Study on agricultural management for sustainable agriculture in Zhangye Oasis, middle reaches of Heihe River Basin: A case study in Linze County

Abstract

Proper management of irrigation and fertilizer for different crops is beneficial to the sustainable development of agriculture. Zhangye Oasis, which is an arid region surrounded by water dependent agricultural areas with canal-type irrigation systems, has been utilising the majority portion of the discharge of Heihe River. Maize is the dominant cash crop, while the cultivation of a new cash crop, stevia, has also been under expansion in recent years. This study was conducted with both a social survey approach and science experiment approach, aiming to comprehensively understand the management of irrigation, fertilizer and soil data, simultaneously. The water consumption, fertilizer application and soil condition of stevia and maize fields in Linze County were investigated and compared. The social survey on the perception of farmers revealed that the cultivation of stevia, which had greater cash ability, required less fertilizer than maize cultivation, while water consumption showed little difference. The nitrate and ammonium contents of stevia fields were higher than those of maize fields, indicating that stevia fields could be cultivated with less chemical fertilizer. The result that the nitrate contents in the middle and lower soil samples were higher than those in upper soil samples, suggests nitrate leaching. According to the results, it is suggested that less chemical fertilizer can be applied and less water used for irrigation in stevia fields of the Zhangye Oasis, and there is therefore a good opportunity for adopting stevia as a new type of cash crop for sustainable agriculture, with improved management of irrigation and fertilizer usage.