نتایج جستجو برای: agricultural soils
تعداد نتایج: 144345 فیلتر نتایج به سال:
Prior to European contact in 1778, Hawaiians developed intensive irrigated pondfield agricultural systems in windward Kohala, Hawai'i. We evaluated three potential sources of nutrients to windward systems that could have sustained intensive agriculture: (1) in situ weathering of primary and secondary minerals in upland soils; (2) rejuvenation of the supply of rock-derived nutrients on eroded sl...
Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO2) and nitrous oxide (N2O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating gl...
Australia's "Direct Action" climate change policy relies on purchasing greenhouse gas abatement from projects undertaking approved abatement activities. Management of soil organic carbon (SOC) in agricultural soils is an approved activity, based on the expectation that land use change can deliver significant changes in SOC. However, there are concerns that climate, topography and soil texture w...
Inorganic C reactions are among the most important chemical reactions that occur in irrigated soils and may contribute to the total amount of C sequestered in those soils. Because CO2 can escape from soils to the atmosphere or return to precipitate carbonate minerals, soils are open systems with regard to inorganic C. We measured inorganic and organic C stored in southern Idaho soils having lon...
In a survey of plant-parasitic nematodes associated with agricultural crops in nine Maine counties, 744 soil samples from 26 potential host plants were analyzed between November 1987 and January 1989. The most commonly encountered nematode genus was Pratylenchus, occurring in 85% of the samples from most crops, except blueberries and onions. Pratylenchus penetrans and P. crenatus were found com...
Pesticide effects on microbial community structure and activity in soil are reviewed, showing that methodological developments within the past few years have generated new possibilities for assessing pesticide effects. The first example is the use of mRNA quantification showing that nitrification processes are indeed very susceptible to some pesticides, and that there is correlation between the...
Department of Plants, Soils, and Biometeorology, Utah State University, Logan, Utah 84322-4820, Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803-2110, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19717-1303, USDA-ARS, U.S. Salinity Laboratory, 450 Big Springs Road, R...
Department of Plants, Soils, and Biometeorology, Utah State University, Logan, Utah 84322-4820, Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803-2110, Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19717-1303, USDA-ARS, U.S. Salinity Laboratory, 450 Big Springs Road, R...
Pre-plant fumigation of agricultural soils with a combination of methyl bromide (MeBr) and chloropicrin (CP) to control nematodes, soilborne pathogens and weeds has been a common practice in strawberry (Fragaria X ananassa Duchesne) production since the 1960s. MeBr will be phased out by 2005, but little is known about the impacts of alternative fumigants on soil microbial processes. We investig...
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