Appraisal of the spatial and temporal variations of the soil moisture profile in the long furrow irrigation system in kenana sugarcane plantation

الملخص EN

This study has been conducted at the sugarcane fields of Kenana Estate, Sudan in the long furrow irrigation system established in a montmorillonitic clay soil, during the two successive seasons 2000 and 2001 seasons.

In the 1st season the study was carried out in the long-, medium- and short-furrow length fields.

Measurements were taken spatially at top, middle and end of each furrow length, and temporally during the growing season at the development (DEV), middle (MID) and maturity (MAT) growth stages.

For each stage soil moisture contents were determined gravimetrically before (Mb) and three days after irrigation (Ma).

Sampling was done in five equal depths within the 0 to 100cm soil profile.

During the second season similar measurements were taken in the medium-furrow length field but sampling was first taken 3days after irrigation and then immediately prior to the next irrigation to determine the water depletion (consumptive use) of first ratoon crop.

Studies revealed that the soil was composed of sand, silt and clay in the percentile ratios of 20.9, 14.8 and 64.3% respectively.

This gave a field capacity (FC) of 38.8% and a permanent wilting point (PWP) of 20.4% on weight basis.

In the first season the Mb, FC and PWP data indicated that the irrigation was applied during the season with averages of 53.3, 48.3 and 26.1% available water depletion levels (AWDL) in the long-, medium-, and short-furrow fields respectively.

In the second season the Ma and Mb data indicated that values for water depletion were 8.4, 4.8 and 5.6mm/day for DEV, MID and MAT growth stages, respectively.

Generally, the temporal variations of the Mb, Ma, moisture added and moisture depleted were higher than the spatial variations.