| At present,cotton planting in Xinjiang mainly relies on solid water-soluble fertilizers to increase crop production,but the use efficiency of solid water-soluble fertilizers is low and it is easy to cause problems such as pipeline blockage.Compared with solid watersoluble fertilizer,liquid fertilizer has obvious advantages,such as high fertilizer efficiency,low manufacturing cost,and basically no environmental pollution.But China’s liquid fertilizer application technology is not very mature,mainly reflected in two aspects: First,the development of liquid fertilizer application machinery technology is backward;Second,the differences in fertilization modes caused by regional environment and planting methods have limited the spread of fertilization machinery.This paper aims at the status of liquid fertilization system and the characteristics of fertilizing environment in cotton fields in Xinjiang,A complete set of variable fertilizer control system for liquid fertilizer in cotton fields was developed.The main research contents of this paper are divided into the following points:(1)Design of Variable Fertilization Control System for Liquid Fertilizer.PLC,touch screen,inverter,solenoid valve,squeeze pump,pressure sensor,flow sensor and other hardware are used as the core components of the liquid fertilization variable fertilizer control system in cotton fields.System design includes hardware structure design,decision-making process design,variable speed design,and software program design of the host computer.(2)Parameter tuning of PID control algorithm.According to the system requirements,plan the software design of the lower computer monitoring system;summarize the PID algorithms involved in the control system;The software design of the pressure information acquisition and flow control unit in the lower computer monitoring system was completed,and a closed-loop control model between the actual fertilizing flow rate and the speed of the fertilizing pump and the water supply pressure value was constructed.The simulation software was used to optimize the parameters of the flow PID control algorithm.(3)Realization of system remote communication,data acquisition and monitoring.Using GPRS to realize the data collection of the distributed fertilization equipment in the cotton field,you can obtain the fertilization amount,fertilization time,fertilization date,fertilization time,remaining liquid fertilizer amount,equipment alarm information and other fertilization data and real-time remote of a single device Surveillance.(4)Experiment and research on the variable fertilizer application control system for liquid fertilizer.A drip irrigation network tube for cotton field was set up at the test site.The effects of liquid fertilizer flow rate,water supply flow rate,and fertilization time on the uniformity of fertilization were analyzed by studying the variable mass flow process of fertilizer liquid inside the network tube.The variable fertilization control system was tested in a cotton field test site,and the test data showed that the system had better control performance in variable control and fertilization accuracy. |
