良种苗期年生长模型的探讨

柳树良种苗期年生长模型的探讨

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摘 要：以柳树良种品种为材料，利用Logistic方程对各个品种（系）的1a生扦插苗木的苗高、地径的年生长节律进行拟合。根据因素数列的几何形状发展态势的接近程度，将苗木的生长量与影响苗木生长的空气温度、空气相对湿度、降水量和日照时数组成一个灰色系统，进行关联度分析。结果表明：利用Logistic方程拟合效果显著，相关系数皆在0.90以上。并以此将柳树良种品种（系）扦插苗的生长过程分为成活期、生长前期、速生期、和生长后期4个时期，年生长量表现出明显的“慢－快－慢”的节律，其中速生期内的苗高生长量占总生长量的比率平均为60.5％，地径生长量占总生长量的比率平均为64.0％。关联度分析表明空气温度对苗木的高生长影响最大，降水量影响最小；而日照时数对苗木的粗生长影响最大，降水量影响最小。通过对苗木年生长节律和影响苗木生长的主要环境因子进行分析，为加强柳树良种苗木生产管理，提高苗木的质量和土地的生产力，提供了理论依据。

关键词：柳树良种；苗期；Logistic方程；生长模型；灰色关联度

Study on Annual Growth Model of willow excellent fineseed at

Nursery Stage

Abstract: Logistic equation is applied to model growth increment of willow excellent clone fineseed at nursery stage. Influence of climatic factors such as air temperature, relative humidity, precipitation and illuminating Hours on the seedling growth are analyzed. The results show that correlation of the modeling is significant And the correlation coefficients are more than 0.90. Based on the equation, annual growth of the seedlings Can be divided into four periods, namely survival period, pre-growth period, fast-growth period and post-growth period. Average height and ground diameter in fast-growth period is 60.5%and 64.0% respectively of the total annual. Air temperature is believed to have the most significant influence on the height growth and precipitation the least, whilst illuminating hours have the most significant influence on the ground diameter growth and precipitation the least. This paper has provided theoretical basis for the production of high quality willow seedlings and enhancement of land productivity.

Key words: willow excellent; seedling; Logistic equation; growth model; gray correlation analysis

为了解柳树良种各品种（系）苗木在甘肃省中部半干旱地区的生长规律，为扩大繁殖、培育良种壮苗提供理论依据，确定各品种（系）在苗木生产中最佳的经营措施，进行了苗期生长节律研究，利用Logistic曲线方程对一年生苗木的生长进行拟合，对影响苗木生长的空气温度、降水量、空气相对湿度和日