耕作方式对华北平原麦玉两熟农田土壤固碳及作物生长的影响

发布时间：2018-04-12 06:03

  本文选题：耕作方式 + 土壤有机碳　； 参考：《中国农业大学》2017年博士论文

【摘要】：为明确秸秆还田技术与耕作方式互作对华北平原麦-玉两熟区农田土壤固碳和作物生产的影响,本研究于2008年在中国农业大学吴桥实验站开始了长期定位试验,分别设置了免耕秸秆还田(NTS)、深松秸秆还田(STS)、旋耕秸秆还田(RTS)、翻耕秸秆还田(CTS)和对照翻耕秸秆不还田(CT)5个处理。本文主要研究了2013-2015年冬小麦-夏玉米生长期内耕作方式对各作物收获期农田土壤物理结构、有机碳库和作物生产的影响,同时综合评价了麦-玉两熟农田作物生产的碳足迹以及有机碳与作物产量的相关性。主要结果如下:(1)耕作方式对土壤物理结构的影响差异较大,NTS处理增加了0-20 cm土层的容重,而对深层的影响与其他耕作方式相同,而且NTS处理的土壤总孔隙度和毛管孔隙度均比其他4个处理低。CTS和STS处理减小了0-20 cm土层容重,增大了0-30 cm土层的土壤总孔隙度和毛管孔隙度。NTS处理增大了5-20cm土层2mm团聚体的比例,且显著提高了0-20cm土层内土壤团聚体平均重量直径(P0.05)。(2)秸秆还田与耕作方式互作条件下,对土壤有机碳的影响主要集中在0-30 cm土层。0-5 cm土层的有机碳含量随耕作强度的降低显著增加。0-10 cm 土层,NTS增加了土壤有机碳含量和储量,提高了土壤有机碳的层化率(P0.05),而RTS处理的有机碳含量与其相差较小。CTS和STS促进了 0-20 cm土层土壤有机碳的均匀分布,且CTS处理增加了 10-20 cm 土层的有机碳含量,减小了 0-30 cm土层的层化率。0-5 cm土层的各粒级水稳性团聚体有机碳含量均以NTS处理最大,显著高于其他处理(P0.05);10-20cm土层,0.25-2mm有机碳含量以CTS处理最大,CT处理最小,但其他3个处理差异不大(P0.05)。(3)耕作方式对有机碳组分的影响主要表现在0-30 cm土层,而对大于30 cm 土层影响较小。NTS处理增加了0-5 cm土层的颗粒有机碳、重组和轻组有机碳组分,而降低了易氧化有机碳的含量,但均高于CT处理(P0.05)。RTS处理增加了0-10 cm土层的有机碳组分,易氧化有机碳含量均高于其他处理。STS和CTS处理增加了 10-20 cm土层的土壤有机碳组分含量,促进了有机碳组分的均匀分布,CT处理有机碳组分含量在各土层中均为最小。(4)与CT相比,NTS处理延长了冬小麦生育期,对夏玉米生育期的影响与其它处理一致。STS和CTS提高了冬小麦的出苗率,NTS处理降低了冬小麦出苗率(P0.05),但各耕作方式对夏玉米出苗率影响无差异。NTS和STS相对提高了冬小麦净光合速率,减小了光合午休现象。比较其产量得出,CTS和STS冬小麦、夏玉米产量较高,水分利用效率表现为CTS处理相对较大,CT处理的最小。(5)比较各耕作方式的碳足迹发现,在考虑或不考虑有机碳储量的变化时,均以NTS处理的碳足迹最小,其值为-0.03-0.63 kg C02-eq hm-2 year-1,CT处理最大,其值为0.22-0.75 kg C02-eq hm-2 year-1其他3个处理在不考虑有机碳时相差不大,考虑有机碳时的大小顺序为RTSSTSCTS。且当计算有机碳时,CT处理的碳足迹有所增加,主要是由于有机碳储量减少所致。通过对各指标的相关性分析得出,有机碳与水稳性团聚体有机碳以及有机碳组分呈极显著正相关关系(P0.01)。
[Abstract]:Clear straw technology and interactive effects of Tillage in North China wheat maize cropping area two farmland soil carbon sequestration and crop production, the study on 2008 at the Wuqiao experiment station of China Agricultural University began a long-term experiment were set up (NTS), no tillage subsoiling and straw (STS), rotary tillage and straw returning (RTS), conventional tillage (CTS) control and conventional tillage without straw (5 CT). This paper mainly studies the 2013-2015 year winter wheat summer maize growth period of Tillage on the crop harvest period of soil physical structure, effects of organic carbon and crop production, and comprehensive evaluation of wheat maize two crops crop production of carbon footprint and correlation between organic carbon and crop yield. The main results are as follows: (1) the difference of tillage effects on soil physical structure of the larger, NTS treatment increased 0-20 cm soil bulk density, and The deep influence of the same with other farming methods, and NTS soil total porosity and capillary porosity were lower than the other 4 treatments.CTS and STS treatment decreased 0-20 cm soil bulk density, increased 0-30 cm soil total porosity and capillary porosity of.NTS treatment increased 5-20cm 2mm soil aggregate proportion, and significantly increased in 0-20cm soil layer soil aggregate mean weight diameter (P0.05). (2) of straw and tillage interaction conditions, effects on soil organic carbon mainly concentrated in the organic carbon content of 0-30 cm.0-5 cm soil layer decreased with soil tillage intensity significantly increased.0-10 cm soil, NTS increased soil organic carbon content and reserves, improve stratification ratio of soil organic carbon (P0.05), organic carbon content and RTS and.CTS STS are small and promote the uniform distribution of 0-20 cm soil organic carbon, and CTS With the increased organic carbon content of 10-20 cm soil layer, 0-30 cm soil layer decreased the rate of.0-5 of the cm soil water stable aggregate organic carbon content in NTS treatment was the highest, significantly higher than other treatments (P0.05); 10-20cm 0.25-2mm soil organic carbon content in the CTS treatment, CT treatment is the lowest. But the other 3 treatments had no difference (P0.05). (3) effects of Tillage on soil organic carbon fractions mainly in 0-30 cm soil layer, and the soil above 30 cm affected.NTS treatment increased the particulate organic carbon in the soil layer of 0-5 cm, and the recombinant light fraction organic carbon fractions, and decreased the content of easy the oxidation of organic carbon, but the treatment was higher than that of CT (P0.05).RTS treatment increased organic carbon group 0-10 cm soil layer, easily oxidized organic carbon content is higher than other treatment.STS and treatment CTS increased the soil organic carbon fractions in 10-20 cm soil layer, promote the organic carbon The uniform distribution of components, CT contents of organic carbon fractions in each soil layer was the smallest (4). Compared with CT, NTS treatment prolonged the growth period of winter wheat, the effects of the growth period of summer maize and other favorable.STS and CTS increased the germination rate of winter wheat, NTS treatment reduced winter the wheat germination rate (P0.05), but the tillage on maize seedling emergence rate of no difference between.NTS and STS relatively improve the net photosynthetic rate of winter wheat decreased, photosynthetic midday depression. Compared to the yield obtained, CTS and STS of winter wheat, maize yield, water use efficiency for CTS processing is relatively large CT, the smallest. (5) found that the tillage carbon footprint, considering or not considering the variation of organic carbon, the carbon footprint of NTS treatment was the minimum, the value of -0.03-0.63 kg C02-eq hm-2 year-1, CT, kg C02-eq hm-2 0.22-0.75 whose value is yea R-1 the other 3 treatments are not considered when the organic carbon had little difference, considering the organic carbon in the order of RTSSTSCTS. and the calculation of organic carbon, CT carbon footprint increased, mainly due to a decrease in organic carbon storage. The correlation of each index analysis, organic carbon and water stable aggregates carbon and organic carbon fractions showed significant positive correlation (P0.01).

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S512.1;S513
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本文编号：1738474