矮化密植香梨园灌水均匀度评价与模拟

Evaluation and simulation of irrigation uniformity in dwarf and densely planted fragrant pear orchard

明确不同灌水技术参数对香梨园灌水均匀性的影响可为库尔勒香梨节水技术的使用提供数据参考与技术支撑。以7 a生库尔勒幼龄香梨为研究对象,设置小管出流(一行两管)和地表滴灌(一行三管、一行四管)处理,测定0~100 cm土层土壤含水率,设定27种灌水技术参数组合(灌水量Q1、Q2、Q3;滴灌管布置方式D1、D2、D3;滴灌管间距S1、S2、S3)并用HYDRUS-2D模拟灌水后24 h时土壤水分变化,通过计算灌水均匀度优选滴灌技术参数组合。结果表明:灌溉结束后24 h内,土壤含水率随土层深度增加而逐渐升高;通过对比土壤含水率的实测值与模拟值,HYDRUS-2D模型模拟的RMSE值均大于0.01 cm^(3)·cm^(-3)、NRMSE值均低于20.5%、MAE值均不大于0.02 cm^(3)·cm^(3)、NSE值均高于0.65,模拟精度较高;HYDRUS-2D模型模拟上述情景结果显示:土壤含水率与灌水量和滴灌管数量呈正相关关系、与滴灌管间距呈负相关关系,在滴灌管下方位置处不同深度的土壤含水率随时间的增加呈先增加后降低趋势;当滴灌管布置方式与间距一定时,灌水量与土壤水分分布均匀度变化率呈负相关关系。综上,一行三管+布置间距30 cm组合与一行四管+布置间距40 cm组合的6种处理(Q1D2S1、Q2D2S1、Q3D2S1、Q1D3S2、Q2D3S2、Q3D3S2)下,香梨根系集中区域内的含水率较高且水分分布均匀,可为库尔勒香梨滴灌技术应用提供参考依据。

The aim of this study was to clarify the impact of various irrigation technical parameters on the uniformity of irrigation in fragrant pear orchards,providing data references and technical support for the implementation of water-saving technology in Korla balsam pear cultivation.Taking 7-year old Korla young fragrant pear as the research object,set small tube outflow(one row of two tubes)and surface drip irrigation(one row of three tubes and four tubes)to determine the soil moisture content of 0~100 cm.Setting 27 irrigation technical parameters(irrigation amount Q1,Q2,Q3;drip irrigation pipe arrangement D1,D2,D3,drip irrigation pipe spacing S1,S2,S3)combination and using the HYDRUS-2D to simulate the changes in soil moisture within 24 h after irrigation.Optimizing the change of soil moisture technical parameters was achieved by calculating the uniformity of irrigation.The results showed that within 24 h after the completion of the irrigation,soil moisture content gradually increased with the increase of soil layer depth.By comparing the measured and simulated values of soil moisture content,all the RMSE values simulated by the HYDRUS-2D model were greater than 0.01 cm^(3)·cm^(-3).The NRMSE values were all lower than 20.5%.The MAE values were not greater than 0.02 cm^(3)·cm^(-3).The NSE values were all higher than 0.65,reaching high simulation accuracy.The results of the above scenario of HYDRUS-2D model showed that the soil moisture content was positively correlated with the amount of irrigation and the number of drip irrigation pipes and a negative correlation with drip irrigation tube spacing.The moisture content of the soil at different depths below the drip irrigation pipe showed a trend of increasing first and then decreasing along with the increasing time.When the drip irrigation pipe was arranged and separated from a certain distance,irrigation amount was negatively correlated with the rate of uniformity of soil moisture distribution.In summary,six treatments(Q1D2S1,Q2D2S1,Q3D2S1,Q1D3S2,Q2D3S2,Q3D3S2)involving one row of three tubes with 30 cm spacing and one row of four tubes with 40 cm spacing resulted in a higher and more uniform concentration area of the balsam pear root system within the moisture distribution.This can provide an important reference for the application of drip irrigation technology to Korla balsam pear.