| In order to change the raditional tillage and overbalance fertilization in grain field,which is prevalent in Weibei Highland,to achieve the goal of steadily increasing the rainfall infiltration,soil storage and efficient utilization of the limited precipitation,and continuously improving the drought resistance,fertilization and production capacity of grain fields,so as to promote the sustainable development of grain production in WeiBei Highland,a long-term experiment of fertilization and tillage was carried out in Heyang,Shaanxi from 2007 to 2018.The fertilization treatment includes conventional fertilization(CF),balanced fertilization(BF)and low fertilization(LF),the tillage treatment includes NT/ST(no-tillage in first year,subsoiling in second year,a new round of soil tillage begins next year),ST/CT(subsoiling in first year,conventional tillage in second year,a new round of soil tillage begins next year),CT/NT(conventional tillage in first year,no-tillage in second year,a new round of soil tillage begins next year),NT/NT(continuous no-tillage),ST/ST(continuous subsoiling),CT/CT((continuous conventional tillage).This study discussed the effect of different fertilization and cultivation patterns on soil moisture,soil physical structure and soil fertility,analyzed the response of nutrient absorption,agronomic trait and yield of winter wheat to the change of soil water and fertilizer,which is based on the experimental observation data of two production years in 2015-2016 and 2016-2017,so as to provide scientific basis for the selection of reasonable fertilization and tillage pattern in the Weibei Highland.The main results were as follows: 1.Effects of fertilization and rotational tillage on soil moisture and water use efficiency.In the long-term application of fertilizer,low moisture layer of soil appeared,and the low moisture layer depth was 220 cm under conventional fertilizer,the balanced fertilization treatment was 200 cm.After 10 years of continuous wheat production,The average soil moisture content of conventional fertilization decreased by 4.59%,and the balanced fertilization and low fertilizer increased by 11.93% and 11.04% respectively.The soil water storage was the highest in low fertilizer treatment before winter,and the balance fertilization was 20.33% and 7.69% higher than conventional fertilization and low fertilizer after winter.6 kinds of tillage treatment for a long time,The average soil moisture content of NT/ST,ST/CT,CT/NT,NT/NT and ST/ST treatments increased by 12.44%?6.92%?10.69%?4.70% and 4.62%,but the average soil moisture content of CT/CT treatments decreased by 2.62% compared with those before the test.From the period of seedling establishment,the difference between traditional CT/CT and other treatments was gradually increased.NT/ST is more effective in preserving rainfall and improving moisture content,which is beneficial to water accumulation in the deep soil.2.Effects of fertilization and rotational tillage on soil physical propertiesLong-term rotational tillage can reduce soil bulk density,increase soil porosity more effectively.Compared with before,The soil bulk density of NT/ST,ST/CT and CT/NT treatments decreased by 4.39%,3.95% and 4.73%,and NT/NT,ST/ST and CT/CT increased by 2.65%,1.55% and 2.23%.Because the smallest soil disturbance,the Mechanical stable aggregate under NT/NT is the highest,followed by NT/ST.The content of water stable aggregate under NT/ST treatment was 7.42%,1.83%,8.74%,6.01% and 15.07% higher than ST/CT,CT/NT,NT/NT,ST/ST and CT/CT treatment.NT/ST could significantly increase the content of water stable aggregate in the 0-30 cm soil layer,especially the 20-30 cm.3.Effects of fertilization and rotational tillage on soil chemical structureThe contents of soil organic matter,total nitrogen,total phosphorus,total potassium and available potassium were highest under balanced fertilization,and the content of alkaline nitrogen and available phosphorus were the highest in conventional fertilization.The nutrient contents of different tillage treatments were decreased with the increase of soil layer.In the whole,the nutrient contents was higher in NT/ST,in which the soil layers were evenly distributed,ST/CT and ST/ST can significantly increase the nutrient content of the lower soil,NT/NT had a higher nutrient content in soil surface layer.After 10 years of straw mulching and different tillage,the soil organic matter,alkaline nitrogen,total phosphorus,available phosphorus and potassium content were all improved compared with those before the test.The total nitrogen content is lower than that before the test.Compared with before,the available potassium content was increased under NT/ST,but ST/CT and CT/NT was not increased significant.The available potassium of 3 kinds of continuous tillage NT/NT,ST/ST,and CT/CT were decreased by 3.43%,2.19% and 5.54%.4.Effects of fertilization and rotational tillage on nutrient uptake and agronomic traits of winter wheatThe nutrient content of conventional fertilization was higher than that other fertilizing methods in the early stage of procreation,but the nitrogen content under balanced fertilization were 1.30% and 7.73% higher than under cventional fertilization and low fertilization,the phosphorus content were 3.08% and 13.56%.The biomass of conventional fertilization is the highest during elongation stage to heading stage,balanced fertilization is the highest during grouting period to maturity stage.The chlorophyll content of flag leaf under balanced fertilization was 0.39% and 7.35% higher than under cventional fertilization and low fertilization.The photosynthetic rate under balanced fertilization was 24.76% and 11.00% higher than under cventional fertilization and low fertilization.In the early stage,there was a high nitrogen content in wheat under NT/NT and ST/ST,and rotational tillage patterns were beneficial to root deep roots and promote nutrient absorption in the middle and late stage,especially the NT/ST treatment.The average nitrogen content and phosphorus content under NT/ST treatment were 3.63%,6.24% higher than other treatments.The biomass of wheat was high in ST/CT,NT/ST,The chlorophyll content of the flagellum under NT/ST was 13.82% higher than other treatments.5.Effects of fertilization and rotational tillage on yield and economic benefit of winter wheatUnder three different levels of fertilization,compared to conventional fertilization and low fertilization,the spike number under balanced fertilization was increased by 4.59% and 9.59%,the kernel per spike increased by 1.93% and 6.96%,1000-kernels weight increased by 1.33% and 3.69% and the yield increased by 9.56% and 21.97%.Under six different tillage patterns,compared to continuous tillage,the spike number under rotational tillages was increased by 8.90%,the kernel per spike increased by 7.41%,1000-kernels weight increased by 4.47%,rotational tillages NT/ST was the highest.The water use efficiency of NT/ST was 8.26% higher than other treatments.The pure economic returns in turn is NT/ST>CT/NT>ST/CT>NT/NT>ST/ST>CT/CT,the cost of NT/NT is low in machinery,ratio of outputs to inputs in turn is NT/ST>NT/NT>CT/NT>ST/CT>ST/ST>CT/CT.In conclusion,the long-term balanced fertilization and NT/ST can increase soil physical structure and the quality of soil fertility,improve the ability of rainfall infiltration,maintain soil moisture,promote nutrient uptake of winter wheat,it also led to the high and stable yield of winter wheat in dryland.Therefore,balanced fertilization and NT/ST are considered more suitable fertilization and rotational tillage pattern in Weibei Highland. |
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