陕北黄土丘陵山地枣树生物量模型

目的]探索一种在不损伤枣树条件下估算枣树生物量的方法,为研究灌溉施肥与枣树生长关系提供技术支撑。方法]在大量实际测定调查数据的基础上,用线性和非线性生物量模型分别对枣树枝条、枣吊、叶片及果实的生物量进行建模,以相关系数R2,拟合指数W,标准误SEE,变异系数CV和预估精度p作为模型的精度评价指标,对模型进行了检验,并对两类模型进行了对比分析。结果]线性模型适用于枝条生物量的预测,R2为0.980~0.984,p介于0.909~0.926;叶片生物量和枣吊生物量的最优模型为非线性模型,R2介于0.880~0.943,p介于0.897~0.976;果实生物量最优模型为二元非线性模型,R2为0.999,p为0.998;枝条、叶片和枣吊的鲜重与干重的比例系数分别为2.085,2.854和2.675;单个枣吊长度和枣吊上的叶片数目呈现出良好的一元线性关系,R2达到0.88。结论]本研究中使用的枣树生物量模型的模拟精度较高。

Biomass Models for Jujube in Loess Hilly Mountain of Northern Shaanxi Province

Objective] In order to provide useful technical support for performance evaluation of irrigation and fertilization in jujube plantations, a jujube shoot biomass estimation method without damaging trees was explored. Methods] Based on a large number of measurements, both linear models and non-linear models were used to estimate the biomass of branches, hangings, fruits and leaves for jujube. In addition, these models were evaluated and compared according to the correlation coefficient(R²), fit index(W), Standard error(SEE), coefficient of variation(C_V) and forecast accuracy(p). Results] The linear models exhibited a superior performance for branch biomass modeling with R² ranged from 0.980 to 0.984, p ranged from 0.909 to 0.926. While, non-linear models were more suitable for hanging and leaf biomass modeling(R² was between 0.880 and 0.943, p ranged from 0.897 to 0.976). The optimal fruit biomass model is the dual non-linear model (the R² is 0.999 and p is 0.998). The ratio of fresh and dry weight for branch, hanging and leaf was 2.085, 2.675 and 2.854, respectively. A good linear relationship was showed between the length of a single jujube hanging and the number of leaves on it (R² reaches 0.88).Conclusion] In this reserch, the simulation precision of the jujube tree biomass model was higher.