地表连年覆盖雷竹林叶片养分利用特征

Nutrient use characteristics of Phyllostachys praecox leaves as affected by continuous year soil-surface mulching

对连续覆盖雷竹林换叶期林地土壤和叶片养分利用效率、养分再吸收效率进行了研究,旨在阐明地表连年覆盖栽培对雷竹林养分利用特征的影响。结果表明:连续覆盖3年雷竹林土壤N养分有效性、N素利用效率以及再吸收效率均显著性提高,雷竹林表现出较高的保存N养分的能力;土壤P元素有效性水平显著升高,而叶片P养分的利用效率显著降低,反映出叶片对土壤高P含量的适应策略,N、P养分利用效率之间存在显著的负相关关系(P<0.05);土壤K元素的有效性水平显著降低,竹林通过提高自身的K再吸收效率来维持养分的正常循环,再吸收效率高达95.8%;不同覆盖年限雷竹林Nm/Pm均<14,连续覆盖3年雷竹林Nm/Pm比值极显著下降,经推断是此时雷竹林对土壤有效P高吸收的结果。成熟叶片的Nm/Pm与N、P的再吸收效率均无显著相关性,Nm/Pm并不能很好地反映叶片在凋落前的养分再分配格局。

To reveal the effects of continuous year soilsurface mulching on the nutrient use characteristics of Phyllostachys praecox leaves, this paper studied the leaf nutrient use efficiency and resorption efficiency in a P. praecox forest during refoliation across three years soil-surface mulching. With the mulching, both the soil nitrogen （N） availability and the P. praecox leaf N use efficiency and N resorption efficiency had a significant increase, showing a higher N-nutrientconserving ability of the forest. The soil phosphorus （P） availability increased significantly but the leaf P use efficiency was in adverse, reflecting the leaf adaptation strategy to high soil P content. There was a significant negative correlation between leaf N and P use efficiency. Opposite to soil N and P, soil potassium （K） had a significantly decreased availability. The leaf K resorption efficiency increased up to 95.8%, suggesting that the forest could maintain normal nutrient circulation through enhancing its leaf K resorption efficiency. The leaf Nm/Pm across the three years soil-surface mulching had a significant decrease, being less than 14, indicating the high capability of P. praecox leaves to absorb soil P within the three years soil-surface mulching. The matured leavesNm/Pm had no significant correlations with leaf N and P resorption efficiency, and thus, leaf Nm/Pm could not best reflect the nutrient resorption pattern of the P. praecox forest.