The effects of residual phosphate (P) fertilizer were monitored for six seasons on Mediterranean
grassland. The phosphate fertilizer was originally applied annually at three rates (0, 25 and 60 kg
P2O5/ha) for 7 years (1984–1990) to phosphate-deficient grassland at Tel Hadya, northern Syria. The
herbage biomass productivity, botanical composition and the seed bank in the soil were monitored
for six seasons (1991/92–1996/97). The experiment was grazed at two annual stocking rates
(1·1 sheep/ha (low) and 2·3 sheep/ha (high)). The experimental site was typical of native grassland
within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and
steep slopes.Available soil phosphorus in May 1991 was 6·5, 20·8 and 40·1 mg P/kg under the 0, 25 and
60 kg P2O5/ha treatments and 6·6, 13·4 and 14·8 mg P/kg respectively, in May 1997. Yields of both
legumes and total herbage (legume+grass+other species) were significantly influenced by the
residual phosphate. Legume yields were between 6- and 7-times the control yield in the first two years
of the study. This decreased with time but was still in the range of 1·5 to 1·9 times the yield of the
control in 1997, six years later. Total herbage yield was consistently higher on the plots previously
fertilized with P, which ranged between 1·5- and 2·5-times the control. Both legume seed and grass
seeds were significantly larger with residual P, which ranged between 5·4- and 2·0-times the control
for the legume and 2·5- and 1·4-times for the grasses. All these factors have practical implications for
the use of P fertilizer on grassland which could help control soil erosion and improve livestock
production on marginal lands on which farming communities largely depend.
Changes in availability and uptake of soil phosphorus influenced by management practices and crop growth stages under peanut cultivation in medium black clay soil of Saurashtra region, Gujarat
