Effective rainfall in Central Sudan-Gezira

الملخص EN

This study was carried out to estimate the portion of rainfall that is added to soil moisture considered as an effective part of total rainfall; it also shows the effects of over and under estimation of effective rainfall on crop water requirement calculations, and its effects on determining areas that can be cultivated.

The experiment was carried out in a field adjacent to the meteorological Station at Gezira Research Station (GRS), in central Sudan.

The experiment was based on a daily balance of stored water content of the soil.

The samples were taken randomly over the study area for two seasons.

The results showed that moisture changes in Gezira clay soils are confined to- the top 60 cm, unless there is standing water.

Effective rainfall was found to represent 83% of total rainfall in the start of rainy season and decreased to 67% towards its end.

The mean value of 75% of effective rainfall can be used to calculate quantities of rainfall available for the crops grown during the period under investigation.

If rainfall contribution to crop water requirement is considered then it is possible to increase the cropped area for the same amount of irrigation water.