Crust formation on sandy soils in the Sahel I. Rainfall and infiltration
TL;DR: In this article, the causes of crust formation and its effect on the infiltration rate are discussed on untilled soils, and the presence of a crust is a permanent feature on these soils.
Abstract: Sandy soils of the Sahel area in West Africa, mainly cropped to millet (Pennisetum typhoides) are very sensitive to crust formation Crusts strongly reduce infiltration capacity In this area most fields are gently sloping (1–3%) and hence runoff is a widespread phenomenon; on the average 25% of the rain (mainly in the form of a few large storms during the rainy season) is lost by runoff The causes of crust formation and its effect on the infiltration rate are discussed On untilled soils the presence of a crust is a permanent feature Rainfall characteristics play a key role in crust formation Major rainfall characteristics of the Sahel differ significantly from those of other semi-arid areas
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01 Jan 1986TL;DR: In this article, a review of worldwide land degradation problems is presented, focusing on delineating and estimating the magnitude of soil erosion, quantifying erosion and sedimentation impacts on land productivity, establishing quantitative values for erosion-causing parameters, and implementing global and regional soil and water conservation programs.
Abstract: This is a review of worldwide land degradation problems. Four themes are emphasized: delineating and estimating the magnitude of soil erosion, quantifying erosion and sedimentation impacts on land productivity, establishing quantitative values for erosion-causing parameters, and implementing global and regional soil and water conservation programs. Papers deal with both developing and developed countries and illustrate how erosion control techniques used in developed countries can or cannot be applied in developing countries.
1,698 citations
Cites background from "Crust formation on sandy soils in t..."
...Reductions in infiltration of 50 (Hoogmoed & Stroosnijder 1984) to 100 per cent (Torri et al. 1999) can occur in a single storm....
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TL;DR: In this paper, the authors provide an up-to-date review of the research on this topic and an analysis of the causes for the different effects observed and the implications for soil system functioning and for the hydrology of the affected areas are also discussed.
475 citations
TL;DR: In this paper, an analysis of the factors influencing infiltration and runoff was carried out using data obtained under simulated rainfall conditions on 87 plots in arid and semi-arid areas of West Africa, arranged in a hierarchical sequence.
332 citations
TL;DR: In this article, the relation between conservation tillage and sustainable agriculture is discussed and appropriate conservation-tillage systems for different soils, crops, and agroecological region are identified.
Abstract: Publisher Summary This chapter discusses the relation between conservation tillage and sustainable agriculture, and identifies appropriate conservation tillage systems for different soils, crops, and agroecological region. Conservation tillage is a generic term encompassing many different soil management practices. It is generally defined as any tillage system that reduces loss of soil or water relative to conventional tillage and often a form of noninversion tillage that retains protective amounts of residue mulch on the surface. Timing of tillage operations can also be adjusted to facilitate operations during the periods of peak labor demand. The latter includes practices such as plowing at the end of rains in the tropics and fall plowing followed by spring disking in temperate zone. A no-till system has proved effective for soil and water conservation and for production of pastures and grain crops on Alfisols prone to crusting and accelerated erosion in Northern Territory, Australia. There are subtle differences in tropical vis-a-vis temperate regions that must be considered when assessing the applicability of the no-till system. It is found that for soils prone to crusting and hard-setting, shallow tillage without inversion and with the crop residue retained on the surface as mulch is the most appropriate conservation tillage.
316 citations
TL;DR: Analyzing the importance of abiotic, biotic and associated crop management constraints for cassava production in a range of socio-economic settings as found in smallholder farms in the region revealed that many fields were affected by multiple and interacting production constraints.
239 citations
References
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01 Jan 1978
TL;DR: The Universal Soil Loss Equation (USLE) as discussed by the authors is a model designed to predict the average rate of soil erosion for each feasible alternative combination of crop system and management practices in association with a specified soil type, rainfall pattern and topography.
Abstract: The Universal Soil Loss Equation (USLE) enables planners to predict the average rate of soil erosion for each feasible alternative combination of crop system and management practices in association with a specified soil type, rainfall pattern, and topography. When these predicted losses are compared with given soil loss tolerances, they provide specific guidelines for effecting erosion control within specified limits. The equation groups the numerous interrelated physical and management parameters that influence erosion rate under six major factors whose site-specific values can be expressed numerically. A half century of erosion research in many states has supplied information from which at least approximate values of the USLE factors can be obtained for specified farm fields or other small erosion prone areas throughout the United States. Tables and charts presented in this handbook make this information available for field use. Significant limitations in the data are identified. The USLE is an erosion model designed to compute longtime average soil losses from sheet and rill erosion under specified conditions. It is also useful for construction sites and other non-agricultural conditons, but it does not predict deposition and does not compute sediment yields from gully, streambank, and streambed erosion
6,947 citations
TL;DR: In this paper, the authors used scanning electron micrographs (SEM) to study the formation of crusts of loessial soils. But they focused on the final stage of the crust formation, when the coarse particles were washed away, and a thin seal skin, about 0.1 millimeter thick, formed the uppermost layer.
Abstract: Scanning electron micrographs (SEM) of crusts of loessial soils are presented. SEM observations were performed on crusts formed by raindrop impact at various stages of their formation. The crust structure was compared to the natural undisturbed soil. During the crust formation, a middle-term stage developed at which coarse particles, stripped of the fine ones, composed the surface layer of the soil. At the final stage of the crust formation, the coarse particles were washed away, and a thin seal skin, about 0.1 millimeter thick, formed the uppermost layer of the soil. A depositional crust, which was formed mainly by the translocation of fine particles, was marked by the presence of a thin skin also about 0.1 millimeter thick, suggesting involvement of similar secondary mechanisms of formation. This work illustrates the use of SEM for the study of soil crust formation and structure.
218 citations
207 citations
01 Jan 1976
204 citations