Grazing management strategies for massaigrass-forage peanut pastures: 2. productivity, utilization and sward structure

Carlos Mauricio Soares De Andrade,Judson Ferreira Valentim,Odilon Gomes Pereira,Rasmo Garcia

doi:10.1590/s1516-35982006000200003

Carlos Mauricio Soares De Andrade, Judson Ferreira Valentim + Show 2 more

Open Access

https://doi.org/10.1590/s1516-35982006000200003

Copy DOI

Abstract

This study was carried out to evaluate the productivity, utilization and sward structure of a mixed massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pasture, intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% of live weight). In each grazing cycle, dry matter (DM) accumulation rates, defoliation intensity (%), grazing depth (%) and grazed horizon (cm) were evaluated. The structure of massaigrass tussocks was characterized in both dry and rainy seasons by measuring its pre-grazing morphological composition and post-grazing height and density (tussocks/m). Pastures submitted to higher herbage allowance (HA) levels showed higher productivity, but were less efficiently utilized. On average, over the experimental period, DM accumulation rates increased linearly from 56.8 to 81.3 kg/ha/day as HA levels increased from 9.0 to 18.4% of live weight. However, defoliation intensity and grazing depth declined linearly with increasing HA levels. During the dry season, pre-grazing morphological composition of massaigrass was characterized by 41% of green leaf blades, 10% of pseudostems and 49% of dead material, irrespective of HA levels. In the rainy season, however, it showed higher percentage of green leaf blades and lower percentage of pseudostems when submitted to lower HA levels, although there were not differences in relation to percentage of dead material. The structure of massaigrass tussocks tended to deteriorate at high HA levels.

Highlights

As a result of the evaluation of a large collection of Panicum maximum accessions since 1984, Embrapa already released in Brazil the cultivars Tanzânia (Embrapa, 1990), Mombaça (Embrapa, 1993) and Massai (Lempp et al, 2001b; Valentim et al, 2001)
Over the experimental period, dry matter (DM) accumulation rates increased linearly from 56.8 to 81.3 kg/ha/day as herbage allowance (HA) levels increased from 9.0 to 18.4% of live weight
Pre-grazing morphological composition of massaigrass was characterized by 41% of green leaf blades, 10% of pseudostems and 49% of dead material, irrespective of HA levels

Summary

Introduction

As a result of the evaluation of a large collection of Panicum maximum accessions since 1984, Embrapa already released in Brazil the cultivars Tanzânia (Embrapa, 1990), Mombaça (Embrapa, 1993) and Massai (Lempp et al, 2001b; Valentim et al, 2001). Some characteristics that contributed to the release of this cultivar include: a) high drymatter production potential; b) high leaf/stem ratio; c) vigorous root system, enabling good adaptation to water deficit and to adverse soil conditions such as compaction and low fertility; d) smaller phosphorus demand and higher aluminum tolerance than other P. maximum cultivars; and, e) higher resistance to spittlebug as compared to cultivars ‘Tanzânia’, ‘Mombaça’ and ‘Tobiatã’ (Valentim & Moreira, 1994; Euclides et al, 2000; Lempp et al, 2001b; Valentim et al, 2001). Some studies have shown that some anatomical characteristics of massaigrass leaf blades hinder its digestion (Lempp et al, 2000, 2001a)

Objectives

Methods

Results