不同种植模式下土壤有机碳特性研究

发布时间：2018-10-09 11:58

【摘要】：随着气候变化在国际间的讨论逐渐深入,提高农田土壤固碳减排能力以应对气候变化成为目前科学界研究的重点。有机种植作为低碳经济的重要模式之一,在固碳减排上具有巨大潜力。本文重点研究了有机和常规两种不同种植模式下土壤有机碳的特性,通过定位研究,比较两种种植模式下土壤有机碳及其组分的动态变化;通过团聚体分级,明确两种种植模式下土壤有机碳及其组分在团聚体内的分布特点,从物理化学角度探讨土壤的固碳机制;并比较了我国不同地区在有机和常规种植模式下土壤有机碳特性。通过以上研究旨在探讨有机种植是否具备应对气候变化的能力,从而进一步推动我国农业的可持续发展。对有机和常规种植模式下土壤有机碳及其组分的长期定位研究表明,经过10年有机种植后,土壤理化性质得到改善,有机质、全氮、有效磷和速效钾均比常规种植高;常规种植除了有机质有所升高,其他养分指标均有不同程度的降低。有机种植模式下过氧化物酶和多酚氧化酶活性分别为2.66、0.98 mg没食子素g-1·2h-1,常规种植这两种酶活分别为1.64、0.67mg没食子素g-1·2h-1。有机种植土壤有机质、重组有机质和活性有机质均高于常规,且呈逐年增长的趋势,分别从2004年的21.52 g·kg-1、20.75 g·kg-1 和 5.93 g·kg1 增加到2013年的30.94 g·kg-1,28.29 g·kg-1和7.83g·kg-1。有机种植初期有机质增长较缓慢,种植5年后增长明显加快。常规种植有机质从2009年开始出现下降趋势;重组有机质从2011年开始略有下降;活性有机质增加相对平缓。从长期定位试验来看有机种植模式促进了有机质及其组分含量的增加,有利于提高土壤酶活,促进有机碳由活性有机碳向更稳定的腐殖酸发展。通过比较有机和常规两种不同种植模式下土壤团聚体组成、分配及团聚体内有机碳组分的差异。结果表明,常规种植模式下随着团聚体粒级的减小,团聚体四个粒级(1 mm,1～0.5 mm,0.5～0.25 mm 和0.25 mm)的百分含量均值分别为 23.75%、15.15%、19.98%和38.09%,而有机种植模式下各粒级团聚体(1mm,1～0.5mm,0.5～0.25 mm 和0.25 mm)的百分含量分别为 9.73%、18.41%、24.46%和 43.90%,0.25 mm微团聚体百分含量显著高于常规种植。有机种植模式提高了土壤有机碳和全氮含量,平均值分别为17.95 g·kg-1和 1.51 g·kg-1。有机种植模式下相同粒级间,团聚体中重组有机碳平均含量显著高于常规种植,且重组有机碳在0.25 mm这部分稳定性有机碳主要储存场所的微团聚体中富集。有机种植模式下易氧化态碳在1 mm大团聚体中的含量显著高于常规种植,其它粒级间没有显著差异,易氧化态碳在1mm大团聚体中富集。有机种植模式增加了土壤有机碳及其组分含量,缓解了耕作对团聚体的破坏,并增强了有机碳的稳定性,有利于土壤固碳。各粒级团聚体中铁铝氧化物的含量分布规律不明显,可能在该农场铁铝氧化物对有机碳的化学稳定不起主要作用。不同地区有机和常规种植模式下土壤有机碳的特性因种植地区、种植作物和种植年限等的不同而差异较大。有机种植年限3年以内的金坛、山西和扬州三个地区在有机碳、重组有机碳和易氧化态碳含量上与常规种植没有显著性差异(P0.05),种植年限在4~6年的上海、山东和云南三个地区的这三个指标均显著高于常规种植(P0.01)。随着有机种植年限的延长,有机与常规的C/N比差值有变大趋势。两种种植模式下有机碳与重组有机碳、易氧化态碳有显著的正相关关系。有机种植模式下,随着有机碳含量的增加,重组部分和活性部分的碳积累更快,且重组部分的积累快于活性部分。
[Abstract]:With the deepening of the international discussion on climate change, the ability of soil solid carbon emission reduction in farmland to cope with climate change has become the focus of scientific research at present. As one of the important modes of low carbon economy, organic planting has great potential in carbon sequestration and emission reduction. In this paper, the characteristics of carbon black carbon in organic and conventional planting modes were studied, and the dynamic changes of carbon and its components in two planting modes were compared by location research. The distribution characteristics of carbon and its components in the agglomerate were determined in two planting modes, and the carbon sequestration mechanism of soil was discussed from the point of physical chemistry. The carbon characteristics of the carbon and its components under organic and regular planting modes were compared. The above research aims at exploring whether organic cultivation has the ability to deal with climate change, thus further promoting the sustainable development of agriculture in China. Long-term positioning of carbon and its components in organic and regular planting modes showed that after 10 years of organic planting, the physical and chemical properties of soil were improved, organic matter, total nitrogen, effective phosphorus and quick-acting potassium were higher than those of regular planting. Other nutrient indicators were decreased in varying degrees. The activities of peroxidase and multi-phenol oxidase in organic planting mode were 2.66, 0.098 mg and g-1 路 2h-1, respectively, and the two kinds of enzyme activities were 1.64, 0.67mg without food additive g-1 路 2h -1, respectively. The organic matter, the recombinant organic matter and the active organic matter in the organic planting soil were all higher than those of the conventional, and the trend of increasing year by year was from 21. 52 g 路 kg -1, 20. 75 g 路 kg -1 and 5.93 g 路 kg -1 in 2004 to 30. 94 g 路 kg -1, 28. 29 g 路 kg -1 and 7. 83g 路 kg -1 in 2013 respectively. Organic matter increased slowly in the early stage of organic planting, and the growth of organic matter increased significantly after 5 years. In 2009, the organic matter decreased slightly from the beginning of 2011, and the organic matter increased relatively gently. From the long-term positioning test, the organic planting model promotes the increase of organic matter and its component content, which is beneficial to improving soil enzyme activity and promoting the development of organic carbon from active organic carbon to more stable humic acid. By comparing the composition, distribution and agglomeration of organic carbon components in soil aggregates under the two different planting modes of organic and conventional plants. The results showed that with the decrease of agglomerate size in the conventional planting mode, the mean content of the four fractions (1 mm, 1 ~ 0.5 mm, 0. 5 ~ 0. 25 mm and 0. 25 mm) were 23. 75%, 15. 15%, 19. 98% and 38. 09%, respectively. The percentages of 0. 5 ~ 0. 25 mm and 0. 25 mm were 9.73%, 18.41%, 24.46% and 43. 90% respectively, and the percentage content of microaggregates was significantly higher than that of conventional planting. The organic planting model increased the total nitrogen content and the mean value of 17. 95g 路 kg-1 and 1.51 g 路 kg-1, respectively. The average content of the recombinant organic carbon in the agglomerate was significantly higher than that of the conventional planting in the organic planting mode, and the recombinant organic carbon was enriched in the micro-aggregates of the main storage sites of 0. 25 mm of the stable organic carbon. In the organic planting mode, the content of easily oxidized carbon in the 1 mm large aggregate was significantly higher than that of conventional planting, and there was no significant difference between the other fractions, and the easily oxidized carbon was enriched in the 1 mm large aggregate. the organic planting mode increases the content of the organic carbon and the components thereof, relieves the damage of the cultivation on the aggregates, enhances the stability of the organic carbon, and is favorable for the solid carbon of the soil. The content distribution of iron-aluminum oxide in each size agglomerate is not obvious, and it may not play a major role in the chemical stability of organic carbon on the farm iron-aluminum oxide. The characteristics of carbon in organic and regular planting patterns in different regions were different from those of planting area, planting crops and planting years. There was no significant difference in organic carbon, recombinant organic carbon and easily oxidized carbon content in three regions of organic carbon, recombinant organic carbon and easily oxidized carbon in three years of organic planting years (P0.05). The three indexes of Shandong and Yunnan were significantly higher than those of the conventional ones (P0.01). With the increase of organic planting years, the difference between organic and conventional C/ N ratio is large. Organic carbon in two planting modes has a significant positive correlation with the recombinant organic carbon and the easily oxidized carbon. In the organic planting mode, with the increase of the organic carbon content, the carbon accumulation of the recombinant part and the active part is faster, and the accumulation of the recombinant part is faster than that of the active part.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153.6

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