圆形喷灌机施肥灌溉均匀性及蒸发漂移损失

Fertigation uniformity and evaporation drift losses of center pivot irrigation system

为了评估圆形喷灌机施肥灌溉均匀性和蒸发漂移损失量,通过测试圆形喷灌机入机压力为0.15 MPa时,与喷灌机连接的计量隔膜泵吸肥流量与工作比例间的关系.分析了计量隔膜泵吸肥性能,并通过田间试验测试圆形喷灌机水力性能,评估了不同肥料类型和肥液浓度的施肥灌溉均匀系数及蒸发漂移损失量.结果表明:计量隔膜泵吸肥流量实测值和理论值的标准均方根误差为8.9%,且流量控制精度在工作比例为60%~100%时(相对误差|RE|≤5.6%)远高于工作比例为20%~40%时(|RE|≥13.3%).圆形喷灌机行走速度百分数为100%时,径向肥液水深与施肥量的修正赫尔曼-海因均匀系数基本相等,其变化分别为80%~85%和78%~86%,均小于径向肥液浓度的均匀系数96%~99%.不同肥料类型和肥液浓度处理间灌水、肥液浓度均匀系数差异不具有统计学意义.当风速小于2 m/s时,利用圆形喷灌机进行施肥灌溉产生的蒸发漂移损失量占灌水量的比例为1.5%~10.1%.

Uniformity is an important parameter in operation of center pivot irrigation system, and evaporation drift loss （ EDLs ） is a significant factor affecting water and fertilizer utilization efficiency of sprinkler irrigation system. The relationship between flow rate and operational range of diaphragm metering pump connected with a center pivot of 0.15 MPa pressure was tested. Field experi- ments were conducted to evaluate uniformity of water and fertilizer application and EDLs . The results indicat that RMSE of injection connected with center pivot is 8.9% and a small relative error （ RE ） is achieved in the operational range of 60%-100% （ RE ≤5.6%）, while a substantially higher RE （ RE ≥13.3%） is got in the range of 20%-40%. When the pivot rotational speed is 100% of the full speed, the modified Heermann-Hein uniformity coefficients of radial irrigation and fertilizer application are equal basically, within variation ranges of 80%-85% and 78%-86%, respectively, which are all less than the uniformity of radial solution concentration ranged in 96%-99%. There is no significant difference in uniformity of fertilizer solution application and solution concentration between different fertilizer types and concentrations. When the wind speed is less than 2 m/s, EDLs are ranged in 1.5%-10.1% （average 5.1%） with center pivot.