Farm Radio International provide much information about desertification and soil preservation.
Desertification is caused by changes in climate and human activities like over-cultivating the soil, by allowing animals to overgraze the land; by cutting down or burning trees; and by using improper watering methods which turn cropland salty. Drought sometimes makes soil to dry up and crack, or makes the soil problems that already exist even worse.
In parts of Africa, farmers make cracked hardpan soils productive again, by planting grain in small pits. Apart from improving the soils these pits also improve crop yields. This is a method is effective even if the soils with have a hard dry crust.
Take the following steps to make pits:
1.) Pits of almost the same size are dug all over the field, about a metre from each other. Each pit should be 20 centimetres deep and 20 centimetres wide.
2.) Put some manure or leftover crop residues in each pit.
3.) It is necessary to know when to dig these pits. Most farmers dig and fill the pits in the dry season so that the manure decomposes before the rainy season. Other farmers dig pits at the end of the rainy season when the soil crust is easier to break.
Take the following steps when the rain comes:
1.) Plant about five seeds in each hole.
2.) In these pits, seeds will germinate quickly and the plants will grow faster because water soaks easily into the hole and gathers where plants can use it.
3.) Also, manure acts as a good fertilizer because it will attracts termites:
Farmers have proven that this method can make poor soils produce again. In some cases farmers who could not grow any grains at all were able to produce 400 kilograms per hectare. And that's in a year of low rainfall. And in a year of good rainfall, some farmers harvested as much as 1000 kilograms per hectare. The pits can also be used to plant tree seeds or seedlings and are easy to water and tend.
Source: Farm Radio International, "Make Drylands Productive with Planting Pits," Package 41, Script 1, July 1996.