Study On The Effects Of Phosphorus On Alfalfa Growth And Seed Yield

Studied on the effects of alfalfa seed yield and the growth indicated: the plant height with different Phosphorus treatment has significance influence (p<0.01)in mature stage. Phosphorus can enhance the height,maily through increasing nod number,when Phosphorus application was increased ,at same time height increased. Alfalfa growth speed appeared the variation of'slow～quick～slow', growth speed was improved. With different Phosphorus treatment, stem diameter, nods number and No.shoots/plant had significance influence(p<0.01). Phosphorus had obviously increase stem diameter, nods number number, No.shoots/plant and root weight, these were increased while application improved, .but it had littler significance influence on nods length and dreased the rate of losing pod and flower. As improved Phosphorus application, the rate of losing pod was fall down. Phosphorus application significantly increased the accumulation of stem and leaf dry weight ,and accumulation speed at branching stage ~ florescence, its advantage for nutritive organ growing. leaves area in mature stage was less than it in florescence , Phosphorus had littler significance influence on it.Phosphorus application significantly increased the concent of soil available Phosphorus, from branching stage to pod stage, it declined, the tendency which dropped slowly along with increased Phosphorus application.The totle Phosphorus content of nutritive organ and fructification was also increased by application of Phosphorus. At all stage of alfalfa, Phosphorus always has the trend which transfers toward the growth center of this stage. the total Phosphorus content in overground plant organ increased upw Phosphorus the ground, the increase rank order of it was stem, leaf in seedling stage, stem, leaf, bud Phosphorus stem, leaf, flower in florescence and root, stem, leaf pod, seed in seed stage.In pod stage, Phosphorus application significantly increased No.shoots/plant, No.inflo/plant, Seed weight/plant that had significant difference(P<0.05)among all treatment. No significant d- ifference was feld on No.pods/plant, No.seeds/pods and Thousand seed weight among all treatme- nt at pod stage , and increased the rate of black pod/flower, ahead of growth stage.The total phosphorus content of root, stem and pod demonstrated a significant nonlinear relation with seed yield, the totle phosphate content of leaf and seed, the concent of soil available Phosphorus and Phosphorus application had a significant linear relation with seed yield at pod stage. The concent of soil available Phosphorus was 3.18kg/mg, when the amount of phosphorus is 135kg/hm~2,alfalfa seed yield can definitely be increased by 75%,and reaches the amount of 564.8kg/hm~2, Hardseed, germination and 1000seed weight had litter significance influence.