Effect of biogas manure on arthropod community structure in eggplant field and eggplant yield

Three fertilizer application treatments (chemical fertilizer, half chemical fertilizer and biogas manure, and biogas plus cake manure) were adopted under equal N, P (P₂O₅) and K (K₂O) rates to study the effects of biogas manure on yield of eggplant and structure of arthropod community in eggplant fields. The results showed that the number of pest species under combined application of biogas and cake manure was 3.67±0.88 in 4 m² in eggplant field, significantly less than that under application of chemical fertilizer or half chemical fertilizer and biogas manure. Pest species number under application of half chemical fertilizer and biogas manure was also significantly less than that under chemical fertilizer application. The individual number of pests and target pests Myzus persicae (Sulzer) and Henosepilachna vigintioctopunctata (Fabricius) under combined application of biogas and cake manure was 64.67±4.06, 31.67±0.56 and 8.00±0.15 in 4 m², respectively. This was significantly less than that under chemical fertilizer application, but not significantly different from that under half chemical fertilizer and biogas manure application. The individual number of spiders and dominant nature enemy Aranea ventricocus (Koch) under combined application of biogas and cake manure was 12.67±1.76 and 7.67±0.67 in 4 m², respectively, significantly greater than that under chemical fertilizer application, but not significantly different from that under half chemical fertilizer and biogas manure application. Under combined application of biogas and cake manure, arthropod community diversity index was 1.68±0.04 and evenness index was 0.53±0.003. This was significantly higher than those under applications of chemical fertilizer, and half chemical and biogas manure. The dominant concentration of arthropod community under combined application of biogas and cake manure was 0.33±0.02, also significantly less than that under chemical fertilizer application, but not significantly different form that under half chemical fertilizer and biogas manure application. In terms of arthropod community stability, Ss/Si index was 0.112 5±0.001 1 under combined application of biogas and cake manure, significantly higher than that under chemical fertilizer application, but not significantly different from that under half chemical fertilizer and biogas manure application. Sn/Sp index under combined application of biogas and cake manure was 1.650 0±0.005 5, which significantly exceeded that under applications of chemical fertilizer, and half chemical fertilizer and biogas manure. Eggplant yield under the three fertilizer application treatments was not significantly different.