北方稻蟹共作系统氨挥发损失的研究

摘要

为探索稻蟹共作系统氨(NH3)的挥发损失,在辽宁盘锦开展田间实验.实验采用二因素裂区设计,以养蟹为主因素,施肥为副因素,设置4个处理,即单作稻不施肥(R0M)、稻蟹共作不施肥(R0C)、单作稻施肥(R1M)和稻蟹共作施肥(R1C).结果显示,在水稻全生育期,R0M、R0C、R1M和R1C的NH3挥发量分别为8.56、7.37、45.64和41.34 kg·hm-2.施肥是影响稻田NH3挥发的主要因素,R1M和R1C的NH3挥发量分别较R0M和R0C提高4.33倍和4.65倍.在施肥稻田,NH3挥发主要集中在淹水后10 d内,该阶段的挥发量占全生育期的67.6% ~76.7%.不施肥稻田的NH3挥发速率整体较平稳.施肥也显著提高水稻氮(N)素积累量,R1M较R0M提高53.3%,R1C较R0C提高69.7%.养蟹可以降低稻田的NH3总挥发量,从河蟹放入稻田后计,R1C的NH3挥发量较R1M降低28.4%,差异显著;然而整个水稻生长季,R1M和R1C处理NH3的总挥发量无显著差异.R1M和R1C处理NH3总挥发量分别占当季施N量的28.5%和26.0%.养蟹提高了水稻N素积累量,在水稻成熟期R1C的水稻N素积累量较R1M增加25.0%.在不施肥稻田中,养蟹对削弱NH3挥发损失和提高水稻N素积累量的效果不显著.%In order to explore ammonia volatilization(AV)in the rice-crab system, a field experiment was carried out in Panjin,Liaoning Province. A split-plot design with two factors was arranged in this experiment, no crab and crab as the main factors,with and without fertilizer as sub-factors. The treatments included rice monoculture without fertilizer(R0M),rice-crab culture without fertilizer(R0C), rice monoculture with fertilization(R1M), and rice-crab culture with fertilizer(R1C). AV fluxes were measured via ventilation method. The results showed that season-al AV losses from R0M,R0C,R1M and R1C fields were 8.56,7.37,45.64 and 41.34 kg·hm-2,respectively. N fertilization was the dominant factor which significantly affected AV losses from the treatments. AV losses from R1M and R1C treatments were 4.33 and 4.65 times than those of R0M and R0C, respectively. In fertilized rice fields, 67.6% -76.7% of the AV losses occurred during 10 days after flooding. The rates of AV losses from no fertilized paddy field were small and stable. Compared with R0M and R0C,amounts of N accumulation in rice plants were sig-nificantly increased by 53.3% and 69.7% for R1M and R1C plots. Raising crab could significantly decrease AV losses from rice fields. AV loss from R1C was 28.4% lower than that from R1M treatment after the crab rearing in paddies,but there was little difference between them during the whole rice growth period. AV losses from R1M and R1C accounted for 28.5% and 26.0% of the seasonal N inputs,respectively. Rearing crab in rice fields could in-crease the amounts of N accumulation in rice plants. At maturity, N accumulation in rice plants in R1C treatment was 25.0% above that in R1M treatment, while the difference of AV and N accumulation were not significant be-tween them under no fertilization.