Macronutrients requirement of a snap bean genotype with determinate growth habit in Brazil

Abstract

Obtaining nutrient accumulation curves is very important in knowing the plant nutritional requirement dynamics and to direct the strategies for its supply. The aim of this work was to study the uptake, compartmentalization and exportation of macronutrients of a snap bean genotype with determinate growth habit. An experiment at field conditions at Londrina State University -UEL, Londrina-PR, Br azil, was performed in a randomized block design with five replications, using UEL-1 genotype. It was observed that dry matter production, as nutrients accumulation, were slow until 20 days after emergence (DAE), V4 stage, and became more pronounced after that period. The macronutrients were more accumulated in the pods, except for Ca, which had the leaves as preferred organ. The maximum amounts of N, P, K, Ca, Mg and S uptaken were 91.0; 35.2; 131.1; 35.2; 9.1 and 4.7 kg ha -1 , respectively, while exportation to produce each ton of pod's fresh matter were 7.01 kg of N; 3.30 kg of P; 7.91 kg of K; 0.6 kg of Ca; 0.48 kg of Mg and 0.31 kg of S. One must pay attention to the proper management of quantity and epoch of N and K supply, because of the high demand and exportation of these nutrients.

Sources and rates of nitrogen on the nutrition and productive performance of determinate growth habit snap bean

“…Differently from the N content in index leaf, the N accumulation in plant shoots, even with the higher fertilizer rate applied, showed to be inferior to the observed by Barzan et al (2016) and Carr et al (2020), respectively for field and greenhouse conditions in determinate growth habit snap bean cultivars, reinforcing the influence of genetics and environment for N uptake. Viçosi and Pelá (2020) observed quadratic increase of N content in plant shoots for the determinate growth habit snap bean Stringless Green cultivar, as a function of N rates applied at side dressing as urea (45% N), with maximum values obtained between 43 and 44 kg ha -1 N rates.…”

“…The N accumulated in plant shoots had moderate positive correlation with both N content in index leaves and the number of pods. This may be explained because these two plant organs, leaves and pods, contribute directly to the storage of the nutrient in plant shoots with a high N tissue concentration, especially for the pods in the end of the plant cycle (BARZAN et al, 2016), so the higher is the number of pods and the N content in index leaves, the higher is the plant accumulation of this nutrient.…”

“…It is necessary to maintain enough nutrient levels in the soil to attend the plants requirements, either by fertilization or preexisting contents in soil organic and mineral fractions. The snap bean with determinate growth habit presents high nutrient requirements, especially potassium (K) and nitrogen (N), accumulating 131 and 91 kg ha -1 , respectively, and exporting about 47% of K and 53% of N in the pods (BARZAN et al, 2016), demonstrating the potential to exhaust soil stocks if an adequate maintenance fertilization is not performed.…”

“…The high N requirement is due to various roles that the element plays on plant metabolism, being part of proteins, nucleic acids, chlorophyll, coenzymes, plant hormones and secondary metabolites (MARSCHNER, 2011). Besides, nitrogen is one of the only nutrients which may be absorbed by root cells in different chemical forms, mainly as ammonium (NH 4 + ) and nitrate (NO 3 -) (BREDEMEIER; MUNDSTOCK, 2000), but also as organic compounds (PAUNGFOO-LONHIENNE et al, 2008;NÄSHOLM et al, 2009). The soil nitrogen dynamics is very complex, making it difficult to predispose its availability for plants by soil chemical analysis, unlike the other nutrients (CANTARELLA, 2007).…”