| In order to improve the impediment factors such as poor physical structure and low nutrient content of Shajiang black soil,which affected crop yield increase,this study explored suitable cultivation and fertilization measures for Shajiang black soil through field experiments.Rotary tillage(0-20cm)and deep tillage(0-30cm)are set,no fertilization(CK),farmers customary fertilization(NPK),NPK with 7.5t/hm2(7.5B/7.5M),15t/hm2(15B/15M)and 22.5t/hm2(22.5B/22.5M)biochar and organic fertilizer,a total of 8 fertilization treatments,to study the physical and chemical properties and crop yields of Shajiang black soil with different tillage methods and appropriate amount of fertilizing materials 1.Improvement effect of soil microbial community structure.The result shows:1.Tillage had no significant effect on the pH of Shajiang black soil,but the addition of biochar significantly increased the pH of the topsoil,and the addition of organic fertilizer would lower the pH of the topsoil.In the 0-10cm soil layer of the 2019 wheat season,the 7.5M is significantly lower than NPK by 11.55%,and 7.5B and 15B are not significantly different from NPK,(but 7.5B and 15B are significantly increased by 21.05%and 20.00%respectively from 7.5M;In the deep ploughing of 10-20cm soil layer,there is no significant difference between the fertilization treatment and NPK,but 15B is significantly improved by 16.28%and 12.69%compared with 7.5M and 15M respectively;in the deep ploughing 20-30cm soil layer,compared with NPK,7.5M and 15M significantly reduced 7.50%and 6.87%.2.The content of organic matter,total nitrogen,available phosphorus and available potassium in Shajiang black soil increased significantly with the increase of the use of organic fertilizer and biochar,and the improvement effect of organic fertilizer on organic matter,total nitrogen and available phosphorus was better than that of biochar.The improvement effect of quick-acting potassium is better than organic fertilizer.As the age of biochar increased,the soil nutrient content decreased relatively.Compared with rotary tillage,deep tillage reduces the nutrients in the 0-20cm soil layer and increases the nutrients in the 20-30cm soil layer.In the 2019 wheat season,the content of organic matter,total nitrogen,available potassium and available phosphorus in the 0-10cm soil layer were significantly increased by 2.82%-15.72%,1.51%-9.56%,0.97%-18.92%and 3.27%-10.42%;the organic matter,total nitrogen,and available potassium content of the rotary tillage in the 10-20cm soil layer were significantly increased by 1.78%-11.24%,1.83%-16.96%,and 5.71%-16.44%,respectively;the organic matter in the deep tillage of the 20-30cm soil layer,Total nitrogen,available potassium and available phosphorus content increased by 0.45%-20.12%,13.51%-23.90%,2.80%-30.00%and 32.93%-55.22%respectively compared to rotary tillage.3.Fertilization has a significant effect on the bulk density and compactness of 0-20cm,and cultivation has a significant.effect on the bulk density and compactness of 20-30cm.The improvement effect of biochar on the bulk density and compactness of Shajiang black soil is greater than that of organic fertilizer.In the 2019 wheat season,under the condition of 0-10 cm soil layer rotation,the bulk density of 7.5B and 15B was significantly reduced by 5.56%and 7.94%compared to NPK;under the condition of 10-20 cm soil layer rotation,7.5M,15M,7.5B,15B significantly reduced 6.75%,8.59%,8.59%,and 10.43%respectively compared to NPK;20-30cm soil layer,deep ploughing bulk density was significantly reduced by 1.80%-5.95%than rotary tillage.In the 2018 corn season,the 0-5cm soil layer,15B and 22.5B soil compactness were 8.64%and 19.77%lower than NPK,respectively.In the deep ploughing 5-10cm soil layer,7.5B,15B and 22.5B soil compaction were respectively 36.83%,27.00%and 34.00%lower than NPK;in 2019 0-20cm soil layer,deep tillage reduces soil compaction by 2.39%-78.56%;in 20-30cm soil layer,deep tillage reduces soil tightness than rotary tillage Solidity 8.30%-36.06%.Compared with rotary tillage,deep ploughing reduces the soil water content of the 0-20cm soil layer and increases the soil water content of the 20-30cm soil layer.In the 2018 wheat season,in addition to the 22.5B treatment,the water content of rotary tillage was significantly increased by 0.66%-19.25%compared to deep tillage.In the 2018 corn season,except for 15B treatment,the water content of rotary tillage was 0.08%-9.61%higher than that of deep tillage.In 2019 wheat In the 20-30cm soil layer of the season,except for NPK,the water treatment of the other treatments is 1.32%-15.94%higher than that of rotary tillage.4.Wheat production in 2018,deep tillage increased significantly by 4.12%-15.93%than rotary tillage;2019 significantly increased by 1.20%-5.33%,2019 corn yield deep increase significantly by 4.61%-48.44%.In the 2019 wheat season,under the condition of rotary tillage,7.5B increased significantly by 7.79%compared to NPK,and under deep tillage conditions,15M,7.5B,and 15B increased significantly by 7.60%,8.41%,and 7.83%.In the 2019 corn season,under different tillage conditions,biochar and organic fertilizer did not significantly increase corn yield.5.In 2019,deep ploughing increased the Shannon diversity index of soil bacteria by 2.20%-11.31%than rotary tillage,of which 15B treatment increased significantly;under deep ploughing conditions,the Shannon index of 15B treatment increased significantly by 10.75%compared to NPK treatment.RDA analysis showed that the microbial structure of the deep ploughing and 7.5B and 15B treatments and the rest of the treatments showed significant differences in soil nutrient content,bulk density,water content,and pH on soil bacterial community structure,of which the organic matter content had the greatest influence(p=0.048).In summary,on the premise of improving the shajiang black soil the best,and considering the cost of use,the recommended cultivation plan is deep ploughing with 7.5t/hm2 biochar.The result of this study is the improvement of the physical and chemical properties of shajiang black soil,Crop yield increase and microbial community structure improvement provide theoretical basis and data support. |
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