ISWC OpenIR  > 水保所知识产出(1956---)
微润线源入渗湿润体特性试验研究
张 俊
Subtype硕士
Thesis Advisor牛 文 全
2013-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword微润灌溉 线源入渗 湿润体 土壤水分 均匀性
Abstract

微润灌溉是在地下滴灌基础上发明的一种新型高效灌溉技术,可实现作物全生育
周期连续灌溉。它利用功能性材料半透膜作为灌水管,通过地埋方式将灌溉用水缓慢
释放到作物根区土壤中,供作物根系吸收利用。与地面灌溉技术相比,微润灌溉具有
节水效果明显、改善作物根区土壤环境、运行成本低、抗堵塞性能强等优点,适宜旱
区作物用水需求。基于微润灌溉出流近似成线源,亦称之为线源入渗,微润灌溉是依
靠土吸力和半透膜内外驱动力为主的被动供水方式,与常规的地面灌,线源滴灌、垂
直线源入渗不同,作为灌水新技术,微润灌尚缺乏完整的灌溉试验参数。微润灌溉条
件下土壤水分运移规律的试验研究,是正确设计微润灌溉系统和对田间作物水分进行
精准管理的前提和基础。为了探索微润灌条件下土壤水分的运动规律及分布状况,本
文进行了线源条件下的室内土槽模拟试验。本文主要分析研究了微润带埋深、土壤质
地,土壤容重,土壤初始含水率等关键因素对微润灌溉湿润体特性的影响,包括湿润
锋运移规律,湿润体内水分分布规律以及均匀度评价;线源入渗条件下,工作压力水
头与流量间关系的测试试验。主要研究成果如下:
(1)微润灌溉湿润体是以微润带为轴心的柱状体,其中粘壤土湿润体为圆柱体,
砂土为“倒梨”形柱状体。土壤容重和质地是微润灌溉湿润体的重要影响因素,湿润
体体积受质地影响较大,相同灌水时间,粘壤土湿润体明显小于砂土湿润体。容重对
微润灌湿润体体积影响非常大,湿润体体积随着容重的增大而减小,并且随着灌水时
间的延长,差异性逐步增大。根据试验数据拟合粘壤土不同容重湿润体体积预测公式,
误差较小。粘壤土扩散系数随容重的增大而减小,水平、垂直向上扩散指数约为 0.5,
受容重的影响较小,而垂直向下的扩散指数受容重的影响很大,随着容重的增大而增
大。
(2)湿润锋运移距离与灌水时间 t 之间呈良好的幂函数关系,砂土的扩散系数
大于粘壤土,扩散指数小于粘壤土;微润灌溉累计入渗量与灌水时间呈线性函数关系,
R 2 大于 0.9。湿润体垂直剖面含水量呈以微润管带为轴心的同心圆面分布。克里斯琴森均匀系数公式可用于微润灌溉灌水均匀性的评价,微润灌溉湿润体内不存在土壤饱
和含水区,大部分土壤水分分布于田间持水量的 80%~90%之间,灌水均匀度高,达
85%以上。
(3)不同初始含水率条件下湿润体深宽比约为 1,深宽比受初始含水率的影响
较小。湿润体体积随初始含水率的增大而增大。初始含水率对微润灌溉土壤水分扩散
有很大的影响,湿润锋推进速率与初始含水率呈正相关关系,扩散系数与初始含水率
成指数递增关系,扩散指数受初始含水率的影响很小,不同初始含水率的不同方向土
壤水分扩散指数介于 0.50~0.60 之间。湿润体内平均含水量受初始含水率的影响非常
小,其质量含水率约为 22%,均匀度随初始含水率的增大而增大。
(4)微润灌溉适宜地埋方式,地埋微润带流量和累计入渗量均显著大于地表铺
设。在 0~2.5m 压力水头范围内,微润带流量与工作压力水头呈线性增大的趋势。不
同埋深累计入渗量随时间变化过程符合 Kostiakov 模型,入渗系数随着埋深的增大而
减小,入渗指数接近常数。建立累计入渗量与埋深间的经验公式,并用实测值进行了
验证,实测值与预测值具有较高的相关性。
(5)埋深对湿润锋影响较大,水平运移距离与宽深比 γ 均随埋深的增大而减小,
垂直运移距离随埋深略微增大,最终趋于一致。湿润体剖面土壤含水率垂直分布存在
明显差异,不同的埋深导致湿润体运移规律和土壤水分均匀性不同,建议微润灌溉条
件下粘壤土最适埋深为 15cm~20cm 左右。
关键词:微润灌溉,线源入渗,湿润体,土壤水分,均匀性

Other Abstract

Moistube irrigation is a new invention of high-efficient on the basis of subsurface drip
irrigation,this method can bring about irrigation of the whole growth cycle for crop.It use
functional material semipermeable membrane as irrigation pipe,realize irrigation water to
the soil of crop root zone tardily by means of buried way, for uptake and utilization crop
root. Compared with surface irrigation technology, moistube irrigation has many
advantages, such as, water-saving effect is obvious, improving soil environment of rop root
zone,low running costs, strong anti-clogging performance. All of those can suitable crop
water demand in arid areas. The moistube irrigation flow approximates as line source,
therefore,it’s also called “Line Source Infiltration”. Moistube irrigation is a passive way of
water supply that depends on soil suction and driving force between internal and external
of semipermeable membrane,which is different with the conventional ground irrigation,
drip irrigation from line source,vertical line source infiltration. Moistube irrigation as the
new irrigation technology,which was lack of complete irrigation experiment parameters.
Experimental Study on Soil water movement during moistube irrigation is the premise and
foundation of designing moistube irrigation system properly and managing soil water
precisely. In order to investigating the soil water movement and distribution of line source
infiltration under miostube-irrigation,this study had conducted soil box experiments from
line source in door. This paper had mainly analyzed the effect of the key factors soil texture,
bulk density, initial soil water content and buried depth on the characteristic of wetted soil.
It concluding wetting front migration pattern,soil water distribution in wetted soil and
irrigation uniformity evaluation,test on relationship between irrigation amount with
pressure head. The main results as follow:
(1)The wetted soil looked like cylindrical object which with pipe as it’s axle centre  and clay loam soil was approximate with cylinder, the cross section of sandy soil as
obpyriform shape. The effects of the soil texture and bulk density on the characteristic of
wetted soil were significant in mois-tube irrigation. The volume of wetting body is affected
by soil texture,in the same irrigation time, wetting soil of clay loam soil is less than sandy
significantly. Moist body volume decreased with increasing bulk density, and with the
extension of the irrigation time, difference gradually increases. We had fitted the prediction
formula between volume of wetting body with bulk density,which error is small. The
diffusion coefficient of clay loam decreased with bulk density increasing,the Horizontal,
vertical upward diffusion index equal to 0.5 approximately, which is less affected by bulk
density .However, the diffusion index of downwards is influenced by bulk density clearly
and that increased with increasing of bulk density. The ratio of R : X: H was 1:0.90:0.99 in
clay loam soil and 1: 0.81:0.95 in sandy soil, respectively. (R: horizontal migration
distance; X: vertical upward distance; H: vertical downward distance).
(2) There was a typical power function relationship between the horizontal and
vertical distance of wetting front and irrigation time. The diffusion coefficient of the sandy
is bigger than clay loam, its diffusion index is less than clay loam soil. Miostube-irrigation
has small flow, which could automatically adjust with the change of soil water content,
cumulative infiltration has a linear relation with irrigation time.R 2 is much than 0.9. Water
distribution in the volume of wetted soil was a concentric circle with the pipe.
Christiansten uniformity coefficient formula can be used for the irrigation uniformity
evaluation under Moistube irrigation ,there was no water saturated zone in wetted soil,
most of soil water content lied between 80% and 90% of field capacity. Miostube-irrigation
has high irrigation uniformity, which reached 85%. The effect of water saving of
miostube-irrigation is prominent, which is suitable for crop water demand in the arid
regions.
(3)Initial water content had a great effect on line-source diffusion under moistube
irrigation, the advance rate of wetting front and surface wetting time increased with the
raise of initial water content, and presented a power function relationship with the
irrigation time. Meanwhile,the shape of wetting soil was lightly affected by initial water
content the cross section of which is proximal circular. During an irrigation event, the
cumulative infiltration and average infiltration rate were positively correlated with initial  water content, while the time to reach stable infiltration rate was negatively correlated
with it. The diffusion index of different directions by initial water content in soil moisture
ranging from 0.50 to 0.60.The water inside wetting soil was concentrically distributed,
and the moisture gradient decreased with the raise of initial water content, while irrigation
uniformity of moistube-irrigation increased.
(4)Moistube-irrigation was fitted the buried way,discharge and cumulative
infiltration of buried moistube environ-grower were larger than the surface laying
significantly. The Pressure head range within 0~2.5m,amount and pressure head was
linear increasing trend. The changing process of infiltration with irrigation time was
accorded with Kostiakov infiltration model, infiltration coefficient decreased with the
increase of buried depths and little change in infiltration index; Empirical formula
between cumulative infiltration and buried depths was fitted,and the model was tested
with measured values, results show that the experimental equation of infiltration has a
high correlation coefficient between the measured value and the calculated value.
(5)Buried depths of miostube-belt had significant effect on the shape of wetted soil,
horizontal migration distance and ratio of width to depth of γ decreased with the increase
of buried depths and vertical migration distance slightly increased with the increase of
buried depths; There was a significant different in vertical moisture distribution of moist
soil profile. Different buried depth lead to different migration regularity and uniformity
of soil moisture in wetting front. The suitable buried depths of clay loam of
miostube-irrigation were between 15 and 20 cm.
Key Words:Moistube-irrigation,line source infiltration,wetted body,soil moisture,
irrigation uniformity

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8961
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
张 俊. 微润线源入渗湿润体特性试验研究[D]. 北京. 中国科学院研究生院,2013.
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