 |  | Better Farming Series 28 - Water: Where Water Comes from (FAO, 1981, 31 p.) | ||
 |  | When rain falls | ||
|  | (introduction...) | ||
| | How much rain falls | ||
| | Kind of soil | ||
| | Slope of the land | ||
| | Plants | ||
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31. When it rains, some of the water sinks into the soil and some of the water stays on the surface or runs along the surface.
32. how much water sinks into the soil and how much water stays on the surface depends on several things. It depends on:
· how much rain falls;
· the kind of soil where the rain falls;
· the slope of the land where it falls;
· how many plants there are and what kind of plants they are where the rain falls.
33. Whether rain goes into the ground or stays on the surface depends on how much rain falls and for how long it falls.
34. If a little rain falls for a long time, more water is likely to go into the ground.
Little rain falls for long time
35. If much rain falls for a short time, less water is likely to go into the ground and more will stay on the surface.
Much rain falls for short
time
6. Whether water goes into the ground or stays on the surface depends on the kind of soil where the rain falls.
37. In some kinds of soil, very much water sinks in.
Much water sinks in some kinds of
soil
In other kinds of soil only a little water sinks in.
Less water sinks in other kinds of
soil
38. In some kinds of soil which have a rocky surface, no water at all may sink in.
No water sinks in some kinds of
soils
39. If the structure of the soil is good, water sinks in well. Soil with a good structure can held more water.
40. The structure of the soil is good when it is made up of sand, clay and silt which are joined together by a mixture of clay and humus.
41. If the structure of the soil is poor, water does not sink in well. Soil with a poor structure holds less water.
42. The structure of the sold is poor when there is no humus and the sand, clay and silt are not joined together.
43. To understand better about good and poor soil structure, see Booklet No. 4.
44. Whether water goes into the ground or stays on the surface also depends on the slope of the land where the rain falls.
45. If the land is flat, rainwater is more likely to sink into the around.
Rainwater sinks into around
46. If the land is flat and the soil structure is good, all of the rainwater will go into the ground until the soil becomes so full of water that it cannot held more.
All rainwater goes in the ground
47. If the land is flat and the soil structure is poor, water remains in pools on the surface. After a while, part of the water in the pools may sink slowly into the ground and the rest evaporates.
48. If the land is hilly, water will run off more quickly and very little may sink into the ground.
Very little water sinks in the
ground
49. Hilly land with poor soil structure holds very little water. Hilly land with good soil structure holds more water. Land that is very hilly holds less water than land that is not very hilly.
50. Whether water goes into the ground or stays on the surface depends on the number, size and kind of plants that are growing there.
51. When rainfall is heavy and very much water falls in a short time, there may be too much water for the ground to held and much of the water will stay on tile surface.
52. When there are plants present, their limbs, branches and leaves help to slow the water as it falls.
Plants slow the water as it falls
53. Small plants with few leaves will slow rainfall less and more water will stay on the surface.
54. Large plants with many leaves will slow rainfall more and less water will stay on the surface. More water sinks into the ground.
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