Influence of the fungicide strobilurin on forage rye production under different harvesting systems

Abstract

The goal of this study was to evaluate the effects of successive harvests, with or without application of foliar fungicide, on the morphometric characteristics, yield and nutritional value of rye forage harvested at the hard dough grain stage, aiming at silage production. The preventive control of foliar diseases was carried out with the fungicide OrkestraTM SC®, in a single application, at early flowering, for both harvesting systems. The first harvest was conducted at the full vegetative stage and the second, at the hard dough grain stage. The system with two harvests resulted in higher cumulative yield compared with the single-harvest system (40,680 and 9,029 kg ha-1 fresh and dry biomass with two harvests, against 8,816 and 5,375 kg ha-1 fresh and dry biomass). Fungicide application promoted a reduction in neutral detergent fiber content in both systems, with values of 753.9 against 790.6 g kg-1 for the single-harvest system and 734.4 against 773.3 g kg-1 for the two-harvest system, with and without fungicide, respectively. For lignin content, the application of the fungicide reduced values (97.2 against 110.3 g kg-1) only in the two-harvest system. Rye management with a harvest at the vegetative stage increases the cumulative dry biomass yield without negatively affecting the harvest yield at the hard dough grain stage, and without drastic changes in the nutritional value of the plant. Even under adverse conditions, fungicide application positively interferes with plant cell wall components

Effectiveness of pyraclostrobin on the production, morphology and nutritional value of winter cereal forage in successive cuts

“…In the second harvest, the percentage of stem increased compared to that of leaves, corroborating Meinerz et al (2012), who state that the leaf: stem ratio tends to decrease with the increase and/or advancement of harvests. With the application of pyraclostrobin, the increase in the proportion of leaves corroborates the data found by Silva et al (2022), which showed an increase in leaf area, when pyraclostrobin was applied to rye crops. Fungicide application increased the number of viable leaves (Kalebich et al, 2017), thus improving the leaf: stem ratio.…”

“…Dry matter values were lower in the treatment with pyraclostrobin, probably because it has characteristics that increase water retention within the plant due to reduced stomatal opening (Grossmann et al, 1999). However, Heker et al (2020) and Silva et al (2022) report that the application of pyraclostrobin did not change the dry matter values of plants harvested at the vegetative stage.…”

“…Increased crude protein values were also found in rye silage treated with pyraclostrobin (Silva et al, 2022) and in wheat and black oat silage (Venancio et al, 2004).…”

“…When winter cereals are used at the vegetative development stage, the forage obtained, in the general average, is nutritionally characterized by a high content of crude protein (>15%) and mineral matter (>8%), with greater digestibility http://dx.doi.org/10.1590/1678-4162-13106 of dry matter (>75%), and low content of dry matter (<20%) and neutral detergent fiber (<45%) (Silva et al, 2022).…”