Effects of glyphosate plus foliar manganese application on the production and quality of marandu grass

Luciane Da Cunha Codognoto,Glaucia Amorim Faria,Jucilene Cavali,Katia Luciene Maltoni,Thassiane Telles Conde

doi:10.4025/actascianimsci.v43i1.52796

Abstract

In this study, the stimulatory effects of application of glyphosate herbicide coupled with manganese sulfate (8%) foliar fertilizer on the production and bromatological characteristics of Brachiaria brizantha ‘Marandu’ were evaluated. The experiments were performed using randomized complete block design with a 5×4 factorial scheme in plots subdivided over time (across four evaluations) with four repetitions, totaling 100 observations. The effects of sublethal doses of acid equivalent (a.e.) of glyphosate (5.40, 21.60, 64.80, and 108.00 g·a.e.·ha-1) and control plus manganese sulfate foliar fertilizer (1,000 g ha-1) were assessed in four successive evaluations at a defoliation frequency of 21 days. Foliage at 20 cm height (to evaluate forage production); leaf/stem ratio (LSR); and contents of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and lignin (LIG) were measured in experimental plots with a usable area of 7.5 m2. Application of sublethal doses of glyphosate plus manganese sulfate did not increase forage production, increased LSR, reduced LIG content, and did not affect CP content in all four evaluations. NFD and ADF indicated satisfactory qualitative indices for animal feed following the application of sublethal doses of glyphosate plus manganese sulfate in all four evaluations.

Highlights

IntroductionGlyphosate affects plant physiology; for instance, application of sublethal doses of glyphosate can degrade chlorophyll, leading to temporary yellowing of newly emerged leaves (Yamada, & Castro, 2007)
The forage production (FP) response was inversely proportional to glyphosate dose
A previous study indicated that the presence of manganese in a glyphosate-based spray solution did not alter the effectiveness of the herbicide (Bernards, Thelen, Penner, Muthukumaran, & McCracken, 2005), which is consistent with our results

Summary

Introduction

Glyphosate affects plant physiology; for instance, application of sublethal doses of glyphosate can degrade chlorophyll, leading to temporary yellowing of newly emerged leaves (Yamada, & Castro, 2007). These symptoms are similar to those of manganese deficiency, indicating that glyphosate interferes with the balance of elements in plants. We hypothesized that foliar manganese supplementation would alter the metabolism of plants treated with glyphosate To test this hypothesis, we assessed the effects of sublethal doses of glyphosate in the presence of manganese on the yield and nutritional value of B. brizantha ‘Marandu’ (Marandu grass) applied in four cycles at a defoliation frequency of 21 days

Material and methods

Results and discussion

Evaluation

Conclusion