Retention of High Levels of Crop Residue on Soil Surface During Tillage

Retention of High Levels of Crop Residue on Soil Surface During Tillage

Summary

Development of the Residue Saver continued. This implement chops cover crops or picks up surface residue and redistributes these materials behind an attached tillage implement. Although the residue saver works well in dry materials like dead rye or corn stover, wet or green material jams in the output chute. Numerous modifications were made to overcome this problem. The most recent modification is still in process. Two experiments were run comparing the Residue Saver with conventional tillage in rye cover crops. Yields with the Residue Saver were lower in one experiment due to poor planter performance in the rye and lower in the other due to competition from volunteer rye.

Objectives/Performance Targets

1. To develop machinery that will till the soil to kill perennial weeds and improve crop establishment relative to no-till planting while retaining most crop residue on the soil surface for erosion control and suppression of annual weeds.

2. To test this equipment in high residue levels created by winter cover crops in agronomic and vegetable production systems, and evaluate residue coverage, weed control, and crop emergence and productivity in comparison with conventional tillage and no-till systems.

3. To demonstrate the feasibility and cost-effectiveness of this approach to tillage in on-farm grain and vegetable production systems.

Accomplishments/Milestones

The project has three components: construction of the prototype Residue Saver, on-farm and experiment station trials with this implement, and extension and outreach. Knowledge gained from the trials plus comments from farmers and others viewing the trials and equipment will be used to further refine the machine.

Construction of the prototype Residue Saver:

The prototype is a trailing implement with a category II three-point hitch built into the rear of the frame for connection to tillage implements like chisel plows and field cultivators. The implement is raised and lowered for transport and connection with tillage implements by means of hydraulic cylinders attached to two pairs of wheels. A PTO-driven flail chopper is suspended near the middle of the frame. A gear box and drive line will continue rearward to allow use of a rotary tiller or spading machine with the implement. The chopper chops cover crops and crop residues and either blows them over the tillage implement, or into a box. The box is used with long, trailing type tillage implements like disks and combination tools. The residue is distributed from the box onto the tilled ground with a high-speed beater. A set of ground-driven spoked wheels mounted ahead of the flail chopper lifts residue into the flail.

The primary activity this year was improvement of the Residue Saver. During winter and spring of 2002 we refined the sliding hydraulic suspension for the flail component so that it can easily be raised and lowered relative to the frame. This allows the height of the cut to be adjusted without changing the depth of tillage, and it also allow the operator to lift the flail quickly when approaching a large surface stone. We also developed a more flexible mounting system for the residue pickup wheels so that they lift the residue as much as possible without striking each other or other parts of the machine.

Testing during the summer and fall of 2001 was necessarily on dry materials (dead standing rye, corn stover, and old hay) since the machine was not ready for field testing until mid August and the growing season was dry. When we tried the machine on green rye and clover in spring of 2002 we encountered two problems. First, green rye tended to wind up on the ends of the flail shaft. We solved this problem by adding shoes to the ends of the flail housing that direct the rye into the flail rather than allowing it to strike the end of the shaft. These work well. The second problem was that damp material tended to jam in the chute that directs the residue upward after it leaves the flail housing. To solve this problem, we first changed the air flow dynamics by opening the front of the flail housing while extending the sides and back to decrease air intake by these routes. That proved insufficient, so we changed both the radial position and angle of the chute, and also the degree of curvature of the flail knives. These changes improved the situation sufficiently that we were able to establish two trials in standing rye residue, but we were unable to get the machine to work properly in clover or other succulent materials. Since the jamming always starts at the edge of the chute and builds inwards, this fall we redesigned the chute to give it curved sides that will reduce turbulence. We also curved the floor and ceiling of the chute so that it follows the natural arc of the moving residue (formerly the chute was a simple box). While the chute was disassembled we also had the interior sandblasted and painted with a special paint that decreases friction. Reassembling the chute with its multiple curvatures has been challenging, but that task is nearly done and we expect to have the machine reassembled and ready for work by spring.

All of this work was accomplished despite several serious injuries sustained by our principal fabricator, Jim Frisch. He is currently recovering from shoulder surgery resulting from a fall off of a ladder.

On-farm and experiment station trials:

The wrapping and jamming problems delayed use of the machine until late June. This prevented trials on the Potenza and Van Pelt farms where the crops would have been a tofu soybean and field corn.

The Residue Saver pulling the chisel and crumbler assembly described in last year’s report was used to till 16-foot strips in standing live rye at the Mandeville farm on July 3. Plots were flagged and the field was planted to snap beans and pumpkins. The bean planter performed poorly in the rye mulch and the stand was very spotty. The potential yield in the Residue Saver plots did not justify the expense of applying metolachlor herbicide as in the conventional plots, so the Residue Saver plots became very weedy. Pumpkins grew poorly in both treatments due to extreme drought. Although beans were harvested from the conventional plots the experiments were essentially abandoned and no usable data were obtained.

We also ran an experiment at the Musgrave experiment station farm in which soybeans were planted into rye. Treatments were (1) conventional tillage (moldboard plowed and disked), (2) no-till (Roundup Ultra Max) to kill rye and weeds and then flail mowed, (3) Residue Saver with chisel (`9” spacing), crumbler and leveler, and (4) Residue Saver with field cultivator, crumbler and leveler. Plots were 20’ by 80’ and arranged in a randomized block design with 5 replications. Asgrow AGO801RR 80 day (group 0) soybeans were planted on July 5 at 175,00 seeds per acre in 30” rows with a Kinze no-till planter equipped with trash wheels. The experiment was sprayed with Roundup Ultra MAX to control weeds and volunteer rye. Beans were harvested October 30. Bean stands did not differ significantly between treatments although the conventional treatment appeared to have about 25% more beans than the others. Yield was significantly greater in the conventional tilled treatment (34 bushels per acre) than in the no-till and Residue Saver treatments (average 15 bushels per acre). Bean growth in the no-till treatment may have been slowed by the hard dry soil there, whereas competition from dense stands of volunteer rye both before and again a few weeks after the roundup treatment probably slowed growth and maturation of the soybeans.

Residue cover measurements by the beaded string method collected three weeks after planting showed no significant difference between the no-till and residue saver treatments. Visual observations indicated that the chisel, crumbler and leveler produced a better seedbed with fewer clods than the field cultivator, crumbler and leveler treatment.

Extension and outreach:

The experiments were so poor due to late planting and volunteer rye in the Residue Saver treatments that showing them to the public seemed counterproductive. A planned fall demonstration of chisel plowing corn stover with the Residue Saver was planned but proved impossible due to injury of the principal fabricator slowing progress on reconstruction of the chute.

Impacts and Contributions/Outcomes

We have demonstrated that it is possible to thoroughly till the soil while still retaining high rates of crop residue on the soil surface. This technology will allow retention of high levels of residue at the soil surface for erosion control and suppression of annual weeds while avoiding many of the problems associated with no-till practices like increased run-off, poor crop establishment, and high use of herbicides.

Collaborators: