| 其他摘要 | 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 |
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