低缓坡茶园水分运移特性及喷灌自动控制技术

发布时间：2018-04-09 15:11

本文选题：低缓坡茶园　切入点：根系　出处：《江苏大学》2017年硕士论文

【摘要】：干旱胁迫条件下茶树生长受阻,导致茶叶产量和品质下降。茶园中常采用喷灌方式为茶树提供所需水分,但其控制往往依赖于经验(如土壤含水量设定值),易造成过量灌溉,且灌溉水在不同坡度茶园中再分布范围不同。本论文以江苏丘陵低缓坡茶园喷灌自动控制技术为研究目标,在“十二五”农业部公益性行业(农业)科研专项—茶园综合作业机械化技术与装备研究的资助下,设计和构建坡度可调式栽培箱架和田间喷灌试验系统;试验研究低缓坡上土壤水分运移特性;建立不同坡度和喷灌强度下的土壤水分入渗深度模型,制定喷灌控制策略,并研制茶园喷灌控制系统;最后通过田间试验,进行模型和控制节水性能的验证。主要研究内容与结果如下:(1)茶树根系分布及喷灌系统设计以安吉白茶为供试对象,在3个不同地点进行全株挖掘,测量茶树根系的分布。结果表明,试验区域的茶树根系最深可达40 cm,即所需的喷灌水分湿润深度约为40 cm;超过50%的茶树根系分布于10~20 cm处。通过测量确定了试验茶园坡度的范围,据此设计了一种可升降茶树栽培试验箱架,可实现0~15°的坡度调节,以模拟真实茶园的坡度状况。经水利计算,设计构建了箱架和茶园田间的喷灌试验系统,其喷灌强度设定为6 mm/h。(2)低缓坡茶园土壤水分入渗深度模型研究以坡度和喷灌强度为因素,以湿润深度为指标,在箱架中先后设置9个不同的试验处理,在有茶树种植的条件下,研究了其土壤水分入渗过程中坡度、喷灌强度对湿润锋运移速率的影响,以及水分再分布过程中对湿润深度的影响,从而建立土壤水分入渗深度模型。此外,比较了有、无茶树种植土壤中水分运移的差异。并基于建立的土壤水分入渗深度模型修正了所需的入渗深度并进行了试验验证。结果表明:在水分入渗过程中,湿润锋运移速率与喷灌强度成正相关关系,与坡度成负相关关系;在水分再分布过程中,入渗深度和湿润深度的比值与喷灌强度成正相关,与坡度成负相关,表明喷灌强度越小,坡度越大,越有利于水分的垂直运动;在坡度研究范围内,无茶树种植时存在使湿润锋运移速率随坡度变化趋势改变的临界坡度值。有茶树种植尚未发现临界坡度值。在低坡度时,茶树根系的存在减小再分布的湿润深度。而大坡度时,茶树根系的存在却增加再分布的湿润深度。此外,0~10 cm处水分散失量与大气温度、太阳辐射和风速成正相关。经验证,模型计算得到的入渗深度与实测值之间的平均误差为1.71%,所需的湿润深度与实测值之间的平均误差为2.92%,水分入渗深度模型田间试验结果表明,理论入渗深度为21.52 cm,测得的入渗深度为22.69 cm,误差为5.44%,理想的湿润深度为40 cm,测得的湿润深度平均值为38.91 cm,误差为2.73%。该模型可以较好的应用于所选定的试验茶园。(3)茶园喷灌控制系统开发及田间试验控制技术的思路为:(1)针对一定坡度的茶园和喷灌强度,当某一深度的土壤水分小于设定值时,启动喷灌;(2)基于以上水分入渗深度模型,经控制器运算得到所需的喷灌时间,即喷灌运行的时间;(3)重复以上(1)和(2)过程。基于上述控制技术,采用PLC、土壤水分传感器和触摸屏,研制了茶园喷灌控制系统,将茶园坡度、喷灌强度(依据喷头特性参数确定)和茶树根系最大深度为外部输入参数,来执行喷灌作业。在田间试验中,试验结果表明:在茶园喷灌控制系统下实测的入渗深度与计算值的误差为2.60%,实测的湿润深度与预期值的误差为3.40%。因此在茶园喷灌控制系统下可以很好的达到预期的喷灌效果。在对比试验中可得基于茶园喷灌控制系统下的耗水量为7.252 m~3,与传统喷灌控制技术的耗水量11.378m~3相比,节水率达到了36.26%。
[Abstract]:Under drought stress the growth of tea is blocked, resulting in decreased yield and quality of tea. Tea is often used to provide irrigation water needed by the tea, but its control often depends on the experience (such as soil moisture, easy to set value) caused by excessive irrigation, and irrigation water in different slope in the tea garden is different. This again this thesis takes Jiangsu low slope hilly tea garden irrigation automatic control technology as the research object, in 12th Five-Year the Ministry of agriculture public sector (Agriculture) of comprehensive operation of special scientific research - tea mechanization technology and equipment under the support of the design and construction of slope adjustable cultivation box frame and field irrigation experiment system; experimental study on low slope on soil water transport characteristics; the establishment of soil moisture in different slope and irrigation intensity under the infiltration depth of irrigation model, formulate control strategy, and the development of tea plantation sprinkler control system; the through field test Test model and verify the control water-saving performance. Main research contents and results are as follows: (1) the design of tea sprinkler system and root distribution in Anji white tea as study objects, were excavated in 3 different locations, measuring the distribution of tea plant. The results showed that tea root test area of the most up to 40 cm, which is required for irrigation wetting depth is about 40 cm; more than 50% tea root distribution in the 10~20 cm. The range of test garden slope was determined by measuring, designs a new kind of test box lifting tea cultivation frame, can achieve 0~ 15 degrees slope adjustment, to simulate the real tea garden the slope condition. By hydraulic calculation, design of sprinkler test system of box frame and tea field, the irrigation intensity is set to 6 mm/h. (2) low slope soil water infiltration depth model on slope and irrigation intensity factors in deep moist As index, has set up 9 different treatments in the cradle, in tea cultivation conditions, studied the soil water infiltration process of slope, effect of irrigation intensity on the wetting front migration rate, effect on wetting depth and water redistribution process, so as to establish the soil water infiltration the depth of model. In addition, there is no difference between, tea planting water movement in the soil. The soil moisture and the infiltration depth model required infiltration depth and the experiments are carried out. Based on the results showed that: in the process of infiltration, wetting front migration rate and a positive correlation between the intensity of spray irrigation and a negative correlation with slope; in the soil water redistribution process, infiltration depth and wetting depth ratio was positively correlated with irrigation intensity and negative correlation with slope, showed that irrigation intensity is smaller, the greater the slope, the more conducive to water Vertical motion; slope in the scope of the study, there is no tea planting the critical slope wetting front migration rate change trend with the slope value. Tea cultivation has not yet found the critical gradient. In low slope, the tea root decreases and wetted depth distribution. While the large slope, there are tea root increase the wetting depth distribution. In addition, 0~10 cm water loss amount and air temperature, solar radiation and wind speed were positively correlated. After verification, the infiltration depth and the average error between the measured values of the 1.71% model, the average error between the desired wetted depth and the measured value was 2.92%, water infiltration depth model test results show that the theory of infiltration depth is 21.52 cm, the measured infiltration depth is 22.69 cm, the error is 5.44%, the ideal wetting depth is 40 cm, the depth of wetting the measured average value is 38.91 cm, error Test the tea garden for 2.73%. the model can be better applied to the selected. (3) the development of tea garden and field test system control technology of irrigation control: (1) according to the certain slope of the tea garden and sprinkler irrigation intensity and start when the soil moisture of a certain depth is less than the set value; (2) above the water. Infiltration depth model based on the desired irrigation time controller operation, the sprinkler operation time; (3) repeat the above (1) and (2). The control technology based on PLC, soil moisture sensor and touch screen, the development of tea garden irrigation control system, the garden slope, irrigation intensity (based on the characteristic of nozzle parameters) and the maximum depth of tea root as the external input parameters, to perform the sprinkler operation. In the field test, the test results show that: the infiltration depth error and the calculated values of the 2.60% tea garden irrigation control system under test, test Error of the wetted depth and the expected value of the 3.40%. in the tea garden irrigation control system can achieve good effect. It can be expected the sprinkler irrigation control system based on tea consumption under 7.252 m~3 in contrast test, and 11.378m~ water consumption of the traditional irrigation control technology compared to the 3, water-saving rate reached 36.26%.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S571.1;S275.5

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