基于构件特征的内蒙古典型草原植物羊草个体地上生物量估算

摘要

Biomass is an important component of grassland ecosystem productivity.Models able to describe the productivity of the main plant species in grassland offer the potential to estimate aboveground biomass without physical cutting.In this research the relationships among plant characteristics (leaf number,leaf length×leaf width,stem diameter,stem height and plant height)and individual above-ground biomass was analyzed,sub-sequently those characteristics able to best predict changes of individual above-ground biomass were selected for modelling.Ninety Leymus chinensis plants were sampled in June (early growing season),July (middle grow-ing season)and August (late growing season),respectively,and total of 270 observations were used to build models able to estimate individual plant above-ground biomass.Equations were obtained using regression anal- ysis using Minitab 16.0,and T-Test analysis was used to compare observed and predicted values.The results showed that leaf length × leaf width and plant height could describe individual above-ground biomass of L. chinensis plants;model Y =-0.193 +0.009X 2 +0.011X 5 (X 2 indicated leaf length×leaf width,X 5 indicated plant height,P <0.01,R 2 =0.854).%生物量是评价草原生态系统生产力的重要指标，草原主要植物个体地上生物量估算模型的建立，可为采用非刈割方法获取较准确的草原地面数据资料提供新方法。通过分析内蒙古典型草原植物羊草的主要构件特征（叶片数、叶长宽积、茎粗、茎高和株高）与其个体地上生物量之间的关系，比较并筛选出能较好预测羊草个体生物量变化的构件指标，采用 Minitab 软件的回归分析方法，分别利用6月、7月和8月采集的90株和总体270株羊草植物样本，建立羊草不同生长阶段（生长初期、生长旺盛期和生长末期）以及总体样本的个体地上生物量估算方程，并对实测值与模拟值进行 t 检验分析。结果表明，叶长宽积和株高相对于其他构件信息能够更好地描述羊草个体地上生物量，方程Y ＝－0．193＋0．009X 2＋0．011X 5（X 2为叶长宽积，X 5为株高，P ＜0．01，R 2＝0．854）为最优羊草个体生物量估算模型。