Determining Threshold Values for a Crop Water Stress Index-Based Center Pivot Irrigation with Optimum Grain Yield

Agriculture

Sen Li¹  Aiwang Duan¹  Anzhen Qin¹  Ben Zhao¹  Zhandong Liu¹  Dongfeng Ning¹ 

[1] Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture and Rural Affairs, Institute of Farmland Irrigation, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China;

关键词: canopy temperature;    soil water storage;    crop evapotranspiration;    infrared thermometer;    Triticum aestivum L.;    Zea mays L.;   

DOI  :  10.3390/agriculture11100958

来源: DOAJ

【 摘 要 】

The temperature-based crop water stress index (CWSI) can accurately reflect the extent of crop water deficit. As an ideal carrier of onboard thermometers to monitor canopy temperature (T_c), center pivot irrigation systems (CPIS) have been widely used in precision irrigation. However, the determination of reliable CWSI thresholds for initiating the CPIS is still a challenge for a winter wheat–summer maize cropping system in the North China Plain (NCP). To address this problem, field experiments were carried out to investigate the effects of CWSI thresholds on grain yield (GY) and water use efficiency (WUE) of winter wheat and summer maize in the NCP. The results show that positive linear functions were fitted to the relationships between CWSI and canopy minus air temperature (T_c − T_a) (r² > 0.695), and between crop evapotranspiration (ET_c) and T_c (r² > 0.548) for both crops. To make analysis comparable, GY and WUE data were normalized to a range of 0.0 to 1.0, corresponding the range of CWSI. With the increase in CWSI, a positive linear relationship was observed for WUE (r² = 0.873), while a significant inverse relationship was found for the GY (r² = 0.915) of winter wheat. Quadratic functions were fitted for both the GY (r² = 0.856) and WUE (r² = 0.629) of summer maize. By solving the cross values of the two GY and WUE functions for each crop, CWSI thresholds were proposed as being 0.322 for winter wheat, and 0.299 for summer maize, corresponding to a T_c − T_a threshold value of 0.925 and 0.498 °C, respectively. We conclude that farmers can achieve the dual goals of high GY and high WUE using the optimal thresholds proposed for a winter wheat–summer maize cropping system in the NCP.

【 授权许可】

Unknown