Sheep Production on Seeded Legumes, Planted Shrubs, and Dryland Grain in a Semiarid Region of Israel

Abstract

During a period of 10 years in an area in which rainfall ranged between 170 and 413 mm, grain yields ranged between 0.8 and 3.6 tons per hectare. When grazing was combined with cropping, between 20 and 200 kg of lamb liveweight were produced per hectare at different stocking rates and in different years. Grazing the grain fields had left enough grain to be harvested only under stocking rates lower than 0.4 hectare per ewe in most years, and under stocking rates lighter than 0.2 ha/ewe only in a year in which ungrazed fields produced 3.5 tons of grain per hectare. Of several legume species tried in the same area, Medicago polymorpha and M. tribuloides (= M. truncatula) survived to form dense swards of 3-6 t/ha dry matter yields. After 5 years, legumes were largely replaced by ruderal annuals. This grass sward forms a highly palatable pasture with yields equaling those of the legumes, probably due to the high nitrogen build-up in the soil. At stocking rates of 0.4-0.6 ha/ewe, sheep could be maintained on this pasture without supplements the whole year round. Annual lamb yields ranged from 15 to 40 kg/ewe and from 40 to 80 kg/ha. Fertility disorders, apparently due to estrogenic activity in the medics, were recorded in one of the high legume years. Native saltbush (Atriplex halimus) was planted at a rate of 1600 shrubs/ha as a range improvement technique. Shrub development was excellent and the shrubs soon formed a dense, impenetrable stand, crowding out most of the annual herbaceous grass and vegetation. Sheep performance on this vegetation was poor in comparison with unimproved native pasture.