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Ammonia volatilization is an important mechanism of N loss from flooded rice soils. Inhibition of urease may delay the formation of conditions favorable to NH3 volatilization in the floodwater, thus giving the soil and plant a better chance to compete with the atmosphere as a sink for N. The experiments reported here were designed to identify the site of(More)
This paper presents the concept and theoretical specification of a multi-agent based model for spatio-temporal simulation of a coupled human–landscape system. The model falls into the class of all agents, where the human population and the landscape environment are all self-organized interactive agents. The model framework is represented by four components:(More)
The objective of this article is to apply fuzzy set and interpolation techniques for land suitability evaluation for maize in Northern Ghana. Land suitability indices were computed at point observations using the Semantic Import (SI) model, whereas spatial interpolation was carried out by block kriging. Interpolated land suitability shows a high correlation(More)
Soil salinity in the Aral Sea Basin is one of the major limiting factors of sustainable crop production. Leaching of the salts before planting season is usually a prerequisite for crop establishment and predetermined water amounts are applied uniformly to fields often without discerning salinity levels. The use of predetermined water amounts for leaching(More)
institutions that shared the burden of hosting me was heart warming and very rewarding. The opinions expressed in this paper are strictly those of the authors. Land Decline in Land‐Rich Africa The Science Council of the CGIAR encourages fair use of this material provided proper citation is made.
As part of a research program to determine the fate of N fertilizers applied to dryland sorghum in the semi-arid tropics,15N balance studies were conducted with various N sources in the greenhouse. Two American soils, Houston Black clay (Udic Pellustert) and Windthorst sandy loam (Udic Paleustalf), similar in properties to the Vertisol and Alfisol in the(More)
Extensive degradation of irrigated croplands, due to increasing soil salinity and depletion of soil nutrient stocks, is a major problem in Central Asia (CA), one of the largest irrigated areas in the world. To assess the potential for improving the productive capacity of degraded lands by afforestation, we examined N(2) fixation of Elaeagnus angustifolia L.(More)
An important process which affects the fate of fertilizer nitrogen (N) applied to a rice crop is crop N uptake. This uptake rate is controlled by many factors including the N-ion species and its concentration. In this study the relation between N concentration at the root surface and N uptake was characterized using Michaelis-Menten kinetics. The equation(More)
In an effort to provide an explanation for the reported variability in fertilizer N efficiency from deepplaced urea on flooded rice, a set of controlled experiments was conducted to evaluate the effect of water percolation on fertilizer loss and plant uptake from15N labeled urea supergranules. Three soils of different texture (silt loam-clay) were subjected(More)