秸秆还田下土壤有机碳固持能力提升机制研究

发布时间：2018-03-22 11:18

本文选题：农田土壤　切入点：有机碳固持　出处：《西北农林科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：目前,随着国家大力推行秸秆还田,秸秆还田已成为增加土壤有机质,提高土壤肥力的重要途径之一,但秸秆在腐解过程中相当一部分碳以CO2形式释放。如何使更多秸秆碳被固持于土壤中对于农田土壤固碳减排具有重要意义。为此,本研究首先通过培养试验研究秸秆还田条件下有机碳损失机制,并通过一个培养试验研究在秸秆还田的条件下中微量元素对农田土壤有机碳固持的影响,另外通过大田试验研究秸秆还田条件减氮施肥并配施生物炭对土壤有机碳提升的研究。主要结果如下:1.在秸秆还田条件下,土壤有机碳累积释放量、激发效应(PE)、微生物微生物量碳(MBC)均随着土壤原有有机碳的增加而增加;秸秆的添加加速土壤有机碳的矿化;但秸秆添加降低了原有有机碳损失,随着有机碳含量降低,土壤原有有机碳积累增加,秸秆残留碳也增加。因此,在土壤有机碳含量较高的土壤上秸秆还田不利于土壤有机碳的固持。2.秸秆腐解过程中分别添加S(硫磺)、Fe(FeCl3·6H2O)和Zn(ZnSO4·7H2O)元素,均提高了微生物生物量碳(MBC)及土壤CO2-C矿化速率,52 d腐解培养结束后,CO2-C的累积矿化量显著提高,但土壤有机碳含量并未显著降低;3种元素中,添加Fe和Zn的处理提高了土壤惰性碳库、惰性碳库比例及土壤有机碳表观平衡,有利于土壤有机碳固持,而添加S的处理却降低了惰性有机碳比例及土壤有机碳表观平衡,不利于有机碳固持。因此,在施N、P肥基础上,秸秆还田添加S、Fe或Zn均能促进土壤有机碳矿化进程,但添加Fe或Zn可使更多有机碳固持于土壤中,S不利于土壤有机碳固持3.在秸秆还田条件下减氮施肥和配施生物炭对小麦籽粒和秸秆产量均无影响;减氮施肥降低了NO3--N、NH4+-N和TN含量,而生物炭的施用却提高了这3种养分的含量;减氮施肥对有机碳及活性有机碳组分均无显著影响,而施用生物炭不仅提高了有机碳储量和土壤有机碳固持能力,而且还提高了活性有机碳组分。总之,在有机碳含量相对较高的土壤进行秸秆还田不利于有机碳的固持,通过秸秆还田下添加微量元素(Fe或Zn)和生物炭均能提高土壤有机碳的固持。
[Abstract]:At present, the state vigorously with straw, straw has become increasing soil organic matter, one of the important ways to improve the soil fertility, but straw in composting process in a considerable part of the carbon release in the form of CO2. How to make more straw carbon is fixed in the soil for carbon sequestration in agricultural soil has important significance for. First of all, this study through culture experiment under straw incorporation of organic carbon loss mechanism, and through a culture experiment in the straw under the condition of trace elements on soil organic carbon sequestration effect, the other through the study of field experiments of straw treatments reduce nitrogen fertilization and fertilizer of biochar on Soil organic carbon research upgrade. The main results are as follows: 1. in the straw under the condition of soil organic carbon accumulation release, stimulating effect (PE), microbial biomass carbon (MBC) with the original soil The increase of organic carbon increased; straw added to accelerate the mineralization of soil organic carbon; but straw decreased by adding organic carbon loss, with the decrease of organic carbon content, soil organic carbon accumulation, straw residual carbon is increased. Therefore, the higher soil organic carbon content of the soil on the straw is not conducive to soil organic carbon the fixation of.2. straw decomposition process were added to S (sulfur), Fe (FeCl3 - 6H2O) and Zn (ZnSO4 - 7H2O) elements, increased the microbial biomass carbon (MBC) and soil CO2-C mineralization rate, 52 D decomposition after incubation, cumulative mineralization of CO2-C increased significantly, but the soil the organic carbon content did not decrease significantly; 3 elements, Fe and Zn added increased soil inert carbon, inert carbon ratio and soil organic carbon balance, is conducive to soil organic carbon sequestration, and the addition of S processing is lower than the inert organic carbon Cases and soil organic carbon balance, is not conducive to organic carbon sequestration. Therefore, the application of N, P fertilizer based on straw added S, Fe or Zn could promote soil organic carbon mineralization process, but Fe or Zn was added to make more organic carbon sequestration in soil, S is not conducive to soil organic carbon holding 3. in the straw under the condition of reducing nitrogen fertilizer and combined application of biochar on wheat straw and grain yield had no effect; less nitrogen fertilization decreased the NO3--N, NH4+-N and TN content, and the application of biochar has increased the content of the 3 kinds of nutrients; reduction had no significant effect on organic carbon and nitrogen fertilization active organic carbon fractions, and biochar can not only improve the organic carbon storage and soil organic carbon sequestration capacity, but also improve the activity of organic carbon fractions. In short, the straw in the relatively high organic carbon content of soil is not conducive to the retention of organic carbon, added by straw returning Trace elements (Fe or Zn) and biological carbon can improve the fixation of soil organic carbon.

【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S153.6

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