京郊设施农田土壤水氮淋失模拟与评价

发布时间：2018-04-10 11:46

本文选题：填闲作物 + 硝酸盐淋失　；参考：《中国农业大学》2016年博士论文

【摘要】：近年来,“都市型现代农业”逐渐成为北京市农业生产的主要发展方向。随着京郊种植结构的调整,作为保障城市居民基本生活需求的“菜篮子”,蔬菜产业在现代都市农业结构中的地位愈发重要。市场上品种齐全的反季节蔬菜不仅提高了人民的生活质量,也为菜农带来了较高的经济效益。但随着京郊设施蔬菜产业的蓬勃发展,大水大肥造成的水肥利用率降低,土壤环境质量下降,地下水污染严重等问题严重制约着京郊现代农业的可持续发展。本研究以京郊日光温室土壤为研究对象,对不同水氮供应条件下的温室番茄土壤水氮淋失和水氮利用效率状况进行了分析,同时以甜玉米为填闲作物,定量评价了温室休闲期种植填闲作物对土壤氮素淋失阻控的效果。并对在农田安装无压渗漏计后形成的渗漏界面处的水氮运移规律和影响因素进行了模拟分析,在此基础上研究了在不同田间气象条件下安装分散流控制壁对无压渗漏计水氮淋失定量精度的影响。全文主要结论如下：在2008-2009年三个番茄生长季(秋冬茬、冬春茬和春夏茬)设置了四个化肥氮用量处理(传统氮肥N,:360kg N ha-1、25%减氮施肥N2:270kg N ha-1、44%减氮施肥N3:203kg N ha-1、 63%减氮施肥N4:135kg N ha-1)。三茬番茄灌水量根据农民习惯灌水量分别定为215、219和271mm。结果表明：在相同灌水量的条件下,与传统施氮量相比,即使减少63%的化肥氮投入,番茄产量仍没有显著下降。而在相同施氮量条件下加大约54mm灌水量的春夏茬较秋冬茬和冬春茬相比番茄产量分别提高约55.5%和36.1%。三茬番茄的水分利用效率平均分别为38、41和44kg m-3,水分渗漏量平均分别为85、91和109mm。春夏茬各处理硝酸盐淋失量为58-97kg N ha-1,占氮素总投入量的20.1-22.6%,而秋冬茬和冬春茬硝酸盐淋失量减小为20-55kg N ha-1,占氮素总投入量的比例也降至7-12%。减少氮素投入量有利于降低土壤硝酸盐淋失和提高氮素利用率,三茬番茄种植过程中,化肥氮施用量最少的N4处理硝酸盐淋失量较N1处理降低40.2-60.5%,其氮素利用率较N1处理增加11.6-17.5%。农民习惯灌水量会造成大量的水分渗漏损失,水分供应量应进一步降低从而减轻土壤硝态氮淋失风险。在京郊温室菜地进行了为期三年的田间试验(2008-2010年),试验在两种前茬作物施肥量(360kg N ha-1和270kg N ha-1)基础上设置了不同氮素残留量和是否种植填闲作物两个处理。结果表明,甜玉米在生育期其蒸散作用导致在100cm土层深度处形成了较长时间的水分和硝态氮上行通量,最高可达1.0mm d-1 and 0.7kg N ha-1 d-1,降低了1 OOcm土体水氮淋失量。种植甜玉米的处理在三年试验期间180cm土层深度处硝态氮淋失量分别为32.3、63.8和22.5kg N ha-1,而休闲地处理则分别为54.1、113.3和58.4kg N ha-1,种植甜玉米后0-180cm土体硝酸盐淋失量占土体起始硝酸盐累积量的比例较休闲地平均降低35.3-57.9%。强降雨情景模拟的结果表明,当降雨量达到150mm d-1时,种植甜玉米仍可降低180cm土层深度处的部分氮素淋失,但降低幅度有限。利用种植填闲甜玉米的方式降低温室休闲季土壤硝酸盐淋失风险是较直接有效的措施。在假定土壤均质、各向同性的条件下,为准确描述田间水分渗漏量和土壤溶质的运移过程与规律,基于HYDRUS-2D模型模拟结果,对无压渗漏计不同设计(加装不同高度分散流控制壁)和不同适用环境条件(土壤质地、灌水量、土壤蒸发量和初始土壤含水率)下的土壤水分渗漏收集效率(We)及影响因素进行了数值模拟和定量评价。结果表明,在砂壤土、壤土和粉土安装环境中,未加装分散流控制壁的无压渗漏计,在0.35cm3 cm-3土壤初始含水率、0.2cm d-1蒸发量和1000mm灌水量条件下的We分别仅为11%、13%和26%,而在相同环境条件下安装分散流控制壁的无压渗漏计,当控制壁高度为20cm时可使We提升到50%以上。安装的分散流控制壁高度随灌水量的降低、土壤持水能力的提高和士壤蒸发量的增大而升高,初始土壤含水率降低会使在偏砂性土壤中安装的无压渗漏计We降低。增加无压渗漏计的安装深度可能会导致其We降低,在某一特定安装深度对无压渗漏计We的计算的结果并不适用于其他深度。在2010-2011年京郊温室夏季敞棚休闲期安装无压渗漏计,以前茬作物施氮量高低设置高氮残留(N1)、低氮残留(N2)两个处理。在利用无压渗漏计对各处理水氮淋失量进行测算的基础上,结合HYDRUS-2D模型对其在多年不同气象条件下加装不同高度分散流控制壁后的收集效率进行了模拟分析。结果表明,两年田间试验期间各处理无压渗漏计均未收集到土壤渗滤液,这与下渗水到达毛管中断界面时形成的绕流现象有关,而相同处理安装60cm高的分散流控制壁后可使无压渗漏计水分渗漏收集效率(We)、氮素淋失收集效率(Ce)提升到15.4%、19.3%,但N1、N2处理间的We、e差别不大。多年不同气象条件的情景分析表明,在雨量较大的年份加装10cm高的分散流控制壁便可使无压渗漏计的We、Ce增加到23.7%、29.5%,而在雨量较小的年份即使加装60cm高的控制壁,We、Ce仍为0,表明在大量降雨并使毛管中断界面处土壤含水率接近饱和的条件下,无压渗漏计可以较准确的测算土壤水氮淋失量。无压渗漏计在不同土壤氮素残留处理间的水氮淋失收集效率相近,且均随分散流控制壁高度和降雨量的增加而增大。
[Abstract]:In recent years, "urban agriculture" has gradually become the main development direction of agriculture in Beijing city. With the adjustment of planting structure, guarantee the basic living needs of city residents as the "food basket", the status of vegetable industry in the modern urban agriculture in the structure of the market is more and more important. All kinds of anti season vegetables not only improve the quality of people's life, it also brings higher economic benefits for farmers. But with the vigorous development of the vegetable industry, reduce the rate of big fat caused by water and fertilizer use, soil environment quality decline, underground water pollution problems seriously restricts the sustainable development of modern agriculture. In this study, solar greenhouse soil as the research object, the effect of different water and nitrogen supply conditions of greenhouse tomato soil water and nitrogen leaching and water and nitrogen use efficiency were analyzed, at the same time with sweet corn for Catch crop, the quantitative evaluation of the greenhouse planting catch crop fallow period on soil nitrogen leaching control effect. And the factors of installation without leakage formed at the interface pressure after lysimeter of farmland water and nitrogen transport rules and influence are analyzed, on the basis of the research on the influence of wall installation dispersion flow control no pressure lysimeter leaching of water and nitrogen in the same field of quantitative accuracy of meteorological conditions. The main conclusions are as follows: the growing season in 2008-2009 years three tomato (autumn, winter and spring and spring and summer) set up four fertilizer nitrogen treatment (traditional n N, 360kg N ha-1,25% N2:270kg N ha-1,44% in reducing the loss of nitrogen fertilizer N HA-1 63% N3:203kg nitrogen fertilizer, reducing nitrogen fertilization N4:135kg N HA-1). The three tomato crop irrigation irrigation respectively according to the habits of farmers showed that 215219 and 271mm. results: under the same irrigation conditions, and the traditional nitrogen. Even if the nitrogen fertilizer ratio, reduce the investment of 63%, yield of tomato is still not significantly decreased. Under the same irrigation amount and nitrogen application about 54mm capacity under the condition of spring and summer than in autumn winter tomato yield were increased by about 55.5% and three 36.1%. tomato crop water use efficiency average respectively 38,41 and 44kg compared with M-3 in winter and spring. The average water leakage volume were 85,91 and 109mm. each spring and summer treatment of nitrate leaching amount was 58-97kg N HA-1, the total nitrogen input amount of 20.1-22.6%, while the autumn winter and winter spring nitrate leaching amount is reduced to 20-55kg N HA-1, the proportion of the total investment amount of nitrogen is also reduced to 7-12%. to reduce the amount of nitrogen input to reduce soil nitrate leaching and improve the utilization rate of nitrogen, three tomato planting process, nitrogen fertilizer application amount of at least N4 nitrate leaching amount compared with the N1 treatment decreased 40.2-60.5%, the nitrogen utilization rate higher than N1 11.6-17 .5%. farmers used irrigation will cause the loss of water leakage, water supply should be reduced so as to reduce nitrate leaching risk of soil. The field experiment for three years in the greenhouse vegetable (2008-2010 years), the test in the two previous crop fertilization (360kg N HA-1 N and 270Kg HA-1 Foundation) set up different nitrogen residues and planting catch crop two treatments. The results showed that the growth period of sweet corn in the transpiration resulted in 100cm soil layer formed at the upstream water and nitrate flux for longer periods of time, up to 1.0mm D-1 and 0.7kg N HA-1 D-1, 1 OOcm lower soil water the amount of nitrogen leaching. Processing of sweet corn during three years of testing 180cm depth of nitrate leaching amount of 32.3,63.8 22.5kg and N HA-1 respectively, and the leisure treatment were 54.1113.3 58.4kg and N HA-1, planting sweet After maize 0-180cm nitrate leaching amount of initial soil nitrate accumulation is relatively fallow with an average decrease of 35.3-57.9%. rainfall scenario simulation results show that when the rainfall reached 150mm D-1, sweet corn planting can reduce part of N leaching and soil layer at 180cm depth loss, but the decrease is limited. The use of sweet corn planting catch the way to reduce the greenhouse leisure season soil nitrate leaching risk is more direct and effective measures. Under the assumption of homogeneous isotropic soil, under the condition of migration for accurate description of field water seepage and soil solute process and regularity, simulation results of HYDRUS-2D model based on different design of non pressure leakage (with high dispersion flow control wall) and different suitable environmental conditions (soil texture, irrigation, soil evaporation and soil moisture content and initial soil water leakage rate) the collection efficiency (We) and The influence factors are studied by numerical simulation and quantitative evaluation. The results showed that in sandy loam, loam and silt in the installation environment, no leakage meter without dispersion flow control wall, in the 0.35cm3 cm-3 0.2cm D-1 initial soil water content, evaporation and irrigation conditions 1000mm We were only 11% and 13%. 26%, no leakage and pressure gauge installed dispersed flow control wall in the same environmental conditions, when the control wall height of 20cm can make We up to more than 50%. The dispersion flow control wall height with water reducing installation, soil water holding capacity and the increase of soil evaporation increased, the initial the soil moisture decrease without pressure leakage meter installed in the lower We sandy soil. Increase the installation depth without pressure leakage meter may lead to the decrease of We in a particular installation depth calculation of non pressure leakage meter We result does not apply to other deep No installation. The leakage meter in 2010-2011 years in Greenhouse in summer fallow period before the open shed, crop nitrogen level set high nitrogen residue (N1), low nitrogen residue (N2) two. Based on the non pressure leakage meter to measure the water and nitrogen leaching amount, the with different height under different meteorological conditions of years dispersed flow collection efficiency control wall is simulated with HYDRUS-2D model. The results show that during the two years field experiment the pressureless lysimeter were not collected soil leachate, and the seepage to form fault interface in capillary flow phenomenon, and the same dispersion flow control wall installation 60cm high after the non pressure water leakage leakage meter collection efficiency (We), nitrogen leaching collection efficiency (Ce) increased to 15.4%, 19.3%, N1, N2 between We and E is not very different. For many years under different weather scenarios Analysis shows that the dispersion flow control wall can make the non pressure leakage meter We in greater rainfall year with 10cm high, Ce increased to 23.7%, 29.5%, and in the year even if the rainfall is small with control wall, 60cm high We, Ce is 0, that in the heavy rainfall and the capillary interrupt interface the soil moisture content near saturation conditions, no leakage meter can accurately measure the soil water and nitrogen leaching amount. No leakage of pressure gauge in different soil residual nitrogen leaching of water and nitrogen treatment between the collection efficiency and similar increase dispersion flow wall height and rainfall control increased.

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S153

【参考文献】