7种木兰科观赏植物枯落物层及土壤层水文效应

Hydrological effects of litters and soil of seven Magnoliaceae ornamental plants

为了研究木兰科观赏植物枯落物层和土壤层水文效应和在园林应用中更加合理配置木兰科植物,以7种常见木兰科植物(石碌含笑、紫花含笑、金叶含笑、深山含笑、观光木、华盖木和亮叶木莲)为研究对象,采用室内浸泡法、环刀法对不同木兰科植物枯落物层和土壤层水文功能进行定量研究。结果表明:1)7种植物枯落物蓄积量为5.24~25.11 t/hm^(2),表现为石碌含笑>紫花含笑>金叶含笑>华盖木>深山含笑>观光木>亮叶木莲,亮叶木莲枯枝落叶分解程度高;2)枯落物层最大持水量变化范围为14.32~25.45 t/hm^(2);有效拦蓄量为15.88~53.85 t/hm^(2),表现为石碌含笑>紫花含笑>金叶含笑>华盖木>观光木>亮叶木莲>深山含笑,石碌含笑和紫花含笑枯落物层持水功能较好;3)枯落物半分解层、未分解层持水量分别在浸水8和10 h基本达到饱和,枯落物在浸水2 h内吸水速率变化最大,持水量与浸水时间呈对数关系(R^(2)>0.92),吸水速率与浸水时间呈幂函数关系(R^(2)>0.94);4)不同植物土壤密度均值变化范围为1.22~1.55 g/cm^(3),总孔隙度变化范围为40.03%~49.89%;土壤饱和持水量变化范围为400.34~498.95 t/hm^(2),有效持水量变化范围为26.23~70.33 t/hm^(2),土壤层持水功能表现为金叶含笑>紫花含笑>亮叶木莲>石碌含笑>观光木>华盖木>深山含笑。土壤入渗速率和入渗时间呈幂函数关系(R^(2)>0.90)。土壤层水源涵养能力高于枯落物层,是林地水文效应的主体。石碌含笑、紫花含笑和金叶含笑具有较强水源涵养功能,建议在园林景观应用中优先配置石碌含笑、紫花含笑、金叶含笑等植物。

[Background]Magnoliaceae plants resources is rich in China,which have widely been used in making landscape to demonstrate gardens and cultural connotation by making full use of its aesthetic functions such as posture,culture and good views,and which was introduced in Hainan Tianxiang Magnolia Plant Conservation Research Center in Danzhou county of Hainan province,but lack of understanding the ecological service functions such as soil and water conservation of Magnoliaceae plants in this region.It is of great significance for rational introduction based on the water-holding capacity of each Magnoliaceae plants to render the Magnoliaceae plants configuration more reasonable in garden application.[Methods]Seven common Magnoliaceae plants(Michelia shiluensis,Michelia crassipes,Michelia foveolata,Michelia maudiae,Michelia odora,Manglietiastrum sinicum,Manglietia lucida)in Hainan were selected as the research objects,and the water-holding function of litter layer and soil layer of different Magnoliaceae plants were determined by quantitatively research with immersion method and cutting-ring method.[Results]1)The litter volume of the seven plants was about 5.24-25.11 t/hm^(2),which followed the order of M.shiluensis>M.crassipes>M.foveolata>M.sinicum>M.maudiae>M.odora>M.lucida.The decomposition degree of dead branches and leaves of Manglietia lucida was high.2)The maximum water-holding capacity of litter layer varied from 14.32 to 25.45 t/hm^(2).The modified interception amount was 15.88-53.85 t/hm^(2),which followed the order of M.shiluensis>M.crassipes>M.foveolata>M.sinicum>M.odora>M.lucida>M.maudiae.The water-holding function of M.shiluensis and M.crassipes litter layer was good.3)Semi-decomposed litter could be saturated in 8 h and undecomposed litter reached saturation in 10 h,the water-holding capacity had logarithmic relationship with soaking time(R^(2)>0.92);the absorption rate changed the most within the first 2 h of soaking and there was a power function relationship between water absorption rate and soaking time(R^(2)>0.94).4)The mean soil bulk density of different plants varied from 1.22 g/cm^(3)to 1.55 g/cm^(3),and the total porosity varied from 40.03%to 49.89%.The saturate soil water holding capacity was about 400.34-498.95 t/hm^(2),and the effective soil water-holding capacity was about 26.23-70.33 t/hm^(2).The water-holding capacity of the soil layer was in the order of M.foveolata>M.crassipes>M.lucida>M.shiluensis>M.odora>M.sinicum>M.maudiae.A significant power function relation between infiltration rate and infiltration fitting time was found(R^(2)>0.90).[Conclusions]The water conservation capacity of soil layer is higher than that of litter layer,which is the main part for hydrological effect of forest land.The water conservation capacity of M.shiluensis,M.crassipes and M.foveolata is better than those of other Magnoliaceae plants,which suggested to give priority to the mixed planting of M.shiluensis,M.crassipes and M.foveolata in the application of landscape.