太湖湖滨带林草复合带草本植物枯落物量的变化特征

Variation of Herbage Litter Production in Forest-Grass Composite Strips in Lakeside Zone of Taihu Lake

为减少湖滨带林带枯落物的产生,有效降低N、P随降水径流进入湖泊水体的风险,采用人工草坪替代林下杂草的方式,建立林草复合带.以5种草坪草为研究对象,设立3种种植密度,采用定位定期采集的方法,研究草坪建植后草本植物枯落物的变化以及不同种植密度对枯落物量的影响.结果表明:①间距15 cm高密度种植易导致草坪枯落物的产生,以白三叶和红花酢浆草较突出;草坪种植后林下草本植物枯落物量大幅度减少,平均枯落物量减少66%～95%.②草坪枯落物量随生长时间变化无明显规律,7—11月植物生长期间,白三叶草坪10月枯落物量最高;麦冬草坪、红花酢浆草草坪以及与其混种的其他草坪枯落物量最高时期均出现于8月.③白三叶高、低密度种植单种草坪产生的枯落物量大于与红花酢浆草混种草坪,而中密度种植则相反,单种草坪小于混种草坪.

In order to reduce litter production in forest belts in lakeside zones and efficiently decrease risks of N and P flowing into lake water with rainfall runoff,forest-grass composite strips were established by substituting undergrowth weeds with artificial lawns.Five kinds of lawns with three density levels were designed to investigate the variation of herb litter production by positioning and regular sampling methods.The result showed： 1） Litter production in the high density planting case（15 cm separation distance） was the highest,especially for Trifolium repens and Oxalis corymbosa,and the establishment of lawns resulted in a large decrease of herbage litter production（66%-95%）.2） Lawn litter production does not change regularly with growth period.During the growth period from July to November,the greatest litter production of Trifolium repens occurred in October,while those of Ophiopogon japonicus var.nana,Oxalis corymbosa and their mixture lawns occurred in August.3） In both high and low density lawns,litter production produced by Oxalis corymbosa monoculture was greater than that by the mixture of Oxalis corymbosa and Trifolium repens.However,in the medium density planting case,litter production by monoculture was less than that by the mixtures.