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肥料施用对农田土壤生产力及土壤碳循环的影响是农业与陆地生态系统碳循环及全球变化研究的重要科学问题。以太湖地区黄泥土的长期肥料定位试验为例,研究不同施肥处理对水稻土-作物系统作物碳同化及土壤碳固定的影响。所研究的肥料施用处理包括不施肥(NF)、单施化肥(CF)、化肥与秸秆配施(CFS)以及化肥与猪粪配施(CFM)4个处理,始于1987年,一直实行稻-油轮作,实行少耕。连续观测水稻和油菜的产量,并于2004年和2005年分别采集了土壤剖面样品和耕作层(0~5cm和5~15cm)土壤,测定土壤总有机碳含量。研究表明,不同施肥处理对水稻产量有显著影响,尤其以配施有机无机肥处理水稻产量显著最高且最为稳定,而对油菜产量的影响不明显。施肥显著提高了耕层土壤碳密度,而对全土碳密度没有显著影响。施肥处理的固碳速率介于0.1~0.4t/(hm2.a),配施有机肥处理显著高于单施化肥处理。相关分析表明,土壤固碳速率与作物根茬+有机肥源碳的总碳输入量呈显著的对数关系。这提示土壤有机碳积累主要与作物产量有关,而并非依变于有机肥源碳输入。因此,与作物产量直接关联的作物碳输入的增加是土壤中碳固定提高的重要途径。施入N素对水稻碳同化和土壤碳固定的效应均为化肥配施有机肥处理显著高于单施化肥处理,这揭示化肥配施有机肥是提高与稳定稻田生产力和促进土壤固碳和温室气体减排的双赢措施。当然,不同施肥下上述效应的差异可能与土壤-作物系统中碳分配和土壤生物碳利用的差异有关。
The effect of fertilizer application on farmland soil productivity and soil carbon cycle is an important scientific issue in the research on carbon cycle and global change of agricultural and terrestrial ecosystems. Taking the long-term fertilizer experiment of yellow soil in Taihu Lake as an example, the effects of different fertilization treatments on carbon assimilation and soil carbon fixation in paddy soil-crop system were studied. The fertilizer application treatments studied included four treatments of non-fertilization (NF), chemical fertilizer (CF), chemical fertilizer and straw (CFS) and chemical fertilizers and pig manure (CFM). Since the beginning of 1987, - Oil tankers, the implementation of less tillage. The yields of rice and canola were observed continuously. Soil samples of soil profile and tillage (0-5 cm and 5-15 cm) soil samples were collected in 2004 and 2005, respectively. Total organic carbon was measured. The results showed that different fertilization treatments had significant effects on the yield of rice, especially the treatment of organic and inorganic fertilizers was the highest and the most stable, while the yield of rapeseed was not obvious. Fertilization significantly increased soil carbon density of topsoil, but had no significant effect on total soil carbon density. The carbon sequestration rate of fertilization treatment ranged from 0.1 to 0.4 t / (hm2.a), and the treatment with organic fertilizer was significantly higher than that of chemical fertilizer alone. Correlation analysis showed that there was a significant logarithm relationship between soil carbon sequestration rate and total carbon input of crop stubble + organic fertilizer source carbon. This suggests that the accumulation of soil organic carbon is mainly related to the crop yield, not to the carbon input of organic manure source. Therefore, an increase in crop carbon inputs directly linked to crop yields is an important way to increase carbon fixation in soils. The effects of N application on rice carbon assimilation and soil carbon fixation were significantly higher than that of chemical fertilizer application organic manure treatment, which revealed that fertilizer application of organic manure is to improve and stabilize rice paddy productivity and promote soil carbon sequestration and greenhouse Win-win measures to reduce emissions. Of course, differences in these effects under different fertilizations may be related to differences in carbon assimilation and soil bio-carbon utilization in the soil-crop system.