卷盘式喷灌机灌溉施肥计算模型与综合评价体系构建

Irrigation/fertilization model and comprehensive evaluation system for a hose-reel sprinkler

卷盘式喷灌机实现精准水肥一体化作业对农作物生产具有重要意义。该研究以卷盘式喷灌机为研究对象,开展了桁架式喷头车选配的低压喷头径向水量分布特性测试,构建了低压多喷头组合喷灌水量分布模拟模型,提出了水肥一体化条件下灌溉施肥参数计算模型,建立了基于喷灌均匀系数、设计喷灌强度、单机控制灌溉面积、单位面积年投资、年运行费5个指标的卷盘式喷灌机综合评价体系。研发了一款基于Web平台的卷盘式喷灌机灌溉施肥参数设计软件,以北京地区种植冬小麦为例,对JP75-300卷盘式喷灌机桁架式喷头车配置三款低压喷头进行方案优选,采用主成分分析法对初筛的12种机组运行方案进行综合评价,最高综合得分0.78为最优运行方案,即喷头类型PG134、工作压力0.15 MPa运行方案下机组喷灌均匀系数为88.96%,喷灌强度为57.31 mm/h,单机控制灌溉面积为5.05hm2,单位面积年投资1981.04元/hm2,年运行费为1019.99元/hm2。研究成果可为卷盘式喷灌机灌溉施肥的参数设计和设备选型提供技术支持。

A hose-reel sprinkler irrigation machine has been gradually applied for the field crop fertigation in recent years,particularly for the high-standard farmland construction.However,it is still lacking on the reasonable working parameters of the machine,leading to the high operating costs,low irrigation quality,and non-uniform fertilization.In this study,a calculation model of irrigation and fertilization was established to construct a comprehensive evaluation system for a hose-reel sprinkler irrigation machine.The working parameters were optimized to reduce the operating costs for the high quality of irrigation and fertilization.An indoor test was carried out on the typical low-pressure sprinklers,including the PG224 and PG134 sprinklers,as well as the Super Spray sprinkler(Senninger Irrigation,Inc.,USA).A systematic analysis was made to obtain the flow rates,radius of throw,and radial water distributions of three low-pressure sprinklers.The results showed that the flow rate of sprinkler increased gradually,as the working pressure increased.Among them,the PG224 and PG134sprinklers presented the higher degrees of atomization,where the water droplets were mostly concentrated within 0-2 m from the sprinkler.By contrast,there was the lower atomization degree in Super Spray sprinkler.The water droplets were mainly distributed in 4-5 m from the sprinkler,with the maximum water application rate of about 52.6 mm/h.A calculation model was selected to design the irrigation parameters,according to the available parameters of field plot,crop,soil,sprinkler,and irrigation machine.Fertilization parameters were also selected to apply in a piston injection pump.Five indicators were utilized for the evaluation system,including the sprinkler uniformity coefficient,designed water application rate,irrigation area,investment annual investment per unit area,and annual operating cost.Subsequently,a design software was developed to optimize the parameters of the machine,the irrigation,and fertilization using Web platform.A case study was the JP75-300 hose-reel sprinkler irrigation machine that applied for the winter wheat production in Beijing,China.There were the multiple low-pressure sprinklers at the spacing of 2.6 m on a truss with the length of 26 m,and a DC motor to drag the sprinkler cart.12 configuration schemes with three low-pressure sprinklers were selected out after the comprehensive evaluation by principal component analysis(PCA).Specifically,the optimal scheme was the sprinkler type of PG134,with the working pressure of 0.15 MPa,and the corresponding sprinkler uniformity coefficient of 88.96%,the designed water application rate of 57.31 mm/h,the irrigation area of 5.05 hm~2,the annual investment per unit area of 1981.04 yuan/hm~2,and the annual operating cost of 1019.99 yuan/hm~2.The finding can provide the technical support for the selection and parameter design of sprinkler irrigation machine in the irrigation and fertilization.