Using twenty years of statistical data and household survey data from 1998 to 2001, this paper examines the link between socioeconomic factors and conservation of agrobiodiversity in fallow agroecosystems in two small rural villages, Daka and Baka, in Xishuangbanna, southwest China. These communities have long practiced traditional fallow field, or swidden agriculture, which has maintained a high degree of agrobiodiversity. However, it was found that the area of fallow fields is dropping annually by 0.008 ha per capita in Daka and 0.001 ha in Baka. This loss seems to be driven by population increase and the loss of fallow lands to rubber plantation, paddy field, and other high-yield, income-generating crops that are strongly affected by market trends and government policy. In addition, many farmers are reducing the duration of fallow and increasing the amount of time that land is under cultivation. The loss of fallow agriculture means a loss in agrobiodiversity, as the traditional variety of crops and plants is replaced by exotic varieties with great ecological tolerance. In Baka in 1999 there were 20 upland rice varieties; by 2001 this number had dropped to 14 varieties. There is an urgent need to maintain the diversity and knowledge tied to fallow agroecosystems. Practical innovations by the expert farmers that conserve agrobiodiversity are particularly valuable and need to be encouraged.
