The Soil Nutrients Experiment About Two Herbages In Hilly And Upland Farmlands Area Of Western Sichuan

At the hilly and upland farmlands area in west Sichuan province, the trees + herbage vegetation model is suitable for slope farmlands of converting lands into forests. But every grass has its biological, ecological characteristic and its endurance under shaded or drought or barren soil condition. According to the natural condition of an area, it is one of the key techniques to choose reasonable kinds of herbage for the trees + herbage vegetation model. From the research before, if choosing the feat herbage, adopting the reasonable cultivation and technical measures, studying from the nutrient relation, getting the nutrient regulation, evaluating the nutrient condition of the trees + herbage vegetation model, to make sure of growth time limit of the herbage and adjust canopy closer, it may keep more stable and excellent the trees + herbage vegetation model.Two kinds of herbage (Trifolium repens L. and Hemarthria compressa) were planted and its soil were carrying on the fixed site investigation with common management and harvest in 2 years(2004 and 2005) and fertilized Hemarthria compressa in Aug., 2005. From the data including biomass, growth competence, nutrient content of the herbage and the physical and chemical property of the top(0-20cm) and lower (20-40cm)level soil of each herbage were gotten, the analytic result were showed as follows:1. Trifolium repens L. and Hemarthria compressa planted in poor soil could grow normally during 2 years. The canopy closer of Trifolium repens L. and Hemarthria compressa respectively was 60%and 100%. The biomass of Hemarthria compressa was 164400kg/hm~2 in 2004 and 61500kg/hm~2 in 2005. And Trifolium repens L.' was 56800kg/hm~2 in 2004 and 48700kg/hm~2 in 2005.2. The biomass and the growth competence of every period and of that years, Hemarthria compressa were better than that of Trifolium repens L., but nutrients content of the Hemarthria compressa were all lower than that of Trifolium repens L. , and the two herbage trended worse year by year. There was correlation between the fresh weight(fw) of the upper part and the stem diameter(sd), density(d), stem length (sl)and the canopy closer (c)of Hemarthria compressa and Trifolium repens L. about Hemarthria compressa ,fw =-0.286 s1 +0.573 sd +0.850 d -4.681; about Trifolium repens L , fw =0.991 s1 +0.2 sd +(-0.331) c+0.114d-0.738.3. The correlation between the content of total N, total P, total K of the herbage and hydrolysable nitrogen, available phosphorus, rapidly available potassium of top level soil that of the Hemarthria compressa was respectively Sig.;The correlation between the content of total N, total P, total K of the herbage and the content of total N, total P, total K and...