不同管理措施对滨海盐渍农田土壤CO_2排放及碳平衡的影响

Effects of Different Managements on CO_2 Emission and Carbon Balance in Coastal Saline Soils

为探讨不同管理措施对滨海盐渍农田碳平衡的影响,本文通过玉米–小麦轮作试验,研究农田土壤的CO_2释放规律,及其农田碳收支状况。试验设计6个处理:1常规对照(CK);2有机肥常量(OF);3氮肥增施(NF);4秸秆还田(S);5有机肥加秸秆(OF+S);6免耕(NT)。研究表明,秸秆还田和有机肥的施用增加了土壤呼吸的强度,而免耕处理的CO_2平均释放量最低,不同处理下土壤呼吸总体表现为OF+S>S>OM>NF>CK>NT。各处理土壤有机碳含量随着作物的收获逐渐升高,其中OF与NT增加最多,而增施氮肥处理并没有显著提高土壤的有机碳水平。各处理间的有机碳含量没有显著性差异。在两季作物种植结束后,各处理的碳输入均高于碳输出,均为碳净输入,表现出较强的碳汇特征。秸秆还田和单施有机肥的碳净输入均显著高于对照,可有效减缓因农田土壤CO_2排放而造成的全球气候变化问题。

To evaluate the effects of different management measures on carbon balance in the inshore saline farmland, field maize-wheat rotation experiments were conducted to study CO2 emissions and corbon balance under different management measures. The treatments were： 1） conventional control （CK）; 2） application of organic fertilizer （OF）; 3） the increase of nitrogen fertilizer （NF）; 4） application of straw （S）; 5） application of organic fertilizer and straw （OF ＋ S）; 6） no tillage （NT）. The results showed that the measures of straw returned and organic fertilizer application increased the intensity of soil respiration, and the no-tillage led to the minimum average CO2 effiux. The average carbon emission rate under different measures followed the order： OF＋S 〉 S 〉 OM 〉 NF 〉 CK 〉 NT. As crops harvest, soil organic carbon content increased in each treatment, and OF and NT led to the greatest increase in soil organic carbon, while NF did not significantly raise the level of soil organic carbon. The difference of soil organic carbon among different treatments was not significant. After the two cropping seasons, the carbon input was higher than carbon output in each treatment, which led to the net carbon input, showing the strong characteristics of carbon sink. The corbon net inputs in the treatments of S and OF were significantly higher than CK. These measures can effectively slow down the global climate change caused by the CO2 emissions from farmland soils.