Model Analysis Of Forage Response To Split Applications Of Nitrogen. II. Coupling Of Roots And Tops*

Abstract

The extended logistic model provides a useful tool for describing crop response (dry matter and plant nutrient uptake) to applied nutrients. In the previous article model parameters were evaluated for field data on Pensacola bahiagrass (Paspalum notatum Flügge). The analysis showed no advantage to split applications of applied N on poorly drained Myakka fine sand (sandy, siliceous, hyperthermic Aeric Haplaquod). In this article the analysis is extended to data for the root-stolon component. Root production [dry matter and plant nitrogen (N) uptake] is coupled to the tops (aboveground component). Analysis again showed no advantage to splitting of applied N.

Root system characteristics of Marandu palisadegrass supplied with nitrogen and magnesium rates

“…According to Medici et al (2004), plants have several mechanisms to avoid ROS production, such as preventing N excess and the use of anti oxidant enzymes. Manarin & Monteiro (2002) evaluated the growth of Mombaça guineagrass and observed that the increase in N rates resulted in linear increase in N concentration in roots, highlighting the ability of plants to store N in roots, which is a result of the balance between the N concentration in above ground plant and concentration in roots (Overman & Scholtz, 2003).…”