Zhou Hui, Shi Hai-Bin, Guo Jia-Wei, Zhang Wen-Cong, Wang Wei-Gang
College of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China.
Institute of Water-saving Agricultural and Soil-water Environment in Arid area, Inner Mongolia Agricultural University, Hohhot 010018, China.
Huan Jing Ke Xue. 2020 Aug 8;41(8):3811-3821. doi: 10.13227/j.hjkx.202002046.
Combining organic fertilizer with chemical fertilizer may affect the microbial processes related to nitrous oxide (NO) emissions under different degrees of soil salinization. A mild saline soil (S; electrical conductivity (EC) 0.46 dS·m) and moderate saline soil (S; EC 1.07 dS·m) in the Hetao irrigation district of Inner Mongolia were selected. Under equal N rates, the study involved five treatments:U (240 kg·hm of chemical fertilizer), UO (180 kg·hm of chemical fertilizer+60 kg·hm of organic fertilizer), UO (120 kg·hm of chemical fertilizer+120 kg·hm of organic fertilizer), UO (60 kg·hm of chemical fertilizer+180 kg·hm of organic fertilizer), and O (240 kg·hm of organic fertilizer). In addition, a blank control treatment (CK) was employed to investigate the effects of different fertilization treatments on the NO emissions from the two saline soils. The results showed that the total NO emissions from the S soil in the same treatment were between 11.86% and 47.23% higher than those from the S soil (<0.05). the dynamic trend of the soil NO fluxes among the different treatments were similar. The peak NO emissions occurred after fertilization, and the NO cumulative emission fluxes accounted for nearly 60% of the emissions during the entire growth period. The proper application of organic fertilizer could significantly reduce the soil NO emission; the S and S saline soils treated with UO and O, respectively, had the lowest NO emissions, whereby there were significant reductions of 33.62% and 28.51% in comparison to the U treatment (<0.05). Moreover, higher maize yields could be obtained and the NO flux was significantly positively correlated with the NH-N content (<0.01) but negatively correlated with the NO-N content. The results demonstrated that nitrification was the main way to produce NO in the studied salinized maize farmland, and that the addition of organic fertilizer could reduce the NO production by decreasing the soil NH-N content. Based on the changes in the corn yield and a reduction in the greenhouse effect, suitable organic and inorganic fertilizer management models for the Hetao irrigation area were the mild saline soil:120 kg·hm of urea +120 kg·hm of organic fertilizer), and the moderate saline soil:240 kg·hm of organic fertilizer.
有机肥与化肥配施可能会对不同土壤盐渍化程度下与一氧化二氮（N₂O）排放相关的微生物过程产生影响。选取内蒙古河套灌区的轻度盐渍土（S₁；电导率（EC）为0.46 dS·m⁻¹）和中度盐渍土（S₂；EC为1.07 dS·m⁻¹）。在施氮量相等的情况下，该研究设置了5种处理：U（240 kg·hm⁻²化肥）、UO₁（180 kg·hm⁻²化肥 + 60 kg·hm⁻²有机肥）、UO₂（120 kg·hm⁻²化肥 + 120 kg·hm⁻²有机肥）、UO₃（60 kg·hm⁻²化肥 + 180 kg·hm⁻²有机肥）和O（240 kg·hm⁻²有机肥）。此外，设置了空白对照处理（CK）来研究不同施肥处理对两种盐渍土N₂O排放的影响。结果表明，相同处理下S₁土壤的N₂O总排放量比S₂土壤高11.86%至47.23%（P < 0.05）。不同处理间土壤N₂O通量的动态变化趋势相似。施肥后N₂O排放出现峰值，整个生育期N₂O累积排放通量占总排放量的近60%。合理施用有机肥可显著降低土壤N₂O排放；分别用UO₂和O处理的S₁和S₂盐渍土N₂O排放量最低，与U处理相比分别显著降低了33.62%和28.51%（P < 0.05）。此外，可获得更高的玉米产量，且N₂O通量与铵态氮（NH₄⁺-N）含量呈显著正相关（P < 0.01），与硝态氮（NO₃⁻-N）含量呈负相关。结果表明，硝化作用是研究区盐渍化玉米农田N₂O产生的主要途径，添加有机肥可通过降低土壤NH₄⁺-N含量来减少N₂O的产生。基于玉米产量变化和温室效应降低，河套灌区适宜的有机无机肥管理模式为：轻度盐渍土：120 kg·hm⁻²尿素 + 120 kg·hm⁻²有机肥；中度盐渍土：240 kg·hm⁻²有机肥。
