Effects Of Located Rotational Tillage And Fertilization On Continuous Cropping Wheat Field In Weibei Highland

In order to restrict the effect of drought and less rain on agricultural production in Weibei highland, as well as the malpractice of long term single tillage, and increase wheat yield of dry farming. The located experiments of balanced fertilization(BF), low fertilization(LF) and conventional fertilization(CF) levels and NT/ST(no-tillage in first year, subsoiling in second year, again no-tillage followed by alternating the next year), ST/CT(subsoiling in first year,conventional tillage in second year, again subsoiling followed by alternating the next year),CT/NT(conventional tillage in first year, no-tillage in second year, again conventional tillage followed by alternating the next year) rotational tillage, NT/NT(continuous no-tillage),ST/ST(continuous subsoiling) and CT/CT(continuous conventional tillage) were conducted in summer fallow period during 2007-2015 in Heyang, Shaanxi. This study mainly analyzed the effect of different fertilization and rotational tillage on soil physical characteristics, soil moisture and soil fertility, as well as the agronomic trait, physiological property and yield of winter wheat, which was for the scientific basis of optimum fertilizer level and soil rotational tillage of dry farming wheat. The main research results were as follows:1. Effects of rotational tillage patterns on soil physical properties. The rotational tillage could improve soil bulk density and soil porosity. Compared to continuous no-tillage, soil bulk density of NT/ST, ST/CT and CT/NT treatments decreased by 2.7%, 2.4% and 4.1%, and soil porosity increased by 4.0%, 3.7% and 5.9% separately. The mechanical stable aggregate and water stable aggregate content(>0.25mm) in 0-40 cm under different rotational tillage treatments were all higher than the three kinds of continuous tillage, among which the NT/ST performed the best.2. Effects of rotational tillage patterns on soil moisture conditions in different rainfall years. In different rainfall years, average soil water conservation rate of humid years was7.7% higher than that of dry year. Soil water storage rate under NT/ST was 14.4%, 21.7% and26.9% higher than under ST/ST, CT/CT and NT/NT treatments in dry year, respectively.Annual average soil water storage in 0-200 cm of humid year was 10 mm and 7mm higher thanthat of normal and dry year. Annual average soil water storage in 0-200 cm under NT/ST was5.7%, 5.2% and 4.5% higher than under NT/NT, ST/ST and CT/CT treatments in humid years,and was 3.3%, 3.3% and 5.1% in normal years. Especially in the late growth stage of wheat,NT/ST still performed well obviously in humid years, while the ST/CT performed well in dry year, significantly increased 8.7%, 5.2% and 5.5% than under NT/NT, ST/ST and CT/CT treatments.3. Effects of fertilization and rotational tillage patterns on soil fertility. The soil organic matter, nitrogen, phosphorus and potassium content were optimum under balanced fertilization, and the soil organic matter contents in 0-60 cm soil layer under balanced fertilization was 1.9% and 1.4% higher than under conventional fertilization and low fertilization. The rotational and continuous tillage patterns both are conducive to improve soil nutrient content, and the NT/ST treatment was better. The soil organic matter, total nitrogen and total phosphorus content in 0-60 cm soil layer of NT/ST treatment were 4.4%, 4.2% and6.8% higher than NT/NT, 4.4%, 1.5% and 8.4% higher than ST/ST, and 6.1%, 9.3% and13.6% higher than CT/CT, respectively. After 8 years of rotational tillage, the increase rate of soil organic matter under NT/ST, ST/CT and CT/NT were 1.11%, 1.07% and 0.94%, and the increase rate of total phosphorus were 3.16%, 3.29% and 2.83%, respectively.4. Effects of fertilization and rotational tillage patterns on agronomic traits and physiological characteristics of winter wheat. The stems of winter wheat, plant biomass and photosynthetic rate were optimum under balanced fertilization, and the plant dry matter accumulation at maturity under balanced fertilization were 7.5% and 15.2 % higher than under low and conventional fertilization. Compared with low fertilization, balanced fertilization and conventional fertilization were significantly increased the average chlorophyll content by 18.7% and 11.5%, and the soluble sugar content were significantly increased by 6.0% and 4.9%. The CT/NT and NT/ST treatments showed higher stems number,photosynthetic rate and transpiration rate of winter wheat and the NT/ST and ST/ST treatments showed higher plant dry mass, chlorophyll and soluble sugar content. Chlorophyll and soluble sugar content under NT/ST treatment were increased 10.3% and 14.4%, 13.8%and 16.1% separately.5. Effects of fertilization and rotational tillage patterns on yield and water use efficiency of winter wheat. Under three different levels of fertilization, balanced fertilization was more conducive to improving spike number, kernel per spike and 1000-kernels weight, resulting in increases grain yield of winter wheat. The rainfall levels received larger effect of winter wheat yield and water use efficiency, and it shows humid years >normal years >dry years. The grain yield and water use efficiency under NT/ST treatment was better in humid years and normalyears. In humid years, the grain yield and WUE under NT/ST was close to ST/ST treatment,and compared to NT/NT and CT/CT, the yield was increased by 7.3% and 7.5% separately,and WUE significantly increased by 8.9% and 15.7%. In normal years, compared with NT/NT,ST/ST and CT/CT treatments, the yield under NT/ST treatment increased 13.4%, 2.7% and11.1% respectively, WUE increase 16.4%, 9.0% and 31.1% respectively. In dry years,compared with NT/NT, ST/ST and CT/CT treatments, the yield under NT/ST treatment were increased by 9.3%, 18.4% and 21.0% separately, and WUE increased by 16.8%, 19.5% and20.0%. The yield under ST/CT treatment was 6.6%, 15.4% and 18.0% higher than NT/NT,ST/ST and CT/CT treatments separately. The WUE under ST/CT treatment was 14.1, 16.7%and 17.2% higher than NT/NT, ST/ST and CT/CT treatments separately.In conclusion, balanced fertilization levels with NT/ST tillage pattern can improve soil structure, increase soil moisture storage rate of summer fallow period, maintain soil moisture and increase soil fertility, optimize agronomic and physiological characteristics of winter wheat, and also be conducive to increasing and stabilizing the wheat field. So the balanced fertilization levels with NT/ST treatment was a more appropriate fertilization and rotational tillage pattern for the continuous cropping wheat field in Weibei Highland.