Semeadura direta de espécies florestais na implantação de sistemas agroflorestais: alternativa para a restauração ecológica de área de preservação permanente

Abstract

Agroforestry systems (SAFs) comprise forms of land use and plant exploitation, in which tree and shrub species are combined with agricultural crops and / or animal husbandry, simultaneously or in time, interacting economically and ecologically. It represents a great potential for local and regional development, since in addition to the production of diversified environmental services, it increases food production and income generation for rural producers. The use of Biodiverse Agroforestry Systems has, in recent decades, been widely used as an alternative for ecological restoration, being included in Brazilian legislation to restore areas of preservation and legal reserve of small properties or family rural ownership. SAFS are implemented most of the time by planting seedlings and little is known about their implementation through direct seeding. Direct seeding in the Agroforestry System increases the diversity of native species, and in fragmented landscapes, they contribute to the increase in the structural and functional connectivity of ecosystems. However, due to the high diversity of existing forest species, it is still necessary to carry out studies on the physiological potential of the seeds and their initial growth, and establishment, fundamental factors when these species are used in direct sowing. Thus, this work aimed to evaluate the emergence and initial development of forest species sown directly intercropped with different agricultural crops and fertilizers and measure the cost of the applied technique. The experiment was carried out from November 2018 to August 2019 at the Experimental Farm of Agrarian Sciences of the Federal University of Grande Dourados located near BR 162 Dourados - Ponta Porã, Km 20, between the coordinates O 55º 00 '09' '/ S 22º 15' 03 '' and O 54º 59 '02' '/ S 22º 13' 18 ''. Seeds of 23 species occurring approximately the site were planted. The treatments were the interaction of: 2 seed densities (5 and 10), 2 fertilizers (Cattle manure and Chicken litter) and 2 agricultural crops (Watermelon and Pumpkin). The seeds were arranged in sowing lines (linear furrow) 2m long, 10 cm wide and 5 cm deep, spaced 2m apart and 2m between the plots, each treatment had three replicates, each repetition with two lines. The use of direct seeding to compose biodiverse agroforestry arrangements has shown to be quite promising, since agricultural crops did not harm the emergence and establishment of the species used. The best density to compose these arrangements is approximately 4000 seeds per species per hectare, since lower densities decrease the competition for light and decrease the costs of implantation. For the studied species and during the observation period, fertilizers had little influence on the development of the species. The consortium of agricultural cultivars under restoration planting is a profitable alternative to reduce restoration costs, and can be fully amortized in a second cycle of cultivars.