Grazing, Mulching, And Removal Of Wheat Straw In A No-till System In A Semi-arid Environment
Straw mulching and no-till technologies have improved grain yields in the 250-mm-rainfall wheatbelt of the northern Negev region of Israel. However, mulching the soil with straw is incompatible with the traditional practice of baling the straw for animal fodder and/or using the stubble for sheep grazing. We compared 3 wheat straw management strategies in a no-till production system, for 4 consecutive growing seasons. The treatments were straw mulching (SM), manual removal of the straw (MR), and grazing by sheep of the straw and stubble (G). The amount of straw cover for treatment SM declined over the years, and did not reach the minimum threshold value deemed necessary to improve wheat grain yield in the region. Grain yield (1150 kg/ha) and quality (volumetric mass, 75 kg/100 L; crude protein, 127 g/kg) did not differ significantly among the 3 treatments. The density of the total seedbank was 3623, 1675, and 1499/m2 in the G, MR, and SM treatments, respectively. This difference was due to a greater amount of small grasses (e.g. Rostraria smyrnacea). However, treatment G hosted significantly less mole and vole activity than treatments SM and MR (1.1 v. 13.6 and 12.4 dens/ha, respectively). Our data suggest that, relative to straw and stubble grazing, straw mulching offers no advantage that can be quantified in terms of wheat yield, under the conditions of this study.