Our hypotheses were:
i. that fall-winter losses of N leaching in corn fields are avoidable, and can be reduced or prevented if cover crops are used, and are planted early enough to be effective, and
ii. that use of cover crops and nutrient management has economic benefit to the farmer, can be integrated into the cropping system through outreach and education, and is transferable to other regions.
To achieve the objectives research studies and on-farm field experiments were established for corn-cover crop planting date evaluation. These involve field studies demonstrating the effective date for fall establishment of cover crop after corn harvest for optimal N accumulation. However, because farmers are impacted by adverse weather conditions (e.g. excessive rain in two project years) they often have difficulty in meeting the cover crop planting dates for optimum end-of-season N accumulation and thus other approaches are needed. The project involved more than 25 farm studies with data collection and an evaluation of the corn-cover crop system, and more farmers in the review of management strategies for establishment of cover crops in standing corn at the time of topdressing N fertilizer, and field studies investigating the use of early planting of early maturing corn hybrids.
On-farm and research trials have shown early hybrids on average have similar yield and similar or improved quality compared to late season hybrids and if planted would help to ensure earlier planting of a cover crop. Early planting was shown to be very important for maintaining silage yields and quality and for achieving and as with early maturing corn hybrids an early harvest date. Six field studies across Massachusetts for establishing cover crops in standing corn in June at the time of fertilizer topdressing showed this practice was not viable and although farmers suggested use of helicopters in late August they realized this previous practice was cost prohibitive and not likely to return.
Results obtained from all of on-farm demonstrations were presented at farmers meetings, field days, and barn meetings. In these meetings collaborating farmers where on-farm demonstrations were conducted at their farm talked about their learning and the adjustments they made to their management practices. As a result of this project more than 10 farmers who were not planting cover crops before have started planting cover crops by making some adjustments in their management. Five farmers (with the total of 259 acres) are now using shorter season corn hybrids, 3 farmers (with total of 203 acres) are planting corn from 1-2 weeks earlier, 2 farmers (with total of 97 acres) is spreading manure while harvesting corn silage rather than spreading manure after the corn is harvested. One farm moved away from corn and seeded these fields (approx. 100 acres) to pasture and now raises beef rather than dairy cattle. We are also aware of 5 other dairy farmers (2 of them never planted cover crops before) who have made further management adjustments for earlier planting of cover crops in the 2010 growing season.
Cover crop growth and climatic data were integrated into a fall GDD model and incorporated into the economic considerations. All findings were and continue to be shared with and reviewed by farmers. The results are transferable to other farm locations/regions through the development of the GDD model. This work is being continued with other funds to make this information web accessible.
Our objectives are i. to determine critical seeding dates and a growing degree day (GDD) model for rye cover crops. ii. To evaluate methodologies for early establishment of cover crops, and iii. to demonstrate the economic benefit of adopting effective cover crops.
Of 20 dairy/livestock farmers who participate in on-farm studies and farm based outreach, 15 will use the developed assessment methods for cover crop effectiveness in recovering end-of-season nutrients, and 10 will make management decisions (changes) to ensure cover crops are effective for N uptake.