Agricultural expansion in Yunnan Province and its environmental consequences

Yunnan Province with numerous international rivers has huge impacts on downstream countries such as Burma, Laos and Vietnam. Agricultural expansion in Yunnan has conferred and continues to confer detrimental impacts on environments. In the past 43 years (1960-2003), the increase in crop yield was associated with a 99.1-fold increase in fertilizers, 2.0-fold in pesticides, and 0.4-fold in cultivated lands, respectively. Based on linear regression of the past trend, the next doubling of crop yield in the future would be accompanied by the increase in fertilizer application (from about 1.3x10(9) kg to 3.6x10(9) kg), and the increase in application of pesticides (from about 2.7x10(7) kg to 9.6x10(7) kg). Similarly, the total amount of cultivated lands would increase from about 5.9x10(6) ha to 9.3x10(6) ha. In the past decades, these changes have caused a series of environmental problems such as agricultural non-point source pollution (ANSP), deforestation, land degradation, and biodiversity loss. If the escalating status continues as our prediction, those problems would get worse and be tough to be dealt with. As for the situation in this region, some practices to minimize the impacts should be implemented in controlling population growth, protecting wetlands, developing tourism, and utilizing fertilizers and pesticides more rationally.