bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-input, on-farm composting of high C:N ratio residues
Authors: Churchill D.B. , Horwath W.R. , Elliott L.F. , Bilsland D.M.
Published: October 2009

Farm residues with high C:N ratios are difficult to use because of their low economic value and excessive volume. Composting is ideal for upgrading such residues, but was not thought possible without co-composting or lowering of the C:N ratio. We developed a low-input method to compost perennial ryegrass straw on-farm by forming windrows and turning them either zero, two, four, or six times throughout the year with a commercial, straddle-type turner. No water beyond normal rainfall and no N other than that contained in the straw was added. The volume of straw was reduced by up to 88% with four or six turns over 20 to 24 weeks. The average internal temperature of straw windrows reached a maximum of 54°C with four turns. The ability to compost these residues will help in the development of sustainable farming systems by allowing recycling of straw waste.
Economic methods for comparing alternative crop production systems: A review of the literature
Authors: Roberts Wayne S. , Swinton Scott M.
Published: October 2009

New crop production technologies developed in response to growing concern over environmental contamination from agriculture may be neither more profitable nor higher yielding than the systems they replace, but they often reduce environmental contamination or improve soil and water quality. Systems designed with environmental objectives cannot be evaluated fairly just by productivity, which is what often is done in economic studies of alternative systems. We review 58 recent studies comparing alternative crop production systems to identify the key criteria for system comparisons, the system characteristics important in designing the analysis, and the methods most suited for comparing alternative systems.

The four key criteria we looked for in system comparisons are expected profit, stability of profits, expected environmental impacts, and stability of environmental impacts. Most economic studies of crop production focus exclusively on profitability, and incorporate neither environmental criteria nor the dynamic characteristics inherent in alternative systems. We identify promising new approaches that take account of specific environmental characteristics and attempt to balance the objectives of profitability and environmental risk management. Balanced environmental-economic analysis is most likely to be achieved by integrating biophysical simulation models with economic optimization methods to model the trade-offs among profitability, environmental impact, and system stability (both financial and environmental).
Evaluating the sustainability of alternative farming systems: A case study
Authors: Ikerd John , Devino Gary , Traiyongwanich Suthijit
Published: October 2009

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.
Comparison of organic and sustainable fed cattle production: A South Dakota case study
Authors: Taylor Donald C. , Feuz Dillon M. , Guan Ming
Published: October 2009

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.
Agricultural wind erosion and air quality impacts: A comprehensive research program
Authors: Saxton Keith E.
Published: October 2009

With the passage of the 1990 Clean Air Act came the responsibility to monitor and control particulates in the size range 10 μ and smaller (PM10). Many urban areas, particularly in the western U.S., have experienced concentrations of fugitive dust particulates from upwind sources that exceed the federal health standards. Often a significant amount of this material is generated upwind on agricultural fields, and then is entrained and transported in the regional air mass, thus degrading the air quality in downwind urban regions. Current technology cannot adequately quantify the fugitive dust emitted and transported from agricultural sources, nor specify adequate control methods. A comprehensive research plan recently was developed and initia ted for the Columbia Plateau of eastern Washington State that involves multiple disciplines and several state and federal agencies. This research has several components: characterizing the soil, vegetation and climate in a region of 136,000 km2; developing wind erosion and fugitive dust emission relationships for individual farm fields; developing and applying transport-dispersion-deposition models of the region; selecting and testing farm-level control strategies; and providing public information to both the urban and farm communities for understanding the problem and developing management plans. Simultaneous receptor analyses and public health research combine to make this a comprehensive regional research effort on fugitive dust emissions and impacts.
Advances in the production of cool season food legumes
Authors: Muehlbauer F.J.
Published: October 2009

Disease resistance, increased crop residues and altered plant and canopy design are the primary strategies being used to solve the major problems of cool season food legumes that are an integral component of cropping systems in the rainfed areas of the U.S. Pacific Northwest. Dry pea, seed pea and lentil predominate among these legumes, but there is increasing interest in chickpea. Several diseases are major hazards to production, including root rots, wilts, powdery mildew, Ascochyta blight, and viruses. Pea and lentil cultivan resistant to root rots, wilts, and powdery mildew are being developed and released. Progress is being made on resistance to v iruses transmitted by aphids, including pea enation mosaic and bean leaf roll. Development of res istant cultivars has been the principal control strategy for several diseases: Ascochyta blight of chickpea and lentil; root rots and wilts of pea, lentil, and chickpea; powdery mildew of pea; and viruses of pea and lentil. Chickpea cultivars resistant to Ascochyta blight were recently made avallable to producers. Another problem is that crop residues are insufficient to control erosion. Research is underway on genetically increasing biomass and residue production in lentil and dry pea and on producing more lignified stems and other plant parts that are more resistant to breakdown during harvesting and subsequent tillage. Increased biomass also might increase grain yields and red uce harvesting losses. The semi-leafless and woody stem traits in pea, the bushy plant types of lentil and chickpea, and diverse pod traits in all the legumes have shown promise for increased yield potential, ease of harvest, and reduced shattering losses.
Diseases of wheat and barley in conservation cropping systems of the semiarid Pacific Northwest
Authors: Smiley Richard W.
Published: October 2009

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.
GIS and simulation technologies for assessing cropping systems management in dry environments
Authors: Stockle Claudio O.
Published: October 2009

The long-term productivity, sustainability, and environmental impact of cropping systems cannot be assessed adequately using conventional agronomic experiments. This pap erdiscusses the use of computer-based technologies as support tools for this type of assessment, including crop growth simulation models, weather generators, geographical information systems, and risk assessment and economic models. Comprehensive systems that integrate these technologies are just emerging, offering great potential for the analysis of agricultural systems in the future.
Green manure as a nitrogen source for wheat in the southeastern United States
Authors: Nelson Julia B. , King Larry D.
Published: October 2009

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.
Organic versus conventional grain production in the mid-Atlantic: An economic and farming system overview
Authors: Hanson James C. , Lichtenberg Erik , Peters Steven E.
Published: October 2009

A farming systems trial has been conducted at the Rodale Institute Research Center in Kutztown, Pennsylvania since 1981. Over time, the organic rotation has changed to reflect improved knowledge and experience. The current, three-year rotation (hairy vetch/corn, rye/soybeans, and wheat) focuses on mechanical tillage for weed control and year-round live plant cover for pest control and nutrient supply. We constructed long-term enterprise budgets for the organic and conventional cash grain rotations and compared returns earned during the first years of the study, which for the organic rotation involved investment in soil capital, with returns during two later 5-year periods. The organic rotations during these two later periods produced com and soybean yields comparable with the conventional rotation, but grew higher-value crops less frequently and required more family labor and management. The differences in the profitability of the conventional and organic farming systems depend on whether the analysis includes the initial investment in building up the soil and the value of family labor.
Farm structure, market structure and agricultural sustainability goals: The case of New York State dairying
Authors: Welsh Rick , Lyson Thomas A.
Published: October 2009

This paper explores issues of agricultural sustainability in relation to arguments to sustain the family labor farm and the theoretical justification for the recent increase in smallerscale milk processors and differentiated dairy product markets. Using a population of New York State dairy farm households, we identified farm structural variables that influence farmers' use of chemical pesticides and fertilizers and their consideration of intensive rotational grazing. Milk sales, division of hired labor on the farm, and ownership arrangements are found to be interrelated and predict relative use of chemical pesticides and fertilizers within a “conventional” confinement feeding system. Marketing strategies predict production practices within a confinement feeding system less reliably but do predict whether the farm has considered adopting an intensive grazing system. Farms that have higher saks, that use hired labor more extensively, and that are not single family operations are more likely to use chemical pesticides and fertilizers. Farms that sell to differentiated markets are more likely to look favorably on an eventual switch to an intensive rotational grazing system.
Community-controlled economic development as a strategic vision for the sustainable agriculture movement
Authors: Campbell Dave
Published: October 2009

The threat to sustainability posed byglobal economic integration and the surging interest in local and regional food systems provide an opportunity to unite the diverse constituencies of the sustainable agriculture movement behind a common political and economic agenda. Neither the campaign to influence the Farm Bill nor a romantic vision of bygone agrarian communities are sufficient to broaden the movement's existing political base and deepen its influence. This paper suggests an alternative approach: grassroots organizing guided by the vision of “community-controlled economic development.” Theory linking this new paradigm in local economic development to sustainable agriculture is presented, along with practical examples from innovative networks promoted by the California Alliance for Sustainable Agriculture (CASA). I analyze the experience of CASA organizations, both separately and as an alliance, to illuminate how a strategic vision of community-controlled economic development can enable the movement to meet three difficult political challenges: holding power accountable; unifying environmental and social agendas; and developing strong leadership accountable to the movement's community base.
Alternative production systems' effects on the K-factor of the Revised Universal Soil Loss Equation
Authors: Fleming Kim L. , Powers William L. , Jones Alice J. , Helmers Glenn A.
Published: October 2009

The soil erodibility factor (K) of the Revised Universal Soil Loss Equation is currently considered a constant for all soils in the same type, regardless of production practice. To examine the effect of alternative production systems on the K-factor we compared pairs of alternatively and conventionally farmed fields on a Judson silt loam (Fine-silty, mixed, mesic Cumulic Hapludolls), a Yutan silty clay loam (Fine-silty, mixed, mesic Mollic Hapludalf), and a Wann fine sandy loam (Coarse-loamy, mixed, mesic Fluvaquentic Haplustolls). Soil cores were taken from the surface 10 cm and analyzed for organic matter, permeability, structure, and texture. These data were used to estimate K-factors from a nomograph. All soils in the study had a fine granular structure. Organic matter content and permeability were significantly higher for the alternatively managed field at every location, except for no difference in permeability on the Judson soil. However, the K-factor was significantly lower for the alternative system on the Judson soil. Of all the parameters, texture has the greatest influence in determining K-factors within the nomograph, with soils higher in silt being more erodible than soils higher in sand or clay. Thus, the influences of alternative production systems affected the Judson soil to a greater degree than other textures because of its higher inherent susceptibility to erosion. This study shows that alternative production systems affect the K-factor of some soil types and can reduce soil erodibility, and therefore should be considered when developing conservation plans.
Suppression of VAM fungi and micronutrient uptake by low-level P fertilization in long-term wheat rotations
Authors: Clapperton M. Jill , Janzen H. Henry , Johnston Adrian M.
Published: October 2009

The long-term effects of cropping practices on plant-available micronutrient concentrations in soils of the northern Great Plains of North America have not been adequately determined. We measured micronutrient uptake by wheat in a crop rotation experiment established at Lethbridge, Alberta in 1911. Phosphorus application at low rates (20 kg P ha-1 yr-1) since 1972 suppressed uptake of Zn, Cu, and Ca in the two years in which they were measured, 1991 and 1993. Vesicular-arbuscular mycorrhizal (VAM) fungi are plant symbiotic fungi that are known to increase the uptake of relatively immobile micronutrients such as Cu, P, and Zn. The functioning of these fungi is known to be affected by high-levels of P fertilization. Assessment of wheat roots showed that low-level P fertilization had significantly reduced the length of root colonized and the percentage of roots colonized by VAM fungi. The results show the importance of considering microbial ecology when assessing the effects of agricultural practices, including low-input practices, on soil productivity and crop nutrient value.
Agricultural production and nutrition
Authors: Woodward Lawrence
Published: October 2009

Although I admire the scientific discipline, I frequently find myself wondering whether the traditional approach to science involving testable hypotheses, replication, statistical significance and repeatability is adequate to meet the challenge of understanding such things as the complexity of whole ecological systems without taking apart and destroying the very object of the study.
Soil, water and crop management practices in the dryland farming regions of Turkey
Authors: Yesilsoy M. Sefik , Ersahin Sabit
Published: October 2009

Turkey is experiencing pressure to increase crop production per unit area to achieve self-reliance in food supply. The main production concern before 1970 was to increase crop yields to meet the national consumption of an ever-increasing population. During this time the country's capability to produce wheat was insufficient to meet the national demand. After the initiation of the National Wheat Research and Extension Project in 1969 the objectives of wheat production methods were changed to achieve not only higher but more economical yields per unit area. As a result the total area sown to wheat increased by only 9% between 1969 and 1990, whereas yields and total production increased 75 and 90%, respectively. This was due to developing or importing high-yielding varieties adapted to dry areas, increasing use of fertilizers and plant protection chemicals, and timely use of proper tillage made possible with modem equipment. Transferring research results to farmers and exchanging information with international scientists led Turkish scientists to establish the new goal of developing ecologically sound farming systems that could achieve higher, more economical yields per unit area. The key to this approach is to maintain or increase soil organic matter.
Profile of organic dairy farming in Ontario
Authors: Sholubi Yetunde O. , Stonehouse D. Peter , Ann Clark E.
Published: October 2009

Eight dairy farms located in western Ontario were surveyed as part of an ongoing comparative economic study. The sampled farms had been using organic methods for an average of 5.5 y ears and, therefore, were beyond the “transition” stage. Diversified cropping systems were characteristic of these farms, with most crop products (grain and straw) being used directly by the farms' livestock enterprises. Crop rotations were complex, and generally involved sequences of forages and small grains into which cover crops such as oilseed radish and red clover were integrated. Weed control, year-round soil cover, and production of feed and bedding all contributed to the design of cropping systems. Both solid and liquid manures were composted before application. No feed additives or growth hormones were used, but homeopathic remedies, probiotics, and antibiotics were commonly used. The high cost of synthetic fertilizer and concern for the environment were the main reasons given by the f armers f or adopting organic methods.
Effects of clover and small grain cover crops and tillage techniques on seedling emergence of some dicotyledonous weed species
Authors: Blum Udo , King Larry D. , Gerig Tom M. , Lehman Mary E. , Worsham Arch D.
Published: October 2009

We monitored emergence of morning-glory, pigweed, and prickly sida from seeded populations in no-till plots with no debris (reference plots) or with crimson clover, subterranean clover, rye, or wheat debris. Cover crops were either desiccated by glyphosate or mowed and tilled into the soil. Debris levels, soil temperature, moisture, pH, nitrate, total phenolic acid and compaction were monitored during May to August in both 1992 and 1993. Seedling emergence for all three weed species ranged from <1 to 16% of seeds sown. Surface debris treatments delayed weed seedling emergence compared with the reference plots. Rye and wheat debris consistently suppressed weed emergence; in contrast, the effects of clover debris on weed emergence ranged from suppression to stimulation. Gfyphosate application resulted in a longer delay and greater suppression of seedling emergence in May than in April. In 1993, plots in which living biomass was tilled into the soil were also included and monitored. Weed seedling emergence was stimulated when living biomass was incorporated into the soil. Covariate, correlation and principle component analyses did not identify significant relationships between weed seedling emergence and soil physical and chemical characteristics (e.g., total phenolic acid, nitrate, moisture, temperature). We hypothesize that the observed initial delay of the weed seedling emergence for all three species was likely due to low initial soil moisture. The subsequent rapid recovery of seedling emergence of morning-glory and pigweed but notprickfy sida in the clover compared with the small grain debris plots was likely due to variation in soil allelopathic agents or nitrate-N levels. The stimulation of weed seedling emergence when living biomass was incorporated into the soil was likely caused by an increase in “safe” germination sites coupled with the absence of a zone of inhibition resulting from tillage.
Creating positive incentives for farm composting
Authors: Kashmanian Richard M. , Rynk Robert F.
Published: October 2009

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.
Organic vegetable production in the U.S.: Certified growers and their practices
Authors: Fernandez-Cornejo Jorge , Greene Catherine , Penn Renata , Newton Doris
Published: October 2009

Organic farming systems differ fundamentally from conventional ones in their primary focus on management practices that promote and enhance ecological harmony. Organic farmers also tend to have a different socioeconomic profile. In this study, we summarize average socioeconomic characteristics and production practices of a national sample of about 300 certified organic vegetable growers from 14 states and compare them to a large sample of about 6,900 conventional vegetable growers. We also examine the specific materials used by organic growers for pest and nutrient management.

Organic vegetable growers tend to be younger, more educated, less experienced in farming, and less likely to have grown up on a farm than conventional vegetable growers, and tend to operate smaller farms. Over three-quarters of the organic vegetable growers surveyed have small operations (less than 10 acres of vegetables), and they are much younger and work fewer days in off-farm jobs than conventional small growers. In contrast to conventional marketing practices, nearly half the surveyed organic growers, and the majority of small ones, market their vegetables directly to consumers through farmers' markets and other direct marketing channels.

The organic growers rely primarily on traditional organic processes such as green manuring (legumes), animal manuring, composting, and crop rotation to supply crop nutrients, and on cultural and biological tools, including pest-resistant plant varieties, water management techniques, adjustment of planting and harvesting dates, and beneficial organisms, for pest management. Animal meal, fish products, and lime are their most frequently reported supplemental nutrient sources (14, 20 and 28%, respectively, reported using these materials), and Pyrellin EC and petroleum-based soaps were the most frequently reported supplemental pest management materials (used by 6 and 8%, respectively). The pest and nutrient materials used by the organic growers are generally consistent with current guidelines of major certification organizations that provide services to organic growers, and there is high consistency among those guidelines and national recommendations for most of these materials.
Erosion effects on soil moisture and corn yield on two soils at Mlingano, Tanzania
Authors: Tenge A.J. , Kaihura F.B.S. , Lal R. , Singh B.R.
Published: October 2009

Soil erosion is a major threat to sustaining agricultural production in Tanzania. However, quantitative information is scanty on its effects on yields of major crops for principal soils and management practices. We conducted this study to determine erosion effects on soil moisture, related properties and corn yield on Tropeptic Haplustox and Ultic Haplustalf soils at Mlingano in Tanzania. Four erosion classes (least, slight, moderate, and severe) on Tropeptic Haplustox and three erosion classes (slight, moderate, and severe) on Ultic Haplustalf were established according to the thickness of the Ap horizon under natural field conditions. Accelerated soil erosion reduced soil moisture content, soil organic carbon, available water capacity and water use efficiency. Mean volumetric soil moisture content (average of both soils) during the growing season was 23.3% for severe, 24.8% for moderate, and 25.7% for slight erosion. Mean soil organic carbon content was 1.15% for severe, 1.64% for moderate and 1.97% for slight erosion. Mean available water capacity was 2.6 cm for severe, 3.5 cm for moderate, and 4.0 cm for slight erosion. Soil bulk density and excessive degree days of soil temperature above 25°C increased with severity of erosion. These adverse changes accentuated constraints on crop growth and reduced corn (Zea mays) yield on severely eroded soil by 45% and 59% for Tropeptic Haplustox and Ultic Haplustalf soils, respectively. The water use efficiency of corn was 21.6 kg ha-1cm-1in the least eroded class versus 17 kg ha-1cm-1in the severely eroded class for the Tropeptic Haplustox, and 23 kg ha-1cm-1in the slightly eroded and 18.1 kg ha-1cm-1in the severely eroded class for Ultic Haplustalf.
Taking a pragmatic behavioral approach to alternative agriculture research
Authors: Duram Leslie Aileen
Published: October 2009

This article seeks to stimulate thought on the philosophy behind agricultural research. Pragmatism is identified as a philosophical basis for studying environmental issues that focus on human behavior. The ways in which this approach is applicable to the study of alternative agriculture are illuminated. “Behavioral pragmatists” differ from “behavioral positivists” in their aim, focus, process, and approach to research. I describe the main goals of the pragmatic behavioral approach: accepting a systems approach to study the interrelationships between humans and the environment; gaining understanding through human experiences; viewing problems as whole complex “problematic situations”; and promoting social activism and appropriate policy formulation. Combining qualitative and quantitative methods is often most effective. Pragmatism allows for holistic analysis that incorporates numerous factors that influence human uses of the environment. A specific example shows how behavioral pragmatism is effective in research on alternative agriculture.
Impact of agricultural management on nitrate concentrations in drainage waters
Authors: Goldstein Walter A. , Scully Michael J. , Kohl Daniel H. , Shearer Georgia
Published: October 2009

Nitrate contamination of surface water resulting from inputs of agricultural drainage water is a widespread problem. To learn whether alternative agricultural practices might ameliorate this problem, we measured NO-3 in water draining from three neighboring fields from 1970 to 1992. Drainage water from two fields fertilized with N exclusively as composted and liquid manure had NO-3 concentrations less than 2 ppm (20% of the Public Health Service recommended limit for drinking water). When these fields were converted to a corn/soybean rotation fertilized with anhydrous ammonia, NO-3 concentration increased about 7- to 10-fold. On a third field, corn was always fertilized with anhydrous ammonia. Changing this field from a rotation of corn, oats and hay to corn/soybean and increasing the rate of N fertilization by about 18% almost doubled the NO-3 concentration in the drainage water. The corn/soybean rotation most prevalent in the Corn Belt today resulted in high NO-3 concentrations in the drainage water, while the alternative system prevented NO-3 problems.
Assessment of legume and nonlegume ground covers on Coleoptera: Coccinellidae density for low-input pecan management
Authors: Rice Natasha R. , Smith Michael W. , Eikenbary Raymond D. , Arnold Don , Tedders W. Louis , Wood Bruce , Landgraf B. Scott , Taylor Glenn G. , Barlow Gordon E.
Published: October 2009

An annual legume cover crop was evaluated in pecan orchards to increase coccinellids that would reduce pecan aphids. Treatments were a ‘Dixie’ crimson clover and hairy vetch mixture and a grass sod. Coccinellids were abundant on the legume ground covers, but coccinellid density in the tree canopy was rarely affected by ground cover treatment. There were substantial differences between the coccinellid species collected from the legumes and from the trees. In Oklahoma, Olla v-nigrum (Mulsant)andCycloneda munda (Say)were the main species in the trees, whileHippodamia convergensGuerin, Coccinella septempunctataL, andColeomegilla maculata lengiTimberlake were dominant species in the legumes. In Georgia, Harmonia axyridis (Pallas)was the dominant species in the trees, andC. septempunctatain the legumes. Pecan aphids at two Oklahoma sites usually were not affected by cover crop treatment, but at the Georgia site, early-season aphids frequently were lower with a legume cover crop than with a grass sod. The accumulated effect of all aphid predators and parasitoids attracted to the legume aphids may have reduced the density of the pecan aphid.
Soil Improvement Following Addition of Chipped Wood from Twigs
Authors: Lalande Roger , Furlan Valentin , Angers Denis A. , Lemieux Gilles
Published: October 2009

Wood residues are applied to soils to improve their organic matter content and related biological, physical, and chemical properties. We monitored the changes in soil total C and N content, the bacterial, fungal and actinomycetal populations, and microbial biomass and activity during 20 weeks in the first season following the application of chipped wood from twigs (CWT), and as residual effects during the second growing season on a loamy soil (coarse loamy, mixed, frigid, Humic Fragiorthod) in Sainte-Brigitte-des-Saults (Québec) Canada. Wet-aggregate stability and the content of nutrients of the soil also were determined. Adding CWT stimulated the bacterial and actinomycetal populations very rapidly (within 8 weeks); in the second season the effect was less pronounced and gradually disappeared. The most significant and long-lasting effect was on the fungal population in two consecutive years of observation, with increases of up to 24-fold. This stimulation of fungi possibly was responsible for the large and significant increase in wet-aggregate stability observed in the second year. The effect of CWT on alkaline phosphatase activity and total C and N was observed only in the second season. Someimmobilization was seen only in the season immediately following residue application. The addition of the CWT also supplied micronutrients, in particular Zn, which would make it a useful source of some elements in deficient soils. Application of CWT to this soil greatly improved its quality, as revealed by its biological, chemical, and physical attributes.
Comparison of alternative pest and soil management strategies for Maine potato production systems
Authors: Gallandt E.R. , Mallory E.B. , Alford A.R. , Drummond F.A. , Groden E. , Liebman M. , Marra M.C. , McBurnie J.C. , Porter G.A.
Published: October 2009

Potato acreage and total production in Maine have declined steadily since the 1960s. In 1991, a University of Maine research team established a large-scale, long-term, comparative study of three factors that form the foundation of productive potato cropping systems: soil management, pest management, and variety choice. This study, the Potato Ecosystem Project, included 96 main plots (5.8 ha total) and near-by “component studies.” The project contrasted amended vs. unamended soil management strategies; conventional vs. reduced-input vs. bio-intensive pest management strategies; and disease and stress susceptible vs. tolerant potato varieties. Given recent concerns over resistance to pesticides and increasing costs of agricultural chemical inputs, the reduced-input and bio-intensive pest management systems provided encouraging results. Weed growth was similar in the conventional and reduced-input systems. Colorado potato beetle thresholds were exceeded less often and their densities were lower in the bio-intensive system than in the reduced-input and conventional systems. Lady beetles, which are major aphid predators, were more abundant in the bio-intensive pest management system compared with the reduced-input and conventional systems in 5 of the 6 years. Tuber yield and quality were maintained at a high level in the reduced-input system, although difficulties with plant disease, nutrient and weed management contributed to significantly lower yields in the bio-intensive pest management system. Economic analysis indicated that from 1993 to 1996, the reduced-input system had a greater return over variable cost (avg. $973 ha-1) than the conventional (avg. $890ha-1) and bio-intensive pest management systems (avg. $578ha-1). The amended soil management system achieved rapid improvements in soil quality: soil organic matter, water stable aggregates, potassium, and soluble inorganic phosphorus contents increased while requirements for synthetic fertilizers were reduced. These improvements in soil quality enhanced late-season crop vigor, canopy duration and tuber quality, and increased yields by 13% and 30% over the unamended system in 1994 and 1995, respectively, but not in 1996. Improved crop vigor in the amended soil management system also benefited weed control efforts by encouraging a more weed-suppressive potato crop. In the biointensive pest management system, in which weeds were controlled mechanically, the amended soil management system had less weed biomass than the unamended soil management system in 1994 and 1995. Conversely, the amended soil management system consistently increased flea beetle populations and, in one of two years, the incidence of Rhizoctonia. The choice of potato variety also affected pest dynamics. Total aphid density (all aphid species considered together) and almost all disease ratings were higher on ‘Superior’ than ‘Atlantic’ potato.
Comparison of conventional and organic apple production systems during three years of conversion to organic management in coastal California
Authors: Swezey Sean L. , Werner Matthew R. , Buchanan Marc , Allison Jan
Published: October 2009

Conventional and organic semidwarf Granny Smith apple production systems were compared during three years of conversion to certified organic management. Because of differences in fruit load with hand thinning compared with chemical thinning, apple tonnage was higher in the organic production system (OPS) in 1989 and 1991. The organic system was higher than the conventional system in number and weight of fruit per tree, but smaller in average fruit size. Using grower-receivedfarmgate premiums of 38% (1990) and 33% (1991) for unsorted, certified organic apples, comparative cost accounting showed greater net return per hectare for the OPS. The OPS required higher material and labor inputs in all years.

Greater terminal growth in the conventional production system (CPS) in 1991 was the only significant difference in growth indicators between systems. N was generally higher in leaf and new wood bark tissues in the CPS. P was generally higher in the leaf and new wood bark tissues in the OPS. No decline in yield was associated with increased weed biomass in the OPS. There was no difference in fruit damage caused by codling moth between production system treatments (codling moth granulosis virus and pheromone-based mating disruption vs. synthetic insecticide). In 1991, secondary lepidopterous pests (apple leafroller and orange tortrix) caused greater fruit scarring in the CPS. In all years, tentiform leafminers caused greater leaf damage in the CPS. Apple leafhopper density and leaf damage were greater in the OPS in 1990 and 1991.

Soil nutrient levels showed few significant changes during conversion to organic management. Soil bulk density and water holding capacity were useful indicators of changes in soil physical characteristics. Potentially mineralizable nitrogen andmicrobial biomass-C were more sensitive indicators of system change than total N or organic C. Two soil biological ratios, the respiratory ratio and biomass-C/total organic-C, were similar in the two production systems. Earthworm biomass and abundance increased in the OPS in the third year. The introduction ofLumbricus terrestrisinto the OPS greatly increased litter incorporation rates.
Response of corn, soybean and wheat crops to fertilizer and herbicides in Ohio compared with low-input production practices
Authors: Munn D.A. , Coffing G. , Sautter G.
Published: October 2009

Synthetic inputs have become the norm in cash grain production in the Midwest U.S., but do they really increase profitability compared with low-input production methods? This study reports a comparison of cash grain yields, quality and profitability under two management systems, low-input practices and conventional practices. The crop sequence was corn, soybean, and wheat - medium red clover green manure. Low-input practices included crop rotation, manure, and mechanical weed control. Conventional practices added starter fertilizer, side-dress N for corn, early spring topdress N for wheat and herbicides to the low-input practices. The conventional inputs increased yields in each of the five growing seasons, 1992–96. Weather, N fertilizer and weed control appeared to explain much of the yield and grain quality variation. Soil P and K levels were maintained or increased by manure use. Plant foliar analysis indicated that soil macronutrients were mostly in the sufficient range for both management systems. Economic return in excess of the additional cost of the fertilizer and herbicides averaged $172.63 ha−1 for soybean, $165.63 ha−1 for corn and minus $19.19 ha−1 for wheat over the five-year study. Fertilizer and herbicides did pay with corn and soybean, but not with wheat under the conditions of this study.
Evaluation of farmers' perceptions of soil quality indicators
Authors: Liebig Mark A. , Doran John W.
Published: October 2009

Understanding farmers' knowledge of soil quality and health is essential to ensure transfer of appropriate technology for on-farm assessments. The objective of this study was to evaluate farmers' knowledge of soil quality by comparing their perceptions of soil conditions for “good” and “problem” soils on their farms with values of soil quality indicators as determined by established assessment protocol. Twenty-four conventional and organic farmers throughout eastern Nebraska were paired within regions of similar climate, topography, and soil type and their perceptions of soil quality indicators were queried using a written questionnaire. Questionnaire data were compared directly to values of soil quality indicators and perception accuracy indices were calculated. Overall, perception accuracy of soil quality indicators did not differ between conventional and organic farmers. Farmers' perceptions of soil quality indicators tended to be more accurate for “good” soils as compared to “problem” soils. Indicators that were incorrectly estimated at a frequency greater than 33% included available nitrogen and phosphorus, soil color, degree of compaction, and infiltration rate. Despite this, farmers' perceptions were correct or nearly-correct over 75% of the time for the majority of indicators evaluated in the study. Evaluation of social and managerial factors indicated that perception accuracy of soil quality indicators declined as the time of on-farm tenure increased. Results from this study indicate that agriculturists should seek out farmers' knowledge of soil characteristics as a first iteration to pointscale evaluation of soil quality.
An alternative, low-input production system for fresh market tomatoes
Authors: Chellemi D.O. , Rhoads F.M. , Olson S.M. , Rich J.R. , Murray D. , Murray G. , Sylvia D.M.
Published: October 2009

An alternative, low-input production system for fresh market tomato was developed using strip tillage practices in conjunction with established bahiagrass pasture. The alternative system was designed to reduce the impact of soilborne pests, minimize agricultural inputs, improve soil conservation and optimize yields. Field experiments indicate that competition from bahiagrassfor nutrients within the tilled strips significantly impacted yield. Selective colonization of tomato roots by arbuscular mycorrhizal fungi isolated from field plots was observed. Damage from root-knot nematodes was minimized by planting tomato into established bahiagrass pastures. The alternative system was validated on a commercial tomato production farm in a side by side comparison with a conventional production system consisting of raised beds, fumigated with methyl bromide and covered by black polyethylene plastic. Yields were 6.5 t/ha greater under the conventional system. However, the net return was $568/ha greater in the alternative system. The results indicate that the alternative system has the potential to replace or supplement the conventional production system.
Yields and returns from strip intercropping on six Iowa farms
Authors: Exner D.N. , Davidson D.G. , Ghaffarzadeh M. , Cruse R.M.
Published: October 2009

Strip intercropping seeks to capture the biological efficiency of intercropping in traditional agricultural systems and is compatible with agricultural equipment used in the U.S. This efficiency stems from complementary use of resources by constituent crops and is a function of crop selection, strip width and orientation, weed control, and other factors. Strip intercropping requires a high level of management; further, some reports suggest the gains and losses more-or-less balance in actual production situations. These questions are best addressed by the performance of strip intercropping as implemented by farmers in production situations.

Practical Farmers of Iowa (PFI) members have worked with Iowa State University agronomists to evaluate strip intercropping. For three years six farmers compared strip intercropping to field blocks of individual crops. The strip intercrop systems employed three crops: corn, soybeans, and small grains with a forage legume underseeding. The comparison systems, crops grown in sole-crop blocks, consisted of the same three crops on four farms (planting pattern comparison) or, on two farms, just corn and soybeans in rotation (systems comparison). Yields and field operations were recorded and entered in the Iowa State University Crop Enterprise Record System (CER) to derive gross profit, total production cost, and net profit for each crop component and for each cropping system on every farm. Strip intercropping net profit was generally greater than that in field blocks, and intercropping compared favorably with CER results obtained from corn-soybean rotations on other farms around Iowa. Land equivalent ratios (LER) were usually greater than 1.0, indicating satisfactory biological efficiency. Despite occasional problems, in this set of 18 site-years strip intercropping was associated with greater stability of net profit.