| Rice hill-direct-seed technology is a kind of simplified cultivation without growing rice seeding and seeding transplantation. Precision rice hill-direct-seed technology seeding uniformity, which can realize the orderly growth of seedlings,freely breathe and good daylighting collection of plantlet; This technology has features of saving time?manpower and seedling bed, and it has high efficiency, wide applicability, and easy to promote. This article in view of the existing precision rice hill-direct-seed planter mechine, which rice seeder unit adjusting range is small and difficult to meet the requirements of different varieties of rice seeding.Then we designed the rice seeder unit which application rate can be changed illimitably. The rice seeder unite can implement each hole 3-12 seed and adjust stepless, which can meet the requirements of conventional planting. Designed precision rice hill-direct-seed machine with simple structure, which employed chassis of Xie Li XL2Z-6 rice transplanter. Besides a field performance test was carried out. The main research results are as follows.(1)Determination of physical and mechanical parameters of rice. Mechanical characteristic of rice is the study base of rice seed sowing performance and structure parameters. Geometry size, angle of repose and thousand seeds weight of four kinds of typical rice were obtained through the test, and get basic physical parameters by calculation of rice seed of arithmetic mean diameter, geometric mean diameter and single grain rice. Those date provide the basis for the structure design of rice seeder with adjustable hole type.(2) Innovation design of rice seeder with adjustable hole type. The quadratic orthogonal rotating combination design test, and the method of orthogonal regression rotation combination test was used to study on the optimization of structure parameters and working parameters of rice seeder, 10 groups of optimization results were obtained. A full factor experimental with three different variables(disparate length of slot, disparate speed of wheel, disparate breed of rice) was designed to test the sowing homogeneity of riceseeder unit and conformance of seeding rate. The experimental data showed that every hole has 3-12 rice, and the percent of pass number of rice in every hole was upon 80%; the seeding number variation coefficient is between 18.59-44.27%; the seeding rate variation coefficient is between 1.47-14.8%; Different varieties of seed metering device dibbling grain number qualified rate effect was not significant; The suitable seeding rate range of rice seeder with adjustable hole type is from 3 to 12 per hole.(3) Design of precision rice hill-direct-seed machine with simple structure. We employed Xie Li XL2Z-6 rice transplanter chassis, then designed precision rice hill-direct-seed machine with simple structure, its main structure include frame, skateboarding, walking device, power system, transmission device, furrowing device, sowing device,and cavitation mechanism. The duck mouth cavitation mechanism was designed and a testing experiment was also finished. The experimental results showed that the duck mouth cavitation cavitation performance was good. The theoretical analysis of skateboards principle was finished, and the skateboard in the mud surface subsidence depth.was calculated(4) Experiment in field. To check precision rice hill-direct-seed machine situation at work in the field, the experiment in field of precision rice hill-direct-seed machine was carried out in The South China Agricultural University farm field. The experiment has two different factors(whether has duck mouth cavitation cavitation and different hole distance), with hole distance qualified rate, hole grain number qualified rate as indicators of performance evaluation. Experimental results show that different processing hole grain number pass rate above 75% and hole distance pass rate above 90% and yield determination results of 414.5-414.5 kg/mu, higher than the average area yield in Guang Dong province. |
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