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Study on the Soil Moisture Dynamic Change of Soil Water Movement under Drip Irrigation

Author: ZhangZhiGang
Tutor: LiHong
School: Xinjiang Normal University
Course: Physical Geography
Keywords: Subsurface Drip Irrigation Water Movement Redistribution SoilMoisture Content
CLC: S275.6
Type: Master's thesis
Year: 2013
Downloads: 15
Quote: 0
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Abstract


The application of drip irrigation technology to smaller root distribution ofeconomic crops, tree nurseries and trails level arboriculture in Xinjiang region.However, with increasing the age of trees, diameter, the root distribution alsoincrease. How to choose emitter discharge rate, irrigation duration, and the issue ofdistribution of drippers distance range were not solved, for the larger diameter treesin the process of drip irrigation.Research on soil moisture movement of a single-point source drip irrigation, isdevelop reasonable drip irrigation system and the premise and basis of field crops tohigh water management. This article by field tests and keep the soil physicalstructure, through a single-point source drip irrigation for Jujube. During of drip weuse ECH20soil moisture sensor for dynamic monitoring and data acquisition. Thispaper studied in the case of the irrigation lasted for4hours,6hours and dripperflow is4.0L/h,8.0L/h,12.0L/h,16.0L/h, different irrigation lasted and dripper flow ofmoist body shape, the wetting front migration moist ratio, the average migration rateof the wetting front, moist body moisture and wet body after the end of the irrigationredistribution, provide the basis for the application of drip irrigation technology inthe Xinjiang region of large diameter trees.The main results are as follows:(1) In case of a single-point source drip irrigation of the same irrigation lasted,the the moist body shapes and sizes will be increased with the increase of the emitterdischarge rate, the horizontal diffusion distance and the vertical infiltration distancewill be increased with the dripper flow of increase. In case of the same dripper flow,when the irrigation lasted increased, the moist body shapes and sizes also increased.(2) In case of surface drip irrigation, the horizontal and vertical movementdistance of soil wetting front accorded good power function relation with infiltrationtime, the wet peak migration distance in all directions increased with increasingirrigation lasted or dripper flow. Drip process of the wetting front movement velocityalso increases with increasing infiltration time; in the same conditions of irrigationlasted, the wetting front movement velocity also decreases with the dripper flow ofreduce.(3) During of drip, moist ratio increases with the increase of the irrigation lastedor dripper flow; when the drip discharge more lower and the moist ratio more higherin the late. Wetting ratio decreases as the infiltration time increases, and with theinfiltration time showed a good power function.(4) The moisture content of the moist body decreases with the increase of thedistance of infiltration in the horizontal direction and the vertical direction, distancethe drippers closer the variation of the moisture content is the greater. After irrigation,under drippers about40cm, the moisture content reaches a maximum, distance thedrippers closer the contours of the moisture content is more dense. In the same ofirrigation lasted, the dripper flow greater and the range of moist body also greater,the rate of moisture content increases faster. With the distance increase, the moisturecontent gradually reduce. When the dripper flow is fixed, in the vertical direction theamplitude of the moisture content of the moist body increased with the increase in irrigation lasted.(5) After irrigation24hours, the moist peak migration distance of the horizontaldirection distancer than the end of the irrigation, with respect to the infiltration ratein the vertical direction, in the horizontal direction to be slower. When to stopirrigation, wetting the horizontal expansion Caesar distancer than vertical infiltrationdistance. After irrigation24hours, because of soil moisture have a redistributionprocess and gravitational potential so soil moisture will continue movement,Gravitational potential to play a leading role in the movement of this process so inthe vertical direction of the infiltration distance greater than the horizontal direction,at the same time the soil moisture of in the horizontal direction did not stop.

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CLC: > Agricultural Sciences > Agricultural Engineering > Irrigation and water conservancy > Irrigation technology > Drip irrigation
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