有机肥施用对冬小麦—夏玉米产量和土壤肥力的影响

发布时间：2018-06-06 00:27

本文选题：有机肥 + 作物产量　；参考：《中国农业大学》2017年博士论文

【摘要】：目前我国氮肥施用量过高,氮肥利用效率低,资源环境代价大。有机肥施用后可培肥地力,提高作物产量,是实现农业可持续发展的途径之一。本文以华北平原冬小麦-夏玉米轮作体系为研究对象,研究化肥减施后配施有机肥对夏玉米整个生育期地上部生物量累积和氮吸收的影响,同时测定整个生育期不同土层中土壤无机氮,评价其环境效应;通过对玉米整个生育期根系生长的研究,探讨有机肥施用后根系形态特征的改变,阐明其与土壤剖面中氮淋洗的关系;同时对不同年份冬小麦和夏玉米收获季土壤微生物群落和活性的测定,探讨化肥减施后对土壤生物肥力的影响及其季节性变化特征;最后通过室内培养实验测定不同施肥处理原位土壤抵抗干旱的能力。主要结果如下:(1)化肥减施30%后配施有机肥可维持玉米产量,减少土壤剖面中硝态氮损失并提升土壤有机质。与常规施肥相比,有机肥替代化肥对玉米地上部生物量累积和氮吸收影响无显著差异,且玉米产量三年平均增加7-15%。在2014年玉米收获季,与化肥相比,有机肥处理减少了底层土壤中无机氮的含量(50%),提高了氮的农学利用效率(69%)和偏生产力(47%)。经过三年后,有机肥较化肥显著增加土壤有机质7.8-16.8%。(2)在2013-2015年玉米整个生育期采集不同施肥处理0-60 cm 土壤中的根系,发现根系生长在整个生育期呈先增加后降低的趋势,50%以上的玉米根系主要分布在表层土壤(0-20 cm)。在玉米V12叶期,与常规施肥相比,化肥减施30%后配施有机肥可促进50-60 cm 土层中根系伸长(2014年除外)。有机肥施用后增加了表层土壤含水量(V6和R6时期),而后者与表层细根系(0.2 mm)长度显著正相关。此外,土壤表层细根长度与土壤中无机氮含量显著负相关,并且底层粗根系(0.2 mm)长度与地上部氮吸收显著正相关。结果表明,有机肥施用后土壤Nmin含量减少,与有机肥施用后通过改变表层细根系和底层粗根系长度,增加植物对氮素的吸收有关,最终可能会降低土壤中潜在无机氮淋洗的风险。(3)通过对华北平原冬小麦-夏玉米收获季土壤微生物群落和活性的研究发现,与100%NPK相比,化肥减施50%+有机肥未显著降低土壤微生物数量,并且同时和秸秆还田之后可显著提高土壤微生物总数量和细菌数量,分别为29.3%和30.5%(2013年玉米收获季)。小麦季土壤微生物群落结构的改变对施肥的响应高于玉米季(2011年)。施肥显著增加了和碳代谢相关的酶活性(蔗糖酶除外),且小麦季高于玉米季。说明有机肥和秸秆的添加可提升土壤有机质,小麦季土壤碳固持潜力要高于玉米季。(4)通过对9年长期定位试验原位土壤进行盆栽试验发现,未灭菌条件下,干旱处理未显著降低玉米生物量,灭菌后干旱处理较湿润处理平均玉米生物量显著降低了 34.6%,且有机肥处理玉米生物量下降高于化肥处理。有机肥处理土壤灭菌后,干旱处较湿润处理显著提高了根际土柠檬酸和速效磷的含量,未灭菌条件下干旱和湿润处理差异不显著。有机肥施用显著提高了非根际土团聚体结构的稳定性。与不灭菌处理相比,灭菌处理显著提高了玉米地上部生物量和根际土有机酸的含量,降低了土壤团聚体结构的稳定性。发现水分处理效应仅在灭菌下显现,表明土壤微生物可在一定程度上影响植物对干旱胁迫的抗性,有机肥未表现出对植物抗旱性的缓冲作用。本研究从植物、土壤和微生物的角度,系统研究了化肥减施后配施有机肥或秸秆还田对作物产量和土壤肥力的影响。研究发现,在河北曲周目前肥力水平下,化肥减施30%后配施有机肥或秸秆还田可维持作物产量,提升土壤肥力,且小麦季土壤碳固持潜力高于玉米季。通过三年大田试验,发现化肥减施后会促进底层粗根系生长,增加地上部氮吸收,减少土壤剖面中无机氮含量。但与化肥相比,有机肥未表现出对植物抗旱性的缓冲作用。
[Abstract]:At present, the amount of nitrogen fertilizer applied in China is too high, the efficiency of nitrogen fertilizer utilization is low and the resource and environment cost is great. It is one of the ways to realize the sustainable development of agriculture after the application of organic manure, and it is one of the ways to realize the sustainable development of agriculture. The effects of biomass accumulation and nitrogen absorption on the upper part of the growth period were studied. At the same time, the soil inorganic nitrogen was measured in different soil layers of the whole growth period, and the environmental effects were evaluated. The soil microbial community and activity in the winter wheat and summer maize harvest season in the same year were measured, and the effects of chemical fertilizer on soil biological fertility and its seasonal characteristics were discussed. Finally, the ability of soil resistance in situ in different fertilization treatments was measured by indoor culture experiment. The main results were as follows: (1) the fertilizer was reduced by 30% to apply organic fertilizer. Fertilizer can maintain maize yield, reduce the loss of nitrate nitrogen in soil profile and improve soil organic matter. Compared with conventional fertilization, the effect of organic manure instead of fertilizer on biomass accumulation and nitrogen absorption of maize above ground is not significantly different, and the yield of maize increased by 7-15%. in three years in 2014, compared with chemical fertilizer, the treatment of organic manure is reduced. The content of inorganic nitrogen in the underlying soil (50%) increased the efficiency of nitrogen use (69%) and partial productivity (47%). After three years, the organic manure significantly increased the soil organic matter 7.8-16.8%. (2) in the whole growth period of 2013-2015 years and collected the roots of 0-60 cm soil with different fertilization treatments, and found that the root growth was in the whole growth period. The trend of first increasing and then decreasing, more than 50% of the maize roots were mainly distributed in the surface soil (0-20 cm). In the V12 leaf period of maize, the root elongation of the 50-60 cm soil layer could be promoted by the application of organic manure after the fertilizer reduction of 30%, and the organic manure added the soil water content of the surface soil (V6 and R6 period) after the application of organic manure. The fine root length of the surface layer (0.2 mm) was significantly positive correlation. In addition, the fine root length of the soil surface was negatively correlated with the inorganic nitrogen content in the soil, and the length of the root coarse root (0.2 mm) was significantly positively correlated with the nitrogen absorption in the upper ground. The results showed that the soil Nmin content decreased after the application of organic manure, and the surface fine root system and bottom were changed after the application of organic manure. The length of the coarse root system increased the uptake of nitrogen by plants, and may eventually reduce the risk of leaching of potential inorganic nitrogen in the soil. (3) through the study of soil microbial community and activity in the winter wheat and summer maize harvest season in North China, it was found that the amount of soil microorganism was not significantly reduced by the reduction of 50%+ organic fertilizer by chemical fertilizer application to 100%NPK. The total number of soil microbes and the number of bacteria could be significantly increased after returning to the field, respectively, 29.3% and 30.5% (2013 corn harvest season). The response of soil microbial community structure to fertilization was higher than that in corn season (2011) in wheat season. The fertilization significantly increased the activity of enzymes related to carbon metabolism (except for sucrase), and wheat The addition of organic manure and straw could improve soil organic matter. The potential of soil carbon fixation in the wheat season was higher than that of the corn season. (4) through a pot experiment on the soil in situ in the 9 year long-term location test, it was found that under the condition of non sterilization, the drought treatment did not significantly reduce the biomass of maize, and the drought treatment was more than the wet treatment after sterilization. The biomass of maize decreased by 34.6% significantly, and the decrease of maize biomass in organic manure treatment was higher than that of chemical fertilizer treatment. After the organic manure treatment soil sterilization, the content of citric acid and available phosphorus in rhizosphere soil was significantly increased in the dry place, and the difference of drought and humid treatment under the condition of non sterilization was not significant. The application of organic fertilizer improved the non root significantly. The stability of the structure of the soil aggregates. Compared with the non sterilization treatment, the sterilization treatment significantly improved the biomass of the upper part of the soil and the content of organic acids in the rhizosphere soil, and reduced the stability of the structure of the soil aggregates. It was found that the effect of water treatment only appeared under sterilization, indicating that the soil microorganism could affect the drought stress to a certain extent. The effects of organic manure and straw returning on crop yield and soil fertility were systematically studied from the point of view of plant, soil and microorganism. The study found that, under the current fertility level of Hebei Quzhou, the fertilizer was reduced by 30% and applied with organic manure. Straw returning can maintain crop yield and improve soil fertility, and the soil carbon fixation potential in wheat season is higher than that in corn season. Through three year field experiment, it is found that fertilizer reduction will promote the growth of coarse roots, increase nitrogen absorption and reduce the content of inorganic nitrogen in the soil profile. But compared with chemical fertilizer, organic fertilizer does not show drought resistance to plants. The buffering effect.
【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】：S513;S512.1

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