Final Report for FNC96-136

Multiple-site Evaluation of Cover Crops Established in Wheat Stubble

Project Type: Farmer/Rancher
Funds awarded in 1996: $9,613.00
Projected End Date: 12/31/1997
Region: North Central
State: Ohio
Project Coordinator:
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Project Information

Summary:

PROJECT BACKGROUND
Many farmers have a problem with planting corn and soybeans into wheat stubble. No till practices are being abandoned because wheat stubble ties up available nitrogen, creates a dense layer of material which prevents soils from drying in the spring, and does not allow soil tilth to provide good see to soil contact. Therefore, many farmers are reverting back to tillage of the wheat stubble. This subjects the soil to wind and water erosion from September until May when the crop is planted.

This project evaluated cover crops as an economical and sustainable alternative to tillage of wheat stubble.

PROEJCT DESCRIPTION AND RESULTS
The goal of this project was to establish multiple on farm research experiments to evaluate cover crops planted into wheat stubble for their ability to create an improved soil environment for the following crop. Soil and crop improvements from cover crops were measured in terms of additional corn yield, soil nitrate contribution, biomass accumulation, tissue test, and stalk nitrate test.

Cover crops selected for this project were Hairy Vetch and Medium Red Clover. A John Deere no till drill was used for seeding. Hairy Vetch was placed in the main hopper of he drill and clover seed planted with the small grain seeder attachment on the drill. In this way, strips were planted by opening and shutting seed boxes. The drill was driven over the no cover strips to maintain spacing for the 1997 grain crop. Each strip was one round the length of the field, which equals 30 feet in width. This would then match a six row corn planter. A rate of 30 pounds per acre for hairy vetch and 15 pounds per acre for clover was planted.

The following cooperators participated with on farm research plots. All plots were located in Henry County, Ohio within 15 miles of the Rich Bennett farm. Soil test results show a range of soil types and fertility which is typical of Northwest Ohio.

Cooperator plots are identified by the following names:
– Hastedt, cooperator – Robert Hastedt, Hamler, OH
– Johnson cooperator – Dennis Johnson, Napoleon, OH
– Meyer cooperator – Carlton Meyer, Napoleon, OH
– Bennett cooperator – Rich Bennett, Napoleon, OH
– Landfill cooperator – Henry Co. Extension, Napoleon, OH

Plot descriptions:
Hastedt – Wheat had been harvested and the straw had not been cut – leaving stubble about 18 inches tall, the combine had spread the straw evenly over the field. On July 27, Round-Up was applied to the entire field.

About 12 acres were no till planted on July 26, 1996 with the following pattern of 30 foot field length strips.
– Boarder
– Hairy Vetch
– Red Clover
– No cover
– Red Clover
– No cover
– Hairy Vetch
– Hairy Vetch
– No cover
– Red Clover
– Red Clover
– Hairy Vetch
– No cover
– Boarder

This plot received adequate rain following to well establish the cover crops. The following spring, the plot was disked and field cultivated just before planting corn on April 24, 1997. 12 corn rows matched each cover crop strip. All strips were treated the same. On June 15, 1997 the corn was side dressed with 28% nitrogen. A total of 150 lbs nitrogen was applied to the strips with no cover. A total of 120 lbs nitrogen was applied to the Hairy Vetch and Red Clover cover crop strips. This plot was uniform and a good comparison.

Johnson – Wheat had been harvested. On August 1, 1996, 15 lbs/acre of nitrogen was applied on strips designated as no cover. The entire 20 acre field was then disked to incorporate the wheat straw. On August 3, 1996 the field was planted with the following pattern of 30 foot field length strips.
– Boarder
– Hairy Vetch
– Hairy Vetch
– No cover
– Hairy Vetch
– No cover
– No cover
– Hairy Vetch
– Hairy Vetch
– No cover
– No cover
– Hairy Vetch
– No cover
– Boarder

The growth of hairy vetch was less on this plot than the other locations. The following spring this plot was sprayed with Round-Up to kill the cover crop and then was no till planted to corn on April 26, 1997. At planting time the entire field received 150 lbs of nitrogen with no rate difference between strips.

Meyer – Wheat had been harvested. The stubble was cut close to the ground and the straw baled off. Cover crops were no till planted on July 24, 1996. The 20 acre field was planted to the following pattern of 30 feet wide, field length strips.
– Boarder
– Hairy Vetch
– No cover
– Red Clover
– Red Clover
– No cover
– Hairy Vetch
– Hairy Vetch
– Red Clover
– No cover
– Boarder

This plot had good growth of cover crops. The following spring Round-Up was used on April 20 to kill the cover crops. Soybeans were planted on May 1, 1997. No additional fertilizer was applied to the field.

Bennett – Wheat had been harvested. The straw had not been cut leaving 18 inch tall stubble. The combine had spread the straw evenly over the entire field. Only the strips designated for hairy vetch were disked before planting. The 20 acre field was planted to cover crops in the following pattern.
– Boarder
– Hairy Vetch
– No cover
– Hairy Vetch
– No cover
– No cover
– Hairy Vetch
– Hairy Vetch
– No cover
– No cover
– Hairy Vetch
– No cover
– Hairy Vetch
– No cover
– Red Clover
– Red Clover
– No cover
– Red Clover
– No cover
– Red Clover
– Boarder

This plot had fair growth of cover crops. The following spring corn was no till planted into the cover crops on April 25, 1997 with Frontier and 2, 4-D used to kill the cover crops. The entire field received the same rate of nitrogen with a total of 150 lbs/acre applied mostly at side dressing in June. All other inputs were the same.

Landfill – Wheat had been harvested. The straw was not cut, but the loose straw from harvesting was baled off. Round-Up was applied on July 24 and the cover crops were no till planted on July 26, 1996. the field was planted in the following pattern of 30 feet wide, field length strips.
– Border
– Hairy Vetch
– No cover
– Red Clover
– Red Clover
– No cover
– Hairy Vetch
– Hairy Vetch
– Red Clover
– No cover
– Red Clover
– Hairy Vetch
– No cover
– Border

This plot had good growth of cover crops. The following spring corn was no till planted into cover crops on April 24, 1997 with Frontier and 2, 4-D used to kill the cover crops. Only 20 lbs/acre of nitrogen was applied to the entire field as starter fertilizer at planting time. No additional nitrogen was applied. This plot would test the yield difference which cover crop contributed nitrogen would have compared to no nitrogen.

Biomass testing: In a one foot square area, all cover crop growth was removed. This plant material was then microwave dried until no moisture remained. Weights were then recorded and calculated to the number of pounds of biomass dry weight per acre. Sampling occurred once in late fall and twice in April the following spring.

Soil nitrate testing: 12 inch deep soil cores were collected for all soil nitrate testing. On June 11, 1997 each strip was sampled and samples analyzed at the Ohio Ag Research & Development Center REAL Lab. At all other sampling times a portable nitrate test kit was used to analyze samples.

Tissue testing: Corn – at silk emergence time the ear leaf was removed from 12 consecutive plants and sent to the REAL Lab for % nitrogen analysis. For soybeans, leaf samples were collected at flowering time. Samples were collected from each strip.

Stalk nitrate testing: Corn – after black layer maturity, starting 6 inches from the ground, the lower 8 inches of the corn stalk was removed from 15 plants and sent to the REAL Lab for % nitrogen analysis. Samples were collected from each strip.

Grain yield: a weigh wagon was used to weigh each strip. Field length was measured. Grain moisture was measured and yields were determined by using the national corn grower formula for dry corn yield equivalent.

Grain nitrogen content: at the Hastedt plot, the corn grain was collected from each strip and analyzed by the REAL Lab for % nitrogen content.

Results:
Biomass – in al plots, cover crops produced adequate amount of top growth to control erosion throughout the winter. Hairy vetch was able to produce more biomass than red clover.

Soil nitrate – Henry County had a cool, wet spring which may have reduced the amount of soil nitrate released by the cover crops. Corn planting occurred early, by April 25, which caused cover crops to be destroyed before significant spring growth occurred. Soil nitrate readings on June9 remained below 15 ppm on all plots, indicating very little nitrogen contribution from the cover crops. Therefore on Bennett and Johnson, full sidedress N rates were applied. Hastedt sidedress rates were reduced by 30 lbs/acre N on the cover crop strips. The Meyer soybean plot shows the soil nitrate contribution from soybeans by October were slightly increased with Red Clover.

Tissue test – the corn plots showed a slight increase in tissue N% for red clover, however this is not a significant difference. All fertilized plots were in the sufficient range for nitrogen. Cover crops showed a nitrogen contribution in the unfertilized landfill plot compared to no cover. The soybean plot showed hairy vetch strips averaged 5.2% N, red clover 5.5% and no cover 5.55% resulting in no advantage for cover crops.

Corn stalk nitrate- Hastedt plot showed optimum levels for no cover strips which received an additional 30 lbs/acre nitrogen. However the cover crop strips were below optimum levels, which one may conclude that nitrogen was lacking for optimum yields. The Bennett plot had excessive levels in all strips with red clover having the highest levels. One may conclude that Bennett applied too much nitrogen. Johnson had very low levels in hairy vetch strips compared to no cover. Landfill was deficient as expected with no additional nitrogen applied. These results do not show an advantage to cover crops for corn stalk nitrate contribution.

Yield – in all plots there was no significant difference between the cover crop strips and no cover in grain yield. The landfill plot did show an advantage to the cover crop strips versus no cover; however this advantage was not significant.

Grain % nitrogen – at the Hastedt plot, composite corn grain samples were analyzed for % nitrogen. The nitrogen averages for the strips were – Hairy Vetch – 1.32%, red clover – 1.32%, no cover 1.35%. Sufficient ranges are 1.45 to 1.80% N. This matches with corn stalk nitrate and grain yield results for Hastedt which also favored no cover strips.

Economics:
To compare the cost savings of purchased nitrogen vs. the cost of growing cover crops the following was compared:

Seeding expense:
Hairy vetch, 30lbs/acre x $.75/lb = $22.50/acre
Red clover, 15/bs/acre x $1.68/lb = $25.20/acre
Drilling cost = $10/acre

Nitrogen costs
28% nitrogen fertilizer cost = $.28/lb N
115 lb nitrogen/acre x $.28/lb = $32.20

Cover crops would need to contribute 115 lbs of nitrogen to equal the seeding cost. In this study, cover crops contributed less than 30 lbs/acre nitrogen, making them less economical. However other factors such as soil erosion control, weed suppression, and soil tilth and organic matter improvements were not accounted for.

OUTREACH
– A field day was held on August 28, 1996 at the Bennett farm. This research plot was included on the tour. About 50 farmers attended.
– The OSU Extension Sustainable Ag team toured the research plots on October 9, 1996. Ten people attended.
– A poster was presented on this project at the Innovative Farmers of Ohio annual meeting in London, OH on January 18, 1997. Nearly 100 farmers and agency personnel attended.
– A cover crop council meeting was held on April 1, 1997 in Napoleon, Ohio. 35 local farmers attended. Grant cooperators shared their information.
– A field day was held on September 9, 1997 at the Bennett farm. This research project was discussed. About 50 farmers attended.
– The results of this project will be shared with SWCD, OSU Extension, and Innovative Farmers of Ohio.

Research

Participation Summary
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.