添加外源物料对秸秆降解的影响及其效应研究

秸秆还田是秸秆利用的有效途径之一,但田间生产秸秆量大且降解缓慢,添加外源物料对加快秸秆降解、促进养分释放有重要意义。基于网袋法,添加不同浓度的生化黄腐酸和微纤维岩棉,研究其对玉米秸秆降解及土壤碳氮、作物生长的影响。外源物料施入量设计3个梯度,分别为土重的0.5%、1%、2%。设计7个处理：单秸秆(CK)、秸秆+0.5%生化黄腐酸(T1)、秸秆+1%生化黄腐酸(T2)、秸秆+2%生化黄腐酸(T3)、秸秆+0.5%微纤维岩棉(T4)、秸秆+1%微纤维岩棉(T5)、秸秆+2%微纤维岩棉(T6)。结果表明：（1）添加生化黄腐酸的各处理降解前100天慢后快,降解率、降解速率与浓度呈反比,360天后降解率达75.97%~82.60%,处理间无显著差异;秸秆氮释放率以100天为转折点,360天氮释放率达71.51%~74.75%;与CK相比,降低土壤容重19.85%~30.53%,增加土壤总孔隙度19.57%~26.09%,提升土壤碳氮含量;除T1外,对作物生长起抑制作用。（2）微纤维岩棉在各时期均能加快玉米降解,快速释放氮（除T4）,360天达63.60%~78.13%;相比CK土壤容重降低24.43%~29.77%,总孔隙度增加21.74%~26.09%,土壤碳氮含量显著提升;有效提高玉米产量,促进根系发育。两物料一定程度上均能加快秸秆降解,促进养分释放,提高土壤碳氮含量,作物生长受物料浓度影响差异显著,整体效果添加微纤维岩棉各处理优于生化黄腐酸,以土重0.5%、1%为宜。

Effect of Adding External Materials on Straw Degradation

Returning straw to the field is one of the effective ways of straw utilization. However, the amount of straw produced in the field is large and the degradation is slow. The addition of external materials is of great significance to accelerate the degradation of straw and promote the release of nutrients. Based on the mesh bag method, this study analyzed the effects of adding biochemical fulvic acid and microfiber rock wool on straw degradation, soil carbon, nitrogen nutrients and crop growth, and set up 3 gradients of external material input, including soil weight of 0.5%, 1%, and 2%, respectively. 7 treatments were conducted, namely, only straw (CK), straw+0.5% biochemical fulvic acid (T1), straw+1% biochemical fulvic acid (T2), straw+2% biochemical fulvic acid (T3), straw+0.5% microfiber rock wool (T4), straw+1% microfiber rock wool (T5), and straw+2% microfiber rock wool (T6). The results are as follows. (1) The straw degradation of each treatment with biochemical fulvic acid is slow in the first 100 days and then the degradation rate is faster; the degradation efficiency and degradation rate are inversely proportional to the concentration; after 360 days, the degradation rate reaches 75.97%-82.60%, and there is no significant difference among the treatments. The nitrogen release rate takes 100 days as the turning point; the nitrogen release rate of each treatment reaches 71.51%-74.75% at 360 days. Compared with CK, the treatments with biochemical fulvic acid could reduce soil bulk density by 19.85%-30.53%, increase soil total porosity by 19.57%-26.09%, and improve soil carbon and nitrogen content. Except T1 treatment, other treatments could inhibit crop growth. (2) Microfiber rock wool could accelerate the degradation of corn and release nitrogen rapidly (except T4) in all periods, reaching 63.60%-78.13% in 360 days. Compared with CK, the soil bulk density could be reduced by 24.43%-29.77%, the total soil porosity could be increased by 21.74%-26.09%, the soil carbon and nitrogen content are significantly increased, to effectively increase corn yield and promote root development. To a certain extent, both materials could accelerate straw degradation, promote nutrient release, and increase soil carbon and nitrogen content. The growth of crop is significantly influenced by the material concentration. The overall effect of adding microfiber rock wool is better than that of adding biochemical fulvic acid, with appropriate soil weight of 0.5%, 1%.