Mathematical modeling for the influence of nitrogen fertilization level on vegetative growth and yield attributes of broccoli

Abstract

Broccoli plants were grown in coastal calcareous alluvial soil. Effect of nitrogen fertilization level on the growth and development of vegetative organs, the incidence of hollow stems and the quality and yield of flower heads were investigated. Results show that in response to increase in nitrogen levels but within the adequate range, plant height (H) and expansion (K) increased linearly, fresh weight of the above ground tissues (W1) sloped upward, the firmness of flower heads (F) increased linearly, the number of leaves/ plant (L), the width of flower head (D), fresh weight per flower head (W2), the ratio of marketable flower heads (A), and total yield (Y) of flower heads had a "low-high-low" binominal curve. The mathematical model for each of the plant traits was: H=-0.000006N2+0.0113N+56.88, K=-0.000005N2+0.0157N+72.236, W1=-0.0002N2+0.3849N+1439.3,F=0.06N+66.0;L=-0.000005N2+0.0062N+20.073;D=-0. 000006EN2+0.0062N+11.7;W2=-0.0002N2+0.2505N+386.28;A=-0.00009N2+0.0927N+65.271; Y=-0.002N2+2.1991N+866.57. This study has established a correlation between nitrogen fertilization level and traits of vegetative tissues (plant sizes and leaf number/plant), flower head attributes (flower head firmness and color, and thickness of the florets), and the quality of flower heads (the ratio of marketable heads, diseased plants, hallow stalks, and discolored heads). These models should be used to determine the demand for nitrogen fertilizers in broccoli field for producing the highest yield and the best quality crop. © 2011 Springer-Verlag Berlin Heidelberg.