不同灌溉方式下无花果需水规律及作物需水量预报

The Pattern and Forecasting of Water Requirement for Fig Trees Under Different Irrigation Methods

探究不同灌溉方式下无花果需水规律及作物需水量的预报对无花果生产具有重要的研究和指导意义。根据广东省水利重点科研基地2022年5月至2023年12月的无花果种植数据,分析不同灌水方式下无花果需水规律,推求作物系数曲线,结合Hargreaves-Samani模型和单作物系数法,基于公共天气预报进行无花果需水量预报。结果表明:不同灌水方式中沟灌的需水量最大,2023年日均需水量为2.44mm/d,其次是喷灌和地面滴灌,日均需水量分别为2.23mm/d和2.04mm/d,地下滴灌需水量最小,为1.92mm/d,5-9月为无花果需水旺盛期。采用联合国粮农组织(FAO)推荐的单作物系数法推求出试验站无花果Kc作物系数曲线,作物系数地下滴灌<地面滴灌<喷灌<沟灌。气温预报精度较高,最低气温的预报精度优于最高气温的预报精度。经过率定的Hargreaves-Samani模型具有良好的ET0预报精度,相关系数平均值可达0.86。4种灌溉方式无花果作物需水量预报精度低于ET0预报,相关系数范围为0.68~0.74。无花果作物需水量预报模型可以提供未来两周内的无花果需水量,为灌溉决策者提供信息,有利于农民提前安排水资源的分配。

The investigation of water requirement patterns for fig trees(Ficus carica L.)under different irrigation methods and the accurate prediction of crop water demands is of paramount importance in fig trees cultivation,the water requirement(ETc)patterns of fig trees under different irrigation methods were analyzed and the crop coefficient(Kc)empirical values were estimated based on the experimental data from 2022 to 2023 in Qingyuan,Guangdong.Using the Hargreaves–Samani model and single crop coefficient method,the water requirement of fig trees was forecasted based on public weather forecasts with a 14 day lead time.The results showed that furrow irrigation had the highest ETcamong the different irrigation methods,with an average daily ETc of 2.44 mm/d in 2023,followed by sprinkler and surface drip irrigation,with an average daily ETc of 2.23 mm/d and 2.04 mm/d,respectively,and subsurface drip irrigation,with the smallest ETc of 1.92 mm/d.May to September is the peak period of water demand for fig trees.The single crop coefficient method recommended by the Food and Agriculture Organization of the United Nations(FAO)was used to derive the Kc empirical values,and the Kc of subsurface drip irrigation<surface drip irrigation<sprinkler irrigation<furrow irrigation.The temperature forecasting accuracy is high,and the forecasting accuracy of the minimum temperature is better than that of the maximum temperature.The calibrated HS model has good ET0 forecast accuracy,with an average correlation coefficient of up to 0.86.The accuracy of the fig ETc forecasts was lower than that of ET0 forecasts,and the correlation coefficients ranged from 0.68 to 0.74.The forecasting model of fig ETc can provide forecasts of fig water demand for the next two weeks,which can provide information for farmers to make accurate irrigation decisions.