Xem 1-7 trên 7 kết quả Cropland
  • There has never been a very detailed map of existing vegetation types of Texas statewide on a plant association level. Important broad and/or regional studies include those by Bray (1906); Tharp (1926, 1939); Cottle (1931); Dyksterhuis (1946, 1948); Allred, et al. (1954); Gould et al. (1960) and a map by Telfair (1983). Kuchler (1964) published a potential natural vegetation type map of the conterminous

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  • Despite the tremendous progress that has been achieved in water pollution, almost 40% of the U.S. waters that have been assessed by states do not meet water quality goals. About 20,000 water bodies are impacted by siltation, nutrients, bacteria, oxygen depletion substances, metals, habitat alterations, pesticides, and toxic organic chemicals. With pollution from point sources being dramatically reduced, nonpoint source pollution is the major cause of most water that does not meet water quality goals.

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  • 12 Predictive Modeling of Lake Nitrogen, Phosphorus, and Sediment Concentrations Based on Land Use/Land Cover Type and Pattern Pariwate Varnakovida, Narumon Wiangwang, Joseph P. Messina, and Jiaguo Qi 12.1 INTRODUCTION In watershed management and planning, one of the major problems in lakes is the need to reduce nonpoint source pollution.1 Specific land use and land cover (LULC) types, such as “cropland” and “urban”, are associated with human activities and their physical characteristics often affect water quality.2 Land use practices and water resources are unequivocally linked.

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  • Eastern Europe and Central Asia represents a unique situation, where invest- ments in very large farms contrast with an overall contraction of agricultural land use. In the Russian Federation, Ukraine, and Kazakhstan, the area sown to grains has declined by 30 million ha since the end of the Soviet era. These croplands were mostly returned to pastures or fallow, due to lack of suitable technology and market access. Large farms were better able to deal with financing, infrastructure, and technology constraints of the transition, lead- ing to considerable concentration.

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  • Organic milk producers usually begin as operators of conventional dairies that go through what can be a challenging and costly transition process. Many changes in such areas as animal husbandry, land and crop management, sourcing new and different inputs, and initiation of the certification process, among others, are required during transition. For example, the pasture and cropland providing feed for organic dairies must be managed organically for a minimum of 36 months before it can be certified.

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  • Agricultural legislation in the United States attaches high importance to environmental programs in agricultural policy, focusing on measures to convert highly erodible cropland to approved conservation uses (including long-term retirement), reconvert farmland back into wetlands, and encourage crop and livestock producers to adopt practices that reduce environmental problems, on a cost-sharing basis. Furthermore, research and advice has increasingly focused on promoting sustainable farming practices.

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  • The 26th report of the Royal Commission on Environmental Pollution on the urban environment13, proposes an environmental contract between central and local government, which would be a high level agreement to promote environmental action at the local level. On the ground, this would mean a local authority developing a strategy containing a small number of mandatory elements, but would also encourage the authority to design a programme to tackle a variety of environmental activities across sectors with the aim of stimulating improvement and innovation.

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