Water flow characteristics in soil pores as influenced by land use change

Soil and crop managements including tillage, fertilization and irrigation methods play important roles in the sustainability of agricultural and natural resources and can influence the soil attributes differently. So, the objective of this study was comparison of six pore classes contribution to water flow at different land uses. The soils consisted of three long-term (> 20 years) land use types including i) annual cultivated field (ACF) with different rotations of wheat, barley, corn and canola and fallow; ii) orchard field (OF) and iii) perennial alfalfa field (PAF). At the soils of each studied land uses, 25 experimental points were selected on a relatively regular square grid of 5 × 5 m length. In each point, Infiltration test was done at 15, 10, 7.5, 5, 2.5 and 0 cm tensions by using tension infiltrometer and near-saturated hydraulic conductivity were determined. Then contribution of water flow was calculated using near saturated hydraulic conductivity. Results revealed that there is no significant difference in water flow percent between ACF and OF at any pore classes. While, land use change from ACF to PAF showed significant difference in water flow percent at micropores, mesopores 2, 3, and 4 and also macropores. Percentage of water flow at ACF micropores was 2.13 times more than PAF. Whereas, water flow at PAF mesopores 2, 3, and 4 and macropores were signigicantly more than ACF land use. In general, at ACF and OF most of water flow percent is related to micropores but at PAF macropores have more contribution of water flow.

کلیدواژه ها:

contribution of water flow ، land use change ، macropores ، mesopores ، micropores ، nearsaturated hydraulic conductivity ، pore classes