秸秆还田方式及年限对土壤腐殖质组成和结构特征的影响

发布时间：2018-03-05 21:36

本文选题：玉米秸秆　切入点：分解速率　出处：《吉林农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：如何有效合理利用作物秸秆,是中国农业亟待解决的重要问题.诸多研究表明,秸秆还田对于提高秸秆利用率,增强土壤肥力具有重要意义。现阶段关于秸秆不同还田方式和年限对土壤腐殖质组成和结构特征的影响还少有研究,对此进行研究,有利于了解不同还田方式和年限下土壤腐殖质变化差异,为土壤固碳、培肥提供依据。本文通过培养试验研究不同添加方式下秸秆分解速率和土壤腐殖质变化;微区试验对比秸秆不同还田方式下土壤腐殖质组成和结构特征的差异;田间试验研究秸秆深还后,土壤腐殖质组成和结构随年限增长的变化特征。研究结果表明:(1)添加玉米秸秆后,秸秆分解速率在0~24d左右迅速升高至顶峰(194~1103mg/kg/d)后不断下降,在第25~300d分解速率缓慢下降趋于稳定;秸秆累积分解率呈现前期迅速增长,后期增长缓慢的趋势。黑土全量秸秆与土混合处理的分解最快(82%)。(2)不同方式秸秆还田下土壤pH和电导率无显著变化;表层土壤N、P、K养分含量随秸秆浅施用量增加呈上升趋势,秸秆深还显著提高了亚表层土壤养分含量。随秸秆深还年限增加,土壤各速效养分含量呈下降趋势。(3)添加玉米秸秆显著提高了SOC含量;随秸秆用量增加,SOC含量增加;秸秆与土混合更利于SOC含量积累。秸秆不同量浅施对表层SOC影响显著,秸秆深还后亚表层增加更明显。随秸秆深还年限增加,SOC含量呈下降趋势。(4)添加玉米秸秆和不同方式秸秆还田(不同量秸秆浅施和秸秆深还)均有利于提高土壤腐殖质组分有机碳含量,PQ值及HA的ΔlogK值。随秸秆深还年限增长,SOC、FA和HM有机碳含量呈下降趋势,HA有机碳含量呈上升趋势,PQ值变化显著,土壤HA的ΔlogK呈下降趋势。(5)培养试验、微区试验和田间试验均表明:施用玉米秸秆后HA氧化度、缩合度和热稳定性降低,脂族链烃含量增加,芳香性减弱,分子结构趋于简单化。培养试验中随秸秆用量增加,HA结构趋于简单化;秸秆与土壤混合后HA结构变化显著。微区试验中秸秆浅施用量增加,表层HA结构简单化趋势明显。田间试验中秸秆深还对亚表层HA结构影响显著,随深还年限增加,HA缩合度和氧化度呈上升趋势,脂族性减弱,芳香性和热稳定性增强,HA结构趋于复杂化。(6)田间试验表明:秸秆深还1年后玉米产量增加6%;随秸秆深还年限增长,玉米产量高于CK,呈下降趋势。
[Abstract]:How effective and rational utilization of crop straw, Chinese agriculture is an important problem urgently to be solved. Many studies show that straw to improve the utilization of straw, has important significance to enhance soil fertility. At this stage on the effects of different ways of returning straw and life on the composition and structural characteristics of soil humus, there is little research, this paper is conducive to to understand the difference of Soil Humus in different treatments and years, for carbon sequestration in soil fertility, provide the basis for experimental study. In this paper, through the cultivation of the soil humus decomposition rate and the change of different addition methods of straw; differences in micro area test comparison of different ways of returning straw under soil humus composition and structural characteristics; field experiment of straw deep yet and the variation characteristics of soil humus composition and structure with age growth. The results show that: (1) after the addition of corn stalk, straw The solution rate increased rapidly to the peak at about 0~24d (194~1103mg/kg/d) after falling in the decomposition rate of 25~300d decreased slowly stabilized; straw decomposition rate showed a cumulative early rapid growth, slow growth trend. Post processing the full amount of straw and soil mixed with soil decomposition of the fastest (82%). (2) different soil pH and conductivity of straw under no significant change; surface soil N, P, K nutrient content increased with straw shallow rise, straw deep also significantly improved the soil nutrient content of the subsurface. With straw deep also increased years, soil available nutrients content decreased. (3) adding corn straw significantly content of SOC was increased; with the increase of SOC content increased the amount of straw, straw mixed with soil; more conducive to the accumulation of SOC content. Different amount of straw significantly affect the shallow surface SOC, straw deep subsurface also increased more obviously with straw deep. Life also increased, SOC content decreased. (4) add the corn straw and straw in different ways (different amount of straw and straw deep is shallow application) can improve the organic carbon content of the soil humus, a logK PQ value and HA value. With straw deep is the growth in number of years, SOC, FA and HM the organic carbon content decreased, HA organic carbon content increased, the value of PQ changed significantly, logK soil HA decreased. (5) culture test, micro area test and field test showed that the degree of HA oxidation of corn straw, reduce the condensation degree and thermal stability, increase the amount of aliphatic chain aromatic, weakened, molecular structure tends to be simple. Incubation with straw addition, HA structure is simple; the straw with HA structure change of soil mixed significantly. The micro plot experiment of straw increased HA shallow surface, simple structure trend is obvious. The straw in field experiment Depth of the sub surface structure of HA significantly, with the depth increasing period of HA condensation and oxidation degrees rise, aliphatic decrease enhanced aromaticity and thermal stability, the HA structure became complicated. (6) field experiments showed that straw deep also after 1 years corn yield increased by 6% with straw; deep is the growth in number of years, the maize yield is higher than CK, showed a downward trend.

【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S141.4

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