生物炭对白桦种子出苗率与幼苗生长的影响

Effects of Biochar on Seed Germination and Seedling Growth of Betula platyphylla

林火导致大量炭化植物残体(生物炭)输入到土壤中,改变了土壤理化性质与养分循环,进而影响火后群落更新和演替。白桦作为大兴安岭地区火后演替更新的先锋乔木树种,其群落动态对土壤中生物炭的响应对北方针叶林演替进程具有重要意义。通过设置室内盆栽实验,研究不同类型(落叶松叶炭、落叶松干炭、苔藓炭)生物炭对土壤含水量和pH值以及白桦种子存活、幼苗生长的影响。结果表明,生物炭对白桦种子出苗有抑制作用,其中落叶松叶炭抑制作用最大,苔藓炭抑制作用最小;生物炭对白桦幼苗生长有促进作用,显著地增加了植物高度,其中以苔藓炭作用最为显著。此外,生物炭添加提高了土壤最大持水量,降低了水分散失速度,进而改变了白桦种子出苗率和幼苗高度。

Forest fire cause a large number of biochar input into the soil,change the soil physical and chemical properties and nutrient cycling and then affect postfire regeneration and succession.Betula platyphylla is a pioneer tree species in post fire succession in Daxing′anling Mountains.The succession process and community dynamics of coniferous forest in North China are closely related to soil biochar.In this paper,the effects of different types of biochar(larch leaf biochar,larch trunk biochar and moss biochar)on soil water loss and soil pH,and seed germination and seedling growth of Betula platyphylla were studied by pot experiment.Negative effect of biochar on seed germination was observed,in which larch leaf derived biochar had the greatest negative effect,moss derived biochar had the least negative effect on seed germination(larch leaf derived biochar:0.5%,moss derived biochar:1.17%);Positive effect of biochar on seedling growth was observed.Biochar addition significantly increased seedling height,especially the height of seedlings grow in moss derived biochar amended soil.In addition,biochar increased the soil water holding capacity,reduced the water loss rate,which further influenced the seed germination rate and seedling growth of Betula platyphylla.