三江平原地区不同有机物料腐解规律的研究

利用网袋法模拟田间还田方式, 研究不同还田方式下玉米、大豆秸秆的腐解特征。结果表明: 经过150 d的分解, 玉米和大豆秸秆残留率在33.7%~61.1%之间, 秸秆还田分解趋势为: 土埋处理>露天处理, 土埋玉米秸秆>土埋大豆秸秆, 露天条件下大豆和玉米秸秆分解速率一致。从细胞结构上看, 玉米秸秆随着还田时间的延长, 基本组织和维管束遭到破坏, 细胞壁变薄, 细胞内物质消失, 细胞排列疏松; 大豆秸秆组织结构变化不明显。露天和土埋处理各有机物料有机碳分解率分别为39.9%~48.9%、49.6%~65.8%, 土埋玉米和大豆秸秆腐解速度明显高于露天处理。两个处理氮、钾分解率无太大差异, 分别为51.1%~67.7%、74.6%~91.7%, 而磷素变化比较明显, 露天和土埋处理玉米秸秆的磷释放率平均比大豆秸秆高49.4%、56.7%。作为还田物料玉米秸秆要好于大豆秸秆。

Decomposition regularity of organic materials in Sanjiang Plain region

Net bag method was used to determine the decomposition characteristics of soybean and maize stalks under two approaches of returning crop residues into soils. The results show that after 150 days of composting, residual rates of maize and soybean stalks are between 33.7%~61.1% under the two treatments. The order of decomposition rate of the stalks is: soil-covered treatment > open-air treatment, soil-covered maize stalk > soil-covered soybean stalk. Decomposition regularities of soybean and maize stalks in open-air are almost the same. As for the cell structure, with the time of treatments, tissues become blurred and loose, parenchyma and vascular bundles break-down, and intracellular matters disappear in maize stalk. However, there is no significant change in tissue structures of soybean stalk. Organic carbon decomposition rates of different organic materials are respectively 39.9%~48.9% and 49.6%~65.8% under open-air and soil-covered treatments. Stalk decomposition rates under soil-covered treatments are higher than open-air treatments. Decomposition rates of total N and K are respectively 51.1%~67.7% and 74.6%~91.7%. For maize, the decomposition rates of total P are respectively 49.4% and 56.7% higher than soybean under open-air and soil-covered treatments. With regard to material returned to the soil, maize stalk is superior to soybean stalk.