The annual nutrient return through litterfall amounted to 48.528 kg·hm -2 N, 2.324 kg·hm -2 P and 19.843 kg·hm -2 K in the mixed stand and 37.163 kg·hm -2 N, 2.339 kg·hm -2 P and 18.406 kg·hm -2 K in the pure stand.
The experimental results showed that the application amount of pure N 16.20kg/667m~2 had the best effect on annual green asparagus under plastic tunnel,which increased yield by 24.24% and output value by 27.13% compared with the control plot of conventional application(pure N 21.72 kg/667m~2);
Compared with native pasture, cultivation of annual pasture resulted in significant reductions of total organic C by 36% in 0~10 cm, 29% in 10~20 cm and 41% in 20~30 cm depths, whereas in perennial pastures total organic C decreased by 18% only in 0~10 cm depth.
In the condition of different base fertilizer,determine the grass production、root length and root depth of annual Rye grass. The result showed that when the base fertilizer was manure 1 200 kg/667m2 + compound fertilizer 100 kg/667m2,the annual Rye grass production was highest up to 53 226.6 kg/hm2,and the root was the most developed.
Based on the polymer and plastic analogy, the annual market for products that carry nano-components, including all computer chips, half of pharmaceuticals and half of chemical catalysts, will reach $1 trillion by 2015.
(2) During decomposition, the annual return amount of N, K and Mg in fine roots of black locust was highest, followed by the mixed fine roots of the two species, and then the fine roots of poplar.
The two sites have similar altitudes, soil types, annual mean rainfall and seasonality of dry and wet.
The main difference between these two sites is the annual mean temperature with the difference of 3.7°C.
Annual retention of N was 119.47 kg/hm2, return was about 84.13 kg/hm2, among which litterfall was 78.49 kg/hm2 and throughfall, 5.64 kg/hm2.