| 其他摘要 | Treated waste water reuse in agricultural irrigation is an alternative approach for water saving. However it causes
soil water repellency and the other problems. The study of reclaimed treated waste water on soil water characteristic curve is a
important research basis for the water movement. Only a few researches are related to the key factors. In this study, we aimed
to explore the impact of treated waste water quality on soil hydraulic characteristic. The repellent and wettable clay loam were
collected at a soil depth of 0-5 cm and 10-20 cm in grapefruit orchard at Kibbutz Berry, Isreal. The repellent and wettable sand
were collected at a soil depth of 0-5 cm and 10-20 cm in oranges orchard at Kibbutz Magen, Isreal. The orchards irrigated with
treated wasted water about 20 years. The repellency level of clay loam and sand were moderated and severed respectively.
Treated waste water and tap water were obtained in a domestic sewage treatment plant. The water sampling locations were
catchment, anaerobic pool, oxidation pool, sedimentation pool and outlet of reused water. Each treatment had 4 replicates. The
soil moisture characteristic curves were measured with a high-speed centrifuge. The experiment was conducted in the Key
Laboratory of Agricultural Soil and Water Engineering, Ministry of Education, at Northwest A&F University on August 2017.
The van Genuchten-Mualem model was fitted to obtain the hydraulic parameters with RETC software. The comprehensive
water quality index was obtained by principal component analysis. The impact of comprehensive water quality indicators on
soil water characteristic curve, the cumulative pore size distribution, specific water capacity, soil moisture parameters was
analyzed in this paper. The result showed with the imporvement of comprehensive water quality indicators, the soil water
characteristic curve of the water-repellent and hydrophilic clay loam shifted to the left. Under the same suction condition, the
soil moisture of repellent and wettable clay loam decreased with the increase of comprehensive water quality index, while the
soil moisture of repellent and wettable sand changed little. There was no significant difference in saturated soil moisture and
residual soil moisture between different water quality for repellent and wettable clay loams. The reciprocal of air entry value
was significantly different among different water quality for repellent and wettable clay loams. There was a linear negative
correlation between comprehensive water quality index and air entry value soil and (R 2 was 0.94 and 0.78). The air entry value
the repellent soil was less than that of the wettable soil under the same water quality condition. In the low suction stage, the
specific water quality curve with higher comprehensive water quality indexes was above the low water quality comprehensive
indicator. That is, the high comprehensive water quality index caused the water content to become higher. In the high suction
section, the specific water capacity curves of the various water qualities almost coincided. The value was small and closed to 0.
With the increase of comprehensive water quality index, the extreme pores in the water repellent and wettable clay loam
decreased, the medium and large pores increased. There was no significant difference on micropores and small pores among
the water quality. The cumulative percentage less than a certain equivalent pore size increased with the increase in the
comprehensive water quality index increase. For water-repellent and wettable clay loams, the field capacity, wilting coefficient,
effective water, unavailable water and ratio of easily available water decreased with the comprehensive water quality index
increased. But the field capacity and the ratio of easily available water were not significantly decreased to meet the irrigation
requirements. The research outcome can provide the theory support for reclaimed water irrigation and management. |
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