| PLC is used mostly in automatic irrigation system controlled by computer. PLC is a new general kind of automatic control device which is developed on the core of micro processor and synthesizes computer and communication technology, having many advantages, such as simple structure, superior perfect, high reliability, flexible general application , easy to program , easy to operate. System hardware mainly consists of the main PLC, collector, various sensors(Water Potential Fermentation Sensor, Temperature Sensor, Steam Sensor, Precipitation, Evaporation , Pressure, Water Level sensor), Cable Line, Electromagnetic valve, Micro weather station in field(Atmospheric temperature, Atmospheric relative humidity, Wind Speed, Wind direction, Precipitation, Evaporation ), Control box, Pumped well, Pump, main pipeline, Branch pipe, Capillary. The application of PLC on precise irrigation control system in the loquat orchard of reservoir has many advantages:(1)The principle of precise irrigation provides nutrients according to demand of crop and to iriigate according to water balance of crop realize precision irrigation and turn irrigation to irrigated crop.(2) Combining irrigation and fertilization organically and overall planning the two technologies can reasonably realize regulating water using fertilizer, enriching soil by storing more moisture which are usually the important approaches to precision irrigation and fertilization(3)Precision irrigation and fertilization can adjust the quantity and concentration of nutrient of irrigation water to adapt to the need of crop and climate condition. This system can raise utilization rate of fertilizer greatly, enhance the validity of nutrient, promote the nutrient absorption of plant root, improve the utilization ratio of water using of agroindustry. This is an important path to increase crop yield and save time and Labor to increase agroindustry benefit.(4)Under the same climatic conditions and the same fertilizer practices, in the same variety and the same planting density, the production of loquat used drip irrigation controlled automatically improves 22% than the production adopted artificial irrigation. At the same time, it assures the protection of ecological environment in the loquat orchard. |
