Shifting cultivation. An experiment at Nam Phrom, Northeast Thailand, and its implications for upland farming in the monsoon tropics

A report of a 3-yr cooperative research project undertaken by Japanese and Thai scientists with grant aid from the Japan Society for the Promotion of Science, the National Research Council of Thailand, and Khon Kaen University, Thailand. In the first year of the project (1979-80) the experimental site was established by felling and burning the trees as in the practice of shifting cultivation. Four experimental plots were set up: a control, kept under forest cover, and plots for experimental shifting cultivation, continous upland cropping, and study of run off and soil loss. During the second and third years observations were made on maize cropping in the experimental plots. Three forest ecology plots were also delineated, one control for long-term observation and 2 for biomass, nutrient cycling and regeneration studies. The results are reported in 10 chapters by various authors: Introduction; Description of the experimental site; Forest: felling, burning and regeneration; Soil fertility and tilth; Run-off and soil loss; Soil animals; Insect community; Cultivation of maize, its weeds and pathogens; Present situation of upland farming in Thailand; and General discussion and conclusion. The chapter on the forest [pp. 13-62, 36 ref.] describes the vegetation at Nam Phrom (dry evergreen, mixed deciduous and dry dipterocarp types) giving data on forest structure and floristic composition, biomass production, nutrient cycling and regeneration after clearing and burning. The data on regeneration are from 2 plots initially felled and burned in 1979-80, and cleared again in Oct. 1980 (1 also with burning). Biomass of regenerated plants in Oct. 1980 and Oct. 1981 is given for 9 groups of plants: Eupatorium odoratum (the dominant species), other herbs, grasses, ferns, canes, lianas, shrubs, and tree seedlings and shoots. Nutrient contents are given for the major groups (herbs, trees and shrubs and others). A supplement at the end of the book [pp. 205-219, 3 ref.], Vegetation management on the abandoned land after shifting cultivation, describes the agroforestry system in Thailand, discussing possible improvements to it, and a case study at the Somdej plantation (100 km E. of Khon Khaen) in a Melia azedarach/cassava plantation.