陕北矮化栽培山地苹果幼树需水规律预判

Predicting the Water Requirement of Dwarf Planted Apple Sapling in Northern Shaanxi

采用田间试验的方法,通过对陕北地区矮化(自根砧M9-T337)富士一年生长量及其土壤含水量的测定,收集长时间序列气象资料,根据彭曼公式计算得出山地苹果幼树的潜在腾发量ETc与当年降水量进行对比,进而得出试验区第2年生幼树的需水规律。结果表明:在2017年的降水量条件下,试验区内降水量总和大于幼树需水量之和,但是在7月之前存在阶段性缺水问题;进一步分析得出,不管在湿润年、一般年、一般干旱年和特干旱年降水量条件下,由于陕北地区降水的时间分布不均匀性,虽然年内降水量足够满足果树生长所需水量,但在7月之前存在较为严重的水量亏缺,特干旱年甚至在10月之前都存在着水量亏缺,需要在果树萌芽前(3月)、枝条旺长期(4月)、花芽分化期(5,6月)以及开花期(7月)进行人为补充灌溉4～5次,根据前期降水量以及当前土壤含水量来确定灌水定额,灌水量范围选取果园田间持水量的60%～80%为标准。

Using the field test method,through measuring annual growth and soil water content of dwarf Fuji(self-rooted anvil M9-T337)in the field of Northern Shaanxi,long-term sequence meteorological data was collected and the potential evapotranspiration(ETc)of young mountain apple trees was calculated according to the Penman formula,and the result was compared with the annual rainfall of the year,then the water requirement of the second year saplings in the experimental area was obtained.The results showed that under the rainfall conditions in2017,the sum of rainfall in the experimental area was greater than the sum of the water requirement of the saplings,but there was a stage of water shortage before July;further analysis showed that,no matter under the conditions of wet year,general year,general drought year or special drought year,due to the uneven distribution of rainfall time in Northern Shaanxi,although the annual rainfall was enough to meet the water demand for growth of fruit tree,there wasa serious water deficit before July.There even was water deficit before October in the special dry years.Four to five times of supplementary irrigations were needed to carry out before the germination of the fruit trees(March),the long-term growth of the branches(April),the flower bud differentiation period(May and June)and the flowering period(July),and the irrigation quota was determined according to the previous rainfall and the current soil water content.The irrigation amount range was60%~80%of the orchard field water holding capacity.