Manganese accumulation and dry matter production of Guinea Grass (Panicum maximum) after application of increasing doses of Mn fertilizer

Abstract

The manganese (Mn) is an important nutrient to forage development; however, there is a lack of information regarding to adequate Mn-fertilizer rates for Guinea Grass (Panicum maximum) species growing in Brazilian soils. The objective of this research was to evaluate the effect of Mn on growth, nutrition and yield of Guinea Grass. The study was carried out under greenhouse conditions in a randomized block design, with five Mn rates (0, 15, 30, 60 and 120 mg dm -3 ) and four replicates, using manganese sulfate (35.5% Mn) as Mn source. Plant's growth parameters, dry mass production, Mn 2+ levels and accumulation in plant's tissues were measured and Mn efficiencies of absorption, transport and utilization were calculated. Enhancing Mn doses, there was a proportional increase of Mn 2+ levels in the leaves and the roots. Regarding to the growth parameters, the number of leaves and both root and aboveground dry mass were slightly affected by Mn application. The highest Mn efficiency of absorption and transport by Guinea Grass was ob using 30 mg dm -3 of Mn; however, the Mn utilization efficiency was higher when Mn was not applied. In this way, the Mn fertilization in Guinea Grass is economically viable using doses up to 30 mg dm -3 .