干旱半干旱区常见冷季型草坪草调亏灌溉适应机理及灌溉阈值的研究

Turfgrass is ground cover plants of garden with planted largest area in city green surface, which is also one of the largest plants of garden with consumption amount per ground area. Saving turf irrigation water has been one of the favor problems by people. regulated deficit irrigation can not only have turf save water resources but also keep turf lasting function and quality, moreover it can reduce mowing times and save energy. Based on our researches conduted, the common cool season turfgrass Kentucky bluegrass, Perennial Ryegrass, Tall fescue, which are widely planted in arid and semi-arid areas, are as subject investigated, and they will undergo "drought-rewatering-drought-rewatering….." recycle treatment in their growth season, through incorporation of field experiment and soil column test, the change trend of turf quality and the growth and physiology are studied in different regulated deficit irrigation and rewatering treatment and in respective season, Recovery ability after drought stress and mechanism of domination recovery speed of cool-season turfgrass will been disclosed, the effect of different regulated deficit irrigation to dynamic changes of soil water content and evaporation content will be analyzed in different seasons, water consumption rule will be confirmed, and then correlation analysis will be made with the change of turfgrass to confirm the correspondence between different turf quality and regulated deficit irrigation threshold. This study will provide new theory evidence and technology support for saving water and maintenance of turf in arid and semi-arid area, moreover, there will be an important significance in reasonable utilization water resources.

草坪草是城市绿地栽植面积最大的园林地被植物，也是绿地单位面积耗水量最大的园林植物之一，节约草坪灌溉用水已成为人们最为关注的问题之一。调亏灌溉不仅能使草坪节约水资源还可保证持久的功能与质量，同时还能减少修剪次数，节约能源。本项目在我们已有研究基础上，以干旱半干旱区应用广泛的冷季型草坪草草地早熟禾、多年生黑麦草和高羊茅为研究对象，使其在各生长季节经历 "干旱胁迫-复水-干旱胁迫-复水…"循环过程，通过田间试验和温室土柱试验相结合，研究各季节不同调亏灌溉及复水处理下草坪草质量、生长生理变化趋势，揭示草坪草经历干旱胁迫后重新恢复能力和控制恢复速度的机理；分析各季节不同调亏灌溉对冷季型草坪土壤水分含量和蒸散量动态变化的影响，确定其耗水规律，并和草坪质量变化做相关性分析，明确各等级草坪质量对应的最佳调亏灌溉阈值。此研究为干旱半干旱区草坪节水养护提供新的理论依据及技术支持，对合理利用水资源具有重要意义。

冷季型草坪草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，如何有效节约草坪灌溉用水已成为人们最为关注的问题之一。调亏灌溉不仅能使草坪节约水资源还可保证持久的功能与质量，同时还能减少修剪次数，节约能源。由于冷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，因此研究冷季型草坪草在干旱半干旱地区的调亏灌溉方法意义重大。本研究以干旱半干旱区城市绿化应用广泛的冷季型草坪草草地早熟禾（Poa pratensis L.）、多年生黑麦草（Lolium perenne L.）、高羊茅（Festuca arundinacea Schreb.）、白三叶为（Trifolium repens L.）为研究对象，使其在春、夏、秋三季经历“干旱胁迫—复水—干旱胁迫—复水……”的循环过程，通过测定不同调亏灌溉及复水处理（对照：70%~80% FWC，处理2灌溉下限：65%~56% FWC，处理3：55%~46% FWC，处理4：45%~36% FWC，处理5：35%~26% FWC，处理6：25%~16% FWC，FWC为田间持水量）下四种草春、夏、秋三季的蒸散量、草坪质量、生理指标，主要探究出以下结论： .（1）在灌水充足的情况下，草坪蒸散量（ET）主要受季节影响。.（2）在春、夏、秋三季，随着灌溉下限的降低四种草坪草的草坪质量（TQ）和地上生物量基本都呈下降趋势；除白三叶外，其余三种草坪草的地下生物量呈先升高后降低的趋势。从整体看夏季的地上生物量大于春秋季，秋季地下生物量最大。.（3）四种草坪草夏季的Chl含量较春季有明显增加，又在秋季下降。.（4）四种草坪草的 RWC 在春季最高，夏季的RWC最低。.（5）春夏秋三季四种草坪草的电导率都随灌溉下限的降低呈上升趋势。. 对不同土壤水分处理对生长和生理指标影响的综合分析结果表明，可以选择处理4作为干旱半干旱地区草坪灌溉的最低标准；处理2作为干旱半干旱地区草坪灌溉的最高标准；在不同季节，适合于各草种的最低灌溉下限分别为：春季和秋季—多年生黑麦草和草地早熟禾40% FWC，高羊茅30% FWC，白三叶50% FWC；夏季—多年生黑麦草和羊茅不变，草地早熟禾50% FWC，白三叶60% FWC。. 此研究成果为干旱半干旱区草坪节水养护提供新的理论依据及技术支持，对合理利用水资源具有重要意义。