遮荫对峦大杉1年生苗木生长的影响及动态优化

以当年播种的峦大杉(Cunninghamia konishii)幼苗为材料，采用单因素试验设计3个遮荫处理(50%、75%、100%光照)，每隔7 d监测地径、苗高等生长进程；应用Logistic方程拟合苗高、地径生长过程并分析其生长节律。结果表明，遮荫显著促进峦大杉幼苗全生长季的苗高、地径生长，以50%光照表现最好；不同生长阶段遮荫对峦大杉苗高、地径生长量的影响有所不同，进行动态优化十分必要。Logistic方程能较好地拟合峦大杉苗木生长动态。50%光照处理显著提高峦大杉苗高、地径的线性生长速率、最大线性生长速率和线性生长量，显著提前苗高线性生长终期、缩短线性生长持续时间，显著推迟地径线性生长始期。峦大杉苗期光照强度动态优化方案：在t≤133 d前阶段宜采用50%光照，在t＞133 d期间宜采用100%光照。

Effects of Shading Intensity on Growth of One-year-old Seedlings of Cunninghamia konishii and Its Dynamic Optimization

Single factor experiments were used to study the effects of shading intensities (50%, 75%, 100% light) on growth and growth rhythm of one year old Cunninghamia konishii seedlings. Growth indexes (ground diameter, seedling height) of seedlings were measured every 7 d during the experiment. Applying Logistic equation to fit the growth process of seedling height and ground diameter and calculate the growth rhythm at seedling stage of C. konishii. The law of shading affecting seedling growth and growth rhythm was revealed, the dynamic optimization method of light intensity was put forward, and the light condition of C. konishii seedlings was optimized and verified. The results showed that shading significantly promoted the height, ground diameter growth throughout the growth season, and it was the best with 50% light; the effect of shading on the height and diameter growth of C. konishii seedlings at different growth stages was different, so it was necessary to dynamic optimize the light intensity at seedling stage. Logistic equation fitted well the growth dynamics of C. konishii seedlings. 50% light shading intensity significantly promoted the linear growth rate, the maximum linear growth rate and total linear growth of C. konishii seedlings height, ground diameter. Shading significantly advanced the final days of linear growth, shortened linear growth duration of seedling height. Shading significantly delayed the linear beginning days of ground diameter. Dynamic optimization scheme of light intensity in C. konishii seedling stage: 50% light should be used at the stage of t≤133 d, and 100% light should be used at the stage of t>133 d.