443 Chemical Alterations of Substrate in the Cultivation of Peppers H.C.O. Charlo and A.F. Ferreira Setor de Olericultura Instituto Federal de Educação Ciência e Tecnologia Triângulo Mineiro Uberaba-MG Brazil R. Castoldi, P.F. Vargas, J.C. Barbosa and L.T. Braz Departamento de Produção Vegetal Faculdade de Ciências Agrárias e Veterinárias Campus de Jaboticabal Jaboticabal-SP Brazil Keywords: Capsicum annuum, coconut fiber, substrate, fertigation Abstract The objective of this study was to evaluate the chemical alterations of the substrate in the cultivation of peppers grown in coconut husk fiber, in a protected environment. Initially, 160 pepper plants (‘Eppo’) were divided into four blocks, where two pots per block were analyzed every 21 days after transplanting. The cultivation of pepper was carried out in plastic pots of 13 L, containing coconut husk fiber, and placed in double rows with a spacing of 0.5×0.8 m between single rows and 1.10 m between double rows. After removal of the plants from the pots, individual samples of substrate (approximately 1 L) were collected from each pot and dried at ambient temperature. The levels of Ca, Mg, S, Cl, Na, B, Fe, Mn, Cu and Zn were determined for all periods of the cultivation. These analyses were performed using the method of extraction 1:1.5 v/v. There was an increase in the levels of all the nutrients evaluated. Further studies should be conducted to develop a better nutrient solution. INTRODUCTION The cultivation of peppers in Brazil has been mainly carried out in a protected environment, obtaining greater productivity and better fruit quality in relation to the open field. However, because of monoculture, there are various problems caused by phyto- pathogens, primarily root-knot nematodes. To overcome this difficulty, many growers have changed to substrate cultivation. Currently, the main substrate utilized in the production of vegetables in Brazil is coconut husk fiber. Coconut husk fiber is a sub-product of the coconut industry, which in the last years has been largely used in agriculture. However, there is still little information on the modifications of this substrate during vegetables growing. The quality of a substrate is based on its physical and chemical characterization. Important chemical properties include pH, electrical conductivity (EC) and nutrients level. The determination of the nutrients level is necessary for the recommendation and monitoring of fertilization. Fertigation and the application of organic and mineral fertilizers have been practiced in an empirical way by growers, and excessive levels of nutrients are used, affecting the quality of the produce and the production cost (Abreu et al., 2002). In the utilization of substrates, other factors are of great relevance, such as the absence of toxic elements that must not enter the food chain. The disposal of the utilized substrates should not cause environmental impacts. Therefore, the characterization of the chemical properties of the substrates is essential to guarantee not only the quality of these products but also the productivity and quality of the plants grown in this medium (Abreu et al., 2002). The aim of the present study was to evaluate the chemical alterations of the substrate in the cultivation of pepper, in a protected environment. Proc. XXVIII th IHC – IS on Greenhouse 2010 and Soilless Cultivation Ed.: N. Castilla Acta Hort. 927, ISHS 2012