Agronomic and physiological responses of corn intercropped with palisadegrass growing in full sun or in a crop-livestock-forestry systems

Abstract

There is a need to enhance agricultural intensification and diversification by establishing alternative crop-livestock-forestry systems. Our objective was to compare the production and physiological characteristics of corn (Zea mays L.) either intercropped with Marandu palisadegrass [Brachiaria (syn. Urichloa) brizantha (Hochst. ex A. Rich.) R. D. Webster] growing in full sun (FS), or in a crop-livestock-forestry with single-row (CLFs) and triple-row (CLFt) groves of Eucalyptus urograndis (hybrid of Eucalyptus grandis W. Hill ex Maiden and Eucalyptus urophylla S. T. Blake). In the CLFs and CLFt, the trees were spaced at 37 m (90 tree ha⁻¹) and 30 m (135 tree ha⁻¹), respectively. The experiment was carried out for 2 years in a randomised complete block with three replications in a strip-split-plot arrangement with measurements at 5 sites between groves (7 and 13 m on the south face, central, and 7 and 13 m on the north face). The forage mass for full sun, CLFs, and CLFt was 10.9, 9.5, and 6.2 Mg DM ha⁻¹ in 2017 and 28.9, 21.5, and 14.0 Mg DM ha⁻¹ in 2018, while the grain yield was 3.38, 3.34, and 1.66 Mg DM ha⁻¹ in 2017 and 7.90, 4.66, and 2.55 Mg DM ha⁻¹ in 2018. The forage mass (10.1 Mg DM ha⁻¹ in 2017 and 23.9 Mg DM ha⁻¹ in 2018) and grain yield (3.3 Mg DM ha⁻¹ in 2017 and 5.0 Mg DM ha⁻¹ in 2018) in the central and 13 m north distances were greater than in the 7 m north and south, with less light transmission and red: far-red ratio. We concluded that corn intercropped with palisadegrass in an integrated crop-livestock-forestry system was negatively affected by the reduction in radiation transmission, resulting in reduced corn height, forage mass, and grain yield than in the full sun.