Research Papers
Effects of organic nitrogen fortifiers on some growth parameters of green amaranths (Amaranthus caudatus L.)
- O.O. AdeOluwa, G.O. Adeoye, S.A. Yusuff
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- Published online by Cambridge University Press:
- 19 November 2009, pp. 245-250
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Chemical fertilizers for boosting crop production are becoming more expensive and scarce. Green amaranth (Amaranthus caudatus L.) is a fast growing and highly nutritious crop, but its common use in the diet of Nigerians is constrained by its high demand for nitrogen fertilizer. Thus, there is a need to find local fertilizer materials that are readily available to peasant farmers. A preliminary field study was conducted to evaluate urine and neem (Azadirachta indica L. juss) as alternative sources for mineral fertilizers in fortifying organic fertilizer (OF) made from cow dung and market waste compost, and OF fortified with urea and bone meal [organo-mineral fertilizer (OMF)], for yield and growth of green amaranth. Fifteen treatments, based on the percentages of N supplied, were NPK15-15-15, OMF, OF, urine, neem and ten treatments of 50, 60, 70, 80 or 90% OF supplemented with a total of 50, 40, 30, 20 and 10% urine or neem, respectively, to provide a total application rate of 100 kg N ha−1, with no fertilizer treatment as a control. Planting was done in two successions (main with fertilizer treatments and residual without further application). The fertilizer sources and levels had significant effects on plant height, number of leaves, stem girth, fresh weight and dry weight. The residual effects were also significant for plant height, number of leaves, total fresh and dry weights. Forty percent N urine amendment of the OF produced the highest total fresh amaranth biomass (269.3 g plot−1 main effect and 110.8 g plot−1 residual effect), which was significantly better than the values of (140 and 35.3 g plot−1, respectively) obtained with respect to OMF during main planting and NPK during residual planting. Results of our study reveal that 40% N urine fortification of OF was a viable substitute for synthetic fertilizers in production of amaranth, and that urine and neem cake can be alternatives to mineral fertilizer for crop production.
Consumer demand for local produce at extended season farmers' markets: guiding farmer marketing strategies
- David S. Conner, Adam D. Montri, Dru N. Montri, Michael W. Hamm
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- Published online by Cambridge University Press:
- 18 September 2009, pp. 251-259
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Locally grown food is gaining popularity and increasing its prevalence holds potential for broad social, economic and environmental benefits. Season extension technologies such as hoop houses offer a solution to limited growing seasons, a major constraint in many areas, enhancing efforts to supply locally grown food. This paper discusses research conducted at three Michigan farmers' markets, locations where Michigan farmers utilizing hoop houses currently sell their produce. The research measures consumers' willingness to buy local produce at extended season markets using a set of four complementary methods: dot poster surveys, written surveys, focus groups and experimental auctions. Building upon prior research on attributes that create value for local foods (spatial proximity, food quality and relationships between farmers and consumers), our results inform farmers' choice of marketing mix. We find consumers willing to pay a premium for large quantities of locally grown produce, with many placing highest value on products grown in Michigan. We conclude that extended season farmers' markets supplied by hoop house grown produce create an opportunity for farm viability and further development of the market for locally grown food.
Protocol for indicator scoring in the soil management assessment framework (SMAF)
- B.J. Wienhold, D.L. Karlen, S.S. Andrews, D.E. Stott
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- Published online by Cambridge University Press:
- 18 September 2009, pp. 260-266
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Assessment tools are needed to evaluate agronomic management effects on critical soil functions such as carbon sequestration, nutrient cycling and water partitioning. These tools need to be flexible in terms of selection of soil functions to be assessed and indicators to be measured to ensure that assessments are appropriate for the management goals. The soil management assessment framework (SMAF) is being developed to meet this need. The SMAF uses soil physical, chemical and biological indicator data to assess management effects on soil function using a three-step process for (1) indicator selection, (2) indicator interpretation and (3) integration into an index. While SMAF is functional in its present format, it is intended to be malleable so that user needs can be met. Development of additional indicator interpretation scoring curves is one way that this framework can be expanded. Scoring curve development is a multi-step process of identifying an indicator, determining the nature of the relationship of the indicator to a soil function, programming an algorithm and/or logic statements describing that relationship and validating the resulting scoring curve. This paper describes the steps involved in developing an SMAF scoring curve. Scoring curves for interpreting water-filled pore space (WFPS) and Mehlich extractable potassium (K) were developed using the described protocol. This protocol will assist users of the SMAF in understanding how the existing scoring curves were developed and others interested in developing scoring curves for indicators that are not in the current version.
Purchasing foods produced on organic, small and local farms: A mixed method analysis of New England consumers
- L. Berlin, W. Lockeretz, R. Bell
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- Published online by Cambridge University Press:
- 18 September 2009, pp. 267-275
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Research focused on consumer behavior and attitudes toward organic, small-scale and locally produced foods can help organic producers understand consumer values, and in turn develop production and marketing approaches that match these values. This research on New England area food shoppers included focus groups, individual interviews, and a mail survey, all of which helped us to identify relationships between organic food buying and consumers' views of the food system. Comments made in focus groups and individual interviews revealed a frequent blending of the concepts of local, small-scale and organic, and their associated benefits. Subsequent mail surveys identified similar tendencies, although respondents made some distinctions among the reasons why they bought food from the three farm categories. When there were differences, respondents tended to attribute greater importance to reasons to buy from local farms, as compared to organic or small farms. The six questions for which the differences across farm categories had the lowest P-values were related to the environment, rural economy, rural landscape, farmers, product freshness and product taste. However, freshness, taste, nutritional quality and safety were some of the most compelling reasons that were attributed to all three farm categories. The challenge for the small, local and organic producer will be to continue to hold the consumer's attention as the general perception of organic farming shifts to a more industrialized model.
The profitability of organic soybean production
- W.D. McBride, Catherine Greene
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- Published online by Cambridge University Press:
- 19 November 2009, pp. 276-284
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Results from long-term experimental trials suggest that similar yields and lower costs are possible with organic compared to conventional soybeans, but there is little information about the relative costs and returns of these systems on commercial farms. This study examines the profitability of commercial soybean production using a nationwide survey of soybean producers for 2006 that includes a targeted sample of organic growers. Treatment-effect models are specified to characterize adopters of the organic approach and to isolate the impact of organic choice on operating, operating and capital, and total economic costs of soybean production. Organic soybean producers tend to be younger, have less crop acreage, and are less likely to work off-farm than conventional producers. Organic soybean production costs range from about $1 to $6 per bushel higher than those for conventional soybeans due to both lower yields and higher per-acre costs, while the average organic price premium in 2006 was more than $9 per bushel. Long-term cropping systems data suggest significant returns to organic systems result from similar yields and lower costs than conventional systems, but the high returns to commercial organic production found in this study can only be attributed to the significant price premiums paid for organic soybeans. Average organic soybean price premiums have remained high since 2006 despite much higher conventional soybean prices as users of organic soybeans attempt to retain and attract more acreage. However, increases in conventional soybean prices and fuel prices reduce the incentive for planting organic soybeans by improving returns to conventional production and increasing the relative costs of organic production.
Nutritional and quality characteristics expressed in 31 perennial wheat breeding lines
- Kevin M. Murphy, Lori A. Hoagland, Philip G. Reeves, Byung-Kee Baik, Stephen S. Jones
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- Published online by Cambridge University Press:
- 19 November 2009, pp. 285-292
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Soil erosion due to annual cropping on highly erodible farmland is a major ecological concern in the wheat growing regions of Washington State. In response to requests from farmers, the winter wheat breeding program at Washington State University has been developing perennial wheat selected from crosses between wild wheatgrass species and commonly grown annual wheat cultivars. In 2005/06, we conducted field trials of the most promising perennial wheat breeding lines derived from interspecific crosses between tall wheatgrass (Thinopyrum elongatum) and bread wheat (Triticum aestivum). Thirty-one perennial breeding lines and two annual winter wheat cultivars were evaluated for nutritional value in the form of grain mineral concentration, multiple baking and milling quality traits, and ease of grain threshability. The objective of this study was to identify the strengths and weaknesses of these post-harvest traits in the perennial wheat lines derived from these interspecific crosses. Mineral nutrient concentrations in the perennial lines were 44, 40, 24, 23, 32, 30 and 33% higher than the annual control cultivars for calcium, copper, iron, magnesium, manganese, phosphorus and zinc, respectively. The annual cultivars had a higher grain mineral content per unit area of land than the perennial lines, due primarily to the higher grain yields of the annual cultivars. Compared to the annual wheat cultivars, the perennial lines produced grain with smaller seed size, lower test weight and reduced flour yield, mix time and loaf volume. Protein content was 3.5–4.5% higher in the perennial lines than in the annual cultivars. The threshability index (TI) ranged from 0.63 to 0.89 in the perennials (μ=0.75); significantly lower than the mean TI of the annual cultivars (μ=0.97). The significant genotype×location interaction found for TI suggests that the variation in annual precipitation positively influenced some perennial lines to express greater threshability. In addition to transferring traits important to the perennial growth habit in wheat, the wild wheatgrass species also introduced beneficial characteristics (i.e. increased protein and mineral concentration) and deleterious traits (poor threshing grain and inferior baking qualities). This research gives researchers a platform from which to direct further research and selection in the development of perennial wheat.
Browsing for conservation: Springtime forage value of midstory shrubs of degraded oak savannas in southern Wisconsin
- Janet Hedtcke, Joshua Posner, Martha Rosemeyer, Ken Albrecht
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- Published online by Cambridge University Press:
- 28 October 2009, pp. 293-299
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Oak (Quercus spp.) savanna is a rare and dwindling ecosystem primarily due to the clearing of vast areas for agriculture and encroachment of woody midstory shrubs in the remnant areas. There is interest in introducing controlled grazing to re-open these ecologically sensitive semi-wooded areas. We report the forage quality and diet selection by Scottish Highland cattle (Bos taurus spp.), a breed recognized for their browsing behavior, of the most common shrubs in this ecosystem. Shrub species sampled included prickly ash (Xanthoxylem americana Mill), gooseberry (Ribes missouriense Nutt.), gray dogwood (Cornus racemesa L.), multiflora rose (Rosa multiflora Thunb. ex Murr.), black or red raspberry (Rubus spp.) and wild parsnip (Pastinaca sativa L). Leaf biomass was collected in June 2001 and 2002 and analyzed for forage quality. Animal observations showed that diet included a fairly even mixture of shrub leaves, grass and herbaceous forbs. Prickly ash and raspberry were most frequently browsed and had the highest crude protein (CP; 190 g kg−1), while multiflora rose and gray dogwood, neither highly browsed upon, had the lowest levels of CP (120 g kg−1). All shrubs had high in-vitro true digestibility, with prickly ash approaching 850 g kg−1 (as compared to 688 g kg−1 for mature alfalfa). The quality of the shrub layer in late spring is adequate to provide nutritional support for beef cattle as long as dry matter intake is not limited. Integrating shrubs into the rotation could expand the pasture base by providing feed at a time when cool-season pastures are typically quasi-dormant.
Review Article
Soilless cultivation for high-quality vegetables with biogas manure in China: Feasibility and benefit analysis
- Wen Ke Liu, Qi-Chang Yang, Lianfeng Du
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- Published online by Cambridge University Press:
- 21 September 2009, pp. 300-307
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Vegetables, the indispensable staple produce providing humans with many beneficial substances, are readily contaminated by nitrate, heavy metals and pesticides during conventional cultivation. In particular, off-season vegetables grown in protected systems with low light intensity do tend to accumulate more nitrate in tissues due to excess N fertilization driven by farmers' desire for high yields. Over-the-limit accumulation of the harmful substances in vegetables constitutes a serious hazard to human health globally. Soilless cultivation, currently a fraction of vegetable cultivation in China, is a promising cultivation method to decrease the accumulation of harmful substances through nutrient solution regulation and environmental factor control. However, conventional inorganic nutrient solutions present few quality benefits besides plant nutrition for the widely acknowledged formulations. Currently, high-quality vegetables are urgently desired by humans globally, but they are difficult to grow for lack of an effective and practical cultivation method to lower the accumulation of harmful substances and to improve nutritional quality simultaneously. Although some attempts have been made, few commercial formulations have been applied in practice. Biogas manure (biogas slurry and biogas dregs) is a by-product of biogas production. It has been shown to be a good fertilizer with abundant nutrients, amino acids and bioactive substances. In China, as a product of the recycling process of agricultural wastes, biogas manure is an ever-growing resource due to the rapid development of biogas projects. Therefore, the need to utilize biogas manure is an urgent issue that relates both to environment protection and nutrient resources utilization. In this paper, the updated research results on yield and the quality effects of vegetables cultivated with biogas dregs and the solutions modified from biogas slurry in China are summarized, highlighting the feasibility and benefits of biogas manure in high-quality vegetable production. It is concluded that biogas manure is an effective nutrient source for high-quality vegetable production based on its synergistic effects and effectiveness in yield and quality improvement (particularly depression effects on nitrate accumulation), and stress resistance. However, deliberate component regulations need to be developed for better yield and quality of vegetables under soilless cultivation due to the large variability of components of biogas manure caused by various combinations of fermentative materials.
Biological indicators of soil quality in organic farming systems
- E.A. Stockdale, C.A. Watson
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- Published online by Cambridge University Press:
- 19 November 2009, pp. 308-318
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The health of the soil, recognized by its active role in the linked processes of decomposition and nutrient supply, is considered as the foundation of agriculture by the organic farming movement. Nutrient management in organically managed soils is fundamentally different from that of conventional agricultural systems. Crop rotations are designed with regard to maintenance of fertility with a focus on nutrient recycling. Where nutrients are added to the system, inputs are in organic and/or non-synthetic fertilizer sources that are mostly slow release in nature. Hence a greater reliance is placed on soil chemical and biological processes to release nutrients in plant-available forms. In this respect, nutrient availability in organically farmed soils is more dependent upon soil processes than is the case in conventional agriculture. The development and use of biological indicators of soil quality may therefore be more important in organic (and other low input) farming systems. The aim of this paper is to evaluate current evidence for the impact of organic farming systems on soil biological quality and consider the identification of appropriate biological indicators for use by organic farmers and their advisors. Organic farming systems are generally associated with increased biological activity and increased below-ground biodiversity. The main impacts on biological fertility do not result from the systems per se but are related to the amount and quality of the soil organic matter pool and disruptions of soil habitat via tillage. Even within the constraints of organic farming practices it is possible for farmers to make changes to management practices which will tend to improve soil biological quality. It is, however, by no means clear that distinct indicators of soil biological quality are needed for organic farming systems. It is important not only to identify the most appropriate indicators but also to ensure that farmers and land managers can understand and relate to them to support on-farm management decisions.
Front Cover (OFC, IFC) and matter
RAF volume 24 issue 4 Cover and Front matter
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- Published online by Cambridge University Press:
- 19 November 2009, pp. f1-f2
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Back Cover (IBC, OBC) and matter
RAF volume 24 issue 4 Cover and Back matter
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- Published online by Cambridge University Press:
- 19 November 2009, pp. b1-b4
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