不同地下水埋深时甜椒需水量及作物系数试验研究

采用排水式蒸渗仪试验,研究了不同地下水埋深时,甜椒需水量和地下水利用量的变化规律及与外界环境因子的关系。分析和模拟了甜椒作物系数,并与FAO-56推荐作物系数值进行了比较。结果表明,地下水埋深为0.6~0.9m时,地下水与降雨利用量占需水量的40%~50%,灌溉量较低。地下水埋深较浅时,需水量与地下水利用量与蒸发量、气温和地温具有显著的线性关系。地下水埋深较深时,需水量主要受降雨的影响,与环境因子的相关性较小;地下水利用量与蒸发量、气温、地温及饱和水气压差仍具有显著的线性关系。甜椒全生育期作物系数为1.35,与移栽后旬数、地温和需水系数分别表现出3次、2次和3次多项式的关系。生长中期和后期,作物系数分别为1.25和1.25~1.1,高于FAO-56推荐值。研究结果为蔬菜类作物节水灌溉制度的制定和高效灌溉管理提供参考。

Evapotranspiration and Crop Coefficient of Sweet Peppers under Different Groundwater Table

Water requirement of sweet peppers and the relation between it and environmental factors were investigated under different groundwater table by using drainable lysimeter.Crop coefficients were analyzed later and compared with values recommended by FAO56.Results show that: groundwater and rainfall contributed was 40%~50% of water requirement respectively and irrigation was small when groundwater depth was 0.6~0.9 m.Linear relation was found between water requirement and evaporation,air temperature and soil surface temperature with shallow groundwater table.On the contrary,rainfall rather than other environmental factors had main effect on the water requirement.Linear relationship was always existed between groundwater contribution and evaporation,air temperature,soil surface temperature and saturated vapor pressure deficit at any groundwater depth.Crop coefficient estimated was(1.35) for the whole grown season.Cubic,quadratic,and cubic polynomial was observed respectively between crop coefficients and ten days after planting,soil surface temperature and water requirement coefficient(the ratio of water requirement and evaporation).Averaged crop coefficients were 1.25 and 1.25~(1.1) for the mid-season and end of the late-season,which were higher than that suggested by FAO56.Results obtained from the paper would be helpful to the study of water-saving irrigation design and effective irrigation management of vegetable.