Water Conservation by Soil Mulch in Relation to Soil Type, Time of Tillage, Tilth and Evaporativity

The effect of four times of tillage and four tilths, viz., coarse, medium, fine and very fine in two soils under low and high evaporativities was studied. Tillage was performed at soil-water contents between 0.34 to 0.11 cm³ cm⁻³ in the upper 5 cm layer in silty clay loam and 0.25 to 0.09 cm³ cm⁻³ in sandy loam soils. Under low evaporativity, water loss was significantly reduced in both soils by tillage at all the four times. In the silty clay loam, first three times were equally effective and conserved more water than the fourth time of tillage. In the sandy loam, the first two times caused greater evaporation reduction than the third and fourth times of tillage.

Under high evaporativity, water conservation by tillage reached a maximum value in 14–20 days after tillage and declined thereafter. Earliest tillage in the sandy loam and the second time of tillage in the silty clay loam conserved more water than other times of tillage.

Effect of tilth varied with the time of tillage and evaporativity. Under low evaporativity, water conservation with coarse tilth was lower than with other tilths regardless of the soil and time of tillage. Under high evaporativity, coarse and medium tilths appeared more effective with the earliest and finer tilths with subsequent times of tillage.