Kan krachai chong wang khanat tangtang khong din padip khao lae rai luanloi boriwen Doi Pui Chiangmai.
1981
Verasak Udomchock
The study on pore-size distribution of hill-evergreen forest and shifting cultivation soil was conducted at Kog-Ma watershed research staton, Doi Pui Chiengmai. The size distribution of pores that contributed to storage and drainage water in soil were compared between those two areas in particular depth of soil profiles. Physical properties of soils such as particle-size distribution, particle density, and organic matter were analyzed from disturbed soil samples and analysis of pore-size distribution and hydraulic conductivity were studied from undisturbed soil samples. The results indicated that total posity of hill-evergreen forest soil (A, B1, B2 and B3 profiles) decreased from 0.64, 0.59, 0.54 and 0.49% to 0.57, 0.54, 0.49, 0.44% respectively after the utilization of land had been changed to shifting cultivation area. Quick drainage pores (< 30 /um) decreased abruptly in A and B1 horizons from 18% and 10% to 9% and 6% respectively. Slow drainage pores (9-30 /um) in A horizon, on the other hand, increased 2% from 14%. Pore-size distribution index in A and B1 horizons changed from 0.7 and 0.84 to 1.21 and 0.86, but B2 and B3 horizons did'nt change by these impacts. The interpretation of these numbers designated that well-developed structure of hill-evergreen forest soil became poor structure and this affected the permeability of water in soil.
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