Physicochemical properties of the soils associated with shifting cultivation in Northern Thailand with special reference to factors determining soil fertility

Effect of burning on soil organic matter content and N mineralization under shifting cultivation system of Karen people in Northern Thailand

“…Assuming that the bulk density of the soils was 1.0 Mg m-3 (Funakawa et al 1997a), the increase of the amount ofNH 4 -N by burning at the 5 cm depth could be estimated at 21 and 23 kg ha-I in the T-lO and T-20 plots, respectively, while at 40 kg ha-I in the T-100 plot. The much higher N mineralization rate of the soils after burning than before burning suggests that, a large amount of mineral N could be supplied to the plants at the initial growth stages in burned soil.…”

“…The amount of annual precipitation ranged from 1,200 to 1,600 mm and was concentrated during the rainy season from April to November. Most of the soils in the village area were classified into Ustic Dystropepts in the USDA classification system (Soil Survey Staff 1992;Funakawa et al 1997a). Detailed information on our study site and the soils was given in the previous reports (Funakawa et al 1997a, b;Tanaka et al 1997Tanaka et al , 1998a.…”

Ecological study on the dynamics of soil organic matter and its related properties in shifting cultivation systems of Northern Thailand

“…This study was carried out in three villages in the mountainous area of northern Thailand, that is, Ban Rakphaendin (RP village), Ban Huai Mak Nun (HM village), and Ban Du La Poe (DP village). The location and description of the villages studied were reported previously (Funakawa et al 1997). The HM and DP villages are inhabited by Karen people.…”

“…The former was closely related to the contents of basic cations both in the surface and subsurface soils and affected the content of available P in the surface horizon, and the latter primarily determined the CEC values and the content of available N in the surface soils (Funakawa et al 1997).…”

Labile pools of organic matter and microbial biomass in the surface soils under shifting cultivation in northern Thailand

“…They were preserved at 4"C until analysis and used as soon as possible. A portion of the samples was air-dried and used for the determination of the general physicochemical properties, which are summarized in Analytical methods were described in the previous paper (Funakawa et al 1997a). "Number denotes the duration of fallow forest or cultivation.…”