毛竹氮素利用规律及影响因子研究

发布时间：2018-02-21 21:37

本文关键词： 毛竹 ~(15N)示踪氮素利用率高效响应层氮素损失　出处：《中国林业科学研究院》2016年博士论文　论文类型：学位论文

【摘要】：毛竹(Phyllostachys edulis)是我国重要的经济和生态竹种,生长周期短,产量高,养分需求量大,但受自身生长特性和收获方式等的影响,毛竹林养分归还较少,生产上通常通过施肥来补充地力,尤其是氮肥施用非常普遍。然而,在当前毛竹林经营中,为获得更高的经济效益而大量施肥,造成了氮素利用率的持续下降和更大的环境压力。在此背景下,如何提高氮素利用率、减少氮素损失,降低施氮对环境造成的不利影响,成为当前实现毛竹林可持续经营的关键。本研究以安徽省黄山区毛竹纯林为研究对象,运用15N同位素示踪技术,采用沟施和穴施两种处理,每个处理设置0~20 cm和20~40 cm两个土壤层施肥,即0~20 cm沟施(T1)、20~40 cm沟施(T2)、0~20 cm穴施(T3)和20~40 cm穴施(T4),以不施肥作为空白对照,研究了毛竹林氮素去向以及毛竹氮素利用的根系效应、根层效应和年龄效应,探讨了毛竹氮素吸收利用规律,确定了土壤养分高效响应层、根系类型以及重点管理年龄;同时监测了自换叶后、孕笋期、冬季养分积累期到发笋前四个关键生理期的土壤环境因子及其时空变化规律,构建了毛竹林土壤环境因子指标库,采用灰色关联分析、典型相关分析和逐步回归分析研究土壤各指标与氮素利用率的关联度,筛选了影响毛竹林氮素利用率的关键土壤环境因子。主要研究结果如下:1、毛竹林氮素去向主要包括竹株吸收利用、土壤残留和氮素损失等3个方面6大方向,不同施肥处理毛竹林的氮素去向有差异。(1)施肥后,随毛竹生长,氮素利用率呈先增加后减少的趋势,以孕笋期到冬季养分积累期的利用率最高;各施肥处理下,氮素利用状况不同,以20~40 cm沟施的氮素利用率最高,达30.36%。(2)土壤氮残留随毛竹根系吸收及氮素损失而逐渐减少,并具有明显的垂直分布特征。试验结束时(施肥后184天),各施肥处理毛竹林的氮素残留率分别为15.20%、18.22%、20.59%和14.77%。(3)氮素损失是竹林氮素去向的重要部分,四种施肥处理毛竹林的氮素总损失率达51.42%~57.16%。其中,氨挥发损失、淋溶损失和硝化反硝化损失是毛竹林氮素损失的主要途径,损失率分别达13.30%~16.57%、18.08%~20.99%和15.27%~21.35%,而径流损失的氮素损失率最低,为1.43%~2.02%。各施肥处理中,深层施肥的氨挥发损失和径流损失均低于浅层施肥,沟施的氨挥发损失和径流损失均低于穴施;而淋溶损失却表现出相反的规律,硝化反硝化损失未表现出一致的变化趋势。2、毛竹氮素利用具有明显的根系效应、根层效应和年龄效应。(1)不同根系类型(鞭根和蔸根)施肥处理下,毛竹对氮素的吸收利用状况不同。氮素吸收速率和利用率总体表现为鞭根施肥处理高于蔸根施肥;试验结束时,鞭根和蔸根施肥毛竹的氮素利用率分别为28.07%和26.93%。(2)不同根层施肥毛竹林的氮素吸收利用状况差异较明显。氮素总吸收速率表现为20~40cm根层施肥显著高于0~20cm,氮素利用率也以20~40cm根层施肥较大;试验结束时,0~20cm和20~40cm根层施肥毛竹的氮素利用率分别为27.09%和29.41%。(3)不同年龄的竹株对氮素的吸收利用状况差异明显。Ⅰ、Ⅱ和Ⅲ度毛竹随其生长的阶段吸收效率均表现为先升高后降低的趋势,其中Ⅰ度竹在各阶段吸收效率最高;研究期内,Ⅰ、Ⅱ和Ⅲ度毛竹的氮素利用率分别达13.29%、5.12%和3.55%。3、29个土壤环境因子中,土壤含水率、总孔隙度、有机质含量、全磷含量、脲酶活性、细菌plfas量、c:n、n:p和土壤积温是影响毛竹氮素利用率的关键因子。连续监测了4个关键生理期内毛竹林地土壤的物理、化学、酶活性和微生物等环境因子,计算了土壤c、n、p化学计量比,构建了毛竹林土壤环境因子指标库,分析了各土壤环境因子的时空变化规律。采用灰色关联分析、典型相关分析和逐步回归分析相结合的主因子筛选技术确定了影响氮素利用率的关键土壤环境因子。研究发现,土壤环境状况与土层深度关系密切,且土层不同,影响毛竹氮素吸收的关键因子有差异,综合分析发现,土壤含水率、总孔隙度、有机质含量、全磷含量、脲酶活性、细菌plfas量、c:n、n:p和土壤积温是影响氮素利用率的关键土壤环境因子。毛竹氮素利用存在明显的规律性,且利用率受土壤环境因子的直接影响,研究结果为施肥技术提升提供了较强的理论支撑。不同根层施肥毛竹林的氮素利用状况有差异,20~40cm根层施肥毛竹林的氮素利用率高、氮素损失少,建议作为毛竹林施肥区域;不同年龄竹株氮素利用能力不同,以Ⅰ度竹穴施利用率最高。因此,在毛竹施肥抚育中,建议以I度竹作为重点施肥对象,采用穴施,施肥深度控制在30 cm左右;同时,土壤环境因子中以土壤含水率、总孔隙度和脲酶活性影响最大,施肥抚育时应重点调控。
[Abstract]:Bamboo (Phyllostachys edulis) is China's important economic and ecological bamboo, short growth period, high yield, nutrient demand, but affected by their growth characteristics and harvest methods, less production of bamboo nutrient return, usually through fertilization to replenish soil fertility, especially nitrogen fertilizer is very common. However, in the bamboo forest management, in order to obtain more economic benefit and a lot of fertilization, resulting in decreased nitrogen utilization rate and greater pressure on the environment. Under this background, how to improve the utilization rate of nitrogen, reduce nitrogen loss and reduce the adverse effects of nitrogen on the environment caused by the current implementation of sustainable bamboo become key business. In this study, Anhui province Mount Huangshan District of bamboo pure forest as the research object, using 15N tracer technique, the furrow and hole two treatments, each treatment set 0~20 cm and 20~40 cm two soil layers Fertilization, namely 0~20 cm 20~40 cm (T1), furrow furrow (T2), 0~20 cm (T3) and 20~40 in cm fertilization (T4), with no fertilizer as the control of bamboo and bamboo root effect the fate of nitrogen and nitrogen utilization, root layer effect and effect of age, discusses the use of law of absorption bamboo n, define the soil nutrient efficient response layer, root type and key management age; while monitoring the self change of leaves, shoots pregnant period, winter nutrient accumulation period to shoot the first four key physiological period of soil environmental factors and its temporal and spatial variation, constructed of bamboo forest soil environmental factors index system by using grey correlation analysis, canonical correlation analysis and stepwise regression analysis of various indicators of soil and nitrogen utilization rate of the degree of association, screening the key influence factors of soil nitrogen utilization rate of bamboo. The main results are as follows: 1, the fate of nitrogen main bamboo forest To include bamboo plant absorption and utilization, 3 aspects of soil and nitrogen losses in 6 different directions, the fate of nitrogen fertilization is different. Mao Zhulin (1) after fertilization, with bamboo growth, nitrogen utilization rate was decreased after increasing trend, the pregnant period to winter bamboo shoot nutrient accumulation in the highest utilization period all treatments; under the condition of different nitrogen to nitrogen utilization, 20~40 cm furrow utilization ratio was the highest, up to 30.36%. (2) residual nitrogen in soil with bamboo root absorption and nitrogen loss decreased gradually, and has the obvious vertical distribution. At the end of the experiment (184 days after fertilization, the nitrogen fertilization) Mao Zhulin the residual rate was 15.20%, 18.22%, 20.59% and 14.77%. (3) nitrogen loss is an important part of bamboo fate of nitrogen, four fertilizer treatments of Mao Zhulin's total N loss rate of 51.42%~57.16%., ammonia volatilization loss, leaching and nitrification and denitrification The loss is the main way of bamboo nitrogen loss, loss rate of 13.30%~16.57%, 18.08%~20.99% and 15.27%~21.35%, and the loss of nitrogen runoff loss was the lowest, 1.43%~2.02%. for all treatments, deep fertilization ammonia volatilization and runoff were lower than shallow furrow fertilization, ammonia volatilization and runoff were lower than the hole; the leaching loss has shown the opposite rule, the loss of nitrification did not show the same trend.2, with obvious effect of nitrogen utilization of bamboo root, root layer effect and effect of age. (1) types of root (rhizome and root root) treatments, nitrogen absorption and utilization of bamboo different. The rate of nitrogen uptake and utilization rate is higher than the overall performance of the stump root fertilization for rhizome and root fertilization; at the end of the experiment, the nitrogen and fertilization of bamboo rhizome and root stump root utilization rate were 28.07% and 26.93%. (2) is not Nitrogen fertilization of bamboo root layer absorption and utilization of obvious differences. The total nitrogen absorption rate is significantly higher than that of 0~20cm 20~40cm root zone fertilization, nitrogen utilization rate of 20~40cm to root zone fertilization greatly; at the end of the experiment, 0~20cm and 20~40cm in root zone of bamboo utilization rate of nitrogen fertilizer were 27.09% and 29.41%. (3) of different ages the bamboo plants to absorb nitrogen utilization significantly. I, II and III of bamboo with the growth stage of absorption efficiency were first increased and then decreased, were bamboo in various stages of the absorption efficiency is the maximum; the study period, I, II and III of nitrogen of bamboo utilization rate of 13.29% respectively 5.12%, 3.55%.3,29 and soil environmental factors, soil water content, total porosity, organic matter content, total phosphorus content, urease activity, bacteria amount of PLFAs, c:n, n:p and soil temperature is the key factor to affect the bamboo utilization rate of nitrogen. Continuous monitoring of the physical, the bamboo forest soil 4 key physiological period of chemistry, enzyme activities and microbial and other environmental factors, the calculation of soil C, N, P stoichiometry, constructed of bamboo forest soil environmental factor index library, analyzes the law of the spatio-temporal variation of soil environmental factors. Using grey relational analysis canonical correlation analysis, stepwise regression analysis and principal factor combination screening technique to determine the effect of key factors of soil nitrogen utilization rate. The study found that the close relationship between soil environment and soil depth, and soil is different, the key factors affecting the nitrogen absorption of bamboo have difference, comprehensive analysis found that the total porosity of soil moisture. The content of organic matter, total phosphorus content, urease activity, bacteria amount of PLFAs, c:n, n:p and soil accumulated temperature is the key factor to influence the environmental factors of soil nitrogen utilization rate. The obvious regularity of nitrogen utilization of bamboo, and The utilization rate of soil directly affected by environmental factors. The research results provide theoretical support for the strong promotion. Nitrogen fertilization technology of different root layer fertilization of bamboo utilization have difference, 20~40cm layer of bamboo root nitrogen fertilization of high utilization rate, less loss of nitrogen, as Mao Zhulin recommended fertilization area; different age bamboo plants nitrogen utilization ability is different, I can with the highest utilization rate of bamboo. Therefore, fertilization in tending, suggested by I of bamboo as a key object by fertilizing, fertilization, fertilization depth control at about 30 cm; at the same time, soil environmental factors to soil water content, total porosity and urease activity should be the greatest impact, tending fertilization the focus of regulation and control.

【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S795.7

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