Study On Ecological Concept-based Smart Soil Moisture Monitoring System

Increasing shortage and deterioration of water resource is one of the worldwide leadingissues in ecological environment. In the agricultural sector, which is a major water user,conserved, reasonable and efficient use of water plays an important role in improving currentsituation of water resource and promoting ecological environment protection. In China, alongwith the social and economic development as well as the advance of urbanization, waterconsumption by agriculture has decreased from92.7%in1949to present60%around. Ofwhich, the water consumption by farmland irrigation represents for90%–95%of waterconsumption by agriculture. However, due to restrictions of financial condition, personnelquality and technological condition, there are still problems of inefficiency, severe waste, andnon-demand-based irrigation in the water consumption by agriculture. In developed countries,in addition to advanced water-saving irrigation techniques such as spray irrigation andmicro-irrigation which are used generally, advanced automatic control technologies are usedto carry our accurate irrigation. They use crop needs for water as the basis and informationtechnology as the means to improve the accuracy of irrigation, carry out reasonable irrigationsystem and improve the utilization rate of water. Smart automatically-controlled irrigationwill improve the management level of irrigation, and change the arbitrary of human operation,with reduced irrigation labors, lower management cost, and significantly improved benefit.Therefore, to promote the implementation of automatically-controlled irrigation, change thecurrently prevailing extensive way of irrigation, and improve the utilization rate of irrigationwater is one of the requisite measures to address water saving in agriculture.Currently, the combination of agricultural water saving and environmental protectionhas been gradually an important trend of modern water-saving agriculture. To achievecommon development of agricultural water-saving irrigation and ecological protection needsto build and develop an ecological agriculture system based upon ecological principle and byapplying the method of systems engineering, in order to achieve efficient utilization of waterresource through artificial design, coordinate the relationship between agriculturaldevelopment and environment, water resource utilization and protection, and create avirtuous cycle in respect of agricultural production and ecology. As one of the important tools for developing agricultural water-saving irrigation, soil moisture measurement irrigation hasbeen developed to some extent in extensive areas in China. However, over-high cost of input,restricted geological condition, complicated operation, lower degree of decision support andlower degree of network support have been the main bottleneck for wide-range soil moisturemeasurement irrigation. Therefore, to research and develop a set of complete soil moisturemonitoring system to solve the foregoing problems by hardware and software is of greatsignificance to developing agricultural water-saving irrigation in China and promotingregional ecological construction and restoration.Through overall design of soil moisture monitoring plan, based upon careful analysis ofdata transmission plan, interlocked control and decision manner of soil moisture monitoringand irrigation, this study has ended with a set of smart soil moisture monitoring system, witha view to harmonious development between agricultural water-saving irrigation andecological environment. This system can be used for daily irrigation management and controlin such areas as farmland, gardens, and facility agriculture. Following results have beenachieved for the study:1) The study has developed a ZigBee wireless and GSM technology basedcommunication gateway. The gateway is deployed between the field ZigBee network andupper computer, communicates with the field network by using user-defined data frames, andexchange information with the upper computer in a user-defined SMS format. Thus theproblem that ZigBee cannot perform super-long distance communication has eliminated. Atthe same time, if there are multiple soil moisture collection points in the field, the gatewaycan seal and transmit the data at multiple collection points. In the entire system, only thegateway uses the pay network, which has reduced the communication costs significantly.2) The study has designed and developed an “online soil moisture monitoring system”software system which is based both on C/S and B/S modes. The C/S software can operate ina LAN context. B/S can operate in Internet, allowing smart decision and online managementof soil moisture monitoring. The B/S software exchange information with a specialbackground service program by using UDP. The background service program reads andwrites GSM modules through serial ports, and interconnection between the upper computer and the gateway becomes possible, resulting in absence of poor real-time nature of B/Ssoftware, and difficulty in direct operation of hardware.3) With the principal component analysis (PCA) method, the study analyzed the depthand quantity of soil moisture sensor buried. The result showed that, within certain range ofdepth, representative depth can be used to represent the soil moisture content, in order toreduce the quantity of sensors at single monitoring point, and reduce the investment cost.4) The study used the irrigation plan strategy and real-time irrigation strategy to allowdecision support to the system. The irrigation plan strategy used the Shuffled Frog LeapingAlgorithm (SFLA) to optimize the allocation of watering volume to rationed irrigationaccording to the growth period of crops; the real-time irrigation strategy provided irrigationdecision on real-time basis according to the soil moisture monitoring result and usingconditional reasoning, ensuring that the soil moisture content was always maintained withinthe range required by normal growth of crops.5) The study has made it possible for interlocked control of soil moisture monitoring andirrigation process. Based on the soil moisture monitoring result, the software system madeirrigation decision through expert knowledge, and notified the decision result to the irrigationequipment, thus the interlocked control of monitoring, decision-making and control has beenpossible. The decision-making process was completed totally through software, withirrigation control equipment only responsible for execution, and development cost ofhardware system reduced.6) With a basic concept of green and environmental protection in the system design,solar power supply and wireless communication technologies were fully employed in thefield, without destruction to the farmland environment caused by massive wiring; meanwhile,based on expert knowledge, on-demand irrigation of crops was made possible, ensuring thatthe watering volume acted exclusively on the soil layers where crop roots are mainlydistributed, which has effectively controlled the underground water pollution caused by deeppenetration of fertilizer.