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

(Note to the reader: Appendices referenced in the body of this report can be requested in hard copy from Northeast SARE by sending e-mail to nesare@uvm.edu. Please refer to project number LNE01-147 when you make your request.)

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 techniques. Soil physical and biological properties will be evaluated in plots which were in the system for 4 years.

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 10 meetings and demonstrations conducted with approximately 1030 in attendance in 2004. The meetings concentrated on state level NRCS Agronomists and Plant Materials Personnel at two national meetings in Nebraska and Missouri. Information was also presented at the annual National Soil and Water Conservation Society and American Society of Agronomy meetings in Minnesota and Washington. A summary of presentations is given in Appendix A.

In 2004 we worked with 18 farmers and 4 research facilities setting up demonstrations, field trials and research plots. See Appendix B for a summary of some of the corn yield data from the on farm demonstrations. In 2004 the plantings were conducted in New York, Pennsylvania and Vermont working with 5 extension agents 4 consultants and 1 SWCD employees. Some of these worked nearly independently with the farmers. Work increased in Pennsylvania with the support of the NRCS State Agronomist, Joel Myers. We worked with extension agents, consultants, SWCD, ARS and Penn. State University personnel with 6 farmers and 2 research facilities.

A study was conducted at the Big Flats Plant Materials Center looking at corn yields with 5 different herbicide combinations and 10 different cover crops, data in Appendix C. Another herbicide trial was conducted evaluating 18 different herbicide combinations and 14 different cover crops, evaluating only the dry weights and percent cover of the cover crops, data in Appendix D. Peter Kleinman from the USDA-ARS Pasture and Watershed Management Lab conducted more rainfall simulation at the ARS Klingerstown site. These studies evaluated sediment and phosphorus runoff before and after manure application using different rainfall intensities and comparing fall seeded cereal rye cover crop to perennial ryegrass and red clover established at time of corn planting. Soil sampling was conducted at Cornell’s Aurora Research Farm for soil physical and biological evaluation to plots that were in the system for 4 years. We also compared ryegrass with and without tillage. Soil measurements will include: bulk density, infiltration, dry aggregate size distribution, wet aggregate stability test, pore size distribution, particulate organic matter fractions, microbial biomass and mineralizable nitrogen.

Impacts and Contributions/Outcomes

Seven of the farmers conducting plantings in 2004 conducted plantings previously. Four were on their 3rd year. Six of these farmers increased their acreage and had bought their own corn, herbicides and cover crop seed. One of the farmers increased his acreage under the system to over 50 acres. Farmers have figured out that they can mix the cover crop seed with their fertilizer and have it broadcast spread when fertilizing their corn. Another method we introduced is using the insecticide hopper with a minimum amount of adaptation as a seeder for surface spreading the cover crops.

An article ”Effect of cover crops established at time of corn planting on phosphorus runoff from soils before and after dairy manure application” was submitted for publication to the Journal of Soil and Water Conservation.
Rain simulations (60 mm h-1) were conducted to evaluate the initial 30 min of runoff from small (1 x 2 m) plots before and after surface application of dairy manure (50 or 100 kg total P ha-1). Corn yields from plots interseeded with red clover and, at one site, perennial rye grass were comparable to those from conventional silage corn. Prior to dairy manure application, losses of P in runoff were primarily a function of erosion. Because all cover crops increased ground cover (up to 81% greater than the control), total P loads in runoff were significantly lower from cover cropped plots (averaging 10 mg plot-1) than from conventionally cropped controls (averaging 39 mg plot-1). Despite concern that leaching of soluble P from the cover crops could enrich dissolved reactive P (DRP) in runoff, DRP losses from cover crops were generally not different from conventionally-cropped controls. Following manure application, runoff P losses increased by over an order of magnitude. Dissolved reactive P became the dominant form of P in runoff, due to contributions of readily soluble P in manure, with DRP averaging 28% of total P before and 78% of total P after manure was applied. There were no differences in performance between the cover crop species. It was acknowledged in the article that the intense level of rainfall simulation may have allowed for a greater amount of soluble P runoff than what could happen with more moderate rains washing the P into the soil. In as much as some cover crops may reduce the need for manure nutrients (e.g., leguminous cover crops reduce need for manure N) cover crops may lower manure application rates and related P losses. Results highlight the agronomic and water quality benefits of a novel cover cropping system that holds promise for dairy farms in the northeastern U.S.

In 2004 from the Big Flats Plant Material Center research plots, there was a 2.2 t/ac average reduction in silage corn yields 20.8 t/ac (35% DM) from the use of grass cover crops compared to the control with 23.0 t/ac averaged across two pre-emergent herbicide treatments. These herbicide treatments were Pursuit 1.44 oz/ac + Callisto 4 oz/ac + Dual 6oz/ac; and Pursuit 1.44 oz/ac + Python + 0.5 oz/ac and Hornet 2 oz/ac. The grasses evaluated were perennial ryegrass, orchardgrass, bromegrass, reed canary grass, tall fescue, red fescue, timothy, and Kentucky bluegrass all seeded at 8 lbs/ac. The red fescue, and Kentucky bluegrass did not tolerate the shade and provide enough cover. In another study using Pursuit 1.44 oz/ac + Python + 0.89 oz/ac corn yields with alfalfa and red clover cover crops seeded at 8 and 10 lbs/ac were 20.4 and 20.2 compared with the control at 19.8 t/ac. There still appears to be a problem using Pursuit (imazethapyr) and Python (flumetsulam) in combination together. Control plots with Python averaged 18.4 t/ac compared to 20 t/ac for control plots without the Python. There was some problem with crabgrass and fall panicum control on some of the farm plots. The use of Pursuit (1.08 oz/ac) and lightening (.32 oz/ac) combination post emergence a 3:1 ratio of the recommended rate was tried in small plots which allowed for most cover crops to grow the lightening may increase the control of the annual grasses. The use of a reduced rate of Dual or Prowl with Pursuit early post-emergence may increase control of late germinating annual grasses. Pursuit 1.44oz/ac + Banvel 1 pt/ac + Dual 1 pt/ac post-emergence was tried in small plots and allowed for the growth of most grass cover crops. See Appendix C for other options.

Collaborators: