| To reveal the effects interspecific interaction of maize intercropped with soybean on crops and soil,the study,the system of maize intercropped with soybean was used as the research object,and the maize planting density and soybean planting width were used as factors by using the method of two-factor randomized block design.Four different treatments were set up in the study,including,the width of the soybean was 20 cm,the density of maize was 4600-5000 plants·mu-1,and the density of soybean was 10000-11 000 plants·mu-1,and the width of soybean was 80 cm,the planting density of maize was4 600-5000 plants·mu-1,and the density of soybean was 10 000-11 000 plants·mu-1.And the width of a soybean was 20 cm,the planting density of maize was 8 000-8 500 plants·mu-1,and the planting density of soybean was 10 000-11 000 plants·mu-1.The width of the soybean was 80 cm,the planting density of maize was 8 000-8 500 plants·mu-1,and the planting density of soybean was 10 000-11 000 plants·mu-1.In all treatments,the density of soybean was 150 000 plants·mu-1.Analyzing that the effects of maize intercropped with soybean on the growth of crops,the depth of crops absorbing moisture,and soil and soil AM fungal community composition.Initially revealed that the influence regulation was interspecific interaction of maize intercropped with soybean on crops and soil.Clarifying that the response mechanism of soil microorganisms to the interspecific relationship of intercropping crops.The main results are as follows:(1)There were significant differences in dry matter accumulation under different cultivation pattern for 2 consecutive years of maize intercropped with soybean,The growth of crops in 2022 was better than that in 2021.The difference in nitrogen content between maize and soybean is caused by crop species,planting patterns,and different organs of crops.In the intercropping system,when the planting density of maize was 8 000-8 500 plants·mu-1 and the width of soybean was 20 cm,the crop yield was the highest.In addition,interspecific relationship is the main reason affecting the dry matter accumulation of maize and soybean.The nitrogen content is mainly affected by the planting density of maize.The main factors affecting crop yield were the content of N,P and SOM in soil.(2)The depth of water absorption and the enrichment of δD,δ17O,and δ18O in soil moisture under intercropping system was effectively determined using the hydrogen and oxygen stable isotope technique.Using hydrogen and oxygen isotope technology.effective testing that the enrichment of δD,δ17O andδ18O in different water absorption depths and soil moisture under maize and soybean intercropping system.Under the four treatments,the stable isotopes of δD,δ17O and δ18O in soil moisture were mainly enriched in 0-20 cm soil.By comparing the depth of water absorption of maize and soybean in the intercropping system at the maturity stage,it was found that maize mainly absorbed water in the 30-40 cm soil layer,and soybean mainly absorbed water in the 0-20 cm soil layer.In the intercropping system,the change of maize planting density would affect the depth of crops absorbing water.(3)Study that different forms of nitrogen content in soil after 2 years of maize intercropped with soybean,it was found that there were significant differences in the concentrations of nitrate nitrogen and ammonium nitrogen.The soil pH was higher than that before the experiment,and the concentration of AK in the soil decreased obviously.The biomass of the main microbial groups in the soil characterized by the phospholipid fatty acid map method showed the following trends in four treatments:Bacteria>Gram-negative bacteria>Gram-positive bacteria>Actinomycetes>Fungi.Compared with 2021,the total biomass of phospholipids,neutral lipids,and microorganisms in the main soil microbial groups in 2022 increased by 51.79%,28.21%,and 60.03%,respectively.(4)High-throughput sequencing results showed that the dominant genus of soil AM fungi was Glomus.The trend of Shannon index,ACE index and Simpson index of soil microbial Alpha diversity index in 2021 and 2022 was the same,and it showed that 80M1B and 20M2B were significantly higher than other treatments(P<0.05).Based on the discriminant analysis of Beta diversity index ofA M fungi,using PLS-DA models,find that the aggravation of interspecific relationship had significant effect on the community composition of AM fungi in soil.In addition,compared with the fungal community composition of maize intercropped with soybean for 2 years,it was found that the influence of the density of maize and the width of soybean on fungi community composition was reduced.Pearson correlation analysis showed that different forms of N,P,K and pH in soil had significant effects on the alpha diversity index and species level community composition of AM fungal community in soil. |
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