Soil Surface Evaporation Control by Plant-based Mulching during the Energy Limiting and Falling Rate Evaporation Stages

Huge quantities of plant by-products and plant wastes generated are stressing to assess their re-usability, probably as mulching, in conserving soil moisture. Magnitude and timing of evaporation reduction by mulching is vital in scheduling irrigation, particularly in dry areas. This study experimentally investigated the effects of six different plant based mulch treatments [coconut coir dust, coconut husk chips, Gliricidia leaves (Gliricidia Sepium), paddy straw, rice husk and saw dust] on controlling soil surface evaporation in sandy loam soil during the two stages of evaporation (energy limiting and falling rate) and degree of dependence of the soil surface evaporation on weather parameters. During the energy limiting evaporation stage, in comparison to the bare soil, all the mulch treatments exhibited the greatest differences in the soil surface evaporation rates (ANOVA, p<0.05) suggesting their suitability for high-frequency irrigation systems; Gliricidia leaves mulch performed best followed by rice husk mulch and saw dust mulch. Coconut coir dust, exhibiting statistically similar evaporation rates with the bare soil (Tukey’s, p>0.05) during the falling rate evaporation stage, proved as the least effective mulch in providing prolonged evaporation restriction. Evaporation in saw dust mulched soil was highly dependent on temperature (p<0.01) and relative humidity (p<0.01) during the energy limiting stage.