Gas exchange, chemical composition and productive characteristics of tropical grasses deferred II: cultivars BRS Paiaguás and BRS Piatã

Francisca Gisele Rodrigues Dos Santos,Rafael Nogueira Furtado,Magno José Duarte Cândido,Clésio Dos Santos Costa,Marcos Cláudio Pinheiro Rogério,Ricardo Alves De Araújo,Roberto Cláudio Fernandes Franco Pompeu,Valdson José Da Silva

doi:10.1590/s1519-99402122162021

Abstract

ABSTRACT This study aimed to evaluate the physiological parameters, the productive characteristics, structural and chemical composition of Urochloa Brizantha cultivars BRS and BRS Piatã submitted to two deferment periods and three using times. The experimental design was randomized complete block design in a factorial scheme 2 x 2 x 3, being two grass cultivars (Paiaguás grass and Piatã grass), two deferment periods (rainy season and dry-rainy transition) and three sealing times (40, 80 and 120 days). It was observed that, in the rainy season, the grasses had higher leaf transpiration rate when used for 40 days of deferment (1.66 µmol m2/s). During the rainy season, the Stomatal conductance was detected only in the grasses used with shorter seal, with an average of 0.07 µmol m2/s. In contrast, in the period of transition, the concentration decreased to 0.02 µmol m2/s. In a general way, the BRS Paiaguás presented lower content of NDF. The shorter cycle provided greater biomass production of total forage during the period of rain, approximately 2.78 times more than the same pasture grass deferred during the transition period. Generally, the periods of deferment and moments of use cause effects on structural characteristics of pasture, being that the period of deferment of the transition period and used for 40 and 80 days may be a strategy for keeping animals in critical periods.

Highlights

Pastures represent the main food source of ruminant animals, constituting the basis of livestock support
Among the management alternatives to balance the statehood of forage production is the deferment of pasture, which consists of selecting an area of the property and sealing it to grazing
According to Silva et al (2016), the most recommended forage plants for deferment are those with low accumulation of stems and high production of leaf blades, which causes lower reductions in nutritional value over the sealing period, especially most grasses of the genus Urochloa

Summary

Introduction

Pastures represent the main food source of ruminant animals, constituting the basis of livestock support. Among the management alternatives to balance the statehood of forage production is the deferment of pasture, which consists of selecting an area of the property and sealing it to grazing. In this way, it is possible to reserve the surplus of fodder produced in the water period for use in the dry period (SOUSA et al, 2019; CARVALHO et al, 2017). The deferment ensures the intake of grasses during the months of scarcity, it should be emphasized that these fodders have reduced nutritional value (TEIXEIRA et al, 2011) To reduce this problem, some management practices can be applied, such as the use of a shorter deferment period of pasture and fertilization at the beginning of the deferment period (SANTOS et al, 2013). The objective of this work was to evaluate the physiological parameters, structural and productive characteristics, in addition to the chemical composition of grasses of the species Urochloa brizantha, cultivars BRS Paiaguás and BRS Piatã, under two deferment times and three moments of pasture use

Objectives

Methods

Results