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| Titel |
Predicting deep percolation with eddy covariance under mulch drip irrigation |
| VerfasserIn |
Guanghui Ming, Fuqiang Tian, Hongchang Hu |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250124099
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| Publikation (Nr.) |
 EGU/EGU2016-3475.pdf |
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| Zusammenfassung |
| Water is essential for the agricultural development and ecological sustainability of the arid
and semi-arid oasis with rare precipitation input and high evaporation demand. Deep
percolation (DP) defined as excess irrigation water percolating below the plant root zone will
reduce irrigation water use efficiency (WUE). But the DP was often ignored in mulch drip
irrigation (MDI) which has reached the area of 1.6 million hectares in Xinjiang, the northwest
of China. In this study DP experiments were conducted at an agricultural experiment station
located within an irrigation district in the Tarim River Basin for four cotton growing
periods. First it was detected the irrigation water infiltrated into the soil layers below
100cm and the groundwater level responded to the irrigation events well. Then
DP below 100cm soil layers was calculated using the soil water balance method
with the aid of eddy covariance (with the energy balance closure of 0.72). The
negative DP (groundwater contribution to the crop-water use through capillary rising)
at the seedling and harvesting stages can reach 77mm and has a good negative
correlation with the groundwater level and positive correlation with potential evaporation.
During the drip irrigation stage approximately 45% of the irrigation became DP and
resulted in the low irrigation WUE of 0.6. The DP can be 164mm to 270mm per
year which was positive linearly correlated to irrigation depth and negative linear
correlated to irrigation interval. It is better to establish the irrigation schedule with small
irrigation depth and given frequently to reduce deep percolation and meet crop needs. |
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