4种园林绿化植物凋落物混合对其持水特性的影响

Effects of Litter Mixing of Four Common Landscaping Plants on Their Water Holding Properties

适当保留凋落物层有助于改善城市绿地的水文效应,但不同树种凋落物混合对凋落物层的持水特性有何影响尚不清楚。以丁香、垂柳、日本晚樱和五角枫的凋落叶以及上述凋落叶5种形式的混合物为对象,基于室内浸泡试验检测混合形式及其比例对凋落物持水特征参数(含吸水和失水过程)的非加和性影响。结果表明,1)丁香-晚樱凋落叶以7∶3和5∶5(质量比,后同)混合使其最大持水量较预期显著降低,以3∶7混合则使其持水在叶片间隙中的分配比例显著提高;五角枫-垂柳凋落叶混合使其最大持水量(5∶5和4∶6)、间隙分配比例(4∶6)和最大吸水速率(5∶5和3∶7)均较预期显著降低;五角枫-晚樱凋落叶以3∶7混合使其间隙分配比例较预期显著降低;丁香-五角枫凋落叶以4∶6混合使其吸水速率较预期显著提高;而丁香-垂柳凋落叶以7∶3、4∶6或3∶7混合分别使其间隙分配比例和最大吸水速率较预期显著提高(P<0.05)。2)丁香-晚樱凋落叶以7∶3和5∶5、五角枫-垂柳凋落叶以6∶4、3∶7、五角枫-晚樱凋落叶以7∶3、4∶6以及丁香-五角枫凋落叶以4∶6、3∶7混合均使其最大失水率较预期显著降低,而丁香-垂柳凋落叶以除6∶4外的质量比混合则产生相反作用;丁香-晚樱以6∶4和3∶7、丁香-五角枫和丁香-垂柳凋落叶以任一质量比混合均使其最大失水速率较预测显著提高(P<0.05)。

Properly keeping litter layer can significantly improve the hydrological effect of urban green space.However,the effects of litter mixing from different species on their hydrological characteristics remain unclear.In this study,leaf litters from Syringa oblata(So),Salix babylonica(Sb),Prunus serrulata var.lannesiana(Ps)and Acer pictum subsp.mono(Ap),as well as 5 types of mixtures of these litters were selected as the research objects.Based on the indoor soaking method,the non-additive effects of litter mixing on their water absorption or loss related characteristics were detected.The results showed that 1)So and Ps litter mixing with the mass ratios of 7∶3 and 5∶5 significantly reduced their maximum water holding capacity,while the same mixing type with the mass ratio of 3∶7 significantly increased the proportion of water holding capacity in gaps among leaves(WHG)relative to their predicted values;Ap and Sb mixing with mass ratios of 5∶5 and 4∶6 significantly reduced their maximum water holding capacity,while the same mixing type with mass ratios 4∶6 and,5∶5 and 3∶7 also decreased their WHG and maximum water absorption rate;Ap and Ps litter mixing with a mass ratio of 3∶7 significantly decreased their WHG,while So and Ap litter mixing with a mass ratio of 3∶7 significantly increased their maximum water absorption rate;So and Sb litter mixing with mass ratios of 7∶3 and 4∶6,and 3∶7 significantly increased their WGH and maximum water absorption rate(P<0.05).2)So and Ps litter mixing with mass ratios of 7∶3 and 5∶5,Ap and Sb litter mixing with mass ratios of 6∶4-3∶7,Ap and Ps litter mixing with mass ratios of 7∶3-4∶6,and So and Ap litter mixing with mass ratios of 4∶6-3∶7 significantly decreased their maximum water loss rate;while the mixing of So and Sb litter with all mass ratios except for the ratio of 6∶4 caused opposite effects;So and Ps litter mixing with mass ratios of 6∶4 and 3∶7,So and Ap or So and Sb litter mixing with any mass ratio significantly increased their maximum water loss rate(P<0.05).