Effects Of Different Types Of Organic Fertilizers On Soil Quality Improvement In Typical Vegetable Field Systems In Southwestern Region

Due to the large amount of fertilizer application,soil organic matter content is low in the vegetable field system in southwest China,and soil quality is a serious problem.For example,the content of organic matter decreases,excessive surplus of nitrogen and phosphorus nutrition,etc.Screening suitable organic fertilizer types is of great significance to rapidly improve soil organic matter content and vegetable productivity.This study southwest typical outdoor vegetable system（cabbage-pepper rotation）as the research object,a field experiment from 2019 to 2021,to clarify different types of organic fertilizer on vegetable in southwest increase of soil organic matter,nitrogen and phosphorus nutrient balance,the influence of the fertilizer utilization efficiency,yield and quality of vegetables,ultimately selected the region’s best organic type.The experiment consisted of six treatments,including CK（no fertilization treatment）,CONV（farmers’customary fertilization treatment）,BC（biochar treatment）,CM（chicken manure treatment）,KW（kitchen waste resource treatment）and ST（straw treatment）,and each treatment was repeated for 3 times.CONV treatment was 1200 kg C ha^-1、450 kg N ha^-1、450 kg P₂O₅ha^-1.The other four organic fertilizer treatments were based on crop nutrient optimization,and the treatments of carbon,nitrogen and phosphorus fertilization,They are 1700 kg C ha^-1、250 kg N ha^-1、160 P₂O₅ha^-1.The research results are as follows:（1）Various organic fertilizer treatments compared with CONV treatment significantly increased soil organic matter content,soil carbon sequestration,soil C:N and soil C:P.The soil organic matter content of BC and KW treatment was significantly increased 17.6%and 13.1%compared with CM treatment,9.18%and4.98%compared with ST treatment,and 7.69%compared with BC and KW treatment.Soil carbon sequestration was significantly increased 2.34 and 1.38 t ha^-1in BC and KW treatments,2.21 and 1.26 t ha^-1in ST treatment,and 0.95 t ha^-1in BC and KW treatment compared to CM treatment.Soil C:N of BC and KW treatment was significantly increased 18.1%and 20.9%compared with CM treatment,and compared with ST treatment significantly increased 7.09%and 12.4%.Soil C:P of BC and KW treatment was significantly increased 7.04%and 9.91%compared with CM treatment,and was significantly increased 2.30%and 5.03%compared with ST treatment.（2）On the basis of optimizing the dosage of 44.4%nitrogen fertilizer and 64.4%phosphorus fertilizer,the yield of Chinese cabbage under various organic fertilizer treatments was significantly increased 125%～152%compared with CK treatment.The yield of BC and KW was not significantly different from that of ST,but increased14.2%and 10.9%compared with CM,respectively.Compared with CONV treatment,the nitrogen surplus and phosphorus surplus of Chinese cabbage were significantly reduced 61.1%～69.4%and 104%～106%respectively.In terms of fertilizer efficiency,BC and KW treatments had the highest nitrogen fertilizer and phosphorus fertilizer use efficiency,compared with CONV treatment,which increased 13.5%～16.3%and 8.32%～9.52%.BC and KW treatments compared with CM and ST treatments significantly increased nitrogen fertilizer use efficiency 5.90%～8.70%and 1.60%～4.35%,and phosphorus fertilizer use efficiency 2.20%～3.79%and1.00%～2.6%.（3）Applying organic fertilizer to vegetable system significantly increased the yield of pepper,and the yield of various organic fertilizer treatments significantly increased 350%to 442%compared with CK treatment.The yield of BC and KW was6.22%～9.88%higher than that of ST,and 14.2%and 10.9%higher than that of CM,respectively.All organic fertilization treatments compared with CONV treatment significantly reduced the nitrogen surplus 63.1%～71.3%and phosphorus surplus106%～108%..In terms of fertilizer efficiency,BC and KW treatments had the highest nitrogen fertilizer and phosphorus fertilizer use efficiency,which increased24.5%～29.0%and 6.93%～7.98%compared with CONV treatment.BC and KW treatments compared with CM and ST treatments significantly increased nitrogen fertilizer use efficiency 8.85%～13.4%and 4.40%～8.90%,and phosphorus fertilizer use efficiency 1.85%～2.90%and 0.60%～1.65%.In conclusion,the addition of kitchen waste recycling and biochar organic fertilizer under the condition of optimal fertilization management can significantly increase organic matter content,maintain or improve vegetable yield and nutrient absorption,reduce soil nitrogen and phosphorus surplus,and improve the utilization rate of nitrogen and phosphorus fertilizer on the basis of significantly reducing the amount of nitrogen and phosphorus fertilizer.The results can be used as a reference for cultivating healthy soil and high yield and efficiency of vegetables in southwest China.