施肥量对生菜养分与长势的影响及模型模拟

为了研究不同施肥制度对设施生菜长势及产量的影响,将样本分为氮磷钾重度缺失、中度缺失、轻度缺失、正常及过量施用13个处理.在整个生育期利用机器视觉技术连续获取生菜冠层主视及俯视图像,提取与生菜长势显著相关的冠幅投影面积、冠幅周长及株高信息.利用灰色系统理论,研究生菜养分质量分数、长势及产量三者间的灰色关系.不同营养对生菜长势影响从大到小依次为氮,磷,钾,进一步分析了不同施氮条件下,生菜体内的磷钾质量分数及产量的变化规律,当产量达到最大时,氮磷钾3种元素质量分数分别为4.83%,0.63%和2.82%,且氮磷钾元素间存在一定协同交互作用.结合环境信息和生菜“慢-快-慢”的S型生长规律,建立了3个生长时期的养分质量分数与长势关系模型,为指导设施生菜科学施肥,高产栽培提供依据和理论指导.

Effects of different fertilization on nutrient and growth of lettuce and models simulation

In order to study the effects of different fertilization regimes on the growth and yield in facility lettuce, the samples were divided into 13 treatments, including severe, moderate, mild, normal and excessive applications of nitrogen, phosphorus, and potassium. During the whole growth period, the machine vision technology was used to acquire the top view and front view images of lettuce canopy continuously, the top projected canopy area, top projected canopy perimeter and plant height were extracted from the images, which were significantly related to the growth. The relationships among nutrient content, growth and yield of lettuce canopy were studied by grey correlation analysis. The results showed that the order of effect on different nutrition with lettuce growth was nitrogen(N)> phosphorus(P)> potassium(K). The contents of P, K and the yield of lettuce under different nitrogen application conditions were analyzed. When the yield reached the maximum, the contents of N, P, K were 4.83%, 0.63% and 2.82% respectively, and there was a synergistic interaction between them. Combined with the environmental information and the “slow-fast-slow” “s” type growth law of lettuce, the relationship models of nutrient content and growth information in three growth periods were established, which provided a scientific basis and theoretical guidance for the fertilization and high-yield cultivation of facility lettuce.