Produção de mudas de duas espécies de gramíneas nativas para restauração do Cerrado

Abstract

The Brazilian Cerrado is a mosaic of vegetation types, raging from grasslands to forests. Cerrado has been converted and degraded by anthropogenic activities, increasing the need for ecological restoration in many areas. Restoration by planting seedlings is promising, but the efforts for seedling production are currently focused on tree species, not considering herbaceous species. Since grasses are essential in the herbaceous layer of the Cerrado, we tested whether nursery techniques used for tree seedling production would be suitable to produce seedlings of two native grasses. First, we sowed seeds of Schizachyrium sanguineum (Retz.) Alston and Loudetiopsis chrysothrix (Nees) Conert. in seedbeds with Cerrado native soil and sand as substrates and later transferred to definitive containers (30, 55 or 290 cm³) with Cerrado soil, commercial substrate or the mixture of both. Both species accepted the sowing technique, as they germinated under nursery conditions and survival after transfer to definitive containers was greater than 70%. For both species, the seedlings grew more in height and had more tillers when cultivated in the Cerrado soil, in the larger container. In a second experiment, we tested the influence of increasing levels of controlled-release fertilizer (CRF) on the growth of S. sanguineum seedlings. Seedlings growth increased with the increase in CRF levels, and CRF doses between 4.7 kg.m-³ and 6 kg.m-³ provided higher growth and nitrogen, phosphorus and potassium shoot concentration. The Cerrado soil provided higher seedling growth than the non-fertilized commercial substrate, however, lower than the commercial substrate fertilized. We conclude that seedlings of the native grasses L. chrysothrix and S. sanguineum can be produced using tree seedling production techniques currently used in commercial nurseries, and that S. sanguineum growth positively responds to higher nutrient availability in the substrate. Our results confirm the possibility of producing seedlings of native herbaceous species from seed in nursery, increasing the availability of non-tree species for Cerrado grasslands and savanna restoration.