Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal...

Nitrogen availability is often a limiting factor in plant growth and crop productivity, but the application of nitrogen fertilizers to counteract nitrogen deficiencies can have detrimental economic and environmental effects. Therefore, it is important to understand mechanisms of nitrogen uptake, transport, and utilization within the plant. The most common form in which nitrogen is assimilated b...

production of onion all thruough the year particularly in semi tropical regions has been considered as an alternative to fulfil the local markets needs. in order to determine the best amount and method of urea fertilizer application so that to have higher yeild and lower amount of nitrate content the effects of seven levels of urea fertilizer including 0, 90, 180, 270, 360, 450 and 540 kg of ni...

Biochar, an organic product of thermal decomposition biomass in oxygen limited environment can be used as a nutrient carrier to delay the release nutrients into soil, reduce leaching, and improve utilization efficiency fertilizers. Nutritional enhancement biochar through fertilizer blending could low cost but high solution compared non-blended However, rate from blended different soils is ambig...

Improved understanding of year-to-year late-spring soil nitrate test (LSNT) variability could help make it more attractive to producers. We test the ability of the Root Zone Water Quality Model (RZWQM) to simulate watershed-scale variability due to the LSNT, and we use the optimized model to simulate long-term field N dynamics under related conditions. Autoregressive techniques and the automati...

The negative effects of pollution on amphibians are especially high when animals are additionally stressed by other environmental factors such as water salinity. However, the stress provoked by salinity may vary among populations because of adaptation processes. We tested the combined effect of a common fertilizer, ammonium nitrate (0-90.3 mg N-NO3NH4/L), and water salinity (0-2 per thousand) o...

Plains bluestem ( Bothriochloa ischaemum L.) is one of the primary grass species used for pastureland in Oklahoma. Plains bluestem is popular due to its high forage and beef production potential. It is also used for soil conservation on highly erodible areas. Despite the current importance of this species, N fertilizer sources, rates, and timing have not been thoroughly evaluated. The objective...

Mineral nitrogen (N) fertilization in cereals is commonly split into three or four applications. In order to simplify N fertilization, a single N application either broadcast or placed on the soil surface was compared to conventionally split fertilization for winter wheat (Triticum aestivum L.). The 4-year experiment (2007-2010) was performed using a participatory approach on farmers' fields on...

The use of kinetic equations of NO3- transport systems in oilseed rape (Brassica napus), determined by 15NO3- labeling under controlled conditions, combined with experimental field data from the INRA-Châlons rape database were used to model NO3- uptake during the plant growth cycle. The quantitative effects of different factors such as day/night cycle, ontogenetic stages, root temperature, phot...

Research has shown that alum [Al(2)(SO(4))(3).14H(2)O] applications to poultry litter can greatly reduce phosphorus (P) runoff, as well as decrease ammonia (NH(3)) volatilization. However, the long-term effects of fertilizing with alum-treated litter are unknown. The objectives of this study were to evaluate the long-term effects of normal poultry litter, alum-treated litter, and ammonium nitra...