Mulching with composted municipal solid wastes in Central Negev, Israel: I. effects on minimizing rainwater losses and on hazards to the environment

Dry-land farming in arid and semiarid regions requires minimization of rainwater losses. Major causes for the loss of rainwater are: (i) runoff due to seal formation by raindrop impact, and (ii) evaporation from the wet soil surface. Mulching the soil surface is an effective way to prevent seal formation and water losses. We hypothesized that composted municipal solid waste (CMSW) could be used for mulching arable lands and minimizing rainwater losses without posing a hazard to the environment. Our objective was to study the effects of annual application of CMSW at the soil surface on rainwater retention in the soil, crop production and some hazards to the environment. The experiments were conducted during 1996-2000 in commercial rain fed wheat (Triticum aestivum L.) field of a xerosol (Calcic Haploxeralf) in the Central Negev, Israel. Amounts of 0, 100 and 300 m³ ha^-1 CMSW were added annually to the soil surface prior to the rainy season. Water content in the soil was determined four times, soil salinity, and sodicity were determined twice and heavy metals in the soil and the yield of wheat were determined once every year. Yield was determined at the end of each growing season. Application of CMSW increased available water in the root zone mainly due to reduction in evaporation, and almost doubled the yields. No considerable increase in salinity, sodicity and heavy metals was noted in the root zone following CMSW application. Our observations suggested that annual application of CMSW at the rate of 100 m ³ ha^-1 was enough to significantly minimize rainwater losses and increase yield under dry-land conditions, without posing specific hazards to the environment.