bluuebunny/crossref_metadata_2025 huggingface dataset:
Legumes: Their potential role in agricultural production
Authors: Power James F.
Published: October 2009

The energy crisis of the late 1970's has raised the question of the wisdom of depending upon fertilizer nitrogen as the primary source of N input into crop production systems. While present and past price structures have favored fertilizer-N over biologically fixed N, there are a number of other benefits of legumes in a cropping system in addition to their effects on N availability. Among these are less potential for environmental degradation and improved soil physical conditions and water relations, but it is difficult to assign economic value to many such benefits. In addition to the economics of the present price structure, disadvantages of using legumes could include reduced total production and increased need for livestock in a farming enterprise (these could be considered assets from some aspects). Legumes are presently used in shortterm rotation, such as corn-soybean, or in continuous corn with a legume winter cover crop. These systems are finding widespread use and offer the producer many benefits, as well as helping to solve several major environmental problems associated with N use in agriculture.
Riparian forest communities and their role in nutrient conservation in an agricultural watershed
Authors: Fail Joseph L. , Haines Bruce L. , Todd Robert L.
Published: October 2009

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.
Traditional management of a hillside agroecosystem in Tlaxcala, Mexico: An ecologically based maintenance system
Authors: Mountjoy Daniel C. , Gliessman Stephen R.
Published: October 2009

Traditional agricultural systems are increasingly being recognized as important examples of ecologically sustainable production methods and as such deserve agroecological attention. In a study of terrace agriculture in Tlaxcala, Mexico, the authors identify several management features which have been used for as long as three thousand years. The theoretical approach employs the notion of open versus closed agroecosystems for examining soil and water management, species diversity, and nutrient cycling. In the traditional system, conservation of existing resources is the distinctive feature whereas, with modern techniques, the emphasis is on replacement. The most distinctive feature of the Tlaxcalan agroecosystem is the terrace/cajete complex which serves to contain heavy downpours and trap eroded soil, ensures diversity of plant species, and traps and concentrates nutrients. The functioning of this traditional system is endangered by new management strategies that have responded to external political, economic and social pressures for change. This article discusses the ecological repercussions of these new practices and suggests ways that appropriate elements may be integrated to promote the sustainability of food production.
Biological control of arthropod pests: Traditional and emerging technologies
Authors: Hoy Marjorie A.
Published: October 2009

Biological control of arthropod pests has a long history of useful practical application. Parasites, predators, and pathogens have been employed in many cases to control pest arthropods in an efficient, cost-effective, and permanent manner. The traditional tactics used in biological control (classical, augmentation, and conservation) remain vital and valuable tools in the biological control of pests for agricultural crops, range lands, forests, and glasshouses. New technologies offer promise. One emerging technique involves the genetic improvement of natural enemies of arthropods through selection, hybridization, or recombinant DNA technology.
Biological control of weeds
Authors: Templeton George E.
Published: October 2009

A shortage of effective, non-chemical pest control measures is a major constraint to more widespread adoption of sustainable agricultural practices. Overcoming this constraint with biological pest control tactics appears to be an attainable goal but will require substantial public sector support. Biological agents that are self-perpetuating do not offer profit incentive to private industry. On the other hand, microbial pesticides, which do require annual application, often are so highly specific for particular pests that the private sector is unable to risk venture capital for their development. Collaboration between public- and private-sector scientists is essential for biological pesticide development. In the U.S., a model working relationship for technology transfer between the private and public sector has been achieved with two commercial mycoherbicides, Collego™ and DeVine™. The model illustrates the strengths of the public sector for creating and storing fundamental knowledge of biological interactions at the organismal and ecosystem levels, also the capability of the private sector for large-scale production of fungi, for drying labile, living products, for effective patent protection, for satisfying EPA registration requirements, and for the commercial distribution, marketing and servicing of agricultural products. From three perspectives-biological, technical, and commercial—the success of Collego™ and DeVine™ has provided a definite step in the quest for low-cost weed control methods that are not hazardous to the environment nor in ground water. These successes also provide a model for an approach to reducing the dependence of agriculture upon chemical herbicides, the most extensively used chemical pesticides in agricultural production, likewise a useful insight toward technology that can lead to more widespread adoption of low-input, environmentally compatible and sustainable agricultural production.
Economics of biological control of pests
Authors: Carlson Gerald A.
Published: October 2009

Biological pest control techniques usually have identifiable costs and constraints that they must overcome before they will be adopted by farmers. Many biological control agents are developed in the public sector and need economic assessments at an early stage. The methods often have hidden costs related to farm labor adjustments or initial costs of development. Living biological controls frequently escape, and they may be disrupted by pesticides, regulations, or farm commodity programs. Pest control registration procedures and small markets also present obstacles. Area-wide implementation programs and changes in incentives for researchers may speed development and adoption of biological controls.
Biological recycle farming in the People's Republic of China: The Doudian Village experiment
Authors: Xu Cheng , Simpson James R.
Published: October 2009

An explanation is provided of why and how one group of researchers in a Chinese village setting came to focus on what the authors call biological recycle farming. An explanation of applied agricultural research in China is provided. One conclusion reached is that application of research at the village level was largely successful because it was founded on community development principles. Another conclusion is that food production in very marginal Chinese villages can be increased significantly. While the alternative approach discussed cannot be exported wholesale to many other countries of the world, the concepts are very useful for international economic and agricultural development.
Breeding crop varieties for low-input agriculture
Authors: Atlin Gary N. , Frey Kenneth J.
Published: October 2009

Few plant breeding programs involve attempts to develop varieties specifically adapted to low-input cropping systems. Plant breeders generally select varieties in highly fertile, weed-free, densely seeded environments. However, alleles needed for achieving maximum yield in low-input environments often differ from those required in highinput conditions. Thus, when effective selection can be undertaken under low-input conditions, breeding programs specifically targeted at low-input environments should produce the best varieties for those environments. Experimental protocols for identifying such situations are described in this review. These involve (a) testing breeding lines under low- and high-input conditions, (b) estimating both the degree to which yields from the two types of environment are controlled by the same alleles and the relative accuracy with which superior genotypes can be identified in low- and high-input environments, and (c) predicting the direct and indirect responses to selection at each input level. On the basis of published data, it seems feasible to develop corn hybrids specifically adapted to production with lower rates of N application than are now commonly used in the United States.
Profits and risks of using crimson clover and hairy vetch cover crops in no-till corn production
Authors: Ott Stephen L. , Hargrove William L.
Published: October 2009

Winter legume cover crops are receiving increasing attention from agronomists and farmers as a source of nitrogen for summer crops. While agronomists are continually providing new technical information on using legumes as a nitrogen source, little is known on the economics of their use. Previous economic research on legume cover crops has focused mainly on budgeting analysis. In the present work, a twofactorial experiment was designed to test the use of legumes as a nitrogen source for corn(Zea mays L.)in north Georgia. The first factor was winter cover crop with treatments being crimson clover(Trifolium incarnatumL.),hairy vetch(Vicia villosaRoth),wheat(Triticum aestivumL.), and no cover crop or winter fallow. The second factor was nitrogen (N) fertilizer applied at five different rates: 0, 25, 50, 100, or 200 pounds per acre. For each combination of the two factors, mean yield and yield variance were determined. Results indicated that legume cover crops increased both average corn yield and yield variance. The greater yield variance from the use of legume cover crops increases economic risk. Risk-averse farmers must be compensated for increased profit variance by higher average profits. A safety first method was used to evaluate the tradeoff between average profit and profit variance for the risk-averse individual The results showed that hairy vetch with 50 pounds of N per acre was the best combination of cover crop and fertilizer rate for risk-neutral farmers. For risk-averse farmers, hairy vetch without any nitrogen fertilizer is preferred.
High-yield aquaculture using low-cost feed and waste recycling methods
Authors: Schroeder Gerald L. , Serfling Steven
Published: October 2009

Conventional, low-yield aquaculture methods use earthen, standing water fish ponds that typically are stocked with 0.5 to 2 fish/m2and produce 3 to 10 tons of fish/ha/year using refined feeds. At higher fish stocking densities and fish yield, production of metabolites and residues exceeds such a pond's natural recycling capability, so that a higher rate of flushing is required. This wastes water and valuable nutrients and creates a potentially polluting effluent In an alternative system, by increasing the rate at which the metabolites and feed wastes are microbially processed within the culture system, production rates exceeding 500 tons of tilapia fish/ha/year have been attained with less than 0.5 percent water change daily. In preliminary experiments in this closed bioconversion system, we have replaced all formulated feeds with agricultural residues and fertilizers, which are converted into protein by intense microbial processing. The rate of fish growth indicated that much or possibly all the feed requirements of tilapia grown in this type of closed, densely stocked system can be satisfied by intense cultivation of heterotrophic microbes.
CREST farming: A strategy for dryland farming in the Northern Great Plains-Intermountain Region
Authors: Sims James R.
Published: October 2009

In the region concerned, agriculture is conducted under stress from several difficult circumstances. These difficulties include, among others, drought, a limited length of growing season, harsh winters, insect pests and diseases, and weeds. The present paper describes several measures that are taken to combat these problems. Control devices include legume green manure/cereal rotations, use of drought-resistant and insect-resistant varieties, and early seeding of spring grain to cause maturation before the period of maximum drought risk. Recently, a wide range of legumes has been grown on a limited basis in the region, and further progress toward improved legume varieties is being pursued.
Toward a sustainable agriculture: Need for clarification of concepts and terminology
Authors: Keeney Dennis R.
Published: October 2009

Recently there has been a change in thinking among many agricultural leaders and researchers toward a major focus on agricultural sustainability. To make progress toward such sustainability requires a clear delineation of its concepts and components. In this paper, I attempt to clarify relevant concepts and terminology in an effort to facilitate communication and cooperation. I also recognize, however, the intense feelings involved in these definitions. More satisfactory definitions will come in time as research and practice continue.
The role and contributions of animals in alternative agricultural systems
Authors: Baker Frank H. , Raun Ned S.
Published: October 2009

Livestock are important components of agricultural systems. In the U.S., one-half of total agricultural receipts come from the sale of livestock. They are the harvestors of range plants, forages, and crop residues; they level out the effects of the seasonally and variability of rainfall; they cushion disruptions in the trade and marketing of feed grains; they counteract declining soil fertility and soil erosion; and they contribute to the efficient year-round use of farm labor. Unfortunately, farmers are often not inclined to adopt alternative animal agriculture systems despite the advantages they may offer. Constraints that may be encountered include possibilities of reduced short-term profits, difficulties in adapting available technology to alternative farming systems, difficulties in shifting from specialized crop or livestock farms to crop/livestock farms, and the increased needs for labor and management. Some actions needed in the U.S. to improve livestock production in alternative farming systems are: the establishment of government policies to promote the shift of marginal lands to soil and water conserving crops and the incorporation of pastures and forages in crop rotations; research to improve the utilization by ruminants of ligno-cellulosic feeds (pastures, forages, crop residues); and programs to improve range and forest management and to lead to the development of systems that optimize the use of forages for the production of nutritionally desirable lean beef.
Policy barriers to sustainable agriculture
Authors: Young Douglas L.
Published: October 2009

U.S. agriculture, which has developed in a mixed environment of private initiative and government support, is very successful by many measures. American farmers produce record levels of food and fiber per farm worker at very low budgetary cost to consumers. Recently, however, concern about resource depletion and agrichemical pollution has caused critics to question the environmental sustainability of the agricultural production system. Furthermore, pressures to trim the growing contribution of agricultural subsidies to the national budget deficit have led legislators and others to question the sustainability of the federal farm programs. Low agrichemical input or sustainable agricultural practices, such as nitrogen-fixing legumes in rotation with cereals, could reduce environmental damage. The selectivity and structure of historical farm programs, however, have economically favored conventional systems. Farm programs subsidize only about half the total value of agricultural products. Feed and food grains, cotton, and dairy products receive the lion's share of payments. Soil-building crops like forage legumes, most edible legumes, hay, and pasture are excluded. Secondly, the structure of commodity programs favors intensive production of program crops supported by high fertilizer and pesticide applications. This incentive emanates from the policy of computing the farm-wide deficiency payment for a program crop proportionately to the farm's historical “base” acreage and “established” yield for the crop. The leading farm program crops of corn, wheat, cotton, and soybeans occupied slightly over 60 percent of cropped acres and received at least 65 percent of all U.S. agricultural pesticides and fertilizer in the mid 19809s. Despite budget pressures and environmental concerns, near term termination of farm programs or decoupling them from production of particular commodities is unlikely. Fears about aggravating financial stress, reducing land values, and harming agrichemical supply businesses in program crop-growing regions will promote cautious incremental change. Recent promising signs of “creeping decoupling” include the 1986 freeze on established yields, the gradual reduction in target prices, the permitting of multi-year grass or legume plantings as set aside acreage, and the loosening of base acreage restrictions within the 1988 Drought Relief Bill.
Sustainable agriculture: Policy options and prospects
Authors: Benbrook Charles M.
Published: October 2009

Complex policy issues and tradeoffs will arise in crafting the 1990 or 1991 Farm Bill. Efforts to advance progress toward sustainable agriculture production systems could arise in the farm bill's commodity, conservation, and research titles. Key definitional issues are highlighted here, as well as water quality issues and the impact of ongoing GATT negotiations in the context of increasing global demands on American agriculture.
Effects of conversion to organic agricultural practices on soil biota
Authors: Werner Matthew R. , Dindal Daniel L.
Published: October 2009

In the fifth year of an agricultural conversion experiment in Pennsylvania, we studied the soil biological community under three treatment regimes planted with corn: organic-manure, organic-legume, and a conventional system. The organic treatments consisted of complex crop rotations, cultivations, and organic matter inputs to control pests and maintain soil fertility. The conventional system consisted of a simple corn/soybean rotation with synthetic fertilizer and pesticide inputs. High rates of CO2evolution (a measure of potential microbial activity) in the organic plots corresponded with high levels of organic matter input. Soil nematodes were most abundant in organic plots, although seasonal patterns differed between the two organic treatments. Soil microarthropods were dominated by fungivorous Prostigmata mites, which reached peak abundance in organic plots two to five months after organic matter incorporation. Oribatid mites, which were rare throughout the study, followed the same pattern of abundance in each treatment and were probably most influenced by tillage disturbances. Predatory Mesostigmata were generally more abundant in organic plots. Surface-dwelling Collembola were abundant briefly in the spring, but soil-dwelling species dominated numerically throughout the cropping season. Spring tillage appeared to have a strong negative effect on earthworm populations in all plots. Small earthworm species became abundant in organic-manure plots during the summer. Larger earthworm species were abundant in organic-legume and conventional plots after the autumn harvest, when crop residues covered the undisturbed soil The systems-level nature of the Conversion Project experiment makes it difficult to identify cause-effect relationships. The data do suggest that organic amendments tend to enhance soil biological activity, while tillage disturbances tend to disrupt the biotic community.
The influence of conventional and compost fertilization on phosphorus use efficiency by broccoli in a phosphorus deficient soil
Authors: Buchanan Marc A. , Gliessman Stephen R.
Published: October 2009

Phosphorus (P) accumulation and use efficiency by broccoli(Brassica oleraceaevar. italica)were observed in a field plot study comparing management with varying levels of conventional fertilizer, differing composted amendments, and a combination of inorganic Nitrogen (N) and compost sources. Total P accumulation and yield were highest in treatments incorporating solely compost or vermicompost applications of 30 tons ha–1. Applications of N as ammonium sulfate caused significant soil acidification, which lowered yield and P uptake. Poor growth and yield were probably related to manganese toxicity effects on root extension and activity. These effects were partly ameliorated in treatments combining fertilizer N and compost sources. As a result, yield in plots receiving 75 kg N ha–1as ammonium sulfate and 8.9 kg P ha–1as compost was nearly identical to highest experimental yields. Phosphorus use efficiency was highest in this treatment incorporating fertilizer N and compost. Generally, P use efficiency tended to decline at the highest levels of fertilization. We propose that intensive organic matter management may be a good way to improve P use efficiency by vegetable crops.
Policies, programs, and regulations to support the transition to sustainable agriculture in Canada
Authors: MacRae Rod J. , Hill Stuart B. , Henning John , Bentley Alison J.
Published: October 2009

The development of political strategies in Canada to support the transition from conventional to sustainable agriculture has been limited by the absence of a comprehensive conceptual framework for identifying the most critical policies, programs, and regulations. In this paper, we propose a framework that uses an efficiency/substitution/redesign spectrum to categorize both sustainable fanning systems and government activities. The framework is then used to identify a diverse range of short, medium, and longterm strategies to be pursued by governments in Canada to support the transition. Strategies discussed include research, diffusion, and training; market development; and safety net programs and tax provisions. Finally, the implications and implementation of the redesign concept for food production, processing, and distribution are outlined.
Ground water contamination from agricultural sources: Implications for voluntary policy adherence from Iowa and Virginia farmers' attitudes
Authors: Halstead John M. , Padgitt Steven , Batie Sandra S.
Published: October 2009

Contamination of ground water from agricultural sources has been documented in a majority of the contiguous United States. In this study, we examine the potential for voluntary adoption of management practices that reduce risk of ground water contamination and discuss how f arm operators' attitudes regarding the environment might affect the success of voluntary programs. Farmers' behavior and attitudes in Rockingham County, Virginia, and Big Spring Basin, Iowa, reveal that both groups consider the ground water issue to be a serious problem to which they are contributing. This awareness is a significant first step in prompting consideration of management practices that reduce the threat to ground water quality. We also found that the “worst offenders”—that is, farmers applying nitrogen well above agronomic recommendations-were those with the least concern about the problem. If major shifts in farming practices are to occur voluntarily, major incentives or disincentives are needed. Even though the concern about ground water quality is high, the documented risks perceived by farmers are not strongly convincing. The economic incentives for change are questionable at best. Voluntary adoption of best management practices is only one of several policy options. Ultimately, policies designed to reduce ground water contamination may need a mix of strategies, including economic incentives and disincentives, zoning and land use restrictions, environmental regulations, and bans on agricultural chemicals.
Participatory strategies for information exchange
Authors: Francis Charles , King James , DeWitt Jerry , Bushnell James , Lucas Leo
Published: October 2009

Complexity and rapid change in the agricultural industry are pushing us toward more participatory systems of information development and exchange. These changes are driven by a rapidly evolving information environment, with a multiplicity of sources and different clients, and by a technological revolution in communications equipment. At the same time, scientists and farmers are becoming increasingly aware of the complex biological interactions that occur in cropping systems and how these are connected with the overall ecosystem. We are expanding our time and space frame of reference. To address tomorrow's challenges, it will be important to blend the efforts in research and extension, to include farmers as full participants in the planning, execution, and interpretation of experiments, to explore new directions such as model farms and master farmers, and to develop creative educational approaches to encourage practical problem solving. Collaborative efforts of universities, industry, farmer groups, and environmental organizations will be needed to fully empower the individual farm manager to make rational and environmentally sound production decisions in the future.
Responding to farmers' needs: An evolving land grant perspective
Authors: Gardner John C.
Published: October 2009

Farmers and the agricultural research and extension community at the land grant universities have experienced an evolving relationship. The current call for reform in publicly sponsored agricultural research and extension is built upon more than a century of dialog. If specialization and discipline-oriented research is to continue, the ecosystem-based knowledge of the farmer will become increasingly valuable. Involving farmers more actively in research and education could be achieved in several ways. Outside the land grant system, nonprofit agricultural research and demonstration organizations are being developed. Within the public system we need a renewed emphasis on extension at the local level and a revitalized applied research effort aimed at solving problems of the agricultural ecosystem rather than single disciplines. A dynamic and resourceful agriculture could result from including the farmer as a full partner in land grant research and education.
Involving farmers in agricultural research: A farmer's perspective
Authors: Thornley Kay
Published: October 2009

Farmer involvement in agricultural research is limited by inadequate funding, institutional policies and hierarchies, disciplinary specialization, and incompatible personalities. Additional barriers include academic emphasis on carefully controlled experiments, research priorities driven by personal interest, and farmers' reluctance to disclose trade secrets. Priorities for research conducted with public funds should be identified through a democratic process involving representatives from all sectors of agriculture. A broad, multidisciplinary, systems approach to agricultural research is needed; and farmers and researchers should consider long-term implications of projects. Better balance needs to be achieved between basic and applied research, and both should encourage innovation within the context of democratically determined research priorities. Opportunities abound for involving farmers in research as providers and recipients of information, as participants in determining priorities and ensuring practicality of methods, as collaborators and/or subjects for on-farm investigations, and as project evaluators. Farmers also need to take more initiative in getting involved in the political processes that set the stage for agricultural research.
Meeting the challenges to agricultural research and extension
Authors: Sauer Richard
Published: October 2009

The public agricultural research and extension system has provided the foundation for great improvements in U.S. agricultural production. However, our incomparable productivity has brought with it serious problems. These problems have also led to a rapidly changing perception about both agricultural scientists and today's conventional agriculture. Critics are placing high on the agenda of the agricultural research and extension establishment the need for alternative technologies that are more sustainable and less exploitative of our resources. The growing demand for alternative systems offers challenges for every part of the establishment-research and extension administrators, branch station/research center directors, and faculty. These challenges and how they should be met are discussed. Alternative systems will become the conventional agriculture of tomorrow.
Managing nitrogen for sustainable corn systems: Problems and possibilities
Authors: Magdoff Fred
Published: October 2009

Excessive nitrogen fertilizer use in corn production has resulted in widespread nitrate pollution of ground water and economic losses for farmers. In addition, reliance on nitrogen fertilizers produced with large amounts of fossil fuels may not be economically or environmentally sustainable in the future. Although leaching of significant amounts of nitrate to the ground water is inherent in growing corn, several techniques are available for more environmentally and agronomically sound management. The following management practices are discussed in this article: sidedress as the main method of N fertilizer application; the pre-sidedress (Magdoff) nitrate soil test; farm-based nitrogen sources (manures, green manures, and rotations with sod crops); cover crops for lowering profile nitrate during the most likely period for leaching; and the end of season stalk nitrate test.
The growing importance of food safety to Japanese consumers and its implications for United States farmers
Authors: Jussaume Raymond A.
Published: October 2009

Consumer cooperatives in Japan, which is by far the United States' largest overseas market for agricultural commodities, expanded rapidly in the 1980s. Their recent success, according to Japanese reports, has been due to their responsiveness to increasing consumer demand for foods produced with minimal use of petrochemical inputs. I present data that confirm this claim by showing that the high level of concern that Japanese consumer cooperative members have about food safety is the main reason they give for joining cooperatives. I then discuss the significance of this trend for American agriculture, in particular whether Japanese consumer cooperatives could become a marketing channel for Americans who specialize in producing food with less intensive use of agricultural chemicals.
Integrating social, environmental, and economic issues in sustainable agriculture
Authors: Allen Patricia , Van Dusen Debra , Lundy Jackelyn , Gliessman Stephen
Published: October 2009

In the past several years, researchers, educators, policymakers, and activists have initiated sustainable agriculture programs and efforts the world over. This development has sometimes been accompanied by a sense that it is time to stop discussing sustainability at a conceptual level and get on with the work of making agriculture sustainable. Our perspective is that it is critical to pursue a comprehensive definition of sustainability in order to set sustainable agriculture priorities and ensure that sustainable agriculture takes a path that does not reproduce problems of conventional agriculture. In this paper we briefly review some popular definitions of sustainable agriculture and find that their focus is primarily on farm-level resource conservation and profitability as the main components of sustainability. Others have challenged this approach for either not examining the social aspects of sustainability or for containing an implicit assumption that working on the environmental, production, and microeconomic aspects of sustainability will automatically take care of its social aspects. We propose an expanded conceptualization of sustainability—one that focuses on the entire food and agriculture system at a global level and includes not only environmental soundness and economic viability, but social equity as well. In this perspective, issues such as poverty and hunger are as central to achieving agricultural sustainability as those of soil erosion and adequate farm returns.
Understory cover crops in pecan orchards: Possible management systems
Authors: Bugg Robert L. , Sarrantonio Marianne , Dutcher James D. , Phatak Sharad C.
Published: October 2009

Annual legumes and mixtures of annual legumes and grasses can perform several functions as understory cover crops in pecan orchards, such as providing nitrogenrich organic matter to improve soil fertility, or by sustaining lady beetles and other arthropods that may aid the biological control of pecan pests. Remaining questions concern selection of appropriate plant materials; whether to use cover crops singly or in mixtures; how to ensure reseeding as well as a substantial N contribution; whether, when, and how to use mowing and tillage; and fertilization options. Different considerations apply when dealing with cool- vs. warm-season cover crops. With minor adjustments, growers could adapt present cultural practices to include cool-season cover crops. These could be used throughout the orchard, by establishing appropriate self-reseeding species and avoiding both excessive mowing and indiscriminate placement of N-rich fertilizers. Within alleys, alternating 2-m strips of cool-season cover crops could be tilled in mid to late April or allowed to mature. The tilled strips would supply N to pecan trees immediately, whereas the adjoining untilled (remnant) strips could be mowed after seed is mature, to ensure dispersal of seed and reestablishment of cover crops over the entire alley. Cool-season annual legumes that die or are killed in late spring will probably furnish N and other nutrients at a suitable time, particularly in orchards with sprinkler irrigation. Warm-season cover crops, if desired, should be restricted to alleys to reduce possible competition with pecan. Alleys provide better illumination than do tree rows during periods when pecan trees are in leaf, and the tillage mentioned above will encourage emergence of warm-season cover crops. If these die or are killed in late summer or early fall, timing of N release may not be optimal, in the absence of adequate irrigation. Many options and tradeoffs need to be explored before choosing a cover-crop system. Attimes, several objectives may appear to conflict, and even delicately-managed mixtures of species may not fulfill all the desired functions.
Cover crop management effects on soybean and corn growth and nitrogen dynamics in an on-farm study
Authors: Karlen D. L. , Doran J. W.
Published: October 2009

Combining cover crops and conservation tillage may result in more sustainable agricultural production practices. Objectives of this on-farm study were to quantify effects of cover crops on growth and nitrogen accumulation by soybean [Glycine max (L.) Merr,] and corn (Zea mays L.) on a Nicollet loam (fine-loamy, mixed, mesic Aquic Hapludoll) near Boone, Iowa, Our farmer-cooperator planted soybean in 1988 using ridge tillage into an undisturbed strip with a hairy vetch (Vicia villosa L. Roth) cover crop and into a strip where previous crop residue and a negligible amount of cover crop had been incorporated by autumn and spring disking. In each strip, we established four plots for soil and plant measurements. Our cooperator planted corn on the same strips in 1989 into a cover crop that consisted of both hairy vetch and winter rye (Secale cereale L.). We determined the source of N accumulated by the corn by applying 67 kg N/ha of 15N depleted NH4NO3 fertilizer. In the absence of cover crops, early season soil NO3-N levels in the top 30 cm were higher, and corn growth and N accumulation were more rapid. At harvest, the corn grain, stover, and cob together accounted for 36 and 39 percent of the 15N fertilizer for the ridge tillage and disked treatments, respectively. We suggest that lower net mineralization of organic matter or greater denitrification losses before planting reduced the availability of soil N, This created an early season Nstress in corn grown with cover crops that was not overcome by broadcast fertilizer N applied three weeks after planting. Our on-farm research study has helped focus continuing efforts to determine if non-recovered fertilizer N is being immobilized in microbial biomass, lost by denitrification, or leached below the plant root zone.
A survey of organic produce purchases and related attitudes of food cooperative shoppers
Authors: Goldman Barbara J. , Clancy Katherine L.
Published: October 2009

We surveyed shoppers at a food cooperative in New York state to measure the relationship between organic produce purchases and attitudes related to pesticide use in agriculture, food costs, and other factors affecting produce buying. Two-fifths of the co-op shoppers surveyed usually or almost always purchased organically grown produce, and one-third were somewhat or very likely to pay 100 percent more than conventional produce for residue-free produce. Those who usually or almost always purchased organic produce were less concerned than other shoppers about price when they shop for produce, had higher levels of concern about food safety, and were less concerned about insects and surface blemishes on produce. There was no relationship between income and frequency of organic purchases. Most shoppers were concerned about pesticide residues in produce, but a high level of concern appeared necessary to affect the frequency of organic purchases. In their support of organic agriculture, respondents ranked environmental protection higher than consumer protection. Educators should emphasize both the environmental and food safety benefits of organic farming to consumers.
Comparison of the effect of leaf rust on the grain yield of resistant, partially resistant, and susceptible spring wheat cultivars
Authors: Singh R. P. , Payne T. S. , Figueroa P. , Valenzuela S.
Published: October 2009

Three hypersensitive resistant, six partially resistant (slow rusting), and one susceptible spring bread wheat (Triticum aestivum L.) cultivars were evaluated for grain yield, test weight, and kernel weight under artificially created epiphytotics of leaf rust disease (caused by Puccinia recondita f. sp. tritici) with and without fungicide protection for three years. Rusted plot yields were 4 percent lower compared to fungicide-protected plot yields for cultivars with hypersensitive resistance. In rusted plots, grain yield and kernel weight averaged 8 percent less for cultivars with partial resistance but varied from 2 to 20 percent less depending on cultivar. The susceptible check cultivar, Yecora 70, averaged 27 percent lower grain yield, 22 percent lower kernel weight, and 6 percent lower test weight in rusted plots. Slight reduction in test weight was also observed for each cultivar. Losses in grain yield could, therefore, be reduced to levels similar to those of hypersensitive resistant cultivars by the use of partial resistance. We discuss the sustainability of partial genetic resistance to leaf rust. Since partial resistance is expected to be durable, and since rust levels and effects on yield in farmers' fields are likely to be less than in this experimental plot study, partial resistance should give long-lasting resistance at a negligible cost in yield that is insufficient to justify the use of fungicides.
Green leaf manuring as an alternative nitrogen source for castor bean on marginal soils of India
Authors: Reddy G. Subba , Venkateswarlu B. , Vittal K. P. R. , Shankar G. R. M.
Published: October 2009

Chemical fertilizers are used only in a limited way under dry farming conditions in India because of their high cost and the risk of crop failures due to drought Several alternative strategies are being evaluated to reduce the cost of supplying N to castor bean without adversely affecting yield. We report the results of a two-year study on the possible replacement of fertilizer nitrogen by green leaves from Leucaena leucocephala for production of castor beans on a low fertility Alfisol Bean yield and dry matter production were significantly higher when 50 kg N/ha was applied as green leaves compared with 50 kg N/ha as urea. Among substitution levels, 37.5 kg N/ha as green leaves at planting followed by 12.5 kg N/ha as urea at 45 days after planting was found to be the most effective combination. Across all the substitution levels, addition of nitrogen as green leaves at planting was found to be better than application at 45 days after planting. Nutrient and water use efficiencies were higher when the N was applied as green leaves compared to urea. Nitrogen use efficiency was higher for green leaves than for urea under limited rainfall conditions. The overall data indicated that 75 percent of the fertilizer N requirement of castor bean can be supplied by leaves of Leucaena leucocephala when applied at planting.
Runoff impoundment for supplemental irrigation: An economic assessment
Authors: Scrimgeour F. G. , Frasier G. W.
Published: October 2009

Water harvesting technologies capture surface water runoff and recycle it for productive use. Despite the long history of water harvesting and the renewed interest in many places in the world, the technology has not been widely adopted in the United States, in part because of a lack of understanding of its economic benefits. We developed a simulation model for the economic evaluation of water harvesting systems that combines agronomic, engineering, and economic factors and daily meteorological data. The simulation model was used to investigate the economic feasibility of using a water-harvesting, supplemental irrigation system for grain sorghum production over a 44-year period at two locations in Texas. Water harvesting combined with supplemental irrigation was most successful where the precipitation is the highest. However, the net benefits were extremely variable from year to year. The modeled technique could not take advantage of the potential additional water in the wet years and did not harvest sufficient water in dry years to make water harvesting more economically attractive than conventional dryland farming. This does not mean that runoff farming cannot be of economic benefit, depending on local conditions. Widespread adoption of the technology is constrained by the limited profit potential the variability of the profits, and the knowledge required to use the technology successfully. The simulation model was a useful and simple tool for dealing with the complexity of the issues.
The economics of collecting chaff
Authors: Olfert M. R. , Stumborg Mark , Craig Wayne , Schoney R. A.
Published: October 2009

Chaff, a by-product of cereal and oilseed production that is largely treated as waste product, may have significant economic value as a ruminant feed, and its collection and removal may reduce herbicide usage and tillage. We surveyed fifty farms located throughout the Brown, Dark Brown, and Black/Grey Wooded soil zones of Saskatchewan to determine the costs and benefits of their chaff collection systems. Benefits measured or estimated included both the feed value of chaff and agronomic benefits in the form of reduced tillage and herbicide requirements. Costs measured were for equipment and machinery ownership, maintenance and operation, including labor. The survey responses showed that, regardless of the type of collection system utilized, feed-related benefits outweighed the costs under the stated assumptions about prices and methods of assigning costs. Agronomic benefits alone also were sufficient to offset chaff collection costs. The net benefits of chaff collection are related to both the quantity of chaff collected and the distance the material is transported.
Sustainable agriculture: The wildlife connection
Authors: Robinson Ann Y.
Published: October 2009

Wildlife and fish have much to gain from the movement toward alternative, sustainable agricultural practices. Interrelated reasons for the habitat improvements to be expected from a change to sustainable systems include reduced use of agricultural chemicals, better care of the soil, and reintroduction of greater landscape diversity. The most well-documented benefits would result from reduced use of agrichemicals, which often are toxic and frequently change the structure and composition of available food and cover. The wildlife benefits of erosion prevention and landscape diversification are less well-documented but may be as significant for habitat improvement. The opportunities to enhance habitat using sustainable farming methods are beginning to receive increased attention from wildlife professionals. As a result, efforts are under way to expand use of sustainable methods on farmlands managed by the U.S. Fish and Wildlife Service.
An economic comparison of conventional and reduced-chemical farming systems in Iowa
Authors: Chase Craig , Duffy Michael
Published: October 2009

Labor requirements, production costs, yields, and economic returns were evaluated for conventional and reduced-chemical cropping systems in northeast Iowa from 1978 to 1989. Continuous corn (C-C) and corn-soybean (C-Sb) rotations represented the conventional system; a corn-oat-meadow (C-O-M) rotation represented the reducedchemical system. The C-C and C-Sb rotations used both commercial pesticides and fertilizers. The C-O-M rotation used manure for fertilization and applied pesticides only in emergencies. Operations for all systems were implemented by one farm manager. The C-Sb rotation had the highest corn yield over the 12-year period, and the C-O-M rotation the lowest. The corn within the C-O-M rotation, however, produced the second highest average return to land, labor, and management. With costs of production substantially lower than the conventional systems, the C-O-M corn crop had competitive returns despite lower yield. The C-Sb average return to land, labor, and management was significantly higher than for the other systems. Hourly labor charges of $4, $10, $20, and $50 had little effect on the rankings of economic returns. Because of unusually high alfalfa reseeding costs and low average oat yields, returns to the C-O-M rotation were significantly lower than C-Sb but comparable to C-C. With better alfalfa establishment and higher average oat yields, the reduced-chemical system might have been competitive with the C-Sb conventional system.