Cover crop performance depends largely on management factors that must be customized to particular farm situations and, therefore, is suited for on-farm research, with farmers involved in both management and evaluation. Cover crop sequences that were successful in a research station study were tested over a variety of soils and management strategies in collaboration withfarmers. The two-year cover crop sequences consisted of a short-season crop followed by a cover crop in year one and corn in year two. The cover crops themselves were evaluated by their agronomic and economic performance and their acceptance by farmers. Four cover crop systems (companionseeded red clover, sequentially seeded hairy vetch, sequentially seeded oat, and fallow) were compared for ground cover, above-ground biomass and above-ground nitrogen yield, subsequent corn grain yield, and N fertilizer replacement value (N-FRV). Cover crops were essential for erosion control following vegetable crops and tillage, but were not necessary following small grains. Companion-seeded red clover produced the most ground cover, yielded up to 133 kg N/ha, and had a higher average N-FRV than sequentially seeded hairy vetch on sandy loam soils, but was not preferred by farmers who harvested small grain straw as well as grain. Sequentially seeded hairy vetch gave excellent cover when no-till seeded, produced more than 125 kg N/ha in half the siteyears, and had a higher average N-FRV than companion-seeded red clover on silt loam soils. First-year N-FRV for the legume cover crops averaged 67 kg N/ha over both soil types. The participating farmers indicated that their decisions to adopt cover crops would be based primarily on their need for ground cover, and secondarily on the profitability of using cover crops as an N source. However, when valued solely as an N source for the next year's crop (and not for any potential long-term benefits), cover crops were not an economical alternative to N fertilizer. We suggest focusing future cover crop research and extension efforts on outreach to farmers growing crops that do not provide sufficient ground cover, such as short-season vegetable crops, and optimizing the cover crop system to maximize its erosion control benefits and increase its profitability over N fertilizer.

This study evaluated the profitability of several cropping systems during a 10-year period of an experiment comparing rotations and levels of purchased inputs. Continuous corn or sorghum, corn/wheat-soybean (2-year), and corn/wheat-soybean/corn/clover hay (4-year) were managed with recommended fertilizer and pesticide rates and no-till planting (C) or with N from legumes, conventional tillage, and cultivation for weed control (L). Medium input management (M: medium rate of N and banded herbicides) was included during years 5 through 10. Generally, corn was the least profitable crop, regardless of input level or type of rotation. Rotating crops improved profit more than did adding inputs to continuous corn. With L, average annual profit was: continuous corn, -$64/ha; 2-year rotation, $135/ha; and 4-year rotation, $158/ha. With C, the 2-year rotation increased profit to $165/ha from -$119/ha with continuous corn. The increased profit with rotations was due to greater profits from wheat, soybean, and hay offsetting low or negative profit from corn. Sorghum (grown only in monoculture) was more profitable with L ($34/ha) than with C (-$20/ha). During the 6 years when all input levels were compared, the order of average profit was M>L>C with continuous corn. Generally, profit was not increased by M compared with L in the 2-and 4-year rotations. With L, the cost of weed control was 20% of that for C with corn and 44% with soybean. Cost of N from fertilizer was $0.66/kg, but cost of N from crimson clover (seed and planting costs) averaged $0.92/kg when clover was drilled, $1.27/kg when aerially seeded, and $0.16/kg when naturally reseeded.

This study examined how one aspect of intensive cultivation, double digging by hand (loosening the planting bed to 50 cm deep), contributed to crop productivity and nutrient uptake in bush beans (1994 and 1995) and red beets (1995 only). Comparison beds were prepared with the soil cultivated to 25 cm (single dig) and 6 cm (surface cultivation). Although there were significant differences (1994 beans) between the surface cultivated beds and other cultivation types for leaf mass and chlorophyll content, there were no significant differences in the total mass of beans (whole fruit) produced. There were no significant differences in beet green or root (edible portion) biomass among cultivation methods. Levels of Ca, Mg, and K in the bean fruits and beet roots were not significantly different among cultivation methods. This study demonstrated that deep cultivation significantly alters the soil profile as measured by penetrometer resistance, but that this change does not necessarily alter productivity or nutrient uptake. We suggest that deep hand tillage has little effect on crop productivity in well-watered and moderate to high fertility soils. These results are similar to those found in mechanically subsoiled systems.

With the growing concern about the impact of agriculture on water quality and heightened interest in managing agricultural by-products economically, the use of composting by U.S. farmers is increasing. Over 8,000 farms are now composting animal mortalities, manure, crop residues, and selected organic materials from communities and industries. At least 75% of farm composting operations are composting poultry mortalities. Based on discussions with contacts in leading agricultural states and organizations, this paper provides examples of technical and economic incentive programs encouraging farmers to adopt composting as a way to manage farm by-products. These programs have been established largely by the public sector, including state agencies, public universities, USDA, and USEPA. However, they are often initiated by or conducted in partnership with the private sector entities such as farms, livestock and poultry product companies, and composting businesses. Examples of incentive programs include research and demonstration projects, extension educational programs, technical standards, regulatory incentives, cost-sharing, financial grants, and low-interest loans. Many projects have succeeded in expanding the practice of composting among farms. For example, the now common practice of composting poultry mortalities can be traced to research and educational programs at the Universities of Maryland and Delaware, which were followed by a national technical standard adopted by the USDA. Similar success stories are apparent in other composting incentive programs, such as for composting of swine mortalities in Missouri, dairy manure in Michigan, and non-farm materials in California and Pennsylvania.