长期秸秆还田和施用有机肥对连作棉田土壤化学性质及微生物数量的影响

Effects of long-term straw returning and organic fertilizer application on the soil chemical properties and microbial quantity of continuous cropping cotton field

关键词:  秸秆还田  有机肥  连作棉田  土壤化学性质  微生物

Key words:  straw returning  organic fertilizer  continuous cropping cotton field  chemical properties of soil  microorganism

摘要:

为探究棉花秸秆还田和施用有机肥对连作棉田土壤化学性质和微生物数量的影响，采用长期定位试验的方法，设置了氮磷化肥+秸秆清茬(NP)、氮磷化肥+秸秆还田(NPS)、氮磷化肥+有机肥(NPM)及氮磷化肥+秸秆还田+有机肥(NPSM)等4个处理，对不同处理在棉花不同生育期对土壤的化学性质和微生物数量的影响，并对两者之间的关系进行了探究。结果表明: 棉花秸秆还田和施用有机肥均可降低土壤pH，其中NPSM 相比NP在各生育期分别显著降低了3.41%、1.86%、3.19%、2.60%；棉花秸秆还田和施用有机肥均可提高土壤的养分含量，其中NPSM比 NP在各生育期对土壤中碱解氮含量显著增加140.63%~229.17%，速效钾含量显著增加35.86%~60.54%，有效磷含量显著增加146.92%~483.34%，有机质含量显著增加28.06%~63.07%。秸秆还田和施用有机肥均可增加土壤细菌、真菌、放线菌、固氮菌和氨化细菌的数量，NPSM相比NP明显增加了土壤中细菌、真菌、放线菌、氨化细菌和固氮菌的数量，其中细菌的数量在不同时期增加了119.28%~177.21%；真菌数量增加了156.64%~233.42%；放线菌数量增加了107.40%~158.66%；固氮菌数量增加了95.23%~155.53%；氨化细菌数量增加了279.39%~357.29%，均达到显著性差异水平(P<0.05)。因此，秸秆还田配施有机肥后可显著改善土壤性质，增加土壤养分含量及微生物数量，从而达到优化土壤结构、提升土壤肥力的目的。

Abstract:

To investigate the effects of cotton straw returning and organic fertilizer application on the soil chemical properties and microbial quantity of continuous cropping cotton field, four treatments, e. g. , nitrogen and phosphorus fertilizer+straw stubble removal(NP), nitrogen and phosphorus fertilizer+straw returning(NPS), nitrogen and phosphorus fertilizer+organic fertilizer(NPM), nitrogen and phosphorus fertilizer+straw returning+organic fertilizer(NPSM), were set up by using the method of long-term positioning test. The effects of different treatments on soil chemical properties and microbial quantity at different growth stages of cotton in 2021 and the relationship between them were investigated. The results showed that: Returning cotton straw and applying organic fertilizer could reduce soil pH, and NPSM significantly reduced NP by 3. 41%, 1. 86%, 3. 19% and 2. 60% at each growth stage; Returning cotton straw to the field and applying organic fertilizer can improve the nutrient content of soil. Compared with NP, NPSM significantly increased the content of alkali hydrolyzable nitrogen, available potassium, available phosphorus and organic matter by 140. 63%-229. 17%, 35. 86%-60. 54%, 146. 92%-483. 34% and 28. 06%-63. 07% respectively. Compared with the nitrogen fixing bacteria and ammonia fixing fungi in soil, the number of bacteria and ammonia fixing fungi in soil increased by 21. 77% at different stages of straw fertilization; The number of fungi increased by 156. 64%-233. 42%; The number of actinomycetes increased by 107. 40%-158. 66%; The number of nitrogen fixing bacteria increased by 95. 23%-155. 53%; The number of ammonifying bacteria increased by 279. 39%-357. 29%(P<0. 05). Therefore, straw returning combined with organic fertilizer can significantly improve soil properties, increase soil nutrient content and microbial quantity, so as to optimize soil structure and improve soil fertility.