The sustainability of farming systems must be assessed by their potential environmental, economic, and social performance. We present a case study to illustrate an assessment of relative sustainability that uses all three performance criteria.

We developed two scenarios for farmland currently enrolled in the Conservation Reserve Program (CRP) in Putnam County, Missouri: a conventional scenario reflecting farming practices typical of northern Missouri, and an alternative that we hypothesize to be more environmentally sound. We used selected economic and social indicators to assess whether the latter would be at least as economically viable and socially responsible as the conventional system.

Estimated direct farm income was $3.4 million for the alternative and $2.4 million for the conventional scenario. The alternative system applies more labor and management to a given land resource and may support more farming families. Estimated total community economic impacts were 25% greater for the alternative than the conventional farming scenario. CRP land, therefore, could be returned to production in a way that could significantly enhance local economic and social benefits while retaining many of the CRP's environmental benefits.

Interest in developing more sustainable cropping systems has led to renewed interest in legumes as N sources for crops. We conducted a 2-year study to compare the effects of green manure, green manure plus fertilizer, and fertilizer on wheat yield and N leaching potential. In 1991–92, wheat following corn and receiving 0, 45, or 90 kg N/ha was compared with wheat planted after plowing the autumn regrowth of red clover/johnsongrass hay (supplemented with alfalfa) that supplied 107 kg total N/ha. In 1992–93, wheat following corn and receiving 90 kg N/ha was compared with wheat following hay regrowth that either received fertilizer N at 45 kg/ha or 90 kg N/ha or was supplemented with alfalfa (total of 123 kg N/ha). Yield with only green manure averaged 65% of yield with 90 kg N/ha. Yields with green manure plus 45 or 90 kg N/ha were not different from yield with 90 kg N only. The first year, soil to a depth of 30 cm declined from as high as 40 kg/ha in the fall to less than 10 kg/ha as wheat growth increased in the spring. In contrast, concentration averaged 20 kg/ha throughout the growing season. Trends in soil inorganic N were similar the second year. Profile nitrate distribution indicated a greater potential for N leaching with fertilizer than with green manure. Soil from the site was used in a laboratory incubation study to determine the rate of N mineralization from white clover at 10°C. An average of 80% of the clover N was recovered as soil inorganic N; however, in the field study, recovery (soil inorganic N in the 0 to 30-cm zone + Nin above-ground wheat biomass) was only 21%. Supplementing green manures with spring applications of fertilizer N could decrease the leaching loss without decreasing wheat yield.

Sustainable rainfed cropping systems are needed in the Pacific Northwest of the United States to reduce or eliminate wind and water erosion, improve soil quality, and control weeds with reduced chemical inputs. A grass seed cropping system is excellent for improving soil quality and for controlling erosion, and can be grazed by sheep to produce meat and wool Tilla ge and residue management methods that create a rough surface to reduce wind and water erosion and increase water infiltration include: use of a chisel to create large clods; leaving residue on the surface; and use of the Paratill to shatter the soil to increase water infiltration with little disturbance of the soil surface. Including a legume in the rotation may help to break disease cycles, add N and C to the soil, and improve soil biological properties. The use of surface residues and tillage to control erosion and increase water infiltration may demand new approaches to weed contro I Rhizobacteria that attack the roots of weeds but not of wheat may reduce the need for chemica I herbicides. Research being conducted on these techniques in the Pacific Northwest of the United States and in other countries should soon result in guidelines for sustainable agricultural systems for the dryland, rainfed areas of the world.

Organic and sustainable fed cattle production are compared through development and estimation of two production indexes: a Producer Organic Index (POI) and a Producer Sustainability Index (PSI). The POI reflects current production standards for organically certified beef The PSI reflects a broader range of concerns, including long-term natural resource conservation and economic staying-power of cattle producers.

The study shows there may be only a loose connection between the two. The method used to develop the indexes can provide insights to beef cattle extension specialists and individual cattle producers on the strengths and weaknesses of current feedlot management practices.

Tillage, seeding and fertilizing implements for rainfed cereal production with a winter precipitation pattern have unique functional requirements. In designing and developing implements for these systems, soil and water conservation principles are critical and must be integrated into the total production system. Plant diseases, insects, weeds, environmental degradation, crop yield, crop quality and economics all may be influenced by tillage, seeding and fe rtilizing implements. Advances have been made in implements f or improved residue management, stand establishment and crop fertilization that leave more crop residue on the surface for soil and water conservation. However, they alter the seed and root zones, often resulting in uncontrolled pests, reduced yields, or increased production costs. Research is needed to integrate production implements into ecosystem management through automatic control systems for improved tillage, se eding and fertilizing. These systems should include field history mapping, real-time soil sens ors, and models to link data bases with equipment functions.

We evaluated the effects of free-range chickens and geese on insect pests and weeds in an experimental, nonchemical agroecosystem consisting of an apple orchard with intercropped potatoes. The objective was to assess the potential of these domestic bird species as biological control agents. Four insect pests were studied: plum curculio, apple maggot, Japanese beetle, and Colorado potato beetle. Chickens fed on several potential crop pests, including Japanese beetle. Although Japanese beetles were less abundant on apple trees when chickens were present, the proportion of damaged fruit was not reduced. Furthermore, chickens did not affect weed abundance or crop productivity. In contrast, geese were effective weeders. Their activities reduced weed abundance and increased potato plant growth and yields compared with a minimally weeded control. In addition, the activities of geese indirectly reduced apple fruit damage by plum curculio and increased the proportion of pest-free fruit, possibly because removal of vegetation by the geese reduced humidity at the soil surface and therefore reduced the activity of plum curculio.

Cultivars vary considerably in how they respond to moisture stress throughout crop development. In areas of the Pacific Northwest with less than 250 mm of annual rainfall, win ter wheat is under moisture stress most of the time from planting to harvest. Cultivars must be ab le to absorb moisture, germinate, and emerge under high temperature, poor seed zone moisture, and deep seed cover. Moisture stress slows emergence and seedling development and reduces most yield components, including number of tillers, seeds per spike, seeds per unit area, seed size, and seed weight per unit volume. Additionally, leaf senescence and maturity are earfy under moisture stress conditions. A cultivar cannot obtain its potential yield with less than adequate moisture; therefore, under moisture stress fewer tillers and seeds are produced. Which plant structures are reduced is determined by the growth stage of the plant during stress, while the extent of this reduction is determined by the severity of moisture stress and the genotype of the cultivar.

Diseases continue to be important constraints in wheat and barley conservation cropping systems in the semiarid Pacific Northwest. Several diseases are more damaging in highthan low-residue seedbeds, and in crops planted during early autumn to reduce soil erosion during winter, especially unirrigated winter wheat in rotation with summer fallow in low rainfall zones (250–400 mm). Changes in cropping systems in the region have made disease management and maintenance of yield goals and farm profitability more challenging because disease management often is more complex and expensive with conservation tillage than inversion tillage. Practices being developed to meet this challenge are reviewed for diseases that are particularly trouble some in conservation farming systems of the Pacific Northwest.

In “The compatibility of domestic birds with a nonchemical agroecosystem,” by Clark et al. (AJAA Vol. 10, No. 3, pp. 114–121), the statistical significance levels in Figs. 6 through 8 were incorrect; in all figures, *, **, and *** indicate p<.10, p<.05, and p<.025, respectively

Six species of ophids (Homoptera: Aphididae) are the most economically significant insect pests of wheat in Washington. Management technologies under development or in use in Washington emphasize biorational approaches, including development and use of resistance germplasm, manipulation of pest populations through cropping systems, and development of biological controls. We review wheat yield losses caused by aphids, their biological control, and the effects of conservation tillage and systemic seed treatment.

The Pacific Northwest dryland region is moving toward conservation tillage to control excessive erosion on steep slopes, but progress has been slow because of adverse effects on plant growth and yield. Fertility relations in cereal grains with conventional tillage are well known, with deficiencies occurring for nitrogen, sulfur, and phosphorus, in declining order of frequency. N and S deficiencies are more severe in conservation tillage, although the pattern of crop response to nutrient application is the same as in conventional tillage. Placing nutrients in a subs urface band near the seed is more effective than broadcasting on the surface. Higher fertility is required near developing root systems to offset greater competition from grassy weeds and more intense pressure from root-pruning soil pathogens. Conservation tillage alters soil fertility and plant growth in different ways on different landscapes. These differences must be considered to ensure tha t conservation tillage will be effective over the entire field.