稻田不同种类有机肥施用对后季麦田N_2O排放的影响

Effect of Organic Material Incorporation in Rice Season on N_2O Emissions from Following Winter Wheat Growing Season

以稻麦轮作系统为对象,研究水稻生长季基肥施用不同有机物料对后季麦田N2O排放及年轮作系统CH4和N2O综合温室效应的影响.结果表明:与施用化肥(化肥处理)相比,施用菜饼加化肥(菜饼处理)对后季麦田N2O排放量无影响;施用小麦秸秆加化肥(小麦秸秆处理)导致后季麦田的N2O排放量减少15%;施用牛厩肥加化肥(牛厩肥处理)和猪厩肥加化肥(猪厩肥处理)分别增加29%和16%.就稻麦年轮作生长季总体而言,菜饼、牛厩肥和猪厩肥处理稻麦生长季N2O排放总量较化肥处理分别增加6%、17%和7%,然而,小麦秸秆处理N2O排放总量减少16%.20a或500a时间尺度上各处理稻田CH4排放和该轮作周期水稻和小麦生长季N2O排放的总GWP值由大到小的顺序分别为:菜饼处理>小麦秸秆处理>牛厩肥处理>猪厩肥处理>化肥处理或菜饼处理>牛厩肥处理>猪厩肥处理>小麦秸秆处理>化肥处理.单位产量的GWP以作物残体处理最高,农家肥其次,化肥处理最低.因此,稻田基施不同种类有机物料都相应地增加稻麦轮作系统CH4和N2O排放的综合温室效应.

In a field experiment, five fertilizer treatments including chemical fertilizer （CF）, rapeseed cake＋ chemical fertilizer （RC＋ CF）, wheat straw ＋ chemical fertilizer （WS ＋ CF）, cow manure ＋ chemical fertilizer （CM ＋ CF）, and pig manure ＋ chemical fertilizer （PM ＋ CF）, were dedicated to examine the effect of organic materials incorporation in the rice season on NEO emissions from the following winter wheat season and to assess the climatic impacts from CH4 and NEO emissions in a rice-wheat rotation. Organic material was incorporated at the same rate （225 g·m^-2） for organic treatments at the depth of 10 cm in the soil as the basal fertilizer just before rice transplanting. An identical synthetic nitrogen fertilizer was adopted for all treatments. Results show that the seasonal amount of NEO emissions from the following wheat season differed with organic material applied in rice season. No pronounced difference in NEO emissions was found between the CF and RC ＋ CF treatments. In contrast with the CF treatment, however, NEO emission was decreased by 15% for the WS ＋ CF treatment, hut increased by 29% and 16% for the CM ＋ CF and PM ＋ CF treatments, respectively. Over the entire annual rotation cycle, N2O amount was increased by 17 % for the CM ＋ CF treatment, 7 % for the PM ＋ CF treatment, and 6 % for the RC ＋ CF treatment, but decreased by 16 % for the WS ＋ CF treatment in comparison with the CF treatment. Based on total emissions of CH4 in rice season and N2O over the entire rotation cycle, the estimation of combined Global Warming Potentials （GWPs） for CH4 and NEO shows that over a 20 years horizon or a 500 years horizon, the value of annual total GWPs was ranked in the order of RC＋ CF〉WS＋ CF〉CM ＋ CF〉PM＋ CF〉CF or RC＋ CF〉CM＋ CF〉PM＋ CF 〉WS＋ CF〉CF. The highest, middle and the lowest value of the GWPs per unit crop grain yield occurred for the crop residue, farmyard manure and pure synthetic fertilizer treatments, respectively. Compared to the chemical fertilizer treatment, accordingly, organic material combined with chemical fertilizer application in rice season increased climatic impacts from CH4 and NEO emissions in a rice-winter wheat rotation system.