干旱生境下3种植物叶凋落物分解动态特征

以塔里木盆地胡杨、多枝柽柳、胀果甘草为研究对象,应用凋落袋法,研究叶凋落物分解动态,揭示3种植物叶凋落物在干旱生境下分解动态特征,结果表明:①经过810d分解,胡杨、胀果甘草叶凋落物质量残留率分别为48.93%、38.07%,经630d分解多枝柽柳叶凋落物质量残留率为69.55%,分解时间对胡杨、胀果干草、多枝柽柳叶凋落物残留率均有极显著影响,处理(林窗、林下)对胡杨、胀果干草叶凋落物残留率有显著影响、极显著影响。②处理对3种植物叶凋落物分解系数有显著影响(P<0.05),且分解系数(k)表现为k林窗>k林下,k胀果甘草>k胡杨>k多枝柽柳,经810d分解胡杨、胀果甘草叶凋落物t0.95分别为9.159.48a、6.757.03a,经630d分解多枝柽柳叶凋落物t0.95为13.8215.05a。③受植物种类的影响,分解时间、处理对C、N、P元素释放进程影响不同。3种植物C元素都表现出释放-富积-释放的变化过程,多枝柽柳、胀果甘草叶凋落物N元素在观测期内表现出释放-富积的过程,而胡杨林下则表现出富积-释放-富积的规律,观测期内P元素释放过程与N元素表现出相似的变化规律。④叶凋落物分解系数k值与分解时间、残留量、全氮、全磷、木质素、木质素比氮呈极显著相关(P<0.01),土壤湿度、全碳、C/N均与k林窗、k林下存在极显著差异。干旱区微生境(林下、林窗)的变化对叶凋落物分解有显著影响,凋落物质量与土壤湿度对凋落物分解起主导作用。

Dynamic Decomposition of Foliar Litters of Three Plant Species in Arid Habitats

In this study,Populus euphratica,Tamarix ramosissima and Glycyrrhiza inflate in the Tarim Basin were taken as the research objects to analyze the dynamic decomposition of foliar litters of three plant species in arid habitats. The results showed that:① The residual rates of foliar litters of P. euphratica and G. inflata were 48. 93% and38. 07% after a decomposition for 810 days,and the residual rate of foliar litters of T. ramosissima was 69. 55% after a decomposition for 630 days. The decomposition time affected significantly the residual rates of foliar litters of the three plant species. The treatments affected significantly the residual rates of foliar litters of P. euphratica and G.Inflate.② The k values of foliar litters of the three plant species were significantly affected by understory-forest gap treatment (P < 0. 05),and the k values were in an order of kforest gap> kunderstory,kG. inflate> kP. euphratica> kT. ramosissima,the t0. 95 values of P. euphratica and G. inflate were in ranges of 9. 15-9. 48 a and 6. 75-7. 03 a during 810-day decomposition. After a 630-day decomposition,the t0. 95 value of T. ramosissima was in a range of 13. 82-15. 05 a.③ The effects of the decomposition time and treatments on the release process of C,N and P were different because of the difference of plant species. There was a release-accumulation-release process of C content of the three plant species,a process of release-accumulation of N content of T. ramosissima and G. inflata,and also a process of accumulation-release-accumulation of P content of P. euphratica understory during the observation period;④ The k-value was significantly correlated with decomposition time,total nitrogen,the remaining amount of mass,total phosphorus,lignin,ratio of lignin and nitrogen (P < 0. 01),and soil moisture,total carbon,C/N were significantly correlated with kforest gap and kunderstory. Changes of micro-habitats (understory and forest gap) in arid areas have significant influence on litter decomposition,and litter quality and soil moisture play a leading role in litter decomposition.