Effects of Maize/soybean intercropping on soil microbial community and biochemical properties

In Field and Pot culture studies, maize (Zea mays L.) and soybean (Glycine max L.) were intercropped in 3-belowground roots interactions patterns (NS : no roots separation, HS : half roots separation with nylon net and Control: complete roots separation with plastic film). The effects of these roots separation treatments were studied on crop yields, rhizosphere microbial community composition and the relationship between soil microbial community and soil chemical properties. In 2- years field experiment, land equivalent ratio followed the order HS > NS > Control > 1. In belowground interactions, soil soluble substances interactions increased the intercrops yields (10.24 % and 10.63 % in 2018 and 2019, respectively). While in aboveground interactions the shoots interactions increased the intercrops yield (6.12 % and 2.04 % in 2018 and 2019, respectively), while, root interactions decreased the yield. In pot culture, the soil available N, available P, electrical conductivity and soil enzymes (urease, invertase and acid phosphatase) were significantly higher in NS and HS than Control. Both phospholipid fatty acids (PLFA) based Pearson correlation and redundancy analysis showed that in treatments including soil soluble substances interactions and excluding soil soluble substances interactions, there was biggest difference in microbial community. The soil soluble substances interactions enhanced the microbial biomass and Gram-negative bacteria and reduced the physiological or nutritional stress in microbial community. The Gram-negative bacteria was significantly positively correlated with soil acid phosphatase, urease, invertase and available P. We found that soil soluble substances interactions caused major changes in microbial community in intercropping rhizosphere, it increased the microbial biomass, particularly Gram-negative bacteria, which was beneficial to the soil environment.