负水头条件下土壤水分入渗和氮素分布规律研究
发布时间：2018-12-26 09:07
【摘要】：负压灌溉施肥技术是一种节水、节肥、省能、省工的作物主动式土壤水分养分平稳供应技术。这项技术一方面实现了由作物自己决定何时供水供肥,省去人工灌水施肥的必要,有助于解决资源紧缺、环境污染等问题;另一方面实现了土壤水分平稳供应,使得作物能在最适宜的水分和养分状态下生长,可以有效解决水肥利用率低的问题。本文采用室内土柱实验和温室盆栽试验相结合的方式,研究了不同负水头高度情况下土壤水分和硝态氮随时间的动态变化。通过深入探究负水头条件下土壤水分和氮素的分布规律,一方面为保证土壤中水分平稳供应,使得作物全生育期均生长在最适宜的水分和养分状态;另一方面对于负压灌溉的推广应用提供一定的技术支撑,便于促进负压灌溉技术健康发展。取得主要结论如下:(1)在不同高度负水头条件下进行室内土柱实验,对于不同负水头条件下的累计入渗量、湿润峰垂直推进距离、入渗率以及时间的关系进行分析研究。结果显示,累计入渗量与时间呈幂函数关系,与时间平方根呈线性关系,与湿润峰垂直推进距离呈线性关系;湿润峰垂直推进距离与时间平方根呈线性关系;入渗率与湿润峰推进距离倒数呈线性关系。(2)解析不同负水头条件下水分的一维入渗规律,结合室内土柱实验,初步认为Philip入渗公式与Green-Ampt入渗公式在一定条件下的参数之间存在函数关系,在一定条件下Philip入渗公式和Kostiakov经验公式能互相转换。Philip入渗公式、Kostiakov经验公式和Green-Ampt入渗公式拟合与实测的累计入渗量之间显著相关,表明负水头条件下土壤水分基本符合一维入渗规律;通过对比3个公式拟合的累计入渗量与时间关系、入渗率和时间的关系,认为在负水头条件下,Kostiakov经验公式拟合出的结果比较接近实测值,可以很好地拟合出累计入渗量和入渗率与时间的关系,说明该公式在负水头情况下适用性较好。(3)温室盆栽试验发现在相同施肥量和相同施肥方式、不同负水头高度的情况下,土壤中硝态氮含量随时间变化比较稳定。肥料底施处理的土壤硝态氮含量以缓慢平稳的速度因作物吸收而减少;连续施肥处理土壤中硝态氮含量基本保持不变或者以缓慢的速度稍有增加;施全肥处理土壤中硝态氮含量与处理为施一半肥料相比差异显著,但是随着灌溉施肥过程的进行,二者间差异减小;同一负水头高度及相同施肥量情况下,连续施全肥处理和连续施一半肥料处理土壤中硝态氮基本持平或者呈缓慢上升趋势;底施全肥处理和底施一半肥处理土壤中硝态氮呈缓慢下降趋势,随着灌溉施肥过程的进行,两种处理方式条件下土壤中硝态氮含量趋于接近,在长时间灌溉施肥过程之后土壤中硝态氮含量基本相同。说明负水头连续施肥条件下,土壤硝态氮含量变化平稳,分布较为均匀。
[Abstract]:The technology of negative pressure irrigation and fertilization is a kind of active soil moisture and nutrient stable supply technology which is water-saving, fertilizer saving, energy-saving and labor-saving. On the one hand, this technology realizes the decision of when to supply water and fertilizer by crops themselves, saves the necessity of artificial irrigation and fertilization, and helps to solve the problems of resource shortage and environmental pollution. On the other hand, the stable supply of soil moisture enables crops to grow under the most suitable water and nutrient conditions, which can effectively solve the problem of low water and fertilizer use efficiency. In this paper, the dynamic changes of soil moisture and nitrate nitrogen with different negative water head height were studied by the combination of soil column experiment and greenhouse pot experiment. The distribution of soil water and nitrogen under negative water head condition was studied. On the one hand, in order to ensure the steady supply of soil water, the crops grew in the most suitable water and nutrient state during the whole growth period. On the other hand, it provides some technical support for the popularization and application of negative pressure irrigation, which is convenient to promote the healthy development of negative pressure irrigation technology. The main conclusions are as follows: (1) Indoor soil column experiments were carried out under the condition of different negative water head. The relationship among cumulative infiltration amount, vertical advance distance of wetting peak, infiltration rate and time under different negative water head conditions were analyzed and studied. The results show that cumulative infiltration is power function with time, linear with square root of time, linear with vertical advance distance of wetting peak, linear with time square root with vertical advancing distance of wetting peak. The infiltration rate is linearly related to the reciprocal of the advancing distance of the wetting peak. (2) the one-dimensional infiltration law of water under different negative water head conditions is analyzed, and the soil column experiment is carried out in the laboratory. It is preliminarily considered that there is a functional relationship between the parameters of Philip infiltration formula and Green-Ampt infiltration formula under certain conditions. Under certain conditions, Philip infiltration formula and Kostiakov empirical formula can be converted to each other. Philip infiltration formula. The fitting of Kostiakov empirical formula and Green-Ampt infiltration formula was significantly correlated with the measured cumulative infiltration amount, which indicated that soil moisture under negative water head basically accords with one-dimensional infiltration law. By comparing the relationship between cumulative infiltration amount and time, infiltration rate and time, it is considered that under the condition of negative water head, the fitting result of Kostiakov empirical formula is close to the measured value. The relationship between cumulative infiltration amount, infiltration rate and time can be fitted well, which shows that the formula is suitable for negative water head. (3) the greenhouse pot experiment found that the same amount of fertilizer and the same fertilization mode were found. Under the condition of different negative water head height, the content of nitrate nitrogen in soil changed steadily with time. The nitrate nitrogen content in the soil of the fertilizer application treatment decreased slowly and steadily with the crop absorption, and the nitrate nitrogen content in the soil of the continuous fertilization treatment remained basically unchanged or increased slightly at a slow rate. The content of nitrate nitrogen in the soil treated with full fertilizer was significantly different from that in the treatment of half fertilizer, but the difference between them decreased with the process of irrigation and fertilization. Under the condition of the same negative water head height and the same amount of fertilizer, the nitrate nitrogen in the soil of the continuous fertilizer treatment and the continuous half fertilizer treatment was basically equal or slowly rising. The nitrate nitrogen content in the soil decreased slowly with the process of irrigation and fertilization, and the content of nitrate nitrogen in the soil tended to be close under the two treatments. After a long period of irrigation and fertilization, the nitrate content in soil was basically the same. The results showed that under the condition of continuous fertilization with negative water head, the content of nitrate in soil changed steadily and the distribution was more uniform.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7
本文编号：2391862
[Abstract]:The technology of negative pressure irrigation and fertilization is a kind of active soil moisture and nutrient stable supply technology which is water-saving, fertilizer saving, energy-saving and labor-saving. On the one hand, this technology realizes the decision of when to supply water and fertilizer by crops themselves, saves the necessity of artificial irrigation and fertilization, and helps to solve the problems of resource shortage and environmental pollution. On the other hand, the stable supply of soil moisture enables crops to grow under the most suitable water and nutrient conditions, which can effectively solve the problem of low water and fertilizer use efficiency. In this paper, the dynamic changes of soil moisture and nitrate nitrogen with different negative water head height were studied by the combination of soil column experiment and greenhouse pot experiment. The distribution of soil water and nitrogen under negative water head condition was studied. On the one hand, in order to ensure the steady supply of soil water, the crops grew in the most suitable water and nutrient state during the whole growth period. On the other hand, it provides some technical support for the popularization and application of negative pressure irrigation, which is convenient to promote the healthy development of negative pressure irrigation technology. The main conclusions are as follows: (1) Indoor soil column experiments were carried out under the condition of different negative water head. The relationship among cumulative infiltration amount, vertical advance distance of wetting peak, infiltration rate and time under different negative water head conditions were analyzed and studied. The results show that cumulative infiltration is power function with time, linear with square root of time, linear with vertical advance distance of wetting peak, linear with time square root with vertical advancing distance of wetting peak. The infiltration rate is linearly related to the reciprocal of the advancing distance of the wetting peak. (2) the one-dimensional infiltration law of water under different negative water head conditions is analyzed, and the soil column experiment is carried out in the laboratory. It is preliminarily considered that there is a functional relationship between the parameters of Philip infiltration formula and Green-Ampt infiltration formula under certain conditions. Under certain conditions, Philip infiltration formula and Kostiakov empirical formula can be converted to each other. Philip infiltration formula. The fitting of Kostiakov empirical formula and Green-Ampt infiltration formula was significantly correlated with the measured cumulative infiltration amount, which indicated that soil moisture under negative water head basically accords with one-dimensional infiltration law. By comparing the relationship between cumulative infiltration amount and time, infiltration rate and time, it is considered that under the condition of negative water head, the fitting result of Kostiakov empirical formula is close to the measured value. The relationship between cumulative infiltration amount, infiltration rate and time can be fitted well, which shows that the formula is suitable for negative water head. (3) the greenhouse pot experiment found that the same amount of fertilizer and the same fertilization mode were found. Under the condition of different negative water head height, the content of nitrate nitrogen in soil changed steadily with time. The nitrate nitrogen content in the soil of the fertilizer application treatment decreased slowly and steadily with the crop absorption, and the nitrate nitrogen content in the soil of the continuous fertilization treatment remained basically unchanged or increased slightly at a slow rate. The content of nitrate nitrogen in the soil treated with full fertilizer was significantly different from that in the treatment of half fertilizer, but the difference between them decreased with the process of irrigation and fertilization. Under the condition of the same negative water head height and the same amount of fertilizer, the nitrate nitrogen in the soil of the continuous fertilizer treatment and the continuous half fertilizer treatment was basically equal or slowly rising. The nitrate nitrogen content in the soil decreased slowly with the process of irrigation and fertilization, and the content of nitrate nitrogen in the soil tended to be close under the two treatments. After a long period of irrigation and fertilization, the nitrate content in soil was basically the same. The results showed that under the condition of continuous fertilization with negative water head, the content of nitrate in soil changed steadily and the distribution was more uniform.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S152.7
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