Abstract

The results of run-off experiments conducted at Hagari have shown that a large proportion of the rainfall is lost by surface flow. The greatest opportunity for conserving moisture in dry soils, therefore, lies in the redu- ction of losses due to surface run-off. It is naturally impossible to prevent run-off completely. It but a portion of it is saved, a substantial increase in the moisture supply is effected. As mentioned already, in the black soils the main hingari crops, cotton and sorghum have to depend on the moisture that is stored in the soil by their sowing time. Rainfall during their growth period is poor and preca- rious. The effective rainfall for crop growth is that received in the period August to October, normal for August, September and October is 12:3 in. against an annual normal of 20'6 in. (for the last ten years). Conservation methods like bunding, scooping or listing, therefore, help in better utilisation of the rain water. They arrest run-off and allow the water to stand on the field for a longer time, giving greater chance for it to be absorbed by the soil. Ploughing, by throwing the land into better physical condition, helps in better absorption of the rain water by the soil, provided the furrows do not run along the slope. Any implement which cuts a furrow can be used for forming basins, if the furrower can be lifted at intervals. In the case of the basin-lister this is arranged by means of an eccentric cam. The local interculturing implements, dhantulu or blade harrows, can also be used for forming the basins by lifting the harrow at intervals. As moisture is the limiting factor for crop growth in dry areas, a study of its movements under field conditions is essential.

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