• ISSN 1008-505X
  • CN 11-3996/S
李桂花, 周吉祥, 张建峰, 杨俊诚. 有机肥和缓控肥替代部分化肥降低双季稻田综合净温室效应[J]. 植物营养与肥料学报, 2020, 26(6): 1017-1024. DOI: 10.11674/zwyf.19389
引用本文: 李桂花, 周吉祥, 张建峰, 杨俊诚. 有机肥和缓控肥替代部分化肥降低双季稻田综合净温室效应[J]. 植物营养与肥料学报, 2020, 26(6): 1017-1024. DOI: 10.11674/zwyf.19389
LI Gui-hua, ZHOU Ji-xiang, ZHANG Jian-feng, YANG Jun-cheng. Decreasing net global warming potential through partial substitution of urea with manure and slow-release fertilizer in a double-rice system[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(6): 1017-1024. DOI: 10.11674/zwyf.19389
Citation: LI Gui-hua, ZHOU Ji-xiang, ZHANG Jian-feng, YANG Jun-cheng. Decreasing net global warming potential through partial substitution of urea with manure and slow-release fertilizer in a double-rice system[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(6): 1017-1024. DOI: 10.11674/zwyf.19389

有机肥和缓控肥替代部分化肥降低双季稻田综合净温室效应

Decreasing net global warming potential through partial substitution of urea with manure and slow-release fertilizer in a double-rice system

  • 摘要:
    目的 秸秆还田是我国水稻生产中的常规土壤培肥措施,在此背景下,进一步研究有机肥和包膜尿素替代部分普通尿素,以及施用硅肥和微量元素对土壤固碳效应和温室气体排放的影响及机理,为实现稻田“固碳减排”提供依据。
    方法 江西高安县的双季稻田间定位试验始于2013年。在秸秆全部还田、早稻施N165 kg/hm2和晚稻施N 195 kg/hm2条件下,设置4个氮素处理: 100%普通尿素氮 (CK);用20%有机肥氮替代普通尿素氮 (N1);在N1基础上增加Si、Zn和S肥 (N2);在N2基础上用30%的包膜尿素氮替代普通尿素氮 (N3)。于收获期测定作物产量和地上部生物量,2016年测定了早稻和晚稻生育期温室气体 (CO2、N2O和CH4) 排放量。
    结果 与早稻季相比,晚稻季温室气体排放总量较高,其中晚稻季CH4排放量是早稻季的4倍 (P < 0.05),生态系统呼吸增加了7.5%~9.3% (P > 0.05)。同一季节4个处理间生态系统呼吸没有显著差异;N2O排放量以CK 最高,其中早稻季CK处理比N1、N2和N3处理分别增加31.7%、27.2%和43.7%,晚稻季分别增加20.0%、31.5%和40.6% (P < 0.05);与CK处理相比,有机肥替代处理显著增加了CH4的排放量,其中早稻季N1、N2和N3处理分别增加了13.1%、13.9%和21.4%,晚稻季分别增加了19.4%、12.7%和13.7% (P < 0.05)。利用地上部生物量估计当季/年尺度土壤固碳效应,晚稻季有机肥处理 (N1、N2和N3) 与CK相比增加显著 (P < 0.05);2016年早稻产量比晚稻提高30%,所以早稻季综合净温室效应是负值 (碳汇),而晚稻季是正值 (碳源),全年总计为碳源,这表明稻田产生温室效应。与CK处理相比,有机肥和包膜尿素配施处理 (N3) 显著降低了全年综合净温室效应。
    结论 连续4年的田间试验结果表明,在秸秆还田基础上,用有机肥部分替代普通尿素可显著增加CH4排放,但又显著降低N2O排放且增加土壤固碳效应。综合考虑,有机肥投入会显著降低双季稻田综合净温室效应。使用包膜尿素替代部分普通尿素可有效降低施用有机肥产生的CH4排放,且通过提高产量进一步降低双季稻生产系统的综合净温室效应。而施用中、微量元素肥料对综合净温室效应没有显著正效应。由于晚稻的温室气体排放量高于早稻,因此,通过优化施肥技术提高早稻产量是降低双季稻年度温室气体排放的有效措施。

     

    Abstract:
    Objectives Straw returning is a common practice in rice production. In this case, we studied the effect and mechanism of partial substitution of urea with manure and slow-release fertilizeron decreasing the net global warming potential in a double-rice agro-ecosystem under long-term straw return condition to provides the basis for the realization of carbon sequestration and emission reduction.
    Methods Field localized experiments were started since 2013 in a double-rice system in Jiangxi Province, China. Four nitrogen fertilizer treatments were setup on the base of whole straw of pre-crops returning to field, and total of N input of 165 kg/hm2 in early rice and 195 kg/hm2 in late rice. The treatments were: 1) 100% urea (CK); 2) 80% urea + 20% manure N (N1); 3) on the base of N1, applying extra Si, Zn and S (N2); 4) on the base of N2, 30% of total N replaced with coating urea (N3). Rice yield, above ground biomass and soil organic matter content was measured, the greenhouse gas emissions were measured during double-rice growth season in 2016.
    Results Greenhouse gas emissions in late rice season were significantly higher than those in early rice season, e.g. the CH4 emission was as high as 4 times (P < 0.05) and CO2 emissions were 7.5%–9.3% higher (P > 0.05). Among the four treatments, the CO2 emission was not significantly different in both early and late rice season; the N2O emission was significantly decreased in the manure containing treatments (N1, N2 and N3), with decrement of 31.7%, 27.2% and 43.7% in early rice season, and 20.0%, 31.5% and 40.6% in late rice season in turn (P < 0.05). Manure application resulted in a significant increase of CH4 emission compared with CK. In early rice season, the increment in CH4 emission under N1, N2 and N3 were 13.1%, 13.9% and 21.4%, and 19.4%, 12.7% and 13.7% in late rice season, respectively (P < 0.05). Soil carbon sequestration potential in seasonal or yearly scale, which was estimated with above ground biomass, was significantly higher under manure treatments (N1, N2 and N3) comparing to CK (P < 0.05). In 2016, the net global warming potential (GWP) in early rice season was negative (carbon sink) due to 30% increment of the yield, while that was positive in late rice season (carbon source), and the whole year belonged to carbon source. Even so, the net GWP in N1, N2 and N3 treatments were significantly lower than that in CK, in order of N3 < N1 = N2 < CK.
    Conclusions In the field with long-term straw returning, partial substitution of mineral N with manure would increase the absolute CH4 emission, but the increased yield and carbon input would offset the adverse effect, and significantly decrease the N2O emission and increase soil carbon storage, which would significantly decrease the net GWP in double rice system. The extra use of coating urea would strengthen the positive effect, but Si and micronutrient would not. Therefore, optimize fertilizer management to increase early rice yield is an efficient way to decrease greenhouse gas intensity in a double rice system due to much higher greenhouse gas emission in late rice season.

     

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