紫花苜蓿中心支轴式喷灌灌水均匀性试验研究

摘要

为提高紫花苜蓿中心支轴式喷灌灌水均匀性及定量分析其主要影响因子,在鄂尔多斯市鄂托克前旗昂素镇示范区进行了紫花苜蓿中心支轴式喷灌灌水均匀性试验,采用基于标准差的Wilcox-Swailes均匀系数法计算了不同风速条件下的喷灌灌水均匀系数,并定量化研究了喷灌对漂移损失、冠层截留损失、漂移和冠层截留总损失以及土壤含水率的影响.结果表明:风速对喷灌灌水均匀系数影响显著,平均风速为2.57 m·s-1和1.53 m·s-1时均匀系数分别达到0.88和0.92,说明喷灌均匀性良好,平均风速为3.34 m·s-1时均匀系数为0.72,喷灌均匀性较差;研究区喷灌灌水定额40mm时最大土壤入渗深度为80 cml,灌水后0～40 cm土层土壤含水率的提高非常显著,新增灌水量在该土层的分配占85.0％～95.0％;风速对喷灌漂移损失影响显著,随着风速的增大漂移损失率明显提高;风速对冠层截留损失影响不如对漂移损失的影响显著,较大风速时冠层截留损失率反而较低;即使在风速较低时(1.53 m·s-1)紫花苜蓿分枝期喷灌漂移和冠层截留总损失率也在11.0％ ～ 15.0％,损失较大.%In order to increase the uniformity in center pivot sprinkler irrigation of alfalfa and quantatively analyze the main influence factors,carried out the uniformity experiment of center pivot sprinkler irrigation of alfalfa in demonstration area of Angsu Town of Etuoke Banner of Erdos City.Using standard Wilcox-Swailes coefficient method calculated the uniformity coefficients of sprinkler irrigation under different wind condition,and quantitatively researched the influence of sprinkler irrigation to drift losses,the canopy interception losses,total losses of drift and canopy interception and soil water content.The results showed that:The wind speed will be significant influence to uniformity coefficient of sprinkler irrigation.When the average wind speed was 2.57 m· s-1 and 1.53 m· s-1,the uniformity coefficients of sprinkler irrigation were 0.88 and 0.92 respectively,it explained good unifonnity of sprinkler irrigation.When the average wind speed was 3.34 m· s-1,the uniformity coefficients of sprinkler irrigation was 0.72,the uniformity was poor.When the sprinkler irrigation quota was 40 mm in research area,the maximal soil infiltration depth was 80 cm.AfMter irrigation the soil water content in 0 to 40 cm depth was significantly increased,the water distribution in this soil layer by new added irrigation volume was accounted for 85 ％ to 95 ％.The wind speed will be significantly affectetd the drift losses of sprinkler irrigation.The drift loss rate will be significantly increased with wind speed increasing.The impac of wind speed to canopy interception losses was poor than the drift losses,On the contrary the canopy interception loss rate will be lower when the larger wind speed.Even if when the wind speed was rather lower(1.53 m· s-1),the total losses rate of drift and canopy interception of sprinker irrigation was 11.0％ to 15.0％ in Alfalfa branching stage,the losses was too much.