为探明生物炭对紫色土农田土壤NO排放的影响,利用静态箱-化学发光氮氧化物分析法对夏玉米-冬小麦轮作土壤施用生物炭后的NO排放进行了为期一年(2013年6月至2014年5月)的原位观测,比较了生物炭与化肥混施处理(BCNPK)和常规施肥处理(NPK)的紫色土NO排放特征,无肥(CK)作为计算排放系数的对照。结果表明,玉米生长季,NPK处理下的土壤NO排放速率、累积排放通量及排放系数与BCNPK处理下相应参数之间均呈极显著差异(P<0.01)。施用生物炭后,NO排放速率、累积通量及排放系数分别降低了73.1%、77.4%和85.5%,但在小麦季两种处理之间的差异均不显著(P>0.05)。此外,在玉米季和小麦季,BCNPK处理单位产量的综合温室效应(yield-scale GWP)分别比NPK处理降低了79.4%和26.4%。因此,在同等氮肥施用量的条件下配施生物炭既能保证紫色土农田土壤作物不减产又能降低NO的排放。 更多还原
 

In this study, one year monitoring of NO emissions from purple soil farmlands planted with maize (in the summer) and wheat (in the winter) in rotation was carried out in the field after biochar application in Yanting Agro-Ecological Experimental Station (Chinese Academy of Sciences). The static chamber-gas chromatographic techniques and chemiluminescence NO analyzer were used in the study. Three treatments namely conventional fertilization (NPK), biochar application in combination with fertilizer (BCNPK) and control treatment (CK) without fertilizer and biochar, were applied by randomized
design with three replications. Comparisons of NO emission from purple soil farmlands were made between NPK and BCNPK. In addition, CK was used to calculate NO emission coefficient. It was found that NO emission rate was not significantly correlated
with soil temperature and soil dissolved organic carbon content, whereas there was a significantly positive correlation between soil moisture (r = 0.204, n = 165, P<0.01) and inorganic nitrogen content (r = 0.486, n = 165, P<0.01). Consequently, soil moisture and inorganic nitrogen content act as the main influential factors for NO emission from purple soil farmland. N fertilizer application or severe soil moisture alternating caused by rainfall could significantly excite NO emissions. The average NO emission rate throughout the trial period in BCNPK and NPK treatments was 20.1 times and 30.9 times higher than that in CK. During the maize season, the significant differences of NO emission rate, cumulative emissions and emission coefficient were observed between NPK and BCNPK (P<0.01). NO emission rate, cumulative emissions and emission coefficient in maize season were decreased by 73.1%, 77.4% and 85.5%, respectively, for BCNPK as compared with NPK. However, the aforementioned three parameters in wheat season showed no significant differences between the two treatments. Moreover, crop yield of BCNPK during the maize and wheat seasons increased by 6.7% and 13.5%, respectively, in comparison with that of NPK. Yield-scaled global warming potential (yield-scale GWP), a comprehensive indicator for the environmental and yield efficiency evaluation, of
BCNPK exhibited the decreases of 79.4% and 26.4%, respectively, as compared with that of NPK for both maize and wheat seasons. That is to say, under the same level of nitrogen fertilization, biochar application could not only guarantee the crop
production in purple soil farmland not to reduce, but also cut down NO emission. Therefore, biochar application in the purple soil farmland is a promising practice for NO emission reduction.