Study On The Effects Of Different Forage/crop Planting Patterns In Sichuan Purple Soil Hills

Sichuan is a big agricultural province, as the population is increasing, arable land is declining, and serious soil erosion, uncoordinated structure of planting and aquaculture, food security situation in Sichuan faces serious challenges. Making full use of purple soil resources in Sichuan hilly areas, increasing output per unit area, protecting and improving the environment, preventing soil erosion, so to achieve sustainable development, explore a development model of agriculture which could ensure food production and also to ensure the healthy development of animal husbandry is imperative.Based on the former extensive researches, this paper observe and evaluation the soil and water conservation benefits, economic benefits and effects of soil physical and chemical properties of different forage/crop intercropping in the city of ziyang in Sichuan purple soil hills in order to find the effects for controlling soil erosion, improving soil fertility, increasing crop output, increasing the role of farmer income of different crops and different planting patterns in purple soil hills.This research is based on the introduction of forage(Legumes and Grasses) in Sichuan traditional crop pattern(wheat/corn/sweet potato). This paper choses location randomized block experiment, experiment plot are 5m*20m standard runoff plot, there ara 5 treatments,3 times repeat for the research.After 3 years observations, the main results are as follows:1 In 2007-2009, the surface runoff and sediment loss of test areas in 5 different cropping patterns were affected by rainfall which happened mainly in the annual May to October. There was large inter annual variabiiity for surface runoff and sediment loss, and each treatment showed similar changes.Runoff and sediment production were significantly affected by different previous crops collocation. For the average of 3 years, In CK, A, and B, the 3 treatments planted corn and sweet potato in summer, the surface runoff and sediment yield of b treatment(oat/ryegrass-corn/sweet potato)is the least, and then is A treatment(wheat/ryegrass-corn/sweet potato), The runoff and sediment yield of CK((Wheat/corn/sweet potato) is the highest.because of different utilizations, crops vegetation which changed by cutting, the runoff and sediment productions are different. The runoff and sediment yield of D treatment(wheat/vicia villosa-sorghum/sweet potato) is the most in 5 treatments. Implementation of different forage intercropping patterns in Sichuan purple soil hills must consider about crop varieties, plant height, plant density thinning and other factors.2 After planting forage, during whole crop growth period in 2009, soil moisture in the layers showed obvious seasonal variation. Soil moisture among the treatments are changed with time. Soil moisture in 0-10 cm layer is changed tremendously.The tendency of soil moisture in 10-20cm is mostly same as which in 0-10 cm layer, but its change intensity is weak than which in 0-10 cm layer. Soil moisture in 20-40 cm layer has small change ranges.The soil moisture of different cropping patterns is significantly affected by rainfall, vegetation and soil itself3 For 3 years of forage/crop intercropping, the soil pH has been changed, the pH of 0-20cm soil layer is less than 20-40cm soil layer, each treatment changes in the two layers was consistent, pH value of the other treatments were lower than ck, pasture can effectively reduce soil pH value, the change of soil organic matter in two layers is consistent. As the developed root system, more soil humus will be produced after root decomposition, then the soil organic matter content has been increased. Total N,available N,available P and available K of other treatments are lower than CK. The contents of available nutrients of upper soil is more than subsoil. Mainly because root distribution and fertilizer conversion are most in the upper soil.Because of different crop combination, growth situation, absorption of water and fertilizer is very different. To meet the needs of crop growth, each treatment there are some differences in fertilization. After the introduction of grass, especially for grass which needs cutting for many times, we should use more nitrogen fertilizer and phosphate fertilizer to ensure the normal growth need.for this can reduce the excessive consumption of soil nutrients, prevent the impoverishment of soil, and ensure the crop production.4 For average from 3 years, after planting forage, previous crops of different cropping patterns, lead to different nutrient absorption, root stubble, residues in soil, and affection of soil moisture, so that will promotes or prevents the growth of after crop. Except B treatment(oat/ryegrass-corn/sweet potato), other 4 treatments planted wheat in winter.but plant forages in wheat reserve line, Will have competitive effects about water, sunshine, fertilizer between wheat and forages, compared with CK the yield of wheat of A, C, D 3 treatments reduced by 6.80%,5.55%,4%, the yield of corn A, B 2 treatments reduced by 7%and 3%.there were not a substantial impact of reduction of food production. Legumes can significantly increase the yield of sweet potato. Compared with CK, the yield of sweet potato in C, D2 treatments increasd significantly by 30% and 20%.5 Planting forage in the blank lines, fresh forage yield can be doubled, the hilly farmland of forage dry matter production can be increased significantly. Efficient production efficiency and feed protein output and crop production of hill farmland will be increased production which could provide excellent protection for the livestock development.