نتایج جستجو برای: runoff

تعداد نتایج: 14537  

2017
Xinghua Li Baona Wang Tewu Yang Duanwei Zhu Zhongnan Nie Junchi Xu

Soil phosphorus (P) fractions and runoff P concentration were measured to understand the fate of soil P entering surface runoff water during summer cropping season of different double cropping systems under two fertilizer regimes. The dominant form of runoff P was particulate P (PP). Runoff total P (TP) was higher at the vegetative growth stage and lower at the crop reproductive stage. TP and P...

2013
Kazuyoshi Suzuki

Understanding how spring runoff is generated in East Siberia during the spring thaw is important to predicting river flows. To evaluate the snowmelt runoff generated, a simple runoff model was developed. The model involves processes of water and energy balance within the snowpack and energy balance within soil, snowmelt infiltration into the frozen ground, and surface runoff. The model reproduc...

Journal: :Journal of environmental quality 2003
Lewis A Gaston Caye M Drapcho Soma Tapadar John L Kovar

Long-term application of poultry (Gallus gallus domesticus) litter has built high levels of P in certain Coastal Plain soils of north Louisiana. However, soil P/runoff P relationships for soil and environmental conditions of the area have not been examined. This study measured soil P (total, Bray 1, Bray 2, Mehlich 3, resin-exchangeable, and water-extractable) and runoff P (dissolved P, DP; and...

2017
Alfred Awotwi Geophrey Kwame Anornu Jonathan Quaye-Ballard Thompson Annor Eric Kwabena Forkuo

The Lower Pra River Basin (LPRB), located in the forest zone of southern Ghana has experienced changes due to variability in precipitation and diverse anthropogenic activities. Therefore, to maintain the functions of the ecosystem for water resources management, planning and sustainable development, it is important to differentiate the impacts of precipitation variability and anthropogenic acti...

Journal: :Applied and environmental microbiology 1979
J W Doran D M Linn

Runoff from a cow-calf pasture in eastern Nebraska was monitored for total coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) during 1976, 1977, and 1978. Bacteriological counts in runoff from both grazed and ungrazed areas generally exceeded recommended water quality standards. The FC group was the best indicator group of the impact of grazing. Rainfall runoff from the grazed ar...

Journal: :Pest management science 2004
Qingli Ma R Don Wauchope Liwang Ma Kenneth W Rojas Robert W Malone Lajpat R Ahuja

The Root Zone Water Quality Model (RZWQM) is a comprehensive, integrated physical, biological and chemical process model that simulates plant growth and movement of water, nutrients and pesticides in a representative area of an agricultural system. We tested the ability of RZWQM to predict surface runoff losses of atrazine, alachlor, fenamiphos and two fenamiphos oxidative degradates against re...

2003
BRADFORD P. WILCOX DAVID D. BRESHEARS CRAIG D. ALLEN

In semiarid landscapes, the linkage between runoff and vegetation is a particularly close one. In this paper we report on the results of a long-term and multiple-scale study of interactions between runoff, erosion, and vegetation in a piñon–juniper woodland in New Mexico. We use our results to address three knowledge gaps: (1) the temporal scaling relationships between precipitation and runoff;...

2005
D. R. Edwards M. S. Coyne P F Vendrell T C. Daniel P A. Moore J. F Murdoch

Agricultural practices such as cattle grazing and animal manure application can contribute to relatively high runoff concentrations of fecal coliform (FC) and fecal streptococcus (FS). Available information, however, is inconsistent with respect to the effects of such practices as well as to measures that can discriminate among candidate sources of FC and FS. The objective of this study was to ...

2001
BELLIE SIVAKUMAR RONNY BERNDTSSON KENJI JINNO

The transformation of rainfall into runoff is one of the most important processes in hydrology. In the past few decades, a wide variety of automated or computer-based approaches have been applied to model this process. However, many such approaches have an important limitation in that they treat the rainfall-runoff process as a realization of only a few parameters of linear relationships rather...

Journal: :Journal of environmental quality 2004
P D Schroeder D E Radcliffe M L Cabrera

Phosphorus (P) in runoff from pastures amended with poultry litter may be a significant contributor to eutrophication of lakes and streams in Georgia and other areas in the southeastern United States. The objectives of this research were to determine the effects of litter application rate and initial runoff timing on the long-term loss of P in runoff from surface-applied poultry litter and to d...

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