Microbial activities important to effects on crop productivity and nutrient cycling can be altered by agricultural management practices. This study was conducted to determine whether soil microbial populations and their N cycling activities differ between conventional and alternative management practices. Physical, chemical, and microbial soil properties were measured at soil depth intervals of 0 to 7.5, 7.5 to 15, and 15 to 30 cm at a site in southeastern Pennsylvania during the second and fifth years after conversion from a conventional, chemically intensive system to alternative systems utilizing legumes and animal manure as N sources. In the second year after conversion, populations of fungi and bacteria, dehydrogenase activity, and soil respiration in the surface soil layer were greatest with alternative systems planted to red clover (Trifolium pratense L.). Differences in soil biological factors between management systems were related primarily to crop characteristics and, to a lesser extent, to soil physical properties. Levels of microbial populations and activities with conventional management were the same as with alternative management systems when similar crops such as corn (Zea mays L.) or soybean [Glycine max (L.) Merrill] were grown. Soil NO3-N contents, at most sampling depths, were markedly increased by application of fertilizer N or recent plow-down of red clover or hairy vetch (Vicia villosa Roth). The growth of red clover in the second year or hairy vetch in the fifth year was accompanied by significantly increased microbial biomass and potentially mineralizable N (PMN) reserves in the top 30-cm soil layer-these changes being most pronounced in the surface 0- to 7.5-cm layer. Nitrogen deficiency symptoms and lower corn grain yields in a legume/cash grain rotation as compared with conventional management in the second year were associated with lower soil NO3, levels and a greater proportion of N present as weed biomass and belowground microbial biomass. In 1985, management systems comparisons were limited to corn as the main crop; soil NO3 levels during the growing season were inversely related to soil microbial biomass and PMN levels where hairy vetch was overseeded and incorporated as green manure by plowing before corn planting. Under the conditions of this study, the use of chemicals had little effect on microbial populations, their activity, or the cycling of nitrogen. Cropping systems-in particular, the growth of red clover or hairy vetch—profoundly influenced soil microbial biomass levels and soil pools of organic and available NO3-N during the growing season. Competitiveness of alternative management systems employing legumes as? sources for grain crops may depend largely on the grower's ability to synchronize supplies of available soil N with periods of maximum uptake by grain crops.

A survey of organic farmers in New York State identified problems in need of university research. Weed management was the most frequently mentioned problem by far, identified as significant by two-thirds of the organic farmers. Only a few other problems were listed as significant, including insufficient time for farm work, lack of markets, low prices, and lack of appropriate tools. These were cited by more than a third of the farmers. Drought, insect management, and a lack of a dependable supply of labor were cited by about one-third of the respondents. The survey also examined organic farmers' information sources. They do not use conventional sources of agricultural information, such as the extension service and conventional agricultural media, as much as books, magazines, and newsletters on organic f arming, other organic f armers, and on-farm experiments. Many respondents noted that local extension agents did not know very much about non-chemical solutions to organic production problems. They considered University Extension to be accessible, but not very useful in solving problems specific to organic farming, and had many suggestions to improve Land Grant research in organic agriculture.

Riparian forests situated adjacent to agricultural uplands were studied to test the hypothesis that riparian forests intercept and utilize nutrients lost from these uplands. Production rates, tissue nutrient concentrations, and nutrient accretion rates of woody plants were compared between sites that were contiguous to agricultural areas (test sites) and sites that were separated from agricultural areas by grass buffer zones (reference sites). Net primary production was 10,344 kg ha–1yr–1, but trees within a riparian forest that received runoff directly from a pigpen (test site) had production rates that were 2.5 times higher than the average for all other sites. Above ground forest nutrient accretion rates were also highest at the pigpen test site. Woody plants in test site forests had, on the average, higher branch wood and leaf nutrient concentrations than plants in reference site forests. The data provide evidence that riparian forest communities within agricultural environments absorb and retain nutrients lost from agricultural uplands. As such they are important components of agricultural ecosystems helping to maintain acceptable stream water quality. It is suggested that ecologically sound agricultural practice should include longterm maintenance of natural riparian vegetation zones within agricultural areas.

Agricultural pesticides and fertilizers have contaminated ground water in areas throughout the U.S. This contamination may adversely affect more than 50 million people. The cost of monitoring to determine the extent of ground water contamination in vulnerable areas is likely to exceed one billion dollars. To reduce the possibility of contamination farmers can adopt “low-input” production methods. Unfortunately, several factors inhibit farmers from adopting low-input methods. These factors include the tendency of farmers to ignore the external costs of agrichemical use, especially environmental damage, the lack of up-to-date information describing low-input farming techniques, and government support programs that indirectly discourage farmers from adopting low-input methods. The federal government can take several steps to eliminate these obstacles. Farm support programs can be changed to eliminate incentives that encourage heavy agrichemical use and to require more stringent environmental compliance to be eligible for program benefits. Taxes can be imposed on agrichemicals to offset their external costs and to provide new funds for research on alternatives. Finally, current agricultural research priorities can be shifted to emphasize low-input production methods.