不同表土覆盖方式对种子库活力的影响

Effects of different topsoil covering modes on seed bank vitality

【目的】研究表土堆存中不同覆盖方式对种子库活力特征的影响,为荒漠地区煤矿损毁土地植被重建提供技术依据。【方法】本研究采用实地表土堆存和种子库萌发试验相结合的方法,采用密目网覆盖和彩条布覆盖这2种工程上常用的表土覆盖方式,分析不同表土覆盖方式下的土壤温度、种子含水量、埋深对种子活力的影响,并监测种子库损耗情况。【结果】柠条锦鸡儿、沙蒿、羊柴、花棒4种植物种子在堆存4个月后活力均有所下降,彩条布覆盖方式下活力下降速度更快,柠条锦鸡儿、沙蒿种子在密目网覆盖下活力显著高于彩条布,羊柴、花棒种子在两种覆盖方式下无明显差异;温度、种子含水量及埋深是影响种子活力下降的重要因素,埋深对种子萌发率的影响体现在表层种子萌发率最高,最深层次之,中间层萌发率最低;堆存表土初始土壤种子库多为一年生植物,种子库密度为335粒/m^(2),表土堆存4个月后土壤种子库密度显著下降,密目网覆盖方式下种子库密度为192粒/m^(2),彩条布覆盖方式下种子库密度为249粒/m^(2)。【结论】表土堆存使得种子活力下降,温度、种子含水量及埋深对种子活力下降都有不同程度的影响,表土从冬季堆存到春季期间,彩条布覆盖方式下的土壤种子库较密目网覆盖下损失更低,此期间内可以考虑彩条布作为表土覆盖方式。

[Objective]The aim of this study was to investigate the characteristics of seed bank vitality under different covering modes in topsoil stockpiles,and to provide technical basis for vegetation reconstruction of coal mine damaged land in desert area.[Method]The method of combining field topsoil stacking with seed bank germination test was adopted,and two common topsoil covering modes,dense mesh covering and color strip covering,were used to analyze the effects of soil temperature,seed water content and buried depth on seed vitality under different topsoil covering modes,and monitor the loss of seed bank.[Result]The seed viability of Caragana korshinskii,Artemisia desertorum,Hedysarum mongolicum and Hedysarum scoparium decreased after 4 months of storage,and the seed viability of Caragana korshinskii and Artemisia desertorum under dense mesh net coverage was significantly higher than that under color strip cloth.There was no significant difference between Hedysarum mongolicum and Hedysarum scoparium seeds under the two coverage modes;temperature,seed water content and buried depth were important factors affecting the decline of seed viability.The effect of buried depth on seed germination rate was reflected as the highest germination rate in the surface layer,then the deepest layer and the lowest germination rate in the middle layer;the initial soil seed bank of topsoil was mostly annual plants,and the seed bank density was 335 seed/m^(2).After 4 months of topsoil stacking,the soil seed bank density decreased significantly.The seed bank density under dense mesh coverage was 192 seed/m^(2),and the seed bank density under color strip coverage was 249 seed/m^(2).[Conclusion]The storage of topsoil will reduce the seed vitality.The difference of temperature,seed water content and buried depth will lead to different degrees of seed vitality decline.From the storage of topsoil in winter to spring,the density of soil seed bank under the color strip covering method is lower than that under the dense mesh covering mode.During this period,the color strip covering mode can be considered as the topsoil covering mode.