理化预处理方式对玉米秸秆腐解与养分释放特征的影响

该文采用尼龙网袋法,研究了长期培养条件下,不同预处理方式(氨化、酸化、微波、无处理)对玉米秸秆腐解与养分释放特征的影响。结果表明,培养100 d后,包括对照在内的各处理秸秆质量累积腐解率均超过50%,其中酸化、氨化处理有利于促进玉米秸秆的快速腐解;培养300 d后,氨化、酸化、微波处理玉米秸秆的累积腐解率分别为89.22%、91.68%和82.26%,其中氨化、酸化处理显著高于对照(80.81%)。与对照相比,在秸秆快速分解期(0~100 d),酸化处理秸秆可多释放23.95%的氮、13.11%的磷、4.27%的钾;氨化处理秸秆可多释放9.69%的氮;微波处理秸秆可多释放4.28%的碳;培养结束时(300 d),酸化处理更有利于钾素、磷素的释放,比对照多释放了7.73%的钾、6.34%的磷;氨化处理更有利于氮素、磷素的释放,比对照多释放了6.16%的氮、5.41%的磷;微波处理可略增加钾素的释放,比对照提高1.61%。综上可见,玉米秸秆还田前进行适当酸化或氨化处理,可促进其腐解,提高养分释放速率,尤其酸化处理效果更好,但具体田间操作及表现仍需进一步研究。

Effect of physical and chemical pretreatment on decomposition and nutrient release characteristics of maize straw

Abstract: Returning maize straw into soil has been demonstrated to improve soil organic matter and increase crop yields, and widely used in China. However, previous studies demonstrated that the cellulose, hemicellulose and lignin of maize straw tend to slow down the natural decay rate, thereby reducing the utilization efficiency. Consequently, this can lead to low stand establishment and reduce plant growth and yield of crops in next season, particularly in northeast China. Currently, the problem has not been solved yet regardless of being chopped or burned before returning into soil. Moreover, it is not lawful for the latter one. Therefore, effective practices for accelerating the decomposition and promoting the nutrients release of maize straw should be developed to cope with these challenges. In order to explore a more appropriate pretreatment, a successive laboratory incubation experiment was conducted in Chinese Academy of Agricultural Sciences with four pretreatments: ammoniated, acidized, microwaved and non-treated treatments. In this experiment, net bag method was used to investigate the decomposing and C, N, P and K releasing characteristics of maize straw. The results showed that the decomposition rate of maize straw were more than 50% after 100 d incubation in all treatments, especially higher decomposition rate were observed in the ammoniated and acidized treatments than those of other treatments. The decomposition rate with ammoniated, acidized and microwaved treatments was 89.22%, 91.68% and 82.26% after 300 d incubation, respectively. In contrast, the decomposition rate with non-treated treatment was 80.81%, which was lower than that of the other three treatments but significant difference was observed only among the ammoniated, acidized and non-treated treatments. Likewise, most of the C, N, P and K in maize straw have been released on the first 100 d incubation. During those days, the acidized treatment increased the N, P and K release rate by 23.95%, 13.11% and 4.27% when compared to non-treated treatment, respectively. Also, the ammoniated treatment increased the N release rate by 9.69% and the microwaved treatment increased the C release rate by 4.28% during this period. After a successive 300 d laboratory incubation, the acidized treatment was more advantageous to the release of K and P, which was 7.73% and 6.34% greater than non-treated treatment, respectively. However, the ammoniated treatment was more advantageous to the release of N and P, which was 6.16% and 5.41% greater than non-treated treatment, respectively. In this period, the microwaved treatment slightly (1.61%) increased K release rate but decreased C, N and P release rate, compared to non-treated treatment. The present results suggest that both the ammoniated and acidized treatments promoted the decomposition and C, N, P and K release rate of maize straw, especially the acidized treatment. It is should be note that microwaved treatment had no significant effectiveness even lowed the decomposition and C, N and P release rate during latter period. However, in light of the environmental difference between laboratory incubation experiment and field trail, further studies are needed to investigate the performance of different pretreatments for maize straw in the actual agricultural production.