Effects Of Different Tillage And Fertilization Measures On Soil Nutrients And Yield Of Wheat In Weibei Highland

Weibei Highland is located in the southern part of the Loess Plateau,it is a typical rainfed agricultural area,the dark loess soil is the main cultivated soil,and winter wheat and spring maize are the main food crops.There are problems of shortage of rainfall and uneven seasonal distribution,which seriously restricts the growth and yield of winter wheat and spring maize.Tillage has an important impact on soil fertility,water storage in this area.What kind of tillage and rotation system should be adopted to improve soil fertility and crop yield has attracted widespread attention.In this paper,long-term tillage experiments on Weibei Highland were conducted to study six tillage methods（no-tillage（NN）,subsoiling（SS）,conventional tillage（CC）,no-tillage-subsoiling（NS）,subsoiling-conventional tillage（SC）,conventional-no-tillage（CN））under three fertilization levels（balanced fertilization,low fertilization and conventional fertilization）.The effects of soil organic carbon（SOC）,nitrogen（N）,phosphorus（P）,potassium（K）nutrients and wheat yield in different soil layers were studied,and suitable cultivation and fertilization methods were selected for wheat production in Weibei Plateau.The main results were as follows:Under the three fertilization levels,the highest SOC was in balanced fertilization in each layer of 0?50 cm,which was 10.04?13.33%higher than that of low fertilizer,and the20?35 cm soil layer was most abundant.The SOC storage was the highest under balanced fertilization,followed by conventional fertilization,and the smallest under low fertilization.Tillage treatment has a significant impact on soil organic carbon content and storage,in the0?10 cm soil layer,conservation tillage treatment is 3.46?42.38%higher than conventional tillage（CC）treatment.The SOC storage in the 0?50 cm soil layer treated that rotational tillage（NS,SC,CN）,no-tillage（NN）and subsoiling tillage（SS）higher than conventional tillage（CC）,the NS treatment was increased by 7.65%compared with the CC treatmen.Under different fertilization levels,soil total N content showed that conventional fertilization was significantly higher than low fertilizer,with an increase of 6.37?25.1%.Available N content was also the highest in conventional fertilization,which was 3.25?27.36%higher than low fertilizer.Under different tillage treatments,soil total,available N content in0?10 cm soil layer was most significant difference.The overall nitrogen storage in 0?50 cm soil layer showed conventional fertilization（CF）was greater than balanced fertilization（BF）and lower fertilizer（LF）.Under the three fertilization levels,the SOC and total N stratification ratio（SR₁,SR₂,SR₃）were not significantly different.NS treatment increases the stratification ratio（SR₁,SR₂ and SR₃）of organic carbon,compared with CC treatment,NS treatment increased by 62.66%,54.53%and 51.65%respectively.In the 0?10 cm soil layer,the total P content under three fertilization levels showed conventional fertilization（CF）higher than balanced fertilization（BF）and low fertilizer（LF）,and the difference between CF and LF was significant,while at 10?20cm soil layer,conventional fertilization and balanced fertilization were significantly higher than low fertilizer.The content of available P in 0?10 cm soil layer under three fertilization levels showed that conventional fertilization was significantly higher than that under low fertilizer,with an increase of 52%,while in the 20?35 cm soil layer,balanced fertilization increased by51%compared with conventional fertilization.Under the different tillage treatments,the total P content in the soil layer of 0?50 cm was the largest in NS,NN treatment.The available P in the soil layers of 0?10,10?20 and 20?35m was the highest in NN treatment,the lowest in CC treatment.Under three fertilization levels,there was no significant difference in total K content in 0?50 cm soil layers,available K is the highest in balanced fertilization under three fertilization levels,balanced fertilization increased 17.62?86.39%compared with conventional fertilization,which 0?10 cm soil layers had the greatest difference.Under different tillage treatments,the available K content under different tillage treatment was highest in NN at 0?10 soil layer,the NN treatment increased by 36.86%compared with CC treatment.In 10?50 cm soil layer,the content of soil available K was the largest in NN treatment,and the smallest in SC treatment.Under three different levels of fertilization,the spike number,the kernel per spike,1000-kernels weight and yield were the highest in balanced fertilization.Compared to low fertilization and conventional,the spike number under balanced fertilization was increased by 13.24%and 6.71%,respectively,the yield increased by 27.60%and 10.56%.The highest yield was in no-tillage-subsoiling rotation method under different tillage treatments.The principal component analysis of soil fertility extracted three principal components with a cumulative contribution rate of 88.53%.The first principal component is N factor,the second principal component is SOC factor,and the third principal component is K factor.It was found that the relationship between wheat yield and SOC was higher.In general,the highest yield was in balanced fertilization under three fertilization levels,and no-tillage-subsoiling rotation has higher SOC and total N content,and highest wheat yield.Notillage-subsoiling rotation under balanced fertilization was the most suitable fertilization and tillage and mode for Weibei Highland.