冰雪灾害对粤北杉木林凋落物储量及养分动态的影响

为明确冰雪灾害对粤北杉木林凋落物层储量及其养分动态的影响，2008—2011年于冰雪灾害后的杉木人工林内建立样方，测定样方内N、P、K养分的变化情况。结果表明：冰雪灾害后1~4a衫木林凋落物层的储量分别为1597、996、1120和1243t/hm2，表现为先降后升，凋落物层N含量呈现波动上升趋势，P含量为升—降—升，K含量急剧下降后又波动；冰雪灾害后1~4a的凋落物层N累积量分别为10780、9138、9967和13684kg/hm2，P累积量分别为783、605、621和774kg/hm2，均为先降后升，K储量分别为6995、906、1481和1423kg/hm2，呈现为显著下降后波动；凋落物层的养分含量和累积量为N＞K＞P。冰雪灾害后1 a输入了大量的林冠残体到杉木林地，增加了土壤肥力，加快了养分循环速度。

Effect of Ice Storm Damage on Mass Accumulation and Nutrient Dynamics of Litter Layer in a Cunninghamia lanceolata Stand in the Northern Guangdong

In order to research the effect of snow and ice disaster on the litter layer storage and nutrient of a Cunninghamia lanceolata stand in the north of Guangdong province in 2008-2011 year, some quadrates of Cunninghamia lanceolata stand were established after snow storm disturbance, and then was measured the variation of N, P and K. The results showed that the mass of litter layer was 1597t/hm2, 996t/hm2, 1120t/hm2 and 1243t/hm2, respectively in four years, with a trend of decrease followed by an increase. N contents appeared rising trend in four years,P contents increased firstly and then decreased followed by an increase. In contrast, K contents sharply decreased followed by a fluctuation in four years. N accumulation was 10780kg/hm2, 9138kg/hm2, 9967kg/hm2 and 13684kg/hm2 in four years, respectively. P accumulation was 783kg/hm2, 605kg/hm2, 62kg/hm2 and 774kg/hm2 in four years, respectively. K accumulation was 6995kg/hm2, 906kg/hm2, and 1481kg/hm2 in four years, respectively. The nutrient content and nutrient amount in litter layer were in the order of N > K > P. After snow storm disturbance, large of crown debris were input in the stand in one year after snow and ice disaster, which improved soil fertility and accelerated nutrient cycling.