Influence of returning corn straw to soil on soil nematode communities in winter wheat

Abstract

This study used pot microcosms to investigate the influence of returning different amounts of corn straw on soil nematode communities in winter wheat with five treatments: no corn straw (CS-1), 3000 kg/hm2 (CS-2), 6000 kg/hm2 (CS-3), 9000 kg/hm2 (CS-4), and 12,000 kg/hm2 of added corn straw (CS-5). The microcosms were sampled at winter wheat jointing stage, booting stage and harvest stage, and the growth and fertility of soil nematode community dynamics were observed. A total of 37 nematode genera were identified. The genus richness and abundance of soil nematodes were significantly different (P < 0.01) at the different growing stages. The trophic group composition of the nematodes was also significantly different between different treatments (P < 0.01) but the differences in total abundance were not. The abundance and genus richness achieved a maximum at booting stage, and both were significantly higher with the addition of corn straw. The genus richness maximum was in treatment CS-2, and decreased when the addition of corn straw was increased. The maximum number of individuals was in treatment CS-4. The relative abundance of soil nematode trophic groups changed significantly throughout the growth of winter wheat. The relative abundance of bacterivorous nematodes gradually increased and the relative abundance of omnivorous nematodes gradually decreased. Plant parasites had the largest relative abundance at booting stage, and were higher in treatment CS-4 and CS-5. The Shannon–Weaver diversity index, trophic diversity index and maturity index were significantly different at booting stage in the different treatments. The values of these ecological indices significantly increased by the addition of corn straw, but decreased with increasing application. Factor analysis revealed that the first effect factors on soil nematode community composition were the above and belowground biomass of winter wheat and soil N content. The second effect factors were the soil available P and K and soil bacteria content. Returning a small quantity of corn straw positively impacted the nematode community composition and changed the soil nematode taxa of common and rare nematode genera. The growth and development of winter wheat had a significant impact on the abundance and genus richness of the soil nematode community. Corn straw addition at 3000 kg/hm2 could maintain a higher diversity of soil nematode but 6000–9000 kg/hm2 could increase crop productivity.