潮土中残留小麦和玉米秸秆养分含量差异及与微生物群落组成的关系

黄淮海平原典型潮土上小麦和玉米收获后的秸秆往往直接还田,但驱动它们在不同质地潮土(砂质、壤质、黏质)中分解的微生物是否与残留秸秆养分含量有关尚不清楚.本研究基于尼龙网袋法,通过10个月的田间培育试验,监测秸秆分解率、残留秸秆养分含量及微生物群落组成,评估各指标在秸秆类型和土壤质地之间的差异,探究残留秸秆养分与微生物群落...

Differences of Nutrient Contents in Residual Wheat and Maize Straws and Their Relationship with Microbial Community Composition in Fluvo-Aquic Soil

The wheat (Triticum aestivum L.) and maize (Zea mays L.) straw in typical alluvial soil of the Huanghuaihai Plain is often returned to the field directly, however, it was not cleared the relationship of the microorganisms involved in the straw decomposition in different textures (sandy, loam, clay) of alluvial soil and the residual straw nutrient contents. Nylon bag method was used to investigate the effects of straw types and soil texture on the straw decomposition ratio, the nutrient contents of residual straw and the microbial community composition after 10-month decomposition in a field experiment. The relationships of the microbial community composition and residual straw nutrient contents were also studied simultaneously. The results showed that the decomposition ratios of wheat and maize straw increased with increasing soil clay contents. The decomposition ratios of wheat and maize straw were 73.66% and 75.43%, 74.19% and 76.63%, 77.68% and 78.05% in the sandy, loam and clay soils (p < 0.05), respectively. The average N, P and K contents of residual wheat straw were 12.0%, 34.4% and 16.7% lower than those of maize straw (p < 0.05), respectively, but there was no significant difference in carbon content between wheat and maize straw. The C, N and K contents of residual wheat and maize straw were not influenced by soil texture, while the P content significantly increased with increasing soil clay content. The phospholipid fatty acid (PLFA) analysis showed that no significant differences in the contents of bacteria fungi and actinomycetes were observed between wheat and maize straw. The content of gram-positive bacteria (G+) of wheat straw was 20.26% lower than that of maize straw, while the content of gram-negative bacteria (G-) of wheat straw was 16.35% higher than that of maize straw (p < 0.05). Meanwhile, G+/G-, fungi/bacteria, monounsaturated fatty acids/saturated branched fatty acids were significantly different between the two straws. The average content of bacteria, fungi and total PLFA in wheat and corn stalks in clay soil was 25.1%, 30.3% and 22.9% lower than that in sandy fluvo-aquic soil (p < 0.05), but the content of actinomycetes was 93.8% higher than that of sandy alluvial soil (P < 0.05). Redundancy analysis (RDA) showed significantly different microbial community composition between wheat and maize straw, which may be attributed to the differences in G+ and G- contents. The microbial community composition on wheat straw were mainly influenced by the ratios of C/N, C/P and C/K, while the microbial community composition on maize straw were mainly influenced by N, P, K content and decomposition ratio, suggesting different nutrient parameters that affected the microbial community composition on wheat and maize straw.