基于柱塞泵与单片机的可控施肥机设计与喷灌试验

为了实现水肥一体化施肥装备流量精确且无水头损失,设计了一种基于柱塞泵与单片机的高精度可控施肥机,开展了恒流模式下6个流量梯度的喷灌系统施肥均匀性试验;以喷头总流量变化幅度为变量,设计了在1∶10的水肥配比下2种灌溉总流量变化幅度的不同工况,对比启、闭可控施肥机恒定水肥比例模式对水肥一体化支管内肥料浓度稳定性的影响效果.试验结果表明,高精度可控施肥机在流量分别为100,200,400,600,800,1 000 L/h的6种恒流模式时,喷灌均匀系数C_U为99.33%~99.71%、变异系数C_V为0.35%~0.75%;C_U,C_V与施肥机流量分别呈正相关与负相关关系,且喷头喷洒肥液的电导率总平均值E_C_-与施肥机流量之间具有显著的正相关性.在恒定水肥比例模式时,试验组管道内肥液浓度在160 s时趋于稳定,且稳定后肥液电导率与目标值偏差率小于4%.高精度可控施肥机恒流模式试验表明施肥机大流量下施肥均匀性变异系数仅为小流量下的50%,且改变施肥机的流量是水肥一体化喷灌系统实现高均匀度变量施肥的一种有效途径;试验证明恒水肥配比模式可有效减小支管肥料浓度受外界的影响.

Design and sprinkler irrigation experiment of controllable fertilizer applicator based on plunger pump and single chip microcomputer

In order to realize the accurate flow and no head loss of the integrated fertilization equipment, a high precision controllable fertilizer applicator based on plunger pump and single chip microcomputer was designed. The fertilization uniformity experiments of sprinkler irrigation and drip irrigation systems with six flow gradients under constant flow mode was carried out. Under the ratios of water and fertilizer of 1∶10, different working conditions of total flow rate of two kinds of sprinklers were designed. The stabilizing effect of the constant water-fertilizer application with that of inconstant one on the fertilizer concentration in the branch tube of integrative water and fertilizer was compared. The result show that when the flow rates of the fertilizer are 100 L/h, 200 L/h, 400 L/h, 600 L/h, 800 L/h and 1 000 L/h under the constant-current mode, the coefficient of unifor-mity C_U of sprinkler is 99.33%-99.71%, and the coefficient of variation C_V is 0.35%-0.75%. C_U and C_V are positively and negatively correlated with the flow rate of fertilizer applicator. The conductivity equivocation E_C_- of sprinkling fertilizer has a significant positive correlation with the total average conductivity of fertilizer liquid sprayed and the flow rate of the fertilizer applicator. In the constant water fertilizer ratio mode, the fertilizer concentration in the pipeline of the experimental group tends to be stable at 160 s, and the deviation rate between the conductivity value and the target value is less than 4%, respectively. The experiment of constant flow mode of fertilizer applicator show that the variation coefficient of fertilizer uniformity under large flow is only 50% of that under small flow. It is an effective way to achieve variable fertilization with high uniformity for the sprinkler system of integrative water and fertilizer by changing the flow rate of the fertilizer applicator. The experiment shows that the constant-current mode can effectively reduce the external influence on the fertilizer concentration in the branch tube.