Development And Experimental Study On Automatic Duck Shed In Paddy Field For Duck-rice Farming System

Rice-duck farming technology grows ducks and rice together of which ducklings are released into the field about 10 days after rice seedlings transplanted. Utilizing the omnivore property of ducks, the weeds and pests can be controlled biologically. The movement and excreta of ducks in the field can improve the organic nutrients. During the period of rice and ducks growing before rice flowering, no pesticides, fertilizers and herbicides are applied and it promotes virtuous cycle of ecological environment in paddy field. It integrates rice growing and duck breeding and realize yield both rice and ducks. However, manually duck breeding consumes time and labor to drive ducks back shed and feed them. The duck shed integrated of duck summoning system, water and feed stuff feeding system and duck identifying system were developed based on properties of rice-duck farming technology and requirement of working environment. The key technologies of vocal training and image process of ducks were studied to realize the automation of breeding ducks in paddy field. It is significant to promote the application of rice-duck farming technology. The main content and conclusions are as folio wings:(1) An automatic control system integrated multi modules was developed to apply for duck shed in paddy field based on microcontroller technology. The control system consists of automatic gate module control, feeding module control, watering supply module control, voice training module control, human-machine interaction module control, communication module control and power supplying module control. The operations of opening and closing the gate, feeding and sound playing to call ducks back were controlled as time sequence to meet the requirement of rice-duck farming according to the laws of the celestial migration and the characteristics of rice-duck farming technology and environmental condition were taken into account. The automatic water supplying, protecting ducks from getting stuck and counting the ducks back to the shed, were accomplished to ensure the safety of ducks in paddy field by utilizing the technology of automatic detection and data delivery.(2) The effect of environmental factors on the intensity of the sound, auditory threshold dynamic curve of ducks and the optimal parameters of the sound suitable for ducks back to the shed were studied. The mathematical model of propagation distance and sound intensity was established and the effect of wind speed on sound intensity was studied through a single factor experiment. Auditory threshold dynamic curve of ducklings affected by the interaction of sound pressure level and frequency was fitted through repeated tests, and the lowest sound parameters that may stimulate the ducks audition were determined. The mathematical model of the time and the time difference of ducks back shed with sound pressure level and frequency was established through orthogonal tests based on the vocal duck training system and it revealed the linear relationship between the velocity and consistency of ducks back to the shed with sound parameters. The parameters were optimized with MATLAB software synthetically considering the time and time difference of ducks back shed. The results showed that the shortest time of ducks back shed was 20.51s and the time difference was 9.18s at sound pressure level of 89dB and the frequency of 15.89 kHz, which was the best effect of ducks back shed.(3) The mathematical model of pixels with ducks number was established based on image processing for ducks feature recognition, and safety gate system was developed which can automatically opening and closing depending on detection of ducks number into the shed. Partitioned histogram analysis method was utilized to extract the background and the real-time updating of background template was realized. The moving foreground template was established based on binarization difference image which was obtained according to the image intensity of current frame and background template image. The images of moving ducks were extracted by removing noise of the difference image and the blanks were filled up according to closed operation. The ducks in the image were normalized and quadratic polynomial fitting model of the foreground pixels and total number of ducks was established. The system may make a decision whether opening the gate or not depending on the number of ducks in the image to ensure all ducks return to the shed. The accuracy of the fitting model was verified by experiment.(4) Automatic water supplying system was developed and the mathematical model of the system was established with dual iteration method. The system was identified and the performance was analyzed according to experimental study and theoretical analysis based on time domain analysis. The results of nonlinear regression analysis and dynamic stimulation with MATLAB showed that the system was a typical first order inertial system. It needed 210s to fill the water tank from bottom level to upper level, and the steady state error was zero. The system could satisfy the need of ducks.(5) Field experiment was carried out to verify the reliability of the automatic duck shed and the feasibility of duck-rice farming in Liaoning Areas. The effect of rice-duck farming technology on ecological environment of paddy field and rice growth was studies as well. Mathematics model of rate of ducks back shed with sound pressure level, sound duration, delay time of automatic gate was established and the optimal parameters to summon ducks back shed were determined based on the model. Field performance test showed that the average failure rate and the mean time utilization factor of water supplying system meet the design requirement. Compared with manual feeding, the weight increase of ducks had no significant difference and the automatic shed has a similar effect with manual feeding. The effect of rice-duck farming on soil chemical properties and rice growth was determined based on experiment with contrast of conventional cultivation. The experiment results showed that the duck-rice farming can modify the soil nutrient, increase the rice yield and increase the economic benefit.