops and the “bare fallow” has been very interesting to us. I have seen a publication from your farm called “Weed the Soil, Not the Crop.” May I purchase a copy?

We have been practicing several of the ideas from within the publication and slowly but surely a more balanced ecology seems to be emerging.

Thank you for creating the articles that you have. They have been quite eye opening and have helped us to ask different questions of ourselves.

PS – A question:

Recently I saw a book called “40 Centuries.” It was a history of rice farming in the Far East. It showed that due to the nitrogen fixing effects of a certain kind of algae that some rice paddies had actually increased in productivity after 4,000 years of more-or-less continuous cultivation.

So, here’s my question. Do you think any form of tillage agriculture, even shallow tillage, is capable of sustainable use over that sort of time frame and without any trucked in inputs?

Just something I’ve been thinking about. How can human use improve the soil quality in a long term sense?

Thank you for your time and consideration.

Yours Truly,
John, Holly, and Noah Arbuckle

It is a testament to the author’s wide ranging interests and insights that everyone who reads Farmers of Forty Centuries takes away something different. For some, the focus of F.H. King’s travels through China, Korea and Japan in 1911 is the super intensive, irrigated cultivation employed in the humid coastal area. For others, it is the more extensive intercropping practices employed in the arid interior. The use of night soil – such a foreign concept in the U.S. – is the takeaway message for many readers. Others see the book primarily as a resource for human and animal powered agriculture and transportation.

Including the reprint in the SFJ, we have read Farmers of Forty Centuries four times, and each time we have been struck by the tremendous amount of human effort devoted to scouring the countryside for organic matter and nutrients to maintain the fertility of the cultivated land. Although King’s travels through East Asia predated the widespread use of trucked in fertilizers, the farm systems he witnessed could hardly be characterized as zero input. The book provides many examples of farm families and laborers harvesting compost materials from the surrounding landscape in order to replenish the nutrients exported with the crops. In addition to human and animal wastes boated in from the cities, these fertility inputs included green matter gathered from the surrounding mountain forests, soil dredged from the nearby canals, the nutrient-enriched bricks from their wood fired stoves, and the animal droppings so meticulously scavenged across these three nations that King did not notice flies of any kind after leaving the shores of America.

Coincidentally, we started a farmers-of-forty-centuries experiment about the same time that we received the Arbuckle’s letter in 2009. Like the peasants of the Far East, we began the labor intensive practice of collecting all the manure in the horse pasture. With wheelbarrow, scoop shovel and rake, we embarked on a daily scavenger hunt, carting the dung to the composting pigpens in the barn. 1/20th of a century into the experiment, we thought it was about time to report on the results.

More Manure

The most immediate effect of collecting the pasture manure was a noticeable increase in compost production. More compost, in turn, has made it possible to increase the application rate in the vegetable fields from 8 to 10-12 yards / acre and to enhance cover crop mulch production by spreading the surplus in the fallow lands. Bulking up the compost with pasture manure has also been the means to realize one of the goals coming out of the work horse costs project (see “Portraits of Four Horsepowered Produce Farms” in the Summer 2012 SFJ), namely, to reduce our small herd from four to three horses to save on out-of-pocket expenses. If we cut out the compost used for the mulching cover crops and cut back the application rate to 8 yards / acre for the vegetables, we might be able to get by with just a team as the sole fertility and power source for the 6 ½ acres in the market garden rotation.

Better Fertility Management

Compost analysis show the new hand-and-hen compost contains half as much phosphorus and potassium as the hog compost. At this stage in the fertility development of the market garden this reduction in P and K may be a good thing because we have built up large reserves of these elements over the years. The new pasture-manure-inspired composting method allows us to increase the amount of compost applied to the vegetable fields while decreasing the amount of phosphorus and potassium added to the soil.

There are at least a couple of explanations for the reduction in P and K aside from the much higher moisture content of the new compost. First, upping the percentage of manure solids in the compost mix by adding the pasture dung should decrease the percentage of potassium in the final product. That assumption is based on textbook examples showing that most of the potassium is concentrated in the urine of large animals and relatively little excreted in the solid manure.

Second, we routinely added colloidal soft rock phosphate during the collection phase of the hog composting process to tie down nitrogen and smell. The new method of manure management does such a superior job of nitrogen and odor control that we no longer need to use the soft rock, eliminating a primary source of phosphorus for the compost.

Shrinking the Repugnancy Zones

Collecting pasture manure has also dramatically reduced the size of the substantial repugnancy zones selected by the horses for their bathroom areas. In some cases, the repugnancy zones have disappeared altogether. As a result, the horses now graze almost all of the grass and we have been able to decrease the size of the year round horse pasture by almost 30%. In addition to the savings in fence moving and pasture maintenance, grass re-growth is much more uniform, looking more like a mowed hayfield than a patchwork of overgrazed and overgrown pasture. However, we have learned the hard way that the horses will quickly re-establish the old repugnancy zones if daily dung collection is neglected for just two or three days.

Worming the Pasture

Due to fecal tests showing moderate-to-heavy loads of strongyles and tapeworms, we had been de-worming the horses twice-a-year at the start of the pasture manure experiment. A year into the pooper scooper project, we discontinued the chemical paste wormers, hoping that daily dung removal had sufficiently disrupted the life cycle of the parasites. Fecal tests a year-and-a-half later proved otherwise. Although the horses were still below the de-worming threshold for strongyles (200 egg cells per gram), they were loaded with tapeworms.

We went back to the twice-a-year worming schedule through the 2011 grazing season, and then tried eliminating the chemical parasiticides again in 2012 and 2013. Fecal tests in the fall of both years showed zero tapeworms. Strongyle counts for twenty-year-old Frank were 0 in 2012 and 100 in 2013, which we thought was acceptable, but 33-year-old Becky’s egg cell counts were 150 in 2012 and over 1200 in 2013, the same as our new young mare, Cindy.

A worm-the-soil-not-the-horse strategy would probably yield more consistent results if we kept a closed herd and had initiated the daily dung removal practice right from the start rather than waiting over 25 years to begin the pasture manure experiment. Based on our belated experience, we cannot recommend pasture manure collection as a replacement for annual fecal exams and / or chemical de-worming. Also, do not expect this pasture sanitation practice to control bots, flukes, and other debilitating parasites which do not require green grass and horse manure to complete their life cycle.

Chicken Feed

Previously, we had tried worming the horse pasture with our small flock of laying hens. However, it was impractical to fence the chickens inside the horse paddocks which averaged two acres in size. Without physical restrain, the layers spent more time visiting the neighbor’s flower beds than scratching through the horse dung in the repugnancy zones. They also seemed much more interested in digging ankle-twisting potholes for dust bathing than patrolling the pasture for horse droppings.

We decided it would be better to bring the pasture to the birds. It only takes a couple of minutes to pick a nice mix of clover, grass, plantain, and dandelion tips for the layers while collecting the pasture manure. And from the middle of May until the end of August the horse droppings are usually crawling with a dozen types and sizes of dung beetles. It is often convenient to rake up earthworms while on pasture manure duty in the fall and the spring. These chicken delicacies are generally more prevalent in and under aged horse droppings saturated with moisture, adding incentive to gather the accumulation of manure in the winter pasture as it thaws in the spring. These additions of fresh, live protein to the hens’ diet improve egg quality, reduce feed consumption, and encourage the layers to do a complete job of scratching through the compost materials.

Yes, collecting pasture manure can be time consuming and tedious. Depending on the size of the paddock and its distance from the barn, daily manure scavenging takes 30-50 minutes. If we put a dollar value on the reduction in the size of the work horse heard and their pasture, the elimination of soft rock phosphate in the compost, and the small savings in de-wormers and chicken feed, we might be able to pay ourselves minimum wage for this peasant activity. But like many of the fertility sustaining practices described in F.H. King’s book, it would be difficult to justify pasture manure collection using short term economics. A long view is necessary.

This brings us, finally, to the Arbuckle’s important question about long term soil quality. Based on less than half a century at this location, we think that some inputs need to be trucked – or wheel barrowed – in to maintain top quality production in the bio-extensive market garden. In fact, soil fertility levels were so low when we arrived here in 1982 that we would have soon gone out of business if we had not used composted horse manure and rock minerals in the vegetable fields. (Although the manure is produced on the farm, we buy in hay, grain, and bedding for the horses and fertilizer for their pasture.)

Now, after 30 years, we have built up the nutrient reserves sufficiently that we could probably coast for another 30 more on zero inputs, relying on shallow-tilled cover crops to maintain organic matter and tilth. However, we are not likely to test this hypothesis because modest applications of compost, rock minerals and lime enhance the quality and flavor of our produce, and that’s what keeps our customers coming back for more vegetables.

We hope that our limited soil fertility experience does not deter anyone from trying a 4,000 year zero input experiment. We know of market gardeners who use little, if any, trucked in nutrients. We also know of truck farmers who use a lot more inputs than we do. The difference might be explained by the intensity of production, the depth and type of topsoil, the bedrock material, the climate, and previous management. In most situations, it may be more realistic to maintain a closed loop system with a diversified farm system than a market garden. Linking the two types of operations together might be the best way to achieve short term profitability and long term soil quality.

STALLING TACTICS

The transition from pig powered composting to composting by hand and by hen required two major changes: instead of bedding the horses with locally grown oat straw we used Canadian pine shavings; and we composted the urine soaked shavings separately from the solid horse manure raked out of the horse stalls and collected from the pasture.

The switch to pine shavings was initially precipitated by the steep hike in the price of straw due to demand from pipeline construction for the unnatural gas industry. The change from local oat straw to imported shavings did not really fit our vision of sustainability, but it certainly made turning the compost by hand a whole lot easier and created a much nicer litter for the hens.

As for segregating the urine soaked shavings from the dung, this was our solution to minimizing odor and the associated loss of nitrogen during the collection phase of composting without the packing power of heavy hogs to slow down combustion. Although we are not scientific minded enough to understand and explain the chemical process, we had read that the combination of manure and urine when exposed to the air somehow increases pH and the generation of more volatile forms of nitrogen. We had also noticed that many compost systems, from composting toilets to large livestock operations, separated the liquids from the solids.

Over the course of a couple of short days, we put up a 12’ by 28’ hoophouse behind the barn for composting the urine enriched bedding. Using wheat straw bales instead of baseboards around three sides of the tunnel increased head room and created a retaining knee-wall plus insulation for the wet litter piled 18-20” deep with the wheelbarrow. We drove 4’ pieces of rebar through the straw bales to hold them and the 20’ PVC hoops in place, then lashed down the greenhouse plastic with ropes, caterpillar-style, as described in the Spring 2010 CQ. In lieu of a ridge pole, we supported the peak of the flimsy 1” PVC pipes with a 4” x 4” beam and posts to prevent this flexible structure from collapsing under a heavy snow load. We also made sure to use 24’ wide poly to completely cover the straw bale walls and shed moisture away from the tunnel.

Depending how much time the horses spend in the barn (8-18 hours / day) and how much urine they are producing, we clean out their straight stalls every 3-7 days, dumping the urine soaked shavings on top of a 2-3” bed of waste hay in the hoophouse, then covering the wet litter with a compost fleece to retain moisture and heat. To hold in the more volatile nutrients, we mix a couple of shovels of soil and a pint or two of humates in each wheelbarrow load of litter. Even so, the urine soaked shavings are usually a little stinky until the litter starts heating within 12-24 hours. After a few weeks of low-heat composting and curing, the urine enriched shavings turn dark peat-moss-brown and sweet smelling. They also trap odors so effectively that we recycle this pre-composted litter through the horse stalls to keep the stables odor-free.

In the “Muck is the Mother of Money” CQ (Spring 1998 SFJ), we detailed the construction of the moisture-retentive horse stalls with the one-foot deep pits dug in the clay floor under the horses’ back feet to capture as much of the urine as possible. After removing the urine soaked shavings, we re-bed the pits with 3-5 gallons of peat moss on the bottom. We cover the peat with half a bale of pine shavings and top off the shavings with a wheelbarrow load of pre-composted litter from the hoophouse, filling the pit to ground level. Layered in this fashion, the urine pooled at the bottom of the pit is soaked up by the dry peat and pine underneath while the moist pre-composted litter on top holds in the smell.

As for the daily maintenance of the horse stalls, we add a scoop shovel or two of fresh shavings over the wet portion of the pit, then cover the shavings with a half a wheelbarrow of pre-composted bio-filter. We also pick the solid manure out of the horse stalls a couple of times a day, pitching the dung directly into one of the adjacent compost middens where the chickens go right to work tearing it apart looking for undigested grain.

Inevitably, some of the pre-composted litter gets raked up with the solids, but this addition to the compost middens – much of it recycled three or more times through the horse stalls and hoophouse – seems to enhance decomposition, odor control, and the hens’ environment. Including the daily wheelbarrow load of fresh manure collected from the horse pasture, we estimate that the compost mix in the middens contains 70-80% solid manure and 20-30% recycled, urine enriched litter.

It usually takes 3-4 weeks to fill one of the three 9’ by 15’ middens two feet deep with the daily collection of pasture manure and the mix of dung and recycled litter picked out of the horse stalls. The two foot depth prevents the compost materials from overheating during the collection phase (typically running a temperature of 100-120 degrees), makes the initial turning of the compost relatively easy, and provides enough room in the middens to pile the material 3’ high for more active composting and higher temperatures (120-140).

We aim to turn the compost 3-4 times over a 6-8 week period before spreading the friable, dark humus-brown material in the market garden. With one midden receiving fresh materials and the other two in the early or late stages of composting, we can pace ourselves by hand turning one midden per week.

Although this relaxed turning schedule is physically manageable, it takes two to three hours out of a busy market gardener’s week. Hand turning the compost also exposes the farmer to ammonia and potentially harmful molds which we try to minimize by wearing a N95 particulate respirator containing a thin layer of charcoal (several inexpensive options to choose from in the Gemplers catalog) and positioning fans to blow the temporary steam bath away from the work site. In the heat of the summer, the compost materials often dry out during the collection phase, making it necessary to hose down the compost while turning it.

For all of these reasons, we are considering three alternatives to hand turning the compost: recruiting a work hog or two to do this job (the infrastructure is already in place); purchasing an 8’ diameter motorized compost tumbler (an expensive investment that would also require a facility to house it, to keep it warm enough for year round composting, and to store the finished compost); or transitioning to a no-turn system (which would involve another learning adventure and a lot more middens to accommodate this slower, low temperature process).

In this respect, the new compost system is still a work in progress. A few years from now, it may look totally different. For the time being, we are thankful that the pasture manure experiment forced us to re-think our whole approach to manure management and set us on the path to a superior compost for this stage in the market garden’s fertility.

Farmers of Forty Centuries

by F.H. King

In China enormous quantities of canal mud are applied to the fields, sometimes at the rate of even 70 or more tons per acre. So, too, where there are no canals, both soil and subsoil are carried into the villages and there between intervals when needed they are, at the expense of great labor, composted with organic refuse and afterwards dried and pulverized before being carried back and used on the fields as home-made fertilizers. Manure of all kinds, human and animal, is religiously saved and applied to the fields in a manner which secures an efficiency far above our own practices…

Four months before the camera fixed the activity shown, men had brought waste from the stables of Shanghai fifteen miles by water, depositing it upon the canal bank between layers of thin mud dipped from the canal, and left to ferment. The eight men were removing this compost to the pit seen in Fig. 99, then nearly filled. Near by in the same field was a second pit, excavated three feet deep and rimmed about with the earth removed, making it two feet deeper.

After these pits had been filled, clover which was in blossom beyond the pits would be cut and stacked upon them to a height of five to eight feet and this also saturated, layer by layer, with mud brought from the canal, allowed to ferment twenty to thirty days until the juices set free had been absorbed by the winter compost beneath, helping to carry the ripening of that still farther, and until the time had arrived for fitting the next crop. This organic matter, fermented with canal mud, would then be distributed by the men over the field, carried a third time on their shoulders, notwithstanding its weight was many tons…

The amount of this earth compost prepared and used annually in Shantung was large, as indicated by the cases cited, where more than five thousand pounds, in one instance, and seven thousand pounds in another, were applied per acre for one crop. When two or more crops are grown the same year on the same ground, each is fertilized, hence from three to six (dry) tons may be applied to each cultivated acre…

If we state in round numbers the total nitrogen, phosphorus and potassium thus far enumerated which Japanese farmers apply or return annually to their twenty or twenty-one thousand square miles of cultivated fields, the case stands 385,214 tons of nitrogen, 91,656 tons of phosphorus, and 255,778 tons of potassium. These values are only approximations and do not include the large volume and variety of fertilizers prepared from fish, which have long been used. Neither do they include the very large amount of nitrogen derived directly from the atmosphere through their long, extensive and persistent cultivation of soy beans and other legumes…

But this intensive, continuous cropping of the land spells soil exhaustion and creates demands for maintenance and restoration of available plant food or the adding of large quantities of something quickly convertible into it, and so here in the fields on Honan Island, as we had found in Happy Valley, there was abundant evidence of the most careful attention and laborious effort devoted to plant feeding. The boat standing in the canal had come from Canton in the early morning with two tons of human manure and men were busy applying it, in diluted form, to beds of leeks at the rate of 16,000 gallons per acre, all carried on the shoulders in pails. The material is applied with long-handled dippers holding a gallon, dipping it from the pails, the men wading, with bare feet and trousers rolled above the knees, in the water of the furrows between the beds. This is one of their ways of “ feeding the crop,” and they have other methods of “manuring the soil.”

One of these we first met on Honan Island. Large amounts of canal mud are here collected in boats and brought to the fields to be treated and there left to drain and dry before distributing. Both the material used to feed the crop and that used for manuring the land are waste products, hindrances to the industry and the region, but the Chinese make them do essential duty in maintaining its life. The human waste must be disposed of. They return it to the soil. We turn it into the sea. Doing so, they save for plant feeding more than a ton of phosphorus (2712 pounds) and more than two tons of potassium (4488 pounds) per day for each million adult population. The mud collects in their canals and obstructs movement. They must be kept open. The mud is highly charged with organic matter and would add humus to the soil if applied to the fields at the same time raising their level above the river and the canal, giving them better drainage; thus are they turning to use what is otherwise waste, causing labor which must be expended in disposal to count in a remunerative way.