Characterization of hydraulic properties of an inceptisol for irrigation scheduling of upland crops
2007
Chikushi, J.(Kyushu Univ., Fukuoka (Japan)) | Mallk, S,A. | Karim, A.J.M.S. | Hamid, A. | Islam, M.S. | Miyamoto, H.
Field and laboratory investigations were carried out to study the hydraulic properties of soil representing the Chhiata series of Grey Terrace Soil under Inceptisol of the USDA classification system in order to determine water retention and movement and available crop water for effective irrigation scheduling of upland crops. The relationships between the matric potential (psi m) or the hydraulic conductivity (K) and the water content (theta) have been determined. The psi m - theta relationship was measured in the laboratory and the K - theta relationship in the field. The results of the psi m - theta relationship showed variable available water content in different soil layers. The available water depth for each layer of 15 cm thickness in a 90cm long profile varied from 2.65 to 3.33 cm. This variation could be due to differences in bulk density and clay content of different layers. The total depth of available water in the profile was around 18 cm. With this water content level the cultivation of most upland crops is not feasible, especially in the sowing season. Measurable downward flux continued throughout the investigated period of 60 days following saturation and indicated a very slow movement of water. Thus, the soil profile may be easily waterlogged by heavy irrigation. These results suggest that an upland should be cautiously irrigated so as not to become waterlogged in the crop root zone.
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