Riparian seeps have been recognized for their contributions to stream flow in headwater catchments, but there is limited data on how seeps affect stream water quality. The objective of this study was to examine the effect of seeps on the variability of stream NO3-N concentrations in FD36 and RS, two agricultural catchments in Pennsylvania. Stream samples were collected at 10-m intervals over re...

BACKGROUND AND AIMS There is increased evidence that partial nitrate (NO3-) nutrition (PNN) improves growth of rice (Oryza sativa), although the crop prefers ammonium (NH4+) to NO3- nutrition. It is not known whether the response to NO3- supply is related to nitrogen (N) use efficiency (NUE) in rice cultivars. Methods Solution culture experiments were carried out to study the response of two ri...

Changes in agricultural management can minimize NO3-N leaching, but then the time needed to improve ground water quality is uncertain. A study was conducted in two first-order watersheds (30 and 34 ha) in Iowa's Loess Hills. Both were managed in continuous corn (Zea mays L.) from 1964 through 1995 with similar N fertilizer applications (average 178 kg ha(-1) yr(-1)), except one received applica...

Adsorption and desorption of phosphorus (P) and nitrogen (N) by stalk residues may influence the concentrations of P and N in runoff. A laboratory study was conducted to measure the effects of P and N constituents in solution on adsorption and desorption of P and N by corn, soybean, and wheat stalk residues. Experimental variables included type of stalk material (corn, soybean, and wheat), inor...

Quantifying and simulating the relationships between crop growth, total-nitrogen (total-N) and nitrate-N (NO3--N) concentration can improve crop nutritional husbandry. In this study, the relationship between shoot relative growth rate (RGR) and shoot total-N, organic-N and NO3--N concentration of hydroponically-grown lettuce (Lactuca sativa var. capitata L. cv. Kennedy) was described and simula...

Kucey and Schaalje, 1986; Reeves et al., 1993; Randall et al., 1997; Torbert et al., 2001). Tillage and N management systems can have a significant effect Many soil and water quality problems are associated on N use by corn (Zea mays L.) and nitrate (NO3–N) movement with conventional tillage, along with other problems that through the soil profile. Potential water quality and NO3–N loss probaff...

Protecting water resources from nitrate-nitrogen (NO3-N) contamination is an important public health concern and a major national environmental issue in China. Loss of NO3-N in soils due to leaching is not only one of the most important problems in agriculture farming, but is also the main factor causing nitrogen pollution in aquatic environments. Three typical intensive agriculture farmlands i...

[1] The reactive uptake of the NO3 radical by liquid and frozen organics was studied in a rotating wall flow tube couple d to a Whit e cell . The organic liquids used included alkane s, alkene s, an alcohol, and carboxylic acids with conjugated and nonconjugated unsaturated bonds. The reactive uptake coefficients, g, of NO3 on n-hexadecane, 1-octadecene, 1-hexadecene, cis + trans 7-tetradecene,...