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本研究基于1981年开展的有机肥长期定位试验,研究了不同有机肥种类、用量和施用方式对稻田生态系统碳排放、系统碳固定与净碳汇的影响,并对各处理经济效益进行了比较,为实现农业低碳、高值、高效生产提供理论参考。本研究所选取的有机肥处理包括:不施肥对照(CK);早稻施用绿肥紫云英15 t·hm-2,晚稻不施有机肥(M1);早稻施用两倍绿肥紫云英30 t·hm-2,晚稻不施有机肥(M2);早稻施用绿肥紫云英15 t·hm-2和猪粪15 t·hm-2,晚稻不施有机肥(M3);早稻施用绿肥紫云英15 t·hm-2+晚稻施用猪粪15 t·hm-2和冬季稻草覆盖4 500 kg·hm-2(M4);长期施用化肥(NPK)等5个处理。每5年于晚稻收获后采集土样测定土壤有机碳含量,并测定每年的早晚季水稻产量与生物量,用于估算系统收益与碳收支(5年平均)。结果表明:与不施肥对照相比,各施肥处理水稻产量均显著提高(P<0.05),增幅为30.88%~96.52%,且随着施肥年限的增加,M4处理增产作用最大。长期施用有机肥显著提高红壤稻田土壤固碳能力,且有机肥用量增加系统土壤固碳能力增强,M2、M3、M4处理土壤固碳量显著高于M1、NPK和CK处理;稻田植株固碳量也显著提高(P<0.05),M4和M3最高,双季稻植株固碳量为6.76~8.83 t(C)·hm~(-2)·a~(-1)。长期施用有机肥下稻田系统净碳汇显著增加,与对照相比施肥处理(M1、M2、M3、M4、NPK)系统净碳汇增加1.43~3.93 t(C)·hm~(-2)·a~(-1),系统碳汇效应显著(P<0.05)。同一处理不同施肥年限由生产活动所引起的碳排放量保持不变,系统净碳汇量差异主要表现在系统固碳量上,其变化趋势与水稻产量变化趋势基本一致。长期施用有机肥显著降低了化肥投入,稻田生态系统经济效益显著增加(P<0.05),并以M4处理最高,达25 683.7$·hm~(-2)·a~(-1)。综上结果表明:长期施用有机肥显著提高双季稻田碳汇效应与经济效益(P<0.05),绿肥紫云英与猪粪和秸秆配施稻田生态系统碳汇效益与经济效益较单施绿肥紫云英优势明显。
Based on the long-term organic fertilizer experiment conducted in 1981, this study studied the effects of different types, amounts and modes of application of organic manures on carbon emissions, carbon sequestration and net carbon sequestration in paddy fields, and compared their economic benefits , Provide a theoretical reference for the realization of low-carbon agriculture, high value and efficient production. The treatment of organic manure selected in this study included: no fertilization control (CK); early rice had 15 t · hm-2 of green Chinese milk vetch and no organic fertilizer (M1) in late rice; hm-2, and no-manure (M2) in late rice. In early rice, 15 t · hm-2 of green shoots and 15 t · hm-2 of pig manure were applied, while no M3 was used in late rice. 15 t · hm-2 + 15 t · hm-2 for pig manure in late rice and 4 500 kg · hm-2 (M4) in winter straw; and 5 treatments for long-term application of chemical fertilizers (NPK) Soil organic carbon was collected every 5 years after the harvest of late rice, and annual and early-late rice yield and biomass were measured to estimate system benefits and carbon budget (5-year average). The results showed that compared with no fertilization control, the yield of all fertilizers increased significantly (P <0.05), and the increase ranged from 30.88% to 96.52%. With the increase of fertilization age, the effect of M4 treatment was the largest. Long-term application of organic manure significantly increased soil carbon sequestration in red paddy soils, and increased soil organic carbon fixation increased with increasing organic manure. Soil carbon sequestration in treatments M2, M3 and M4 was significantly higher than that in M1, NPK and CK treatments. (P <0.05), the highest in M4 and M3, and the carbon fixation in double cropping rice was 6.76-8.83 t (C) · hm -2 · a -1. Compared with the control, net carbon sink increased by 1.43 ~ 3.93 t (C) · hm -2 in the system of paddy field under long-term application of organic manure compared with the control (M1, M2, M3, M4 and NPK) a ~ (-1), the system of carbon sink significantly (P <0.05). The carbon emission caused by production activities in the same fertilization period remained unchanged. The difference of net carbon sinks in the system mainly reflected in the amount of carbon sequestration in the system, and the trend of change was consistent with that of rice yield. Long-term application of organic manure significantly reduced the input of chemical fertilizers, and the economic benefits of paddy ecosystem increased significantly (P <0.05), and reached the highest level of 25 683.7 $ · hm -2 · a -1 with M4 treatment. The results showed that long-term application of organic manure significantly increased the carbon sequestration effect and economic benefit of double cropping paddy (P <0.05), and the carbon sequestration and economic benefits of green manure combined with pig manure and straw were higher than that of single manure application Violet cloud advantage obvious.