地下水浅埋区农田水分生产力模型与模拟

发布时间：2018-01-29 13:11

本文关键词： 浅埋地下水农田水转化地下水补给作物生长非充分灌溉灌区空间分布　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：地下水浅埋区农田及灌区水转化过程复杂,地下水对农田耗水的贡献进而影响水分生产力的形成过程。本文以定量研究地下水浅埋区非充分灌溉对农田水转化规律及作物生长过程的影响为主线,通过田间试验及构建模型,揭示不同灌水量、地下水埋深及地下水矿化度对农田水转化、作物生长及耗水的影响,并针对灌区尺度上的水文过程进行了分析研究。主要研究内容和结果如下:1.开展了 2013年和2014年的玉米非充分灌溉试验,并基于定位通量法和水量平衡定量得到土壤水平衡各参量。结果表明,整个生育期的作物耗水量并没有因为灌水量的减少而剧烈下降,当灌水量减少的时候,地下水对作物的补给反而增大。因此灌水量的减少对地下水的向上补给量有促进作用。地下水补给对作物耗水贡献随输入水量的减小呈线性递增,灌水量最小时,地下水补给占作物耗水达到15%。作物水分生产力各处理间无明显差异,而灌溉水分生产力随着灌水量的减小明显增大。2.考虑随实际根系生长而变化的根区水盐转化、地下水与土壤水交换等过程的基础上,耦合了土壤水盐运移与作物生长过程等模块,构建了农田水分生产力模型AWPM-SG。该模型不仅考虑了实际根区水盐状态及其对土壤水盐过程、作物生长的影响还结合了动力学过程进行分析。并采用2007、2008年临河的玉米蒸渗仪控制性试验数据和2016年份子地试验田的田间观测数据分别进行了模型率定和验证。结果表明,模型能较好地模拟地下水浅埋区的土壤水盐运移及作物生长过程。3.在模型率定验证基础上,模拟分析了各水文要素对不同灌水量、地下水埋深和地下水矿化度的响应规律。同一灌水量情况下,地下水补给贡献作物耗水的比例及产量均随地下水埋深增大而减小。当地下水埋深大于3m时,土壤水向下渗漏大于被补给,地下水补给对作物生长可以忽略。同一灌水量情况下,玉米水分生产力(WP)随着地下水埋深的增大呈负相关的抛物线关系。同一埋深条件下,WP随灌水量减小先增大后减小。同一矿化度情况下,地下水埋深越小,土壤根区含盐量越大,玉米生长受抑制越严重。同一地下水埋深条件下,地下水矿化度越大,产量减小小于耗水量减小,因此玉米水分生产力随地下水矿化度的增大而略有增大,而灌溉水分生产力随地下水矿化度的增大而逐渐减小。地下水埋深为1.5m时,地下水矿化度为4.0g/L相比于地下水矿化度为1.0g/L时,玉米水分生产力增大0.01kg/m3,灌溉水分生产力减小0.1kg/m3。4.研究区两年的地下水埋深在0.4-4.24m之间分布,2013年的平均地下水埋深为2.03m,比2012年大20cm。地下水向上补给量(F)的空间分布与地下水埋深有着直接关系,西部乌拉河分区的F最大,2013年可达90mm以上,东部清惠、黄济东北部F较小,出现负值。作物相对产量与作物耗水的空间分布一致,受盐分分布影响显著。空间水分生产力分布与地下水埋深分布呈轻微的负相关抛物线关系。由于2012年降雨量较大且集中,所以田间灌溉水有效利用系数比2013年相对较低。
[Abstract]:The transformation process of farmland irrigation water and shallow groundwater complex, groundwater water consumption on farmland contribution and thus influence the formation process of water productivity. Based on the quantitative study of shallow groundwater area irrigation effect on farmland water transformation and crop growth process as the main line, through field test and model construction, reveal the different irrigation. Groundwater depth and groundwater mineralization degree of farmland water transformation, growth and water consumption of crops, and analyzed the hydrological process of irrigation district scale. The main research contents and results are as follows: 1. in 2013 and 2014 corn non sufficient irrigation experiment, and soil water balance parameters by flux method and positioning based on the water balance quantitatively. The results showed that the whole growth period of crop water consumption and not because of the reduction of irrigation and sharply decreased when irrigation, reducing the amount of land The water supply of crops increases. Therefore the amount of irrigation to reduce groundwater recharge of groundwater recharge on crop water consumption contribution with decreasing water input linearly, the irrigation amount of groundwater recharge accounted for most hours, no significant difference between the crop water consumption reached 15%. crop water productivity among different treatments while irrigation water productivity decreased with irrigation amount increased significantly.2. considering the root zone water and salt with the actual root growth and changes in the foundation, groundwater and soil water exchange process, the movement of water and salt in soil and crop growth process module coupling, constructs the AWPM-SG. model of the agricultural water productivity model considers not only the water the actual state of the salt in root zone and its process of water and salt in soil, crop growth with the dynamic process were analyzed. And the 20072008 years of the corn Linhe lysimeter control The field observation data of test data in 2016 and part of the test field of model calibration and verification. The results show that the model can simulate the shallow groundwater soil water and salt transport and crop growth process in.3. model was verified based on the simulation analysis of the hydrological factors on different irrigation. Response of groundwater depth and mineralization. The same irrigation condition, the proportion and yield of groundwater recharge with crop water consumption increased with the depth of groundwater increases. When groundwater depth is greater than 3m, soil water downward leakage is greater than the supply of groundwater recharge, the same crop growth can be ignored. Irrigation conditions, water productivity of Maize (WP) with the increase of groundwater depth is parabola negative correlation. The same depth under the condition of WP decreased with increasing irrigation increases first and then decreases. The same salinity. Under the condition, the groundwater depth is small, the root zone soil salinity increasing, maize growth was restrained more seriously. The same groundwater table, groundwater mineralization degree is bigger, the yield decreased less than water consumption is reduced, so the water productivity of maize increased with the degree of groundwater salinity and slightly increased, and the irrigation water the productivity increases with the degree of groundwater salinity decreases. The groundwater depth is 1.5m, the salinity of groundwater is 4.0g/L compared to the groundwater salinity is 1.0g/L, maize 0.01kg/m3 increased, irrigation water productivity decreased for two years 0.1kg/ m3.4. study area groundwater depth between 0.4-4.24m distribution, the average groundwater depth of 2.03m in 2013 in 2012, 20cm. than to groundwater recharge (F) and the spatial distribution of groundwater depth has a direct relationship, Western ural partition of F, in 2013 reached more than 90mm, the Eastern Qing Huang Ji Hui, northeast of F is small, negative. The spatial distribution of favorable crop yield and crop water consumption, the salinity distribution was significant. The space distribution of water productivity and groundwater depth distribution is negatively related to parabolic relationship. Due to slight rainfall in 2012 is large and concentrated, so the effective utilization coefficient of irrigation water than in 2013 low.

【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】：S27

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