Effect of vertical mulch on moisture conservation and yield of sorghum in Vertisols

Abstract

The intake rate of the local Vertisol is very low (0.08 cm/h). Vertical mulch was used from 1971 to 1976 in order to improve infiltration. Higher moisture contents were recorded near the mulch. The favourable effects of mulch extended to 1.5 m on either side of the mulch row. Vertical mulching exerted a greater influence on crop yields under dry conditions than in normal and above normal seasons. Compared with low yields in control plots (grain: 0.2 q/ha (20 kg/ha); straw: 9.5 q/ha (950 kg/ha)) mulches spaced at 2, 4 and 8 m produced 3.9 q/ha of grain and 19.0 q/ha of straw under the extremely dry conditions of 1972–1973. However, the increase in grain and straw yields under wet conditions in 1973–1974 was only 47.2 and 15.0%, respectively. Averaged over dry and wet years, vertical mulching resulted in 45.1 and 37.9% higher grain and straw yields. The favourable effects of vertical mulching were found to last for 4 years. Considering dry and wet years, a spacing of 4 m was found to be ideal. Placing sorghum stubble as a vertical mulch to the top of the salt zone (30 cm) was found to be as good as placing it to a depth of 90 cm.