不同氮肥水平集约化栽培模式双季稻生态系统温室气体收支的田间观测

发布时间：2018-05-30 08:34

本文选题：双季稻 + 集约化栽培模式　；参考：《南京农业大学》2016年博士论文

【摘要】：农田生态系统是温室气体重要排放源,在全球大气温室气体(CH4、N20和CO2)净交换和碳收支中占有重要地位。运用生命周期评价方法综合考虑水稻移栽后温室气体(CH4和N20)排放、固碳效应、农业措施碳排放以及水稻育秧期温室气体排放是全面评价净温室效应(NGWP)的科学指标,同时结合水稻产量可以科学评估不同管理措施下农田温室气体排放强度(GHGI)。提高单位面积作物产量是对我国未来粮食安全的重要保障,土壤-作物系统综合管理(ISSM)则是基于在不同资源(如氮肥)投入水平下通过对土壤和作物系统进行综合管理从而获得不同目标产量的栽培模式,该管理系统主要包括不同氮肥施用量、氮肥施用比例、有机饼肥施用以及移栽密度等集约化栽培措施,这些集约化栽培措施将如何影响稻田生态系统温室气体排放鲜有报道。因此,本文研究探讨了不同氮肥水平集约化栽培模式对双季稻生态系统净温室效应的综合影响,为全面合理评价不氮肥水平集约化栽培模式双季稻生态系统产量、氮肥利用率和净温室效应提供科学依据。本研究以我国南方双季稻生态系统为研究对象,以不施氮肥模式NN和当地常规栽培模式FP为参照,依托土壤-作物综合管理(ISSM)设置了三个氮肥水平集约化栽培模式,分别为ISSM-N1 (与FP比,氮肥减少30kgha-1)、ISSM-N2 (与FP等施氮量)和ISSM-N3 (与FP比,氮肥增加30 kg ha-1)。于2011年4月至2014年4月三个早稻-晚稻-休闲轮作期间,采用静态箱-气相色谱法对五种栽培模式的CH4和N2O排放通量以及生态系统呼吸进行了田间原位观测,同时研究了不同栽培模式双季稻生态系统净碳收支(NECB)、农业措施碳排放(Eo、Ei)以及不同育秧方式(水育秧-WSB、旱育秧-DSB和软盘育秧-WPT)下苗床期温室气体排放情况,进而估算双季稻生态系统的净温室效应(NGWP)和温室气体排放强度(GHGI)。主要研究结果如下:1. 2011年4月至2014年4月三年试验期间各栽培模式全年CH4排放动态变化趋势基本一致,主要排放集中在水稻生长季,晚稻季累积排放量显著高于早稻季。各栽培模式早稻与晚稻季CH4累积排放量与水稻生物量之间呈显著正相关。冬季休闲季CH4排放量较小,在不同栽培模式中约占全年总排放量2.0%～2.7%。五种栽培模式双季稻生态系统全年CH4累积排放量变化范围为380 kg CH4 ha-1 yr-(NN)～645 kg CH4 ha-1 yr-1(ISSM-N3),其中施用有机饼肥的两种集约化栽培模式ISSM-N2与ISSM-N3相对于其他三种栽培模式显著增加了全年CH4累积排放量。2. 2011年4月至2014年4月三年试验期间水稻生长季各栽培模式的N2O除个别排放峰外大部分时间处于很低水平。不同栽培模式对N20通量变化趋势无显著影响,但影响其峰值。各栽培模式晚稻季N20累积排放量显著高于早稻季,休闲季开始初期有N2O排放峰出现,整个休闲季N2O累积排放量占全年的18%～27%。全年N2O累积排放量范围为 0.34 kg N2O-N ha-1 yr-1(NN)～1.03 kg N2O-N ha-1 yr-1(ISSM-N3)。除ISSM-N1模式与NN在晚稻季N2O累积排放量差异不显著外,其余各施氮模式早晚稻季N20累积排放量均显著高于NN模式。全年N20累积排放量与总施氮量之间呈显著指数相关。3.本研究中各栽培模式在三年试验期间均表现为碳固定。各栽培模式年均固碳速率为 0.13 t ha-1 yr-1(NN)、0.29 t ha-1 yr-1(FP)、0.49 t ha-1 yr-1(ISSM-N1)、0.56 t ha-1 yr-1(ISSM-N2)和0.61t ha-1 yr-1(ISSM-N3)。与NN模式相比,四种施氮模式均显著提高了固碳速率。同时,与FP模式相比,三种集约化栽培模式均显著提高了固碳速率。栽培模式和年际均显著影响早晚稻产量。三年试验期间早晚稻产量分别为4.63 t ha-1～9.31t ha-1和6.22 t ha-1～10.17 t ha-1,各栽培模式晚稻季产量显著高于早稻季。相对于不施氮肥的NN模式,各施氮栽培模式均显著提高了早晚稻产量。与当地常规FP相比,三种集约化栽培模式显著提高了全年水稻产量,同时也显著提高了早晚稻季氮肥农学利用率。4.双季稻生态系统各栽培模式农业措施碳排放(Eo、Ei)分别为1267.5 kg CO2-eq(NN)、2781.7 kg CO2-eq (FP)、2719.7 kg C02-eq (ISSM-N1)、3439.1 kg CO2-eq(ISSM-N2)、4034.3 kgCO2-eq (ISSM-N3)。与 FP 模式相比,ISSM-N1 降低了农业措施碳排放,ISSM-N2与ISSM-N3提高了农业措施碳排放。双季稻生态系统传统育秧方式水育秧(WSB)、旱育秧(DSB)和近年来推广的软盘育秧(WPT)由CH4和N20排放引起的温室效应(GWP)分别为1429.6、3197.0和1032.2 kg C02-eq。与WSB与DSB相比,WPT的GWP显著降低了 28%和68%。相对于传统的水育秧和旱育秧方式,近年来推广的软盘育秧方式可以显著降低水稻苗床期CH4和N2O排放引起的综合温室效应。5.双季稻生态系统各栽培模式净温室效应(NGWP)以CH4排放为主,农田措施碳排放(Eo、Ei)次之,N20排放与苗床期温室气体排放贡献较小,固碳可以抵消一部分温室效应。当地常规栽培模式FP的NGWP为18.72tCO2 eq ha-1,温室气体排放强度(GHGI)为 1.23 kg CO2 eq kg grain-1。与 FP 相比,ISSM-N1 模式中 NGWP 与GHGI分别降低了 1.3%和10.5%; ISSM-N2与ISSM-N3模式的NGWP则分别增加了27.4%和 32.7%, GHGI 分别增加了 3.6%和 3.9%。综上所述,与当地常规栽培模式(FP)相比,氮肥减量集约化栽培模式ISSM-N1显著提高了我国南方双季稻生态系统水稻产量和氮肥农学利用率,同时对水稻生产过程的温室气体排放强度具有一定减排潜力。ISSM-N2和ISSM-N3两种集约化栽培模式虽然显著提高了水稻产量,但也提高了净温室效应。
[Abstract]:Farmland ecosystem is an important source of greenhouse gas emission, which plays an important role in the net exchange and carbon budget of global atmospheric greenhouse gases (CH4, N20 and CO2). Using the life cycle assessment method, the emission of greenhouse gases (CH4 and N20) after rice transplanting, carbon sequestration, agricultural measures carbon emissions and greenhouse gas emission during rice seedling stage are considered. A comprehensive evaluation of the scientific indicators of the net greenhouse effect (NGWP) and a scientific assessment of the greenhouse gas emission intensity (GHGI) under different management measures combined with rice yield. The increase of crop yield per unit area is an important guarantee for the future food security of China. The integrated management of soil crop system (ISSM) is based on different resources (such as nitrogen fertilizer). ) the cultivation model of different target yields is obtained by integrated management of soil and crop systems at input level. The management system mainly includes different nitrogen fertilizer application, nitrogen application ratio, organic cake fertilizer application and transplanting density and other intensive cultivation measures. These intensive cultivation measures will affect the rice field ecosystem. The greenhouse gas emissions are rarely reported. Therefore, this paper studies the comprehensive effects of Different Nitrogen Fertilizer Level Intensive Cultivation Models on the net greenhouse effect of double cropping rice ecosystem, and provides a scientific basis for the comprehensive and rational evaluation of the ecological system yield, nitrogen utilization rate and net greenhouse effect of non nitrogenous intensive cultivation model. Based on the double cropping rice ecosystem in the south of China, three intensive cultivation models of nitrogen fertilizer were set up based on soil crop comprehensive management (ISSM), based on the non nitrogen fertilizer model NN and the local conventional cultivation model FP, respectively, ISSM-N1 (compared with FP, nitrogen fertilizer reduction 30kgha-1), ISSM-N2 (and FP and so on) and ISSM-N3 (FP ratio, and FP). Nitrogen fertilizer increased by 30 kg HA-1). During the period of three early rice and late rice leisure rotation from April 2011 to April 2014, the CH4 and N2O emission fluxes of five cultivated models and the ecosystem respiration were observed in situ by static box gas chromatography. The net carbon budget of different Zai Peimo type double cropping rice ecosystem (NECB) and agriculture were studied. The greenhouse gas emission of Eo (Eo, Ei) and different seedling raising methods (water raising rice seedling -WSB, dry seedling raising -DSB and soft disk seedling -WPT) under the seedbed period was used to estimate the net greenhouse effect (NGWP) and greenhouse gas emission intensity (GHGI) of the double cropping rice ecosystem. The main results were as follows: from April to three years of 1.2011 years, each plant was planted in each experiment. The dynamic change trend of CH4 emission was basically consistent throughout the year, mainly concentrated in the growing season of rice, and the cumulative emission of late rice season was significantly higher than that of early rice. The cumulative emission of CH4 from early and late season rice was significantly positively correlated with the biomass of rice, and the CH4 emission of winter leisure season was smaller in different cultivation models. The annual total emission of the annual total emission of 2% ~ 2.7%. five cultivation models was 380 kg CH4 HA-1 yr- (NN) to 645 kg CH4 HA-1 yr-1 (ISSM-N3), and the two intensive cultivation modes with organic cake fertilizer were significantly increased in the year. .2. from April 2011 to April 2014 in three years during the trial period of the rice growing season was at a very low level of N2O except for individual emission peaks. Different cultivation patterns had no significant influence on the change trend of N20 flux, but affected its peak value. The N20 accumulation and discharge of each cultivation mode was significantly higher than that in the early season, and the leisure season was open. At the beginning, the N2O emission peak appeared, and the cumulative emission of N2O in the whole leisure season accounted for 18% ~ 27%. of the whole year. The cumulative emission of N2O was 0.34 kg N2O-N HA-1 yr-1 (NN) to 1.03 kg N2O-N HA-1. All the annual N20 cumulative emission and total nitrogen application were significantly exponentially correlated with the NN model. Each cultivation model in the three year experiment showed carbon fixation during the three year experiment. The annual carbon fixation rate of each cultivation model was 0.13 t HA-1 yr-1 (NN), 0.29 t HA-1 yr-1 (FP), 0.49 t. And 0.61t HA-1 yr-1 (ISSM-N3). Compared with the NN model, the four nitrogen application patterns significantly increased the carbon fixation rate. At the same time, compared with the FP model, the three intensive cultivation patterns significantly increased the carbon fixation rate. The cultivation mode and the interannual both significantly affected the yield of early and late rice. The yield of early and late rice was 4.63 t HA-1 to 9.31t HA-1 in the three year test period, respectively. The yield of 6.22 t HA-1 ~ 10.17 t HA-1 was significantly higher than that of early season rice. Compared with the NN model without nitrogen fertilizer, the yield of early and late rice was significantly increased by different nitrogen fertilization modes. Compared with the local conventional FP, three intensive cultivation models significantly increased the annual rice yield and also significantly improved the early and late rice season nitrogen fertilizer farmers. The carbon emissions (Eo, Ei) of the.4. double season rice ecological system were 1267.5 kg CO2-eq (NN), 2781.7 kg CO2-eq (FP), 2719.7 kg C02-eq (ISSM-N1), 3439.1, 4034.3, respectively. The greenhouse effect (WSB), dry nursery (DSB) and CH4 and N20 emissions caused by CH4 and N20 in recent years (GWP) are 1429.63197.0 and 1032.2 kg C02-eq., respectively, compared with WSB and DSB, respectively. The WPT is significantly reduced by 28% and relative to the traditional water raising and drought. The way of raising rice seedlings, the method of raising seedling with soft disk in recent years can significantly reduce the greenhouse effect of CH4 and N2O in the period of rice seedling bed. The net greenhouse effect of.5. double cropping system (NGWP) is mainly CH4 emission, and the carbon emission of farmland measures (Eo, Ei) is the second. The contribution of N20 emission and greenhouse gas emission is less, carbon sequestration can be found. In order to offset a part of the greenhouse effect, the NGWP of the local conventional cultivation model FP was 18.72tCO2 EQ HA-1, and the greenhouse gas emission intensity (GHGI) was 1.23 kg CO2 EQ kg grain-1. compared with FP, which decreased by 1.3% and 10.5% respectively. Combined with 3.6% and 3.9%., compared with the local conventional cultivation model (FP), the nitrogen reduction and intensive cultivation model ISSM-N1 significantly improved the rice yield and the nitrogen fertilizer utilization rate of the southern double cropping rice ecosystem in the south of China. At the same time, the greenhouse gas emission intensity of the rice production process had a certain emission reduction potential of.ISSM-N2 and ISSM-N3. Although intensive cultivation increased rice yield significantly, it also increased net greenhouse effect.
【学位授予单位】：南京农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S511.42;S181

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