Qibiao Han；Xiuqiao Huang；Shaoyuan Feng；Hao Li；Wen Li；Xi Nan

　　School of Hydraulic Engineering and Power Engineering, Yangzhou University,Yangzhou,China; Farmland Irrigation Research Institute , Chinese Academy of Agricultural Sciences, Xinxiang,China;Key Laboratory of Water-saving Agriculture of Henan Province,Xinxiang,China

　　Presently in china, fertigation is applied continuously in micro-irrigation. The pressure differential fertilization is one of the most important method and is popularly used in facility agriculture and cotton fields in Xinjiang. However, what puzzles scholars and users is how to realize precision control and automatic control of this fertigation method due to the constant attenuation of fertilizer solution concentration in its whole fertilization process. In order to achieve the precision or automatic control, the following research was carried out to the pressure differential fertilization. First, the computational fluid dynamics (CFD) model was introduced into the concentration attenuation calculation course, and numerical simulation results was compared with the previous research. The concentration decay process and the adaptive formula were determined. Second, combined with our attenuation theory, We started research about the automation equipment for pressure differential fertilization. Taking into account that the fertigation in micro-irrigation is not a frequent device, we used the PLC control module, with the flow meter solenoid valve, manufacturered a kind of light and small semi-automatic drip irrigation differential pressure fertilizing vehicle. And its application method was given. The third, Although above mentioned fertilizer vehicles could be automated to some extent, However, its application scope should be soluble fertilizer. But solid fertilizer is still widely used in China.Considering this problem, we use APP remote control and on-line conductivity sensors and other technologies, established another automatic control of pressure difference fertilization system, they can achieve the application of solid fertilizer fertilizer pressure.