Establishing Cover Crops at Time of Corn Planting: Determining Soil - Water Quality Benefits

Establishing Cover Crops at Time of Corn Planting: Determining Soil - Water Quality Benefits

Summary

The establishment of cover crops following corn harvest is limited due to the short growing season in the Northeast. The establishment of cover crops at the time of corn planting takes advantage of good soil moisture, a prepared seed bed, and allows for the use of conventional seeding equipment. Herbicides are used to suppress the cover crops while controlling weeds without reducing corn yields. Establishing cover crops at time of corn planting gives farmers in the Northeast the possibility of establishing legumes which are not possible following corn harvest. The establishment of cover crops earlier in the season allows for more growth and nutrient uptake in the fall compared to cereal grains planted following corn silage harvest in October. This system provides the farmers another time within their operation to establish cover crops. This project investigates the use of different cover crops, herbicides, cover crop combinations and seeding rates. The effects of the cover crops on soil and water quality will be investigated. Phosphorus and sediment concentrations, and runoff volumes from the cover crop plots will be evaluated using rainfall simulation

Objectives/Performance Targets

Out of thirty farmers that participated in cover crop demonstrations fifteen will continue to apply cover crops on their own using this system on one field per year for three years after completion of the project.

Out of twenty-five farmers, five will be willing to use their farms for a field day stop or write a testimonial on their experience with the system in a local SWCD or extension newsletter.

Out of seven agency people involved in the project four will instruct dairy farmers on their own on the use of this system resulting in cover crop plantings.

Research is to be carried out according to procedures meeting discipline standards, statistically verifiable. The utilization of the research by NRCS to credit cover crop system for soil erosion reduction and P index will be investigated.

Accomplishments/Milestones

Outreach continues to be a strong component of the work with 13 meetings and demonstrations conducted with approximately 660 in attendance in 2003. These included Cornell’s Musgrave Research Farm Field Days, the Northeast Agronomy Society’s annual meeting and crop advisor training at the University of Vermont and Empire Farm Days in Seneca Co. NY. Presentation were given at major extension winter meetings in cooperation with the University of Vermont in Springfield and St. Johnsbury VT, Cornell University in Ithaca, NY, the Western NY Quality Forage Forum in Delevan, NY, the Agricultural Environmental Management for Comprehensive Nutrient Management Plan Development training session in Binghamton NY, and the NRCS East Region Technology Workshop (for NRCS technical specialist from the NE and Mid-Atlantic states) in Syracuse NY. These meetings attracted a diverse audience of extension agents, farmers, crop advisors, NRCS and SWCD employees. A one hour power point presentation was created to include soil and water quality benefits and other cover cropping systems.

In 2003 we worked with 16 farmers and 4 research facilities setting up demonstrations and/or field trials at 16 sites. A study was conducted at two sites evaluating 2 seeding rates of: red clover, and annual and perennial ryegrass at 8 and 12 lbs/ac, white clover at 6 and 10 lbs/ac and alfalfa at 8 and 15 lbs/ac; and one additional site evaluating 2 seeding rates of annual and perennial ryegrass.

The ARS Klingerstown site this year had problems with cover crop establishment and the corn was knocked down due to wind from a hurricane. It was decided to establish the study next year and conduct the final rainfall simulation. After the first rainfall simulation conducted in 2001 it became apparent that the timing and the intensity of the simulation needs to be adjusted to more reflect natural conditions. When raining on manure the soluble phosphorus tends to go into solution and immediately runoff when rained on at the protocol rate of 2.75 inches /hr. We will conduct some smaller storm events to allow some of the P to interact with the soil prior to an intense event. The soil quality experiment will continue one more year and the data will be taken in the fall of 2004. It had been decided not to do preliminary data collection other than organic matter and just compare control sites with cover crop sites at completion of the study due to the sensitivity of the tests to weather and soil moisture conditions requiring the need for synchrony.

Impacts and Contributions/Outcomes

Six of the farms which conducted cover crop demonstration plantings in 2001 or 2002, conducted plantings in 2003 and are planning to continue in 2004. Four of the farms which conducted plantings in 2003 and one from 2002 are interested in continuing in 2004. Two of the farms had field tours in conjunction with an extension agent and SWCD personnel. Two extension agents, 1 SWCD personnel and 1 university researcher worked with farmers individually on establishing cover crops at time of corn planting. They are planning to work with them again in 2004. Two other NRCS employees, two other extension agents and one crop consultant requested additional information and have farmers they are working with in 2004. Nine farmers signed up for on farm cover crop projects after looking at the Empire Farm Days demonstration. Discussions have taken place with NRCS state agronomists from NY, and PA. who have responsibility for working with the soil loss model, RUSLE-II, about obtaining data for insertion into the model to predict soil loss reduction from the use of this system.

In 2003 there was a 1.3 t/ac average reduction in silage corn yields (35% dry matter) from the use of the cover crops with 18.3 t/ac, compared to the control for all sites with 19.6 t/ac. The ryegrasses had a 1.5 t/ac reduction. There is also typically a reduction in yields from post-emergence spraying when sprayed late compared to conventional pre-emergence systems. Another year of evaluating cover crop seeding rates was conducted at three locations. There was no corn yield benefit observed by lowering the cover crop seeding rates with both high and low rates averaging 18.5 t/ac. This resulted in a 2.6 t/ac reduction compared to the control at those sites. The corn yields with legume cover crops for both seeding rates averaged 19.5 t/ac with a 2.1 t/ac reduction compared to the control. Of the species tested, annual (ARG) and perennial ryegrass (PRG) are the most competitive. The corn yields with the ARG at both the 8 and 12 lb/ac rate was 15.9 t/ac; the corn yields with a PRG cover crop was 18.4 and 17.6 t/ac for the 8 and 12 lb/ac rate respectively compared to 20.4 t/ac for the control. The percent cover in the fall at the 8 lbs/ac rate was 92 and 86 % for the ARG and PRG respectively. Some of the ARG cover was attributed to seed germinating from seed that was produced from the cover crop. Reducing the seeding rate further is still an option to investigate. Summary Tables of corn yields and percent cover crop for all plantings are available upon request at NE SARE.

Other grass species were investigated at the Big Flats PMC to test their response to herbicides and their effects on corn yields. Another herbicide trial was conducted in 2003 at the Big Flats Plant Materials Center evaluating 14 different herbicide treatments with 13 species of cover crops. The species were expanded to include 8 other species, 6 grasses: tall fescue, red fescue, hard fescue, orchard grass, Kentucky bluegrass, and smooth bromegrass and 2 legumes birdsfoot trefoil and hairy vetch. All of the grass species provided over 80% cover in the fall, visual observation of the corn plants and ears showed that these grasses are less competitive than the ryegrasses. The orchard grass and tall fescue visually produce as much fall biomass as the ryegrass for nutrient uptake. The corn yields with the tall fescue and bluegrass cover crops were 21.0 and 22.0 t/ac respectively compared to 21.5 t/ac for the control. The other grasses will be evaluated for their effects on corn yields in 2004.

Callisto, a new herbicide originally derived from allelopathic compounds of the bottlebrush plant, Callistemon citrinus and now synthetically produced was investigated. Callisto at 6 oz/ac and Pursuit at 1.44 oz/ac pre-emergence gave excellent weed control and all C3 grass cover crop species grew through it. The use of Dual and Python pre-emergence was tried for use on conventional corn hybrids with legume cover crops. The legumes averaged 62% cover in the fall. The legumes may have recovered and survived due to the unusually wet growing conditions in 2003 and this treatment needs to be repeated in a drier year. Python herbicide should be used only when the soil temperature and moisture is adequate for rapid corn emergence. The use of ½ rate of Accent and 1 pint/ac of Buctril was tried on one farm and one research plot for use with conventional corn hybrids with legume cover crops; corn yields averaged 21.4 t/ac compared to 22.6 t/ac for the control. Preliminary work with low rates of Banvel showed some potential for suppression of legume cover crops and will be investigated further.

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