SmP Séi-Roll 1.0 for Horse Traction
by Paul Schmit of Tuntange, Luxembourg and Albano Moscardo of Verona, Italy
By multiple field tests, the possible range of use of the new seeder-roller combination SmP Séi-Roll Concept 1.0 for seeding by horse traction was analyzed.
Tests and measurements in summer 2014 showed that this implement requires a medium draft power and is thus suited to a single horse hitch.
By seeding and rolling in one pass, it comes up with good operating results, especially on light soil and this even at the low working speed of a draft horse. Thanks to an adequate working width and fully adjustable hitch and traction devices, a good working comfort for the horse is guaranteed.
In order to improve the working results on heavier soils, the retrofitting of a seed covering harrow should be envisaged. Furthermore a support leg could simplify the hitching and unhitching of the draught horse.
Further information about a horse’s acceptable draft power can be found at www.schaffmatpaerd.org
In every region of the world can be found today new horse drawn tillage equipment. There are not only manufacturers in the US, mainly in the plain communities, but in Europe, in Italy and France, in India, and in some countries of Africa, such as in South Africa and in Zimbabwe.
Modern draft horse equipment for seeding is more difficult to find. This with the exception of some seeder manufacturers in South America, mainly in Brazil, who specialize in implements for direct seeding and whose sales territories are for the most part in the tropical and subtropical regions. The technology of these implements is especially adapted to the agricultural practices and hitches, mainly draft cattle, in this part of the world.
Sustainability and environmentalism deserve more importance in the world. On arable land, enrichment by green and flower strips, as well as intercropping, can contribute to a better protection of natural resources and biodiversity. At present time, an appropriate draft horse technology for seeding with conservative tillage is missing in the northern part of our world. In the last decades there have been projects for transforming implements for draft horse use, which were initially developed for tractors, which gives the disadvantage of excessive draft power requirements.
Because it is a renewable and environmentally friendly energy source, horse traction is currently undergoing a renaissance in small scale agricultural holdings, winegrowing, market gardening and forestry. Within this context, implements for animal traction with mechanical drivetrain and direct draft are gaining importance. One of the goals of the non-profit association Schaff mat Päerd is to support this process by the development of new equipment and related studies and publications.
This test report analyzes the possible range of use of a prototype, which was designed for new planting and reseeding of grassland and biodiversity plots, and for the seeding of green manure in agriculture, market gardening and wine-growing. Further information about this implement, which consists of a seeder in combination with a prismatic roller, can be found at www.schaffmatpaerd.org
Because the topographic, economic and social situations in much of the world do not favor big hitches, this report focuses on a single animal hitch.
Technical Characteristics of the Implement:
|Model:||Séi-Roll Concept 1.0|
|Working width:||1000 mm (3-1/2 ft)|
|Total width:||1570 mm (5-5/32 ft)|
|Total length:||3450 mm (11-5/16 ft)|
|Total height:||1135 mm (3-23/32 ft)|
|Tare weight:||205 kg (452 lbs) with synthetic roller (plastic / plastic)
265 kg (584 lbs) with semi synthetic roller (plastic / grey cast iron)
|Roller diameter:||330 / 380 mm (12-63/64 in / 14-61/64 in)|
|Hopper content:||115 ltr (30.38 gal)|
|Size of seed outlets:||7 x Ø 30 mm (7 x 1 3/16 in)|
|Seeding rate:||3,5 kg/ha (3.12 lbs/ac) (red clover)
145 kg/ha (129.5 lbs/ac) (common vetch)
|Transmission:||Double chain drive 3,53:1 / gear drive 1:1 (for changing the direction of rotation)|
|Clutch:||Claw coupling on the left side of roller axle|
|Height of single tree:||200 … 350 mm (7-7/8 in … 13-25/32 in)|
|Width of single tree:||800 mm (31-1/2 in)|
|Spg. rate draft springs:||17,5 N/mm (100 lbf/in)|
|Shafts:||2 stainless steel tubes DN32 pivotable around longitudinal axis
Inner width 600 … 1000 mm (1-31/32 in … 3-9/32 in)
Length 2950 … 3200 mm (9-43/64 ft … 10-1/2 ft)
Horse in the Test:
|Breed:||French Ardennes (ID-Nr IR0267)|
|Date of birth:||13.05.96|
|Height:||1,52 m (5 ft)|
|Weight:||726 kg (1600 lbs)|
|Collar size:||26” half sweeny|
Materials and Methods
After preliminary tests during the reseeding of a pasture in April 2013 and the intercrop seeding of green manure in a vegetable garden in September 2013, the measuring tests took place on the 1st and 15th of June 2014 on the SCHMIT-LAROCHE farm in Tuntange (Luxembourg).
To evaluate the required tractive effort, the draft force and working speed were measured during different work and on different soil types. These were:
- Seeding of a biodiversity flower strip on a parcel A with a surface of 0,44 ha and light soil after ploughless minimum tillage
- Seeding of grass on a parcel B with a surface of 0,67 ha and medium heavy soil after ploughless minimum tillage
Both parcels were free of stones on the surface. Parcel A was flat, whereas parcel B featured a slope in the direction of work. All measurements were taken between 10.00 and 12.00 a.m.
The measuring device consisted of the following components:
- a Lorenz K-12 force sensor mounted between the single tree and the adjustable traction device on the implement’s front frame
- an AHLBORN FUA9192 speed sensor mounted on the implement’s left side frame with optical scanning of the left outer disc of the prismatic roller with reflective marking
- an AHLBORN Almemo 2690-8 data logger with memory connector and micro SD card mounted on the implement’s main frame
As well as the tractive effort generated by the single hitched horse, the working principle and results for the different work and the operating of the machine were examined. The connection between the evener and the double-stitched leather traces, with inner webbed nylon reinforcement, was achieved for the first test series using draft springs from the Italian manufacturer EQUI IDEA with a spring rate of 17.5 N/mm (100 lbs/in), mounted on both sides. The same horse named Irmi, belonging to the SCHMIT-LAROCHE farm, was hitched for each measurement. The angle of draft was set identically for all measurings on 15° with a single tree height of 300 mm (11-13/16 in). Also the seeding rate was set identically for all measurings at 25 kg/ha (22,3 lbs/ac).
In order to guarantee the statistical significance of the measurements, every measuring was repeated four times, this with measurement times for the partial measurements between 03 min 27 s and 07 min 25 s. The measured values were recorded with a summary measuring rate of 100 Hz resulting in a frequency of 33.33 Hz for each of the three dimensions (time, force, speed). In order to not exceed the scope of the current report, the graphs below represent just a selection of the results, providing an overview of the characteristics of the implement.
The graphs 1.1 and 2.1 show, contrary to all expectations, that the work on medium heavy soil requires more efforts to the horse, on average +18%, as on light soil. By that the greater penetration of the points of the prismatic roller on sandy soil represents no disadvantage in relation to the required draft effort of the horse. Regarding the working results, the greater penetration has to be seen as advantageous, as it permits to bury the seed.
The working results on light soil can be classified as very good, with a uniform distribution of the seed in the lateral direction and a sufficient covering of the seed by the soil. On medium heavy soil, where the rings of the prismatic roller enter less into the soil, due to the small load and the limited working speed of the draught horse, a large portion of the seed remains on the ground surface.
The work with pivoting shafts, represented in graph 2.2, offers a slight advantage concerning the draft force, as the pivotable suspension of the shafts allows for the roller to follow the irregularities of the ground. This constructional detail allows it also to improve the working comfort of the draught horse, as an additional load on the back and the belly of the horse by the shafts is avoided.
On graph 2.3 it comes out that the draught without draft springs between the traces of the harness and the implement, decreases the draft force, this by -10% on average. On the other hand, the irregularity of the draft force, characterised by the mean deviation, increases about +7% without the use of draft springs.
All measuring results discussed above are summarized in graph 3. Graph 4 shows the influence of the slope in parcel B. For all three hitch variants the work uphill increases the draft force by an average of 30-33% compared with the work downhill. During uphill work the horse increases slightly its speed, on average 7%, while maintaining a calm and steady work pace, which favours the optimum transformation of its own muscular strength into draft force.
The machine made little noise during work, which results mainly from the transmission and the seeding mechanism. The communication between the man and the animal was not affected negatively. Walking on the left side of the implement affords the carter a good view of the functioning of the machine and at the same time a good non-verbal communication with the horse. In this way, with sufficiently short lines, a sensitive contact with the bitless horse is assured and it is possible for the horse to see the carter, which refines the communication between the two.
The activation of the claw clutch by a lever on the left side, in good reach of the carter, needs just a small actuating force. Turning on of the implement is preferably done at standstill in order to prevent a premature wear out of the coupling claws. Turning off is also possible during motion of the implement.
The stability and the maneuverability of the machine in difficult terrain are guaranteed thanks to the small dimensions, a sufficiently low center of gravity, and by hitching close to the horse. The shaft and single tree carriers, parts which were tested yet on other prototypes, gave satisfaction by allowing to adapt the length and the width of the shafts as well as the height of the single tree to the horse’s size.
Because of the adjustable hitch device, it is possible to set the intersection of the gravitational force and the draft force of the machine in the rotation axis of the roller, as illustrated in ‘Balance of Forces’. This balance of forces allows it to limit the load on the back pad and its interaction with the draft force. The load on the back pad at standstill of the implement has been determined to be 13,45 kg, which allows for stable work in difficult terrain to be possible.
For all executed works during this comparison test the tractive effort for the horse can be classified as moderate. Due to the higher rolling friction on worked arable land, the measurement results are higher as those, which were determined during the preliminary tests in 2013. The latter were executed on hard ground with partial grass cover, with an average value for the draft force of about 0,275 kN and a mean deviation of 0,118 kN.
As already determined during other tests (see SmP test reports 2013), the oscillations of the draft force increase with the effort of the horse. The fact that the draft springs are not always capable of decreasing the average value of the draft force of each implement, agrees with the results, which were determined by SmP during other tests in Italy, Sweden and Luxembourg, which can be found at www.schaffmatpaerd.org
In order to improve the results on heavier soils, the retrofitting of a seed covering harrow between the seed outlets and the prismatic roller should be envisaged. This in order to prevent damage to the seed by dryness and bird grub.
Additionally, the half of the prismatic roller rings in plastic could be replaced by rings made of grey cast iron, which would increase the weight of the implement and by that the contact pressure on the ground. Doing this, the operating noise increases just slightly, as shown during the preliminary tests. A complete fitting with grey cast iron rings was not satisfactory, as the noise was too high, giving a negative influence to the working comfort of the animal and the human as well as to the communication between the two.
Furthermore, a support leg which should be fixed on the adjustable single tree carrier, could simplify the hitching and unhitching of the draught horse by a single person, while the safety at work could be improved. It would not be necessary to raise or lower the shafts during this action.
Additional tests must be conducted to determine the effect of rigid or freely pivoting shafts on the working comfort of the horse, especially in terms of the support forces of the shafts on the back pad and the steering forces in different working situations. The same applies to a detailed analysis of a better adaptation of the draft springs.