Nutrient Cycling and Trend Modeling of Black Locust Plantation Ecosystem in Gullied Loess Plateau Area

Liu Zengwen1), Li Yushan2) Liu Bingzheng1) Wang Youmin1)(1)Dept. of Soil and Water Conser., NWFC, Yangling, Shaanxi 712100; 2)Institute of Soil and Water Conser., Chinese Academy of Sci./Min. of Water Conser

gullied loess plateau; black locust; nutrient cycling; trend modeling

Based on measurement of biomass, prodcutivity, water balance and nutrient content, the nutrient cycle proceses of black locust plantation ecosystem in gullied loess plateau has been studied systematically. The results showed that the total nutrients accumulations were N 10.940, P 3.755, K 154.611,Ca 169.092, Mg 18.435, S 1.487 t/hm2; the nutrient biocycling fluxes were in the order of Ca>N>K>Mg>P>S; the uptakes of nutrients from soil to produce l ton dry material of biomass were about to N 11.67, P 0.72, K 3.66, Ca 15.08, Mg 2.25, S 0.34 kg, the annual net accumulations in the total ecosystem were N 1.8073, P 0.2106, K 1.3756, Ca 2.7881, Mg 0.4400, S 0.0621 kg/hm2, but the annual net shortages in the soil layer distributed concentratively with roots were N 89.696, P 5.492, K34.479, Ca 88.991, Mg 15.270, S 2.511 kg/hm2. In addition, the trend models of nutrient cycling could be used to predict the nutrient storages in every compart of the total ecosystem.