Rhizosphere soil characteristics and yield changes of waxy sorghum under different intercropping patterns

【Objective】The effects of different intercropping patterns on rhizosphere soil nutrient，enzyme activity，microbial community and yield of waxy sorghum were studied to provide a theoretical basis for selection of reasonable intercropping patterns.【Method】Four intercropping patterns of waxy sorghum+peanut（WP），waxy sorghum+soybean （WS），waxy sorghum+pepper（WC）and waxy sorghum+sweet potato（WSP）were selected，with single waxy sorghum（SW）pattern as the control.The rhizosphere soil nutrients，enzyme activities and microbial contents of waxy sorghum were measured at the jointing stage，flowering stage and maturity stage，and the yield and components of waxy sorghum were measured at the maturity stage.【Result】Under different intercropping patterns，the content of soil organic matter，total nitrogen，total phosphorus，total potassium，available nitrogen，available phosphorus and available potassium were the highest under the WS pattern，followed by those under the WP，WSP，WC and SW patterns.The activity of catalase，polyphenol oxidase and urease of the rhizosphere first increased and then decreased from the jointing to maturity stage，and reached a maximum at the flowering stage.At the flowering stage and relative to the WS rhizosphere，WS，WP，WSP and WC rhyzospheres showed 2.25，1.54，1.21 and 1.06 times catalase activity，2.38，1.60，1.39 and 1.12 times polyphenol oxidase activity，and 1.70，1.67，1.32 and 1.23 times urease activity，respectively.The content of total phospholipid fatty acids（PLFA）and of PLFA from bacteria，fungi，actinomycetes，Gram-positive bacteria and Gramnegative bacteria in the rhizosphere were the highest under the WS pattern，followed by those under WP，WSP，WC and SW pattern.Compared with those under the SW pattern，the yield of waxy sorghum under the WS，WP，WSP and WC intercropping patterns decreased by 1.1%，6.7%，7.7% and 9.0%，and the 1000 grain weight increased by 35.8%，23.7%，13.8% and 7.3%，respectively.The number of grains per spike increased 54.8%，51.4%，41.2% and 36.4%，and the length of spike increased 22.2%，12.9%，8.3% and 5.5%，respectively.The correlation analysis revealed that spike length，spike grain number and weight of 1000 grains were significantly and positively correlated with the rhizosphere soil characteristics of waxy sorghum（P<0.01）.【Conclusion】A reasonable intercropping pattern is favorable for improving the soil microbial community structure of waxy sorghum rhizosphere，which can increase soil nutrients and thereby optimize development of the spike structure in waxy sorghum.WS may be the ideal intercropping pattern for waxy sorghum cultivation.