Erosion control in the tropics - Part 5 pptx

... and at retaining the rain water. ? Minimum tillage, mulching and the use of a cover crops serve to protect the soil against the force of the rainfall, at the same time maintaining the soil fertility ... guideline for the width of strips Slope of Width of 0 - 2% 40 - 50 m 2 - 4% 30 - 40 m > 4% 15 - 30 m in very humid areas 15 - 30 m This...

Ngày tải lên: 02/07/2014, 05:20

... here. Erosion control in the tropics 62 the terrace drain is often laid out down-slope (as in figure 25) because there is not such a danger of silting up here as in wetter areas. In wet- ter ... crops, Erosion control in the tropics 68 The purpose of gully control is not so much erosion control as an at- tempt to limit the effects of erosion th...

Ngày tải lên: 02/07/2014, 05:20

... yourself why erosion occurs in a certain area. Not only will the deeper causes of erosion be found in the socio-economic backgrounds, but the incentive will be found which motivates the farmer ... Underlying causes of erosion 73 8 Underlying causes of erosion In the previous chapters we have seen how the chance of erosion can be lessened by taking certain prec...

Ngày tải lên: 02/07/2014, 05:20

... for erosion control in the tropics and sub -tropics 87 Appendix 3: Legumes; characteristics and utilization 90 Further reading 92 Glossary 94 Erosion control in the tropics 6 1 Introduction Agromisa’s ... an insight into the causes and the course of the erosion process, by stating the factors which influence the mechanism of erosion and how thes...

Ngày tải lên: 02/07/2014, 05:20

... clear that when observing the erosion phenom- ena, the important thing is always to trace the causes of it. In the fol- lowing chapters we will go more deeply into the erosion process, which ... keep the course of the erosion process in mind when looking for signs of erosion in the field. When a certain characteristic is no- ticed, one should ask oneself just w...

Ngày tải lên: 02/07/2014, 05:20

... Erosion control in the tropics 20 Organic matter content of the soil Organic matter probably is the most important factor in binding the soil particles. The better the soil particles ... of erosion is likely to occur. 3.1 Splash -erosion and stream -erosion Within water -erosion there are two types of erosion: splash erosion and stream erosion. Certainly...

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... Erosion control in the tropics 28 Removing this soil from the drainage system or the paths adds to the workload of the farmer. ? The reverse applies of course to the field where the soil ... labour and the farmer is obliged to sow up a smaller area for in- stance. ? When thin layers of soil are continually washed away from the field by erosion, the bigg...

Ngày tải lên: 02/07/2014, 05:20

... again. Burning is an integral part of cattle farming in the tropics and improvements in the technique must be found. The timing and the method of burning seem to determine whether it is damaging ... drinking places and in doing so they trample down the soil. During rain showers water collects in the trampled tracks (the rain does not necessarily affect the str...

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... underestimated. Erosion control in the tropics 76 9.2 Awareness Only if people appreciate the usefulness of the operations to be carried out, will they be inclined to take them up themselves. They should ... concerned or the well-intentioned development worker ei- ther. Sometimes the causes can only be tackled by political influence among the people themselves, a p...

Ngày tải lên: 02/07/2014, 05:20

... criticisms. Erosion control in the tropics 84 The ends of the hose are fixed firmly to the lath. This can be done us- ing part of an inner tube that is then fixed with U-shaped or L-shaped nails. ... of the forces combining the parti- cles within the soil aggregate are bigger than the forces of the sur- rounding environment, thus keeping the soil aggregate...

Ngày tải lên: 02/07/2014, 05:20