兰州地区草地早熟禾水分最优调亏灌溉模式

草地早熟禾(Poa pratensis)在北方城市园林绿化中应用广泛,干旱是限制其生长的主要因子,但冷季型草坪草在经受适度干旱胁迫再复水后普遍存在着补偿或激发效应。因此,研究草地早熟禾在兰州地区的调亏灌溉方法意义重大。本研究以兰州地区绿化常用的冷季型草坪草草地早熟禾为研究对象,使其在春、夏、秋三季的灌水量从对照下降到各处理的灌溉下限后复水至对照,每个季节至少经历3次"干旱胁迫-复水"的循环过程。通过田间试验测定不同程度干旱胁迫以及复水处理条件(对照灌溉下限:70%~80%FWC,处理Ⅰ:65%~56%FWC,处理Ⅱ:55%~46%FWC,处理Ⅱ:45%~36%FWC,处理Ⅳ:35%~26%FWC,处理Ⅴ:25%~16%FWC,FWC为田间持水量)下其在各生长季节的蒸散量、草坪质量、生理指标,分析草地早熟禾在该地区的耗水规律,以确定不同季节最适宜的灌水量,从而为节水灌溉提供理论支持。结果表明,春秋季,处理Ⅰ对草地早熟禾的各指标无影响,处理Ⅱ和处理Ⅲ使其各指标产生显著变化,而处理Ⅳ和处理Ⅴ使其各指标的变化程度进一步增大;夏季,处理Ⅱ对草地早熟禾产生显著影响,但复水后各指标可完全恢复,而其它处理使其各指标变化程度更大,复水后很难完全恢复。因此,兰州地区适合于草地早熟禾的最低灌溉下限:春季和秋季为40%FWC,夏季为50%FWC。

Optimized regulated deficit irrigation of Kentucky bluegrass in Lanzhou

Kentucky bluegrass (Poa pratensis) is widely used as the turfgrass for city landscaping in the north of China,and drought is the main factor limiting the growth of turfgrass.Typically,plants exhibit a compensation or growth stimulating effect after drought and re-watering.Therefore,study on regulated deficit irrigation methods of Kentucky bluegrass in Lanzhou is very important.In this study,we conducted repetitive treatments of ‘drought-rewatering-drought-rewatering’ during the growth season of Kentucky bluegrass,which is widely planted in Lanzhou.We analysed the evapotranspiration,turf quality,physiological index,and water consumption pattern of the turfgass during different seasons to determine the optimum irrigation.The following treatments were performed:control,70％-80％ field water holding capacity (FWC);treatment Ⅰ,65％～56％ FWC;treatment Ⅱ,55％％～46％ FWC;treatment Ⅲ,45～36％ FWC;treatment Ⅳ,35～26％ FWC;treatment Ⅴ,25％～16％ FWC.The results showed that during spring and autumn,the treatment Ⅰ had no significant effect on the analysed indexes of Kentucky bluegrass,whereas the treatments Ⅱ and Ⅲ significantly changed all indexes,and the treatments Ⅳ and Ⅴ resulted in increases of all indexes.The treatment Ⅱ had significant effects on the analysed indexes of Kentucky bluegrass during summer,but complete recovery was noted after rewatering,while in the other treatments,the indexes were more greatly altered and complete recovery was difficult even after rewatering.Therefore,the minimum irrigation limit for Kentucky bluegrass grown in Lanzhou is 40％ FWC in spring and autumn and 50％ FWC in summer.