Development And Experimental Study On Rice Seed Tape Twisting Machine

The rice direct sowing technology has played an important role in rice plantingtechnology in our country for the advantages of lower cost, water saving, less process, laborforce saving, and higher income, etc. The rice direct sowing technology with seed wrapped inpaper tape (RSTDST) was a new technology of rice direct sowing proposed in recent years. Itconverts the traditional process of rice direct sowing of furrow opening, seed metering, soilcovering and suppressing into two steps–first, wraping rice seed into paper tape in factory;second, laying the rice seed tape in paddy field. Precision agriculture and contract farming canbe realized by the application of the technology. The rice seed tape twisting is not affected byconditions of the soil and the season. It’s application can also decrease the production cost,increase income and simplify the operation in the field. Based on the review of rice directsowing technology development at home and abroad, a rice seed tape twisting machine wasdeveloped in according to the new technology of RSTDST proposed by the team, andrelative experiments were conducted. The results are significant for the application of ricedirect sowing technology.The main achievements of this study are as following:(1) The process of the rice seed tape direct sowing was determined where the seed wastreated with several materials. The experiments for the effects of fertilizer and herbicides inthe seed tape on the emergence rate, seedling height and the density of weeds in paddy fieldduring the seedling stage were carried out to determine the rate and position of the seedtreating materials in the tape. The results show that the germination rate and seedling heightwere significantly increased in the condition of single seed per hill, the distance betweenseeds of30mm, the rate of fertilizer of0.04g per hill, the distance of15mm between seed andfertilizer, and without herbicides applied in the tape. The physical and mechanical propertiesof the materials inclusived were tested to provide a theoretical basis for the selection andparameters design of the material-metering device.(2) Four agricultural mulch films (non-woven absorbent cotton, agricultural kraft paper,non-woven polypropylene film, non-woven spun-bonded polylactic acid (PLA) film) usedcommonly were selected and the microstructure observation, FTIR spectral analysis, tensilestrength testing, the effect on rice seed germination and degradation property were testedrespectively. The non-woven.spun-bonded PLA film was selected as the appropriate carrierfor rice seed tape direct sowing technology It has the advantages of biodetadability,environmental pollution free, higher tensile strength and breaking elongation and, noinfluence on rice seed emergence rate, etc. (3) The vertical double-disc pneumatic seed-metering and fertilizer-metering devicewith supporting trapezoidal guiding device were studied in according to the theories ofoptimization design. The optimum parameters were determined through the quadraticregression general rotatable combination test of four factors. The main evaluating indexes forthe device were qualified seed-sucking rate of86.32%and qualified fertilizer-sucking rate of87.44%under the seed-metering shaft speed of15.31r/min, seed disc sucking hole diameter of1.5mm, fertilizer disc sucking hole diameter of2.0mm, the sucking chamber vacuum of4.4kPa. In according to the kinetic analysis for seed and fertilizer in the process of sowing, thestructure and parameters of the guiding device for seed and fertilizer were determined and thecushioning materials pasted on seed board and fertilizer board were also determined to benon-woven spun-bonded PLA paper with density of60g/m2and80g/m2respectively, and the anglesof guiding board are both50°. The experiment of seed guiding and positioning was conductedon the test bed of metering device. The results showed that the performances of seed-meteringdevice, fertilizer-metering device, guiding and positioning device can meet the designrequirements.(4) The analyses of the function and control flow of the system was performed, the flowchart was drafted, and the composition and debugging of the control system was carried out,and performance testing of the mechanism was conducted. On the rice seed tape twistingmachine, a altering frequency converter was used to regulate the rotating speed, a frictionadjusting device of the seed tape disc was utilized to control the circumferential velocity of theseed tape. The optimum parameters were determined through the quadratic regressionorthogonal rotatable combination test of two factors. The main evaluating indexes for themechanism were: peripheral velocity of0.13m/s, tension of14.4N at rotate speed of420r/min ofthe U-shaped rotating frame and the friction of7.9N of the seed tape disc. The seed tapetwisting mechanism runs smoothly with no fracture of seed tape.(5) The overall performance of prototype of the rice seed tape twisting machine wascarried out.At the optimum operating parameters, the qualitied hill space of the seeds is81.4%, qualified distance between seed and fertilzer is84.4%, rice leakage rate is3.85%,fertilizer leakage rate is1.96%and the twisting number is47per meter of the rice seed tape.The results show that all the indexes can fulfill the basic requirements.