Effects Of Cultivation Methods On Grain Yield Formation And Nutrient Use Of Winter Wheat

Dryland in northwest area of China is famous for the abundant resources of land, light and heat, and has the great potential for developing crop production. However, the increase of crop yield is seriously limited due to water deficiency in this area. Consequently, rational use of water resource with high efficiency is the key step to achieve high crop yield with good quality. Although uptake and use capability of water and nutrient of crops was dominated by the inheritance characteristics, environment conditions and crop management practice can also play important roles in increasing grain yields. Optimizing cultivation measures and nutrient and water supply can improve crop assimilation and growth, and elevate grain yields. A long-term field experiment, initiated in 2002, was used to study the effects of cultivation methods on grain yield formation and nutrient use by winter wheat. The Crops were planted at 0, 120 and 240 kg N hm^-2 on the basal application of 43.6 kg P hm^-2, and under five cultivation patterns including the conventional no-mulching (CNM, no soil surface mulching and no supplemental irrigation), the plastic film mulching (PFM, mulching soil surface with plastic film over the entire growing season), the crop straw mulching (CSM, mulching soil surface with crop straw over the entire growing season), the supplemental irrigation (SI, irrigating the crop at the critical growth stage), and the ridge-furrow cultivation (RFC, mulching the ridge with plastic film for harvesting rain water, and in the furrow seeding winter wheat then mulching soil surface with crop straw). Determination was performed on biomass, contents of nitrogen, phosphorus and potassium in plant, and contents of soil water, mineral nitrogen in different growth stages. The main results were shown as follows:1.Mulching soil surface with plastic film was found to elevate tillers, biomass and grain yields in most cases. However, it also increased the invalid tillers, and the percentage of effective tiller and harvest index were decreased as a result. PFM treatment significantly increased dry matter accumulation in the above ground part in the nutritive growth stage, promoted the contribution of pre-heading assimilation to grain in reproduction stage. Grain yield and biomass for the CSM, SI and RFC treatment were not elevated compared to the conventional no-mulching treatment. The main reasons were lay on the reduced tiller amounts, dry matter accumulation in nutritive stage and less dry matter remobilization from vegetative...