Knowledge Resource Center for Ecological Environment in Arid Area
| 地下滴灌对玉米根区土壤水氮分布的影响及其机理 | |
| 其他题名 | Effects of Subsurface Drip Irrigation on Distribution of Soil Water & Nitrogen in Maize Root Zone and their Regulation Mechanisms |
| 谷健 | |
| 出版年 | 2016 |
| 学位类型 | 博士 |
| 导师 | 陈利军 ; 尹光华 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 本研究针对地下滴灌技术大田作物应用中存在的水氮高效利用理论有待完善和技术缺乏的问题，以玉米为研究对象，采用田间测坑模拟试验与可移动遮雨棚水氮精量控制微区试验相结合的方法，研究地下滴灌灌水量和施氮量对玉米根区水氮分布的影响及其调控机理，以期为科学合理制定地下滴灌灌水施氮制度提供一定的科学依据。试验于2014年5月—2015年10月在位于辽西半干旱区阜蒙县的农田水循环综合试验基地中进行。地下滴灌带埋设深度为20cm，采用重力式滴灌方式。田间测坑模拟试验设置滴头流量为1.38L·h-1，施氮量为247.5kg·hm-2，采用时域反射仪（TDR）与定期采样的方法动态监测土壤水氮分布，以揭示其分布规律；可移动遮雨棚水氮精量控制微区试验设置不同灌水定额（田间持水量的40%、50%、60%、70%控制）和施氮量（165kg·hm-2和330kg·hm-2），研究其对玉米产量、耗水量、水分和氮肥利用效率的影响，分析了植株形态、根系生长、光合特性等指标对不同水氮处理的响应机理，确定了适宜的地下滴灌节水灌溉施氮制度。主要结论如下：（1）土壤水分分布状况动态监测结果显示：地下滴灌改变了根区土壤水分的分布状态，使土壤水尽可能的保持在玉米根系活动层（0-60cm），且地表可形成0-5cm干土层；滴头向下形成的湿润饱和区半径大于向上形成的半径，半径与时间的变化呈对数函数关系；土壤垂直湿润锋呈现先快速后速度减慢的趋势推进；水平湿润锋沿滴灌带的方向运移速度大于垂直滴灌带方向。（2）一次施氮土壤氮素分布状况动态监测结果显示：地下滴灌对根区土壤氮素分布的影响顺序为硝态氮>铵态氮。硝态氮分布影响显著，灌水初期硝态氮主要集中在0—40cm土层深度内，随着灌水的进行和水分的再分布，会运移到30—40cm土层内。无论是垂直方向还是水平方向，硝态氮均在湿润土体的边缘浓度升高，而内部浓度有逐渐下降的趋势。（3）通过分析地下滴灌不同水氮处理玉米生长发育指标、根系、光合作用等生理响应，揭示了地下滴灌水氮处理对玉米生长的调控机理，即其可以通过精确控制水氮的供给，氮肥溶解于滴灌水中随水一起进入土壤根区，根系的向水向肥性使其主要集中在土壤水氮分布区，促进了水和氮素的吸收，从而促进了植株地上部分的生长，同时适宜的水氮条件使净光合速率和蒸腾速率维持在较高的水平，促进了干物质积累，最终经济产量提高。（4）地下滴灌对产量、水氮利用效率的影响结果表明：施氮量对玉米产量影响显著。适宜的水氮配施有利于提高水氮利用效率。灌水量主要影响水分利用效率，施氮量对水分利用效率有一定的影响，但不显著；施氮量主要影响氮肥利用效率，但氮肥利用效率随灌水量的增加而呈现先增加后降低的趋势。（5）综合水氮分布规律、产量和水氮利用效率等指标，确定出平水灌溉条件下，氮肥减施，即灌水量为238.7mm，施氮量为165kg·hm-2为较优的地下滴灌节水灌溉施氮制度。 |
| 英文摘要 | In field crops application of subsurface drip irrigation, there is a theory of water and nitrogen efficiency needs to be improved and the lack of technology issues. Aiming at this problem, with maize as the research object, the research used the methods conbined of the field pit simulation experiment and a water and nitrogen precise control experiment under an auto-rain-shelter, to study the effects of soil water and nitrogen distribution of maize root zone and the regulation mechanism of maize growth with the irrigation amounts and nitrogen application under the subsurface drip irrigation. The purposes of the research were to provide certain scientific basis on establishing scientific and reasonable subsurface drip irrigation system.The study was conducted in the water cycle comprehensive experiment site during the spring-autumn season (2014.5-2015.10), which is located in Fuxin Mongolia Autonomous County of semi-arid district in the western Liaoning province. The drip tape was buried in the 20cm depth. The water supply was usedd the gravity drip irrigation. The field pit simulation experiment set emitter discharge to 1.38 L·h-1 and the nitrogen application rate of 247.5 kg·hm-2. The experiment used time domain reflectometer (TDR) and the regular sampling method to dynamic monitor of soil water and nitrogen distribution, in order to reveal its distribution characteristies. A water and nitrogen precise control experiment under an auto-rain-shelter set two factors, including irrigation amount and nitrogen application. Irrigation amount set four levels, field capacity were used respectively 40%, 50%, 60%, and 70% to control. Nitrogen application set 165 kg·hm-2 and 330 kg·hm-2 two levels. The purpose of the experiment was to study the influence of research on corn yield, water consumption, water and nitrogen use efficiency on the subsurface drip irrigation, and analyze different water and nitrogen treatment response mechanism of the indexes of plant morphology, root growth, photosynthetic characteristics and so on, to determine the appropriate system of water-saving irrigation and nitrogen under subsurface drip irrigation. The main results are as follows.(1) The distribution of the soil moisture dynamic monitoring results showed that: the water distribution state of subsurface drip irrigation in the root zone had changed. It keep the soil water as much as possible in the maize root system activity layer (0 to 60 cm), and the surface could keep dried soil layer form 0 to 5 cm. The subsurface of the saturated zone radius was faster than the surface of the drip emitter. The relationship between the saturated zone radius and time was the logarithmic function relationship. The trends of vertical wetting front speed were faster in early irrigation, and then gradually slowed down. Horizontal wetting front migration speed along the direction of the drip tape was greater than the vertical direction.(2) Soil nitrogen distribution dynamic monitoring results showed that: The effect order on the distribution of the root zone soil nitrogen under subsurface drip irrigation was nitrate > ammonium nitrogen. Nitrate distribution effect was significant. At the stage of irrigation, nitrate was mainly concentrated in the early 0-40 cm soil layer depth. With irrigation and moisture redistribution, nitrate was migration to 30-40 cm soil layer. Both vertical and horizontal directions, the concentration of nitrate nitrogen were increased at the edge of the moist soil, and the internal concentration had a tendency to gradually decline.(3) Through analysis the growth, root and photosynthesis physiological response of maize at different water and nitrogen treatment under subsurface drip irrigation, the regulation mechanism with water and nitrogen treatment of subsurface drip irrigation was preliminary revealed. Subsurface drip irrigation could precisely control the supply of water and nitrogen. Nitrogen dissolved with water entered into the root zone of soil. The hydrotropism and fertilizer characteristic of the root system made it mainly concentrated in the soil water and nitrogen distribution area. It promoted the absorption of water and nitrogen, thereby promoting the growth of plants. And the suitable conditions of water and nitrogen made net photosynthetic rate and transpiration rate maintained at a higher level, which was promoted the accumulation of dry matter and eventually leading to increase yield.(4) The effects of the yield and water & nitrogen use efficiency showed that: the influence of nitrogen application had significant effects on maize yield. Appropriate nitrogen and irrigation was able to improve water and nitrogen use efficiency. With the increased of irrigation water, water use efficiency was gradually reduced. With the increased of nitrogen application rate, nitrogen use efficiency decreased significantly. However, with the increased of irrigation water, the nitrogen use efficiency had a trend of increasing firstly and reducing then.(5) Comprehensive water and nitrogen distribution, maize yield, water and nitrogen use efficiency , and other indicators, it is concluded that normal irrigation and low nitrogen application, namely the irrigation amount of 238.7 mm, nitrogen application of 165kg·hm-2, was for a better water-saving fetigation system of subsurface drip irrigation. |
| 中文关键词 | 地下滴灌 ; 水氮分布 ; 玉米 ; 灌水量 ; 施氮量 ; 调控机理 |
| 英文关键词 | Subsurface drip irrigation Water and nitrogen distribution Maize Irrigation amount Nitrogen application Regulation mechanism |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 土壤学 |
| 来源机构 | 中国科学院沈阳应用生态研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287749 |
| 推荐引用方式 GB/T 7714 | 谷健. 地下滴灌对玉米根区土壤水氮分布的影响及其机理[D]. 中国科学院大学,2016. |
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