| Integrated System of Water and Fertilizer is the techology that mixes the water and fertilizer together in the proportion the plants need,and makes the irrigation and fertilization in one process,which could avoid wasting of resource and make good use of it.Recent years in the world,the west developed countries represented by Holland and Israel,not only have the most advanced technologies and experiences on Protected Horticulture,but also success in the Integrated System of Water and Fertilizer.They planted the tech in the machines they produced.This technology is being popularized all over the world.It raises the production of plants,increases the use ratio of water and fertilizer,and lowers the pollution to the environment.But these facilities were produced in Europe,and designed based on the weather of Mediterranean and West Europe,and also based on the bigger Greenhouses?which were usually larger than 3000m2?in these countries.They suited the weather and agriculture conditions there in Europe,and produced the optimal effects in similar conditions.But China are mainly influenced by temperate continental and monsoon climate,which are totally different from Europe.Especially in Northern China,people build smaller solar greenhouses to grow plants,which don't suit the experience in Europe at all.While the market of integrated irrigation system in China was in the ascendant,there were still many problems around,such as lack of irrigation strategies,high cost of the products,and constriction of application.There were not enough suitable facilities for the small solar greenhouses in Northern China.For solutions to the problems above,based on the technology of integrated water and fertilizer,we will develop an equipment applicable in small solar greenhouses.It could control the pumping and mixing of water and fertilizer automatically on the basis of irrigation models,and has the attributes of accuracy,stability and convenience.The main results of the research were listed below:1.With the RaspberryPi 3B+ as the main control core,the system connected the transducers via GPIO pins or I2 C bus,then collected the environment data and controlled the DC pumps with the driving module to mix the water and fertilizer,and ultimately to irrigate using timing strategy or irrigation model algorithm.2.The algorithm was programmed with Python.The database was My SQL.The UI was a B/S structure browser application built with HTML5?CSS?Javascript,and to be extended to a cloud platform in the future.3.The irrigation model was switchable between two different strategies based on the previous researches by our team.The first model fitted moderate climate condition.It calculated LAI?leaf area index?via Boltzmann equation and obtain the irrigation volume needed through equation of linear regression by G.Carmassi?2007?.The equation is as below:LAI=a1+?a2-a1?/(1+e??a3-GDD?/a4?)WU=b1(1-e-k·LAI)·RAD/?+b2a1=-0.335?a2=4.803?a3=755.3?a4=134.7b1=0.946,b2=0.188,k=0.69,?(2.45MJ·kg-1)The second model fitted tougher climate condition.It combined the product of thermal effectiveness and par with the realtime growth offered by electronic scale to obtain the Wu value.The equation is as below:Z=a+b*exp?c/X?+d*Ya=273.0020,b=-0.6970,c=48.1364,d=86.7566... |
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