滴灌系统毛管单/双向供水方式对灌水和施肥均匀性的影响

滴灌系统管网布置形式及运行管理模式是影响滴灌系统灌水和施肥均匀性的重要因素。本研究评价了供水方式、毛管长度及毛管首部压力对沿毛管压力分布、灌水器流量分布、灌水和施肥均匀性及水肥一致性的影响。试验中,毛管供水方式设置单向供水(A1)和双向供水(A2);毛管长度设置70(L1)、100(L2)和130 m(L3)3个水平;毛管首部压力设置0.02(P2)、0.04(P4)、0.06(P6)、0.08(P8)和0.10 MPa(P10)5个水平。结果表明,相同毛管长度及毛管首部压力情况下,双向供水处理流量偏差率较单向供水低18%～43%。在灌水器允许流量偏差率为20%时,双向供水毛管极限铺设长度较单向供水增加约60%。方差分析结果显示毛管供水方式、毛管长度及毛管首部压力对灌水和施肥均匀系数的影响均达到了极显著水平(p0.01),双向供水方式可以显著提高灌水和施肥均匀性。在毛管长度100 m和130 m条件下,双向供水的灌水和施肥一致性较单向供水提高3%～4%。建议在规模化滴灌系统中采用双向供水方式,以达到增加毛管允许铺设长度、提高灌水和施肥均匀性和一致性的目的。

Effect of lateral layout on fertigation uniformity in drip irrigation system

The lateral layout and management parameters are important factors affecting the irrigation and fertilization uniformity of drip irrigation systems. Field expereiments were conducted to evaluate the effects of lateral layout, lateral length, and inlet pressure on the pressure and emitter discharge distribution along the lateral,uniformity of water application and fertilizer applied,and the consistency of water and fertilizer applied. Two lateral layouts (feeding water from one end of laterals (A1) and from both ends of laterals (A2)), three lateral lengths (70 (L1), 100 (L2), and 130 m (L3)), and five inlet pressures (0.02 (P2), 0.04 (P4), 0.06 (P6), 0.08 (P8) and 0.10 MPa (P10)) were considered in this study. The results demonstrated that the discharge deviations for the A2 treatments were 18%-43% lower than those for the A1 treatments. An appxomiate 60% increase of the allowable maximum lateral length was determined for the system with water fed from both ends of laterals than with water fed from one end of laterals while the allowable discharge diviation was set as 20%. The ANOVA results indicated that the lateral layout,lateral length, and inlet pressure imposed significant effect on the water application uniformity and fertigation uniformity at a significance level of p<0.01. Great improve of water application uniformity and fertigation uniformity were observed for the treatments with water fed from both ends of laterals. The indexes of the consistency of water and fertilizer applied for the A2 treatments were 3%~4% higher than those for the A1 treatments with lateral length of 100 m or 130 m. Feeding water from both ends of laterals is recomonded to improve the maximum lateral length,water application uniformity and fertigation uniformity,and the consistency of water and fertilizer applied.