不同育苗基质对圃地崖柏出苗率和苗木生长的影响

Effects of Different Nursery Substrates on Germination Rate and Seedling Growth of Thuja sutchuenensis

【目的】研究不同育苗基质对崖柏出苗率和幼苗生长的影响并探讨其影响机制,为崖柏种子繁殖和优质壮苗培育基质的选择提供参考。【方法】在重庆市雪宝山国家级自然保护区崖柏繁育圃,以森林腐殖土、耕作土、草炭土、珍珠岩和蛭石为基质原料,按体积比配制成3种育苗基质分别为耕作土∶森林腐殖土(1∶1)(FS)、草炭土(GS)和草炭土∶珍珠岩∶蛭石(1∶1∶1)(GPS),采用种子催芽后条播方式,按照随机区组3次重复试验设计方法,布置育苗基质对崖柏种子育苗影响的田间试验。【结果】GPS和GS比FS育苗基质的温度调节能力强,GPS能够在温度较低的月份将基质温度调节到较高水平,GS能够在温度较高的月份将基质温度调节到较低水平;不同育苗基质土壤密度表现为FS>GS>GPS;土壤持水量(包括最大持水量、毛管持水量、田间持水量)与土壤密度的排序相反;不同基质的p H值差异显著,FS偏碱性,GS和GPS呈弱酸性;3种育苗基质都可满足崖柏幼苗对土壤肥力的基本需求,但含有草炭土的GPS和草炭土GS的土壤肥力较高;不同育苗基质的出苗率表现为GS>GPS>FS,GS和GPS的差异不显著;FS的出苗率仅为GS的23%,GPS的27%;在崖柏幼苗生长期间,对3次调查的平均苗高、地径、一级侧枝数、主根长、一级侧根数、平均单株地上和地下干质量这7个形态质量指标的隶属函数值计算及综合评判的结果表明,GPS育苗基质的苗木形态质量最优,其次是GS,FS最差。【结论】GS的质地疏松、保水性能和透气性能良好,是崖柏出苗率较高的重要原因;不同基质水、肥、气、热等因素上的差异,以及各因素的协调能力是导致崖柏幼苗形态质量出现基质差别的重要原因。

[Objective] The effects of different substrates on Thuja sutchuenensis seedling growth and its influence mechanism were investigated to provide a reference for matrix selection of seed breeding and high quality seedling cultivation. [Method]The seed breeding test was carried out in breeding nursery,located in Xuebaoshan National Nature Reserve and completely randomized in design and repeated for three times. Seeds were first presoaked to enhance germination rate and then cultured on three different substrates： FS （Forest humus∶cultivated soil=1∶1）,GS （peat） and GPS （ peat∶ vermiculite∶ pearlite =1∶1∶1 ） in line.[Result]Results indicated that： 1 ） Compared with substrate FS, substrates containing peat （ GS and GPS） were better at regulating soil temperature. More specially,substrate GPS could increase the soil temperature and play a temperature-keeping role during September to next March when the temperature is lower. While substrate GS could lower substrate temperature at a certain level during April to August when the atmosphere temperature is relatively higher. 2） Substrate FS had the highest soil bulk density,then GS,and then GPS. However,the soil water-holding capacity （ the soil maximum moisture capacity,the soil capillary moisture capacity and the soil non-capillary moisture capacity） was opposite （GPS 〉GS 〉FS）. 3） The pH of three substrates were significantly different. The pH of substrate FS was weak alkaline （ 7. 48 ） ,while substrate GS and GPS with weak acid （ pH5. 07 and 5. 86 , respectively）. 4） Although soil fertility of three substrates could meet the basic need of seedling growth,substrates （GS and GPS） had a higher soil fertility than substrate FS. Field garden emergence rate and the seedling quality accorded with the soil physical and chemical properties of different substrates. In field garden emergence rate,substrate GS was the highest,and then GPS and FS. The proportion of FS for GS and GPS was only 23% and 27%,respectively. The difference of field garden emergence rate between GS and GPS was not significant. 5 ） The survey of seven seedling morphological indices （ such as the seedling height,the ground diameter,the branch number,the length of principal root, the number of lateral root,theabove-ground and below-ground dry mass） investigation in three different stages and analysis of membership function value revealed that： substrate GPS had the best seedling quality, and then substrate GS.[Conclusion]The main reason for higher field garden emergence rate of substrates GS and GPS was their more loose soil texture,better water retention property and permeability than substrate FS. The mechanism of better quality seedlings for GS and GPS was their perfect coordination between water,fertilizer,gas and heat.