Effect of Irrigation and Fertilizer on Sandy Grassland Productivity in Horqin Sandy Land, North China

A split-plot field experiment, with watering as main plot and with fertilizer as sub-plot, was conducted in degraded sandy grassland in Horqin Sandy Land. Four treatments (0mm, 30mm, 60mm and 90mm) for watering and four treatments (0 kg/hm, 150 kg/hm, 375 kg/hm, 600 kg/hm) for fertilizer as nitrogen were designed. Results showed that the soil water storage was significant affected by rainfall in this grassland. Watering treatment had significant influence on the soil water storage in 0-30cm depths but no significant influence for deeper than 30cm soil layer. Both the watering and fertilizer took important roles in increasing biomass in degraded sandy grassland. The highest above-biomass appeared at the plot in 90mm with 128.3g/m among watering treatments and at the sub-plot in 600 kg/ha with 147.3g/m between fertilizer treatments, respectively. The water consumption and WUE of each of treatments was 379mm / 0.28 kg/mm·hm in 90mm treatment, 350mm/0.38 kg/mm·hm for 60mm treatment, 313mm / 0.34 kg/mm·hm for 30mm treatment, and 294 mm /0.35 kg/mm·hm for control (0mm), respectively. Based on comprehensive analysis, we can conclude that the basic amount of evapotranspiration in this grassland was 294mm. Keywords-Horqin Sandy Land, Biomass, Water consumption of vegetation, Water use efficiency, Irrigation and Fertilizer, Land productivity