降水格局对科尔沁沙地三种草本植物凋落物分解的影响

基于研究区多年降水特征,设置高频低量、中频中量和低频高量3种降水格局,采用凋落物分解袋法,对科尔沁沙地3种常见一年生草本植物一个生长季地上和地下凋落物分解特征进行了研究。结果表明,降水格局和凋落物埋深均是影响分解率的关键因素。其中地表凋落物的分解率显著低于地下凋落物,随埋深增加地下凋落物的分解率有增加的趋势,10~20 cm层狗尾草地下凋落物分解率显著高于0~10 cm层(P<0.01)。低频高量降水状况下地上凋落物的分解率显著降低(P<0.01)。降水格局与凋落物埋深存在显著的耦合关系(F=3.60, P=0.008),随土壤深度增加,降水格局对凋落物分解率的影响减少,且物种间存在差异性,不同降水格局下狗尾草和黄蒿地上凋落物和0~10 cm埋深地下凋落物分解率均存在显著差异性(P<0.05),而尖头叶藜仅地上凋落物在不同降水格局下的分解率表现出显著差异性(F=48.42, P<0.001)。

Effect of precipitation patterns on litter decomposition in three annual herb species in the Horqin Sandy Land

The effect of precipitation patterns on both aboveground and belowground litter decomposition in three annual herb species in the Horqin Sandy Land was investigated by the litter-bag method.Precipitation patterns,which were designed according to historical precipitation characteristics,included high-,medium-,and low-frequency precipitation,hut the total amount was the same in each treatment.The results showed that precipitation patterns and depth of litter burial were the two main factors affecting the litter decomposition rate.The aboveground litter decomposition rate was significantly slower than the belowground litter decomposition rate.The belowground litter decomposition rate was faster at deeper depths than at shallower depths,especially for Setaria viridis.The decomposition rate of S.viridis litter belowground was significantly (P＜ 0.01) faster at the 10-20 cm depth than at the 0-10 cm depth.The aboveground litter decomposition rate was significantly (P＜0.01) slower under the low-frequency precipitation pattern than under the other precipitation patterns.There was a significant interaction between precipitation pattern and litter burial depth for litter decomposition.The influence of precipitation pattern on litter decomposition decreased with increasing depth.The litter decomposition rate differed among the three plant species.The belowground litter decomposition rate for both S.viridis and Artemisia sacrorum significantly differed among precipitation patterns at the 0 -10 cm burial depth,while the aboveground litter decomposition rate differed significantly (F=48.42,P＜ 0.001) among precipitation patterns only for Chenopodium acuminatum.