海伦撂荒地植物生物量的季节变化

对海伦20年和7年撂荒地的地上生物量和地下生物量，以及农田地上生物量和地下生物量的田间定位调查和实验室分析对比研究结果表明，随着农田撂荒时间的延长，植被生物量（根生物量和地上生物量之和）具有明显增加趋势；地上生物量之间的差异不显著，而根生物量的差异达到显著水平，表明不同撂荒年限样地的生物量差异主要体现在根生物量，撂荒时间越长，生态系统抵抗环境胁迫的能力越强，生态系统越稳定，根生物量的周转值越小，表明生态系统具有更加稳定地供应养分和能量的能力。

Seasonal fluctuation of plant biomass in land remained bare in Hailun experimental station

Analysis of the above-and under-ground biomass of the land remained bare for seven years and twenty years and the farmland in Hailun experimental station showed that total biomass increased over the bare period. There was no significant difference in above-ground biomass between bare lands,while the root biomass showed obvious difference,indicating that total biomass was differed mainly from root biomass between bare lands. With longer bare period,the ecosystem had the stronger resistance to environmental stress and the more stability. Meanwhile,its root biomass turnover value was small,which suggesting the higher ability to supply nutrient and energy stably.