Có 10+ tài liệu thuộc chủ đề "sói mòn đất đai"
tailieu.vn Xem trực tuyến Tải xuống
Erosion control in the tropics. This is a revised version of the first edition of this Agrodok. Hopefully it is a useful introduction to the erosion problem and its control. For this fourth edi- tion we have improved the layout and the pictures, and incorporated improvements in the text.. We are very grateful to Arend Kortenhorst who has taken care...
tailieu.vn Xem trực tuyến Tải xuống
Now an attempt will be made to illustrate the ways in which a farmer is confronted with the physical characteristics of erosion in the daily work. For this, it is important to know how to recognize erosion in the field.. Always keep the course of the erosion process in mind when looking for signs of erosion in the field. An...
tailieu.vn Xem trực tuyến Tải xuống
Some understanding of the way in which the erosion process takes place is needed to appreciate the usefulness of preventive measures. 3.1 Splash-erosion and stream-erosion. Within water-erosion there are two types of erosion: splash erosion and stream erosion. In splash erosion, the falling raindrops break off small parts of the soil aggregates (see Glossary). Water cannot easily infiltrate in the...
tailieu.vn Xem trực tuyến Tải xuống
Erosion control in the tropics. In Chapter 2 a few examples have been given as to how erosion can be observed in the field. To mention one example: small rills, unlike gullies, can still be ploughed by the farmer. By a few examples we will try to show how the farmer in his daily routine on the farm may be...
tailieu.vn Xem trực tuyến Tải xuống
Arable farming is an integral part of the natural surroundings. Think of the cattle pastures where manure will again benefit the soil.. Agronomic measures play a key role in erosion control because in the first place they can be carried out relatively easily and cheaply. In this chapter we will give a survey of the most important agronomic measures. Minimum...
tailieu.vn Xem trực tuyến Tải xuống
The fallow period ensures a natural recovery of soil fertility. This farming system is still very common (it accounts for 8% of the world’s food supply), but unfortunately a high population pressure in many places undermines the system. The land is then used too inten- sively and the fallow period is shortened. Too few nutrients are built up so that...
tailieu.vn Xem trực tuyến Tải xuống
This can be done by making better use of the available water for the crop (water conservation) and/or by controlling the runoff water.. Another way is to develop a drainage system through which the run- off-water is collected and diverged before it reaches the agricultural land. The borders of this area are determined by the so-called watersheds, the tops of...
tailieu.vn Xem trực tuyến Tải xuống
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 precautions. So we are confronted with the un- derlying cause of erosion. A simple comparison can be made here with a farm track (it is sometimes forgotten that roads and paths can...
tailieu.vn Xem trực tuyến Tải xuống
Conditions for the success of operations 75. 9 Conditions for the success of operations. It indicates the direction we should look when deciding on measures to be taken, not only con- sidering the effects the plan will have on the soil, but just as much, if not more, the consequences for the people. The fact that a certain requisite for...
tailieu.vn Xem trực tuyến Tải xuống
It is better if you can fill in the gaps yourself (with the help of this booklet), other literature, advice from different au- thorities and especially with help from the local population and a little common sense. For this we have made up a sort of questionnaire making reference to the chapters in this booklet:. Make a tour, taking note...