Livestock production on Mediterranean grassland in relation to residual phosphate

Available pasture, liveweight gain, milk yield and supplementary feeding of Awassi sheep were monitored for four seasons (1991/92 to 1994/95) on pastu re fertilized with superphosphate between 1984 and 1990. The experimental p lots received three rates of phosphate (0, 25 and 60 kg P2O5/ha) annually, but no application after September 1990. The experiment was grazed at low ( 1.1 sheep/ha per year) and high (2.3 sheep/ha per year) stocking rates. The experimental site was typical of communally owned grasslands within the ce real zone of west Asia, where cropping is not possible because of shallow, stony soil and steep slopes. Plots with residual phosphate contained signif icantly more herbage and supported heavier animal liveweights, especially i n the first two seasons. Milk yield and lamb production were greater and th e need for supplementary feeding was reduced due to increased herbage. The results suggest that benefits of residual phosphate on pasture and livestoc k production can be considerable and should be included when assessing the value of applying fertilizer to degraded marginal lands in west Asia. Provi ded that the stocking rates remain within the range tested in the study, th e pasture would suffer no harm. However, the higher stocking rates now prac ticed in the spring under communal grazing might severely limit flowering a nd seed-set. The property right to own or use the grazing land is seen as a key factor, deserving attention from governments in west Asia in order to apply new technologies to improve degraded marginal lands.