Uso de coprodutos da extração de vermiculita na produção de mudas de espécies arbóreas da Caatinga.

Abstract

Degradation processes occur mainly in arid, semiarid and dry sub-humid regions due to climatic and human induced factors such as cattle ranching and mining. The extraction of vermiculite, in addition to the direct degradation produced by the material removal itself, produces residues with no identified use that are dumped in the areas surrounding the mines with risks of silting up of rivers and reservoirs as well as water pollution. This paper evaluated the use of these by-products (BP-vermiculite) and the amount of cattle manure (CM) necessary to be added to it to produce faveleira (Cnidoscolus quercifolius Pohl.) (Experiment 1) and jurema branca (Piptadenia stipulacea Benth.) (Experiment 2) seedlings, by comparing this substrate with alluvial soil, normally used for seedling production. The experiments were carried out from April 2013 to February 2014 in a screened shed at the UFCG/CSTR-UAEF forestry nursery facilities, in Patos, PB – Brazil, according to a completely randomized design with 6 treatments and 5 replications, totaling 30 vases or plots for each experiment. Mean height, basal diameter and dry biomass of the shoots of faveleira and jurema branca seedlings growing in BP-vermiculite during 100 days, with 20 and 10% manure addition, respectively, were similar to the seedlings growing in alluvial soils with no manure addition, and were lower than those observed for the seedlings cultivated in alluvial soil with 33% of manure addition. However, faveleira seedlings growing in BP-vermiculite enriched with 10 and 20% manure showed equal or higher DM amount in the sprouts when compared to those grown in alluvial soil without manure addition. Mean height, basal diameter and dry biomass of jurema preta shoots growing in BP-vermiculite showed a trend to increase up until 10% manure addition, although those means were lower than the ones observed for seedlings growing on alluvial soil. Despite the smaller seedling size, the use of BP-vermiculite enriched with 20 and 10 and 20% manure is an alternative to the production of, respectively, faveleira and jurema branca seedlings, specially the first one, due to seedling vigor and sprouting power, allowing the utilization and the reduction of the environmental impacts caused by BP-vermiculite, avoiding the environmental degradation caused by the extraction of the alluvial soil for seedling production, as well as allowing the production of seedlings of Caatinga trees.