its total value was 1.25×109yuan/a, in which the economic values of relenting soil nutrition, reducing abandoned land and reducing silt deposition were 1.10×109yuan/a, 1.64×107yuan/a and 1.34×108yuan/a respectively.
Based on the ample N,P and K fertilizer,the experiment in the application effect of 8 kinds of mixed trace element fertilizers(Zn,Fe,Mo,Co,B,Cu,Se and Mn)sprayed on trace element's nutrition of Medicago sativs was conducted.
As a result of improvement the nutrition , it can increase 64-168 kilograms per mu yield of fresh hops, and raise the average acid content from 6. 1-6. 9% to 7. 3-7.6% , it is higher than the export standard.
All testing sows were fed basic diet which other nutrition elements wre identical, and energy concentration were different, they were grouped 3400kcal/kg(A), 3200kcal/kg(B)^ 3000kcal/kg(C)> 2800kcal/kg(D) DE, and gradient difference was 200kcal/kg.
However, in habitats lacking sufficient nutrition and with higher light intensity, survival rates and space-occupying ability of two kinds of seedlings (sexual and asexual produced) were low and the space would be preempted by grown-up plantlets.
In terrestrial ecosystems, soil nutrient regimes at a plant's living site generally represent the plant's "nutrition habitat".
Plant species frequently well adapt to their original "nutrition habitat" during a long process of evolution, and the apparent preference for ammonium or nitrate nitrogen source (NH4+ or NO3-) might be an important aspect of the adaptation.
A large number of studies show that the "nutrition habitats" associated with primary forest soils are typically dominated by NH4+ rather than NO3-, generally with NO3- content much lower than NH4+.
Higher soil N had advantage to non-leguminous plants growth on nutrition-poor sand land definitely.