The Research Of Alfalfa About Growth Character On Different Site Congditions In Weibei Highland

Alfalfa is the most popular perennial legume forages ,and it is also a kind of quality plants which can keep the soil and water conservation, and improve the ecological environment .this study takes six kinds of site conditions as research object , it includes the top of shady slop, the middle of shady slop, the bottom of shady slop, the top of sunny slop ,the middle of sunny slop, the bottom of sunny slop. Systematic study on alfalfa growing in different site conditions is about growth law and dynamic change law of soil water and nutrient in 0-200cm soil layer. Quantitative Analysis is on correlative changing regularity of growth traits and biomass. The result as follows:1. Different site conditions are very significantly affect alfalfa biomass. From different slope positions aspects, the alfalfa's biomass on the bottom of slop is higher than the top of slop by 53.7%. From different slop aspects, the alfalfa's biomass in shady side is higher than the sunny side by 94.7%. The plant height improved by 36.0%, branch number improved by 3.9%, density improved by 22.6%, single stem weight improved by 2.1%.2. Through sizing analysis of the alfalfa biomass and growth character, we know that plant height and branches number directly affected biomass very significantly, but single stem indirect impact the yield.3. Growth rate of alfalfa on different site conditions is remarkable different. The growth rate is different from the bottom of shady slop to the top of sunny slop: the bottom of shady slop> the middle of shady slop> the top of shady slop> the bottom of sunny slop> the middle of sunny slop> the top of sunny slop. From the different stubble times aspects, the growth rate of the first stubble is obvious faster than the second. From the different site conditions, except the middle of sunny slop, the second stubble is slower than the first stubbly by over 43% in the other site conditions. From the growth rate of the two stubbles, the shady slop is faster than the sunny slop, and the bottom is faster than the top.4. The growth process curve of alfalfa is like"S", the fast growth lasted 21-135 days. The day growth rate of alfalfa in the bottom of slop is the fastest of all, and the top of sunny slop is the slowest. The regular change of different site conditions is like"fast-slow-fast". From regeneration performance aspect, the regeneration performance of alfalfa in bottom of the shady slop is stronger than the others. 5. Through analyzed the water content of the alfalfa's soil from 0cm to 200cm in different site conditions, the 0-200cm soil can be divided into three parts: the fast change layer, the slow change layer and the stability layer. The water storage of alfalfa in different site conditions is more and more with the slop position dropping. The water storage of the bottom site is obvious higher than the top. The water storage of the shady slop is obvious higher than the sunny slop. The biomass of alfalfa related the water storage closely (R2=0.958).6. In the organic matter and other available nutrients, they related each other closely (R2=0.992). Through analyzed the organic matter and other available nutrients of the alfalfa's soil from 0cm to 200cm in different site conditions, the available nutrients reducing with the soil depth deepening. There are the most available nutrients in the surface soil. In the 20-140cm, the content of the available nutrients change seriously-long, slow , and rolling . In the 140-200cm soil layer, the content keep calm. From the different site conditions, the content of available nutrients in the bottom of the shady slop is the most of all, and the top of sunny slop is the smallest, and the shady slop is more than the sunny slop.