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

Final Report for LNE99-115

Project Type: Research and Education
Funds awarded in 1999: $98,518.00
Projected End Date: 12/31/2003
Matching Non-Federal Funds: $10,738.00
Region: Northeast
State: New York
Project Leader:
Dr. Charles Mohler
Cornell University
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Project Information


Preservation and improvement of soil quality depends on wise management of tillage. Although no-till, zone-till and less extreme forms of reduced tillage have proven benefits for soil quality, they also pose certain problems. Planting into untilled ground can be difficult, crop growth may be slow due to cold soil in northern climates, and perennial weeds may become problematic. The latter is an overwhelming obstacle to organic producers who cannot use herbicides to kill perennial weeds before planting. Most of the soil conservation problems associated with tillage, however, are not due to tillage per se, but stem from (i) burial of surface crop residues which leaves the soil exposed to erosion and (ii) compaction associated with wheel traffic on freshly tilled soil. Preventing the burial of crop residue during tillage could potentially minimize the first of these problems, whereas the second can be minimized by performing primary tillage and seedbed preparation in a single operation. Single pass tillage implements are becoming increasingly common, but the retention of crop residue on the soil surface during tillage has scarcely been addressed in previous research.
We constructed an implement that allows retention of high rates of surface crop residue during tillage operations, and then demonstrated its use in field and vegetable crops. The implement is called the Residue Saver. It chops standing cover crops and picks up surface residue, and redistributes this material behind an attached tillage implement. The device accommodates a broad range of tillage implements.
Use of the Residue Saver allows retention of surface crop residue for erosion control and suppression of annual weeds while allowing tillage to facilitate planting, loosen the soil for improved root growth, and destroy perennial weeds. Use of the Residue Saver reduces erosion potential relative to conventional plow tillage and most minimum tillage methods, and reduces herbicide use relative to no-till and some minimum tillage systems. Widespread adoption of the technology could therefore conserve soil, reduce water pollution, and reduce human and wildlife exposure to toxins. It will allow increased use of crop residue for weed suppression, and provide organic producers with a means of retaining surface residue while still tilling the soil.
The Residue Saver was tested in 5 trials during the last two years of the project at 3 sites. Two of the three sites were on commercial farms. An extension/outreach program demonstrated the machine at three well-attended field days. One of these was on a commercial farm. Information about the machine, including a digital video clip of the Residue Saver in operation, is available at Further experiments and demonstrations with the Residue Saver are planned for 2004.


2. Introduction
The focus of the project was on development, testing and demonstration of the Residue Saver, an implement for retention of crop residue on the soil surface during tillage. The Residue Saver is a trailing implement with a category II 3-pt hitch built into the rear of the frame for connection to tillage implements. A PTO-driven flail chopper is suspended near the middle of the frame. The chopper chops cover crops and crop residues and blows them over the tillage implement, so that the residue lands on freshly tilled ground. A curved metal canopy controls the distance the residue is thrown and minimizes dispersal by wind. A set of ground-driven spoked wheels mounted ahead of the flail chopper lifts residue into the flail. The implement is raised and lowered for transport and connection with tillage implements by means of hydraulic cylinders attached to two pairs of wheels. The cutting height of the flail is independently adjusted with another cylinder. A gear box and drive line are being installed to provide a PTO at the rear of the implement. This will allow use of a rotary tiller or spading machine with the implement.
We tested the Residue Saver in a variety of residue types in 2003, including 7-foot tall green rye, 2 ft wheat stubble, mature, wet, second-year red clover and 200 bu/a corn stover. The machine performed well in all of these conditions. Several field trials were run in rye in 2003. Surface residue retention rates with a chisel type implement plus a smoothing bar and crumbler ranged from 73% to 86% and left 360 to 540 g/m2 of residue on the soil surface after planting. With a field cultivator type implement plus the smoothing bar and crumbler, 65% of the original biomass was retained (417 g/m2.
Yields in the 2003 trials with rye straw were generally lower in Residue Saver treatments compared to conventional moldboard plow tillage. The control pumpkins at the Mandeville's farm were mulched with plastic and the difference in that case was probably due to colder soil and poorer weed control in the Residue Saver treatment. Weed biomass and counts did not differ between treatments in the potato experiment and potatoes tolerate cool soil so the source of the yield difference in that case is unclear. Soybean yields were lower in the Residue Saver treatment relative to the plowed control at the Musgrave farm due to poor stands caused by the difficulty in planting into the heavy thatch of loose straw. Flail mowing the no-till treatment produced shorter straw that was easier to plant into, and no-till had the highest yield of all treatments. This indicates that straw cover did not inhibit soybean growth. Soybean yields did not differ between a twice disked and the Residue Saver treatment at Potenza's, but yields were variable and very low due to grazing by deer and ground hogs.
We demonstrated the Residue Saver two experiment station and one on-farm field days. The demonstrations drew 70, 85, and 95 people, respectively. A writer with Cornell's IPM program is preparing an article for a farm magazine.

NOTE; This project was approved prior to adoption by SARE-NE of performance based funding criteria, and the requested format for this report does not match with the original proposal. For example, performance targets and milestones were not specified in the original proposal. To comply with the requested report format, the project coordinator has attempted to extract analogous information, where possible. Note also that although the project was successful in accomplishing the proposed objectives, it did not accomplish the sort of immediate impact that is currently expected of SARE projects. We ask that our accomplishments be judged on the basis of the criteria that were in effect when the project was funded.

Project Objectives:

Performance Targets.
To develop a machine (the Residue Saver) that allows thorough tillage of the soil for destruction of perennial weeds and preparation of a seedbed while retaining most crop or cover crop residue on the soil surface.
To test the Residue Saver in cropping systems that involve both vegetable and field crops and both conventional and organic farming systems.
To demonstrate the Residue Saver to farmers and extension personnel at field days, and otherwise publicize the machine.


Click linked name(s) to expand/collapse or show everyone's info
  • Brian Caldwell
  • Brian Caldwell
  • Janice Degni
  • James Frisch
  • K. C. & Janet Mandeville
  • Anthony Potenza
  • Harold Van Es
  • Warren Van Pelt


Materials and methods:

4. Materials and Methods
Development of the Residue Saver.
Mohler and Frisch developed the basic concept of the Residue Saver. Frisch did most of the detailed design work in consultation with Mohler, Potenza and Van Pelt each made important suggestions that were incorporated into the final design. Frisch and Mohler built the machine with some help from undergraduate assistants and some contracted fabrication of parts.
Although the basic concept ultimately proved sound, implementation was an iterative process in which most components were modified at least once. For example, the shape and angle of the chute through which the residue is blown by the flail was changed three times, and one of these changes required reconfiguration of the frame. The means by which the cutting height of the flail is adjusted was completely changed. The shape of the flail knives had to be changed as well, and then they later were removed and reinforced. The suspension of the "tedder" wheels that lift the residue into the flail underwent a similar evolution, and much of the driveline was rebuilt or modified at some point during development. Since the need for extensive modifications from the first version of the prototype was expected, these changes were possible within the original project budget.
Crop residue is of two sorts: residue from the previous crop and residue from cover crops. The former is typically dead and is usually dry when soil conditions are appropriate for tillage, whereas the latter is typically alive and full of sap at tillage. Usually a greater biomass of crop residue can be achieved through use of a cover crop rather than by relying on residue remaining from a previous crop. Since the intent of the work was to develop a flexible machine that could handle even difficult residue situations, we chose to work with planted cover crops. The cover crops chosen were rye and red clover since these are the most commonly used cover crops in central New York, and indeed, in most of the Northeast. The plan was to plant corn into the red clover residue and soybeans and summer vegetables into rye. Chopped fresh red clover is sticky, however, and jammed in the distribution chute of the Residue Saver until changes completed in mid-June 2003 remedied the problem. Consequently, we have not yet had an opportunity to plant the red clover/corn experiments.
Potenza, the Mandeville's and Cornell University all lacked a one-pass tillage implement suitable for use with the Residue Saver. The two farms use multiple passes to prepare their seedbeds, and Cornell's heavy disks and rotovators were not of appropriate size for use with the Residue Saver. Consequently, we constructed an implement for use on those farms. The implement was built from a 3-point hitch mounted Landoll chisel plow. The outer wings were removed to reduce the width to 8 feet, a third tool bar was welded to the rear, and the chisel shanks rearranged in a 4, 3, 4 pattern with approximately 8.5" between shank paths. This is much closer than customary for chisel plows but works in this case since minimal residue is present when the chisels are in the soil. For some treatments the curved chisel teeth were replaced with 10" sweeps, essentially converting the implement to a field cultivator. Behind the chisel we pulled an 8" diameter steel pipe. This leveled out the chisel furrows, and wings on the pipe that extended 4" beyond the width of flail pulled in any clods that were thrown onto untilled ground so that they would not be picked up by the Residue Saver on the next pass. Behind the leveler bar we pulled a basket crumbler to finish preparation of a seedbed. The farmers agreed that this implement produced an adequate seedbed for large seeded crops and transplants. Small seeded crops would not be direct seeded into heavy residue in any case. The implement was designed primarily by Potenza and built by Frisch and Mohler.

Experiments with rye residue were run in 2002 and 2003. At the Musgrave experiment station farm we ran a soybean experiment in each year. In both years, the soil was a moderately well drained Lima silt loam. A field was chiseled, disked, dragged with a roller harrow and drilled with 'Aroostook' rye at 111 lb/a on 10/2/01 for the 2002 experiment and 9/26/02 for the 2003 experiment. The experiment used a randomized complete block design with 5 replications of the following four treatments: (1) conventional moldboard plowing followed by disk and roller harrow, (2) zone-till planting into killed, flail mowed rye, (3) Residue Saver with a field cultivator, leveler bar and crumbler into live rye, and (4) Residue Saver with a chisel plow, leveler bar and crumbler into live rye. In 2002 the conventional tillage and preparation for zone till planting occurred in late May, but multiple problems with the Residue Saver delayed Residue Saver tillage and planting of the experiment until 7/1-2/02 and 7/5/02 respectively. In 2003 field operations in the several treatments occurred concurrently: application of glyphosate to the zone-till treatment on 6/16/03, plowing in conventional on 6/18/03, and Residue Saver tillage on 6/20/03. Mowing the zone-till, secondary tillage in the conventional treatment and planting were delayed until 6/27-28/03 and by heavy rain. Tillage treatments were applied to areas 16' to 24' wide depending on the treatment. Treatment plots were initially 80' (2002) or 100' long (2003) by 10' (4 rows) wide and centered in the tillage strips. Buffer plots that spanned the tillage boundaries were planted between the data plots. After tillage and planting, the plots were reduced to 50' (2002) or 70' (2003) to exclude the end where the rye residue was removed by the Residue Saver and not replaced. Asgro 801 (group 0) Roundup Ready soy beans were planted with 200 lb/a of 6/24/24 fertilizer at 125,000 seeds/a in 2002 and at 180,000 seeds/a in 2003. We used a light seeding rate in 2002 to encourage maturation of the late planting. The planter was a 4-row Kinze no-till planter equipped with Dawn trash wheels and 3 Rawson zone-till coulters per row. The trash wheels were raised (inactive) in the conventional tillage treatment and the Rawson coulters were removed for the two Residue Saver treatments since they caused hairpinning of the rye straw. Soybeans were sprayed with Roundup Ultra Max at 1.5 qt/a on 7/16/02 and at 1 qt/a on 7/30/03. Soybeans were harvested on 10/30/02 by clipping 4 m of row from the center two rows of each plot and later threshing them with a Hege plot combine. The 2003 experiment was field combined with the Hege plot combine on 10/11/03. After threshing, soybeans were cleaned, weighed and weights adjusted to 13% moisture for reporting.
The soybean experiment at Potneza's farm in 2003 consisted of four pairs of alternating strips. The Residue Saver strips were 16' wide (2 passes) and the conventional strips were 30' wide, to accommodate a heavy disk. The soil was a well-drained Honeoye silt loam. Rye was a volunteer stand that had developed from natural seeding of a rye cover crop during the previous fallow year. The rye stand was reasonably consistent in the area of the experiment and about 4' tall at the time of tillage. The Residue Saver was used with a chisel, leveler bar and crumbler on 6/17/03 and the control treatment was disked twice on the same day. On about 6/20/03, 'Vinton' (a tofu variety) soybean was planted at 192,000 seeds/a using a 6 row John Deere 2200 planter equipped with Dawn trash wheels. Rows were 30" apart. In accord with the grower's usual practice, no fertilizer or compost was applied. For purposes of the experiment, the 4 rows at the center of each tillage strip were designated as a plot. After exclusion of the portion from which the Residue Saver removed the straw, plots were 121' long. The rest of the field beyond the area of the experiment was never planted for a variety of reasons. Since the experiment was remote from the grower's other soybeans, the field was never cultivated as had been planned. Severe browsing by deer and ground hogs coupled with heavy weed cover precluded combine harvest. Consequently, the center two rows of each plot were hand clipped on 10/31/03. The plants were dried at 50° C and the beans were broken out of the pods by rubbing the plants on a .0.5" hardware cloth screen. The soybeans were cleaned with a Clipper seed cleaner, weighed, and the weights adjusted to 13% moisture for reporting.
Experiments at the Mandeville farm were on Howard gravelly loam. Experiments comparing pumpkins and snap beans in moldboard plow and Residue Saver tillage were planted in 2002. Due to late planting, lack of irrigation and inconsistent weed management between the two tillage treatments, crop data from those experiments was not considered worth collecting. The experiments did provide data on residue retention and cover.
In 2003, pumpkins and potatoes were planted at the Mandeville farm into rye that had been drilled the previous September. The experiments alternated pairs of 8' wide Residue Saver plots with pairs of 8' wide moldboard plowed and disked plots, with 4 replicates overall. The Residue Saver was used with the chisel, leveler bar and crumbler on 6/10/03 and conventional plots were plowed and disked on 6/12/03. Rye was 5' to 6' tall at tillage.
A 4' strip of black plastic (2.5' exposed) with drip irrigation underneath was laid in the control treatment, and 'Howden' pumpkins were hand planted on 6/16/03. Drip irrigation lines were also laid in the Residue Saver plots. To compensate for the weed control by the black plastic, pumpkins in the Residue Saver treatment were hand weeded once on 8/2/03. One row of pumpkins was planted per 8' plot. Hills had 1-2 plants each and were spaced 3' apart in the row. Pumpkins received 0.74 lb/a of 20-10-20 fertilizer at planting and weekly until Aug 1 for a total application of 5.9 lb/a. Admire (21.4% imidacloprid) was applied to transplants at 0.5 oz/1000 before planting. The growers sprayed a tank mix of 12 oz/a Quadris (22.9% azoxystrobin) and 16 oz/a Admire on 7/31/03 for disease control. Pumpkins were harvested on 9/23/03 by tracing vines back to the plot of origin. Fruit that were more than 50% green were weighed separately from yellow fruit, though the growers ultimately sold them also.
Potatoes were planted at the south end of the same tillage strips used for the pumpkins on 6/23/03. Potato plots were 141' long. Potato rows were spaced approximately 5' apart, with three potato rows per 16' double tillage strip. Thus one row was near the center of each tillage strip and was used for data collection, and the third was a buffer row. Potatoes were planted on 6/23/03 with a no-till transplanter. Seed pieces were placed 14" apart and fertilized with liquid fertilizer at the rate of 93 lb/a of 10-20-10. Potatoes emerged slowly in both treatments but ultimately produced a uniform stand. The growers applied Sencor at 0.5 pt/a (0.25 lb/A of metribuzin) and Prowl at 1 qt/a (0.825 lb/a of pendimethalin) on 6/25/03 for weed control. Potatoes were sprayed with Dithane (mancozeb) at 1 lb/a on 7/12/03 and with Bravo at 1 pt/a (0.75 lb/a chlorothalonil) on 7/31/03 for disease control. Potatoes were hilled up with hilling disks on 8/1/03 and dug on 10/13/03. Potatoes from a 122.75' section of each single row plot were weighed to determine yield.
In experiments at all sites, standing rye was clipped at ground level from two 0.5 m2 quadrats randomly placed near opposite ends of each replication of the experiment prior to tillage. After planting, residue, including any surface stubble, was collected from two randomly placed 0.25 m2 quadrats in each plot, except for the Mandeville pumpkin experiment in which the quadrats were 0.5 m2. Quadrat shape was adjusted to insure equal sampling density across row and inter-row areas. Residue cover was assessed shortly after crop establishment using the beaded string method. In the Musgrave farm experiments 200 points were assessed in each plot. In the Potenza and Mandeville experiments, 300 points were assessed in each plot. Due to slow emergence of the potatoes, it appeared early on that the experiment had been lost and no residue data were collected in that experiment. Plots of the pumpkin and potato experiments lay end-to-end such that plots in both experiments were made with the same pass of the tillage implement. Consequently, residue data from the pumpkin experiment probably apply equally well to the potato experiment. As each crop began to senesce, we clipped weeds in two randomly placed 0.5 m2 quadrats per plot to assess weed density by species and total weed biomass. Quadrat shape was adjusted to correspond with row spacing of the experiment. Because weed density was exceptionally low in the 2003 Musgrave soybean experiment, weed counts were made in an additional pair of qaudrats in each plot.

Research results and discussion:

Milestones (Shown with asterisk)

First form of the residue saver is constructed (fall 1999 – summer 2001).

*First successful test of the Residue Saver -- 10/8/01. Residue saver throws partially lodged dead rye over the chisel/leveler/crumbler implement.

A preliminary field experiment with no-till, conventional tillage, and two residue saver treatments is planted to test our ability to plant into heavy residue -- 8/14/02. The planting was successful and subsequent corn emergence was good.

*First public demonstration of the Residue Saver -- 8/15/01, at the Musgrave farm field day. Since the rye was dead and dry, problems with flow through the chute were not apparent.

Flexible mounting system for the residue pick-up wheels is developed based on advice of Warren Van Pelt. Chute shape and angle is reconfigured twice and the shape of the flail knives is changed. A new suspension system for the flail housing is installed. Shields are developed to prevent wrapping of straw around the ends of the flail shaft (Fall and spring 2001, 2002).

*First full scale field experiment with the Residue Saver is planted—7/5/02, with soybeans at the Musgrave farm.

A curved, tapered chute with rounded sides is developed to reduce drag. The suspension system for the residue pick-up wheels is redesigned and rebuilt. The Residue Saver is painted. (Fall and spring 2002, 2003).

*Multiple successful tests of Residue Saver in green and wet cover crops—6/6/03 to 6/20/03.

*Three on-farm trials and an experiment station trial established—6/16/03 to 6/28/03.

*Well-attended field demonstrations of Residue Saver—8/1/03 & 8/23/03.

*Experiments are harvested—9/23/03 to 10/31/03.

*Successfully tested Residue Saver in 200+ bu/a corn stover.

Participation Summary


Educational approach:

Outreach efforts have mostly centered on demonstrations at field days so far (See Table 3 in Outcomes). A website with information and a video clip of the Residue Saver in action can be found at Publications in extension literature and farm magazines seem premature and counter-productive at this point given the low yields of the 2003 experiments. We are preparing an article describing the Residue Saver for submission to Applied Engineering in Agriculture.

No milestones

Project Outcomes

Impacts of Results/Outcomes

The Residue Saver was highly successful in performing its task, namely, allowing thorough preparation of a seedbed while retaining most crop residue on the soil surface. Residue retention commonly approached 80% of the original biomass (Table 1). Residue cover in all cases exceeded 80% after planting, and was not significantly different from zone-till in the Musgrave farm experiments (Table 1). Residue cover and biomass were even higher before planting, but planting necessarily disturbed the cover somewhat. Post-planting cover is more relevant to soil conservation and is reported here.

Table 1. Cover crop biomass retention above the soil surface (%) and ground cover (%) in the several experiments. Values within a row followed by the same letter do not differ at the P < 0.05 level. Values in parentheses are one standard error of the mean.
Residue Saver Residue Saver
Experiment Conventional Chisel Field cultivator Zone-tillage
Biomass retention (%)
Mandeville, pumpkin 8 a (3) 79 b (7)
Potenza, soybean 29 a (11) 96 b
Musgrave, soybean 2003 2 a (1) 65 b (13) 80 bc (10) 92 c (4)

Cover (%)
Mandeville, pumpkin 6 a (3) 86 b (1)
Potenza, soybean 22 a (5) 82 b (1)
Musgrave, soybean 2002 1.8 a (0.3) 85 b (2) 92 c (1) 87 bc (3)
Musgrave soybean 2003 4 a (2) 78 b (14) 90 b (3) 88 b (4)

Although the residue saver is effective at retaining crop residue on the soil surface during tillage, much work remains before the implement can be integrated into profitable production systems. With the exception of the soybean experiment on the Potenza farm, the Residue Saver treatment(s) yielded less than the control treatment(s) (Table 2). The reason for the lower yield was, however, different in each case.

Table 2. Yield. Pumpkin and potato yields are in lbs/a; soybean yields are in bu/a
Residue Saver Residue Saver
Experiment Conventional Chisel Field cultivator Zone-tillage
Mandeville, pumpkin* 24,700 a (2,800) 4,800 b (900)
Mandeville, potato 9,980 a (970) 5,990 b (1470)
Potenza, soybean 6.7 (3.0) 4.0 (1.0)
Musgrave, soybean 2002 34.2 a (1.5) 14.5 b (2.5) 11.8 b (2.7) 19.0 b (5.2)
Musgrave soybean 2003 33.2 ab (6.2) 13.6 c (5.7) 16.8 bc (6.9) 38.3 a (0.9)
* Orange and green fruit..

In the 2002 soybean experiment at the Musgrave farm, the rye was killed in the conventional and zone-tillage treatments in late May whereas the Residue Saver tillage did not occur until early July. Consequently the rye went to seed in the Residue Saver treatments, germinated, and competed with the crop. Weeds and the first flush of rye were killed with glyphosate on 7/16/02, but rye continued to establish. Dense rye cover after mid-Aug. probably explains the lower yield in the Residue Saver treatments, particularly given the late summer draught of 2002. The Dawn trash wheels worked well in the dry, mature rye straw present in the Residue Saver treatments in 2002. In contrast, in 2003 the rye straw was green and tangled badly in the trash wheels. Consequently, much rye was hairpinned into the planting slot and soybean stands were much lower in the Residue Saver treatments than in the conventional and zone-till (87,000 and 123,000 /a vs. 246,000 and 211,000, respectively). Planting in the zone-tillage treatment was successful (i) because the rye had been killed with glyphosate before mowing, and (ii) because the flail mower used in the zone-tillage treatment cut the rye into shorter pieces than the flail on the Residue Saver. Note that the zone-tillage treatment in 2003 produced the highest yield, indicating that high residue rates per se were not a problem. Also, the few Residue Saver plots that had uniform stands yielded similarly to the zone-tillage treatment.
In the soybean experiment at the Potenza farm, rye biomass in the Residue Saver treatments was less than in the Musgrave farm experiment (). The Dawn trash wheels worked adequately, and soybean stands did not differ between the conventional and Residue Saver treatments. Due to consumption by deer and ground hogs and lack of weed control yields were very low in the Potenza experiment, but did not differ significantly between treatments.
Pumpkin yield was substantially lower in the Residue Saver treatment than in the conventional treatment (Table 2). Cucurbits tend to yield better when planted on black plastic due to higher soil temperatures and this probably explained much of the difference observed here. A higher proportion of the fruit were still green at harvest time in the Residue Saver treatment, which also indicates higher soil temperatures in the conventional treatment. Although the Residue Saver treatment was hand weeded to compensate for the weed controlling effect of the black plastic in the conventional treatment, the Residue Saver treatment still had greater weed biomass at harvest (124 ± 4 g/m2 vs. 31 ± 7 g/m2 in the conventional treatment). Difference in weed pressure may also have contributed to the observed difference in yield.
Reasons for the difference in yield in the potato experiment are unknown. Weed control did not differ between the two treatments. Soil temperatures were probably higher in the conventional treatment, but this would not be expected to have much effect on potatoes, which are tolerant of cold soil. No quality differences were apparent between the two treatments, and the above-ground portions of the plants looked similar.
Thus, although yields tended to be lower with the Residue Saver treatments, the cause of the lower yield related to the particular timing of the experiment, planting equipment used and cultural requirements of the crop. Cropping systems using the Residue Saver in heavy cover crops appear feasible, but will require additional development. Prospects for using the Residue Saver with soybeans seems particularly hopeful. The Residue Saver, and high residue systems in general, are probably better suited to warmer growing conditions than prevail in central New York. In the southern parts of the Northeast and in the South, cold soils are less of a limitation to crop production, and the soil moisture conserving properties of straw mulch provide an incentive for use of mulch systems.
The impact of this project on current farming practices has so far been negligible. Because cropping systems with the Residue Saver must be developed and the technology mass-produced before farmers can adopt its use, we did not expect an immediate impact and did not claim to expect one in the grant proposal. Nevertheless, many growers and agricultural professionals have viewed the Residue Saver in action at field days (Table 3), and interest has been great. Some growers have commented that this project was the highlight of the day. Whenever we have used the machine on a farm, neighbors have gather to watch. Although the Residue Saver will not be in commercial production for at least a few more years, we believe that these demonstrations are leading people to think about tillage in new terms.

Table 3. Field days at which the Residue Saver was demonstrated.
Date Location Sponsor Attendance
8/15/01 Musgrave farm Cornell Dept. of Crop & Soil Sciences 70+
8/1/03 Musgrave farm Cornell Dept. of Crop & Soil Sciences 85
8/12/03 Myer farm NEON, NOFA-NY, NYCO*. 95
* NEON—Northeast Organic Network, NOFA-NY—Northeast Organic Farming Association of New York, NYCO—New York Certified Organic.

Economic Analysis

Economic Analysis
Cropping systems using the Residue Saver are not ready for farmer adoption at this time, and an economic analysis based on 2003 yield data would be highly misleading. Yields following Residue Saver tillage can certainly be improved. Moreover, an economic analysis would require an estimate of the cost of the Residue Saver itself, which would, at best, be highly speculative. Among other unknown factors, the cost of the machine will depend on the number of units produced. For example, high volume production would allow stamping of components whereas low volume production would require fabrication methods that are more costly on a per unit basis. Assuming that the Residue Saver can be priced similarly to other tillage and mowing machinery, we expect the costs of Residue Saver tillage will be closer to no-till or zone-till than to conventional tillage and most forms of reduced tillage (e.g., chisel and disk, disk and drag). Residue Saver tillage requires one pass for field preparation but does not require use of a burn-down herbicide. No-till and zone-till do not require passes for seedbed preparation, but usually do require a burn-down herbicide, and possibly also mowing or other treatment if a cover crop is present. Fuel efficiency for Residue Saver tillage will depend on the implement used. Fuel efficiency with an implement similar to the one used in the experiments reported here would be less than with more conventional tillage practices. Fuel use would be more than with a chisel plow due to closer shank spacing, but less than for a chisel/disk/drag system with several passes over the field and substantially less than any system using a moldboard plow. Horsepower and fuel use by the flail on the Residue Saver are small relative to requirements of the tillage implement.

Farmer Adoption

Farmer Adoption
The impact of this project on current farming practices has so far been negligible. Because cropping systems with the Residue Saver must be developed and the technology mass-produced before farmers can adopt its use, we did not expect an immediate impact and did not claim to expect one in the grant proposal. Nevertheless, many growers and agricultural professionals have viewed the Residue Saver in action at field days (Table 3), and interest has been high. Some growers have commented that this project was the highlight of the day. Whenever we have used the machine on a farm, neighbors have gather to watch. Although the Residue Saver will not be in commercial production for at least a few more years, we believe that these demonstrations are leading people to think about tillage in new terms.

Areas needing additional study

Areas Needing Further Study
Although additional improvements to the Residue Saver can be made, the machine is highly functional in its present form. The driveline is being extended to provide a PTO at the rear of the implement this winter. The PTO will allow use of the Residue Saver with rotary tillers and spading machines. An additional unit to throw residue over very long tillage implements has been designed but we have no immediate plans to install this on the machine.
The principle area that needs further study involves growing crops in very high rates of residue. The challenges appear to be of two sorts. First, planting row crops into high rates of loose straw is a challenge. Several brands of trash wheels are available for removing crop residue from the planting row and all of these need to be tested to see which work best. Trash wheels have been developed primarily for moving corn stalks out of the way of the planting unit, but grain and legume residues are more likely to tangle on trash wheels than are corn stalks. We are currently working on trash wheels that are much larger in diameter than the currently available models so that the axles are further from the straw mat. Other devices that cut the straw in front of the planter unit rather than just moving it may prove useful. Simple coulters will not work since (i) the soil behind the Residue Saver is soft from recent tillage and (ii) green straw is too tough to cut consistently with a coulter. Fortunately, planting does not seem to be a major problem for high-residue vegetable planters since these punch straight down through the straw rather than having rotating wheels onto which the straw can wind.
Second, methods need to be developed for improving soil warming in high residue systems. Cold soil is generally a limiting factor for many conservation tillage systems in northern climates and is a principle reason for slow adoption of no-till cropping systems in New York and New England. One possibility with the Residue Saver would be to form ridges during tillage and plant onto those. Residue deposited on the ridges by the Residue Saver could be swept off with a simple attachment to the planter. The advantage of Residue Saver tillage with ridges over more conventional ridge-tillage systems is (i) that deep tillage can be performed for perennial weed management, and (ii) the Residue Saver system would retain higher rates of surface residue since only residue has to be removed from the ridge, and not soil.
We foresee an important potential use for the Residue Saver in fall tillage. Many growers prefer to perform primary tillage in the autumn to improve soil tilth and speed planting in the spring. This practice, however, poses a substantial risk of erosion. Retaining crop residues on the soil surface using the Residue Saver would largely eliminate the erosion risk but still allow "frost tilth" and early planting. We are presently establishing an experiment to compare corn planted after fall tillage with the Residue Saver versus conventional tillage in the spring.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.