[Influence of Straw Return and Fertilizer Matching on Microbial Quantity and Stoichiometric Characteristics and...

In order to investigate the effects of the interaction between straw return and chemical fertilizer on soil microbial activity， microbial biomass （SMB）， soil microbial entropy （qmb）， and soil-microbial stoichiometric imbalance in agricultural soil so as to realize the stabilization of soil and increase the production of fertilizers， the experiment was carried out in a two-factor split-area design， with the primary treatments of straw return （W1） and straw non-return （W0） and the secondary treatments of no fertilizer， nitrogen fertilizer （N） and nitrogen-phosphorus fertilizer （NP）， and nitrogen-phosphorus fertilizer （NP）， to investigate the characteristics of soil-microbial carbon， nitrogen， and phosphorus changes and the coupling relationship between stoichiometric characteristics， stoichiometric imbalance， and microbial entropy under different treatments. The results showed that the soil organic carbon （SOC） content of W1NP was significantly increased compared with that of W0 （P<0.05）， the soil total nitrogen （TN） content of W1NP was increased by 56.56% compared with that of W0， there was no significant difference in the soil TP content （P>0.05）， and the C/P was significantly increased in the W1NP treatment compared with that in W0 （P<0.05）. The soil microbial carbon （MBC）， soil microbial nitrogen （MBN）， and soil microbial phosphorus （MBP） contents were significantly higher （P<0.05） compared to those of W0. Soil MBN content was significantly higher in all treatments of straw return compared to that of W0 （P<0.05）. The difference in soil MBP content between the W0NP and W1NP treatments was not significant （P>0.05）， but both were significantly higher than those of the other treatments （P<0.05）， and MBN/MBP was significantly higher than that of W0 in all treatments （P<0.05）. Application of phosphorus fertilizer significantly increased qmbc， qmbn， and qmbp （P<0.05）， and the carbon and phosphorus imbalance ratios （C/P_imb） of the W1 and W0 treatments were not significantly different （P>0.05） but were significantly higher than in the other treatments （P<0.05）. The nitrogen phosphorus imbalance ratio （N/P_imb） was significantly lower （P<0.05） in all treatments compared to that in W0. Correlation analysis showed that there was a significant positive correlation between MBC， MBN， and MBP （P<0.05） and all were significantly negatively correlated with stoichiometric imbalance （P<0.05）. Redundancy analysis showed that the closest relationship was between MBC/MBP and qmbc， a significant relationship was between MBN/MBP and microbial mass entropy phosphorus， and the closest relationship was between microbial mass entropy nitrogen and MBN/MBP （P<0.05）. In conclusion， the straw return with the nitrogen and phosphorus fertilizer （W1NP） treatment was optimal for improving soil nutrients and changing soil stoichiometric characteristics， as well as increasing soil fertility.