Effects of fertilization and grazing on the nutrient quantity of a grassland

The experiment was conducted on a grassland located at Andigonia, Kilkis, Northern Greece. Calcium-ammonium nitrate was used as the source of N and super phosphate was the source of P2O3. Three levels of fertilization (0, 100:100 and 200:100 kg/ha) and three levels of grazing (0, 0,8 and 1,6 sheep/ha/year) were used. The quantity of N and P in the standing production was increased by fertilization. On the contrary, grazing decreased them. In addition, fertilization increased the available phosphorus of the soil, without changing the organic nitrogen, while grazing decreased them.