bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractSoil 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

AbstractThis 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

AbstractNitrate 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

AbstractAn 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

AbstractWood 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

AbstractPotato 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

AbstractConventional 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

AbstractSynthetic 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

AbstractUnderstanding 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

AbstractAn 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

AbstractStrip 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.
Effect of conservation tillage on crop yields, soil erosion, and soil properties under furrow irrigation in western Colorado
Authors: Ashraf M. , Pearson C.H. , Westfall D.G. , Sharp R. 
Published: October 2009

AbstractConservation tillage (CS) is used widely in rainfed and sprinkler-irrigated production systems but adoption of CS on furrow-irrigated cropland has been limited. Some crops and crop rotations are more conducive to conservation tillage under furrow irrigation than others. The objective of this research was to evaluate CS in a furrowirrigated crop rotation of corn, soybean, winter barley, and dry bean at Fruita, Colorado in 1991 and 1992. Infiltration rates were 24 and 50% higher and advance times were 37 and 25% longer in the CS treatment during 1991 and 1992, respectively, compared with conventional tillage (CV). Furrows in the CV treatment were 8 and 25% wider than those in the CS treatment after the first and sixth irrigations, respectively. This indicates more soil movement with CV than with CS. In 1992, soil water content in the CS treatment was 17, 17, and 27% higher than with CV throughout the growing season for corn, soybean, and dry bean, respectively. Grain yields of winter barley, soybean, dry bean, and corn were not affected significantly by tillage treatment. Profitability of CS and CV was quite similar when all four crops in the rotation were considered together. This research was conducted under conditions expected to be similar to those that could be used by growers and indicates that corn, soybean, winter barley, and dry bean can be grown successfully in rotation using conservation tillage under furrowirrigated conditions. Successful adoption of conservation tillage under furrow irrigation will require growers to adopt encompassing new production management practices and possibly purchase new equipment such as planters and cultivators that will operate in high residue conditions, and growers must overcome any psychological barriers they may have to maintaining high amounts of surface crop residue when furrow irrigating.
Development of more effective conservation farming systems through participatory on-farm research
Authors: Wuest S.B. , McCool D.K. , Miller B.C. , Veseth R.J. 
Published: October 2009

AbstractResearch aimed at advancing conservation farming practices is typically performed using traditional scientific approaches, which have been highly successful in increasing agricultural output and efficiency. With the current emphasis on environmental and economic sustainability of agriculture, there is a need for a more integrated approach to applied agricultural research. Participatory research helps to bring scientific methods and the integrated production needs of farmers together to develop practical, effective, and carefully tested farming methods. The strength of participatory research is in the synergism of scientists and farmers working together to design, implement, and evaluate research. The development of new technologies for farming systems large or small, conventional or organic, can be greatly enhanced through more extensive use of participatory research.