Soil compaction affects sunflower and Paiaguas palisadegrass forage productivity in the Brazilian savanna

Abstract

Integrated crop-livestock systems maximize land use, infrastructure and labor; diversify production; and minimize costs, thereby reducing risks and adding value to agricultural products. However, growing mechanically harvested crops can negatively affect soil structure, reducing plant biomass productivity. The present study aimed to evaluate soil compaction and its effects on the forage productivity of sunflower and Brachiaria brizantha cv. BRS Paiaguas during the second cropping period. The experiment was conducted as a split-plot randomized complete block design with four replications. Four compaction levels represented by traffic from an agricultural tractor were established: 0 (absence of compaction), 2, 10 and 30 passes over the same spot. Two forage systems were established in the subplots: sunflower grown solely as a monocrop (40,000 plants ha-1) or intercropped with Paiaguas palisadegrass (10 plants linear m-1). The following parameters were quantified: soil bulk density, plant height, capitulum diameter and 1000-achene weight for sunflower; stem length and the leaf/stem ratio for Paiaguas palisadegrass; and total and partitioned forage productivity. The results showed that sunflower was highly sensitive to soil compaction and that the development and productivity of this species decreased in response to the greatest bulk density, which in turn affected the Paiaguas palisadegrass. Overall, intercropping is recommended for increased forage productivity.