Sensitivity to herbicides of ?Imperial? pineapple nursery associated with Piriformospora indica.

Abstract

A baixa oferta de mudas sadias e com qualidade tem sido um obst?culo para o crescimento da abacaxicultura no Brasil. A forma??o de mudas provenientes da cultura de tecidos vem sendo apontada como a possibilidade de se obter alta quantidade de mudas e assegurar a sanidade das mesmas. Por?m, na micropropaga??o, as mudas necessitam de um per?odo de aclimatiza??o, o que aumenta o tempo para a sua forma??o. A utiliza??o de fungos micorr?zicos pode ser a alternativa na redu??o do tempo de produ??o de mudas, porque eles podem otimizar o sistema radicular na absor??o de ?gua e nutrientes. Ap?s o plantio das mudas em campo, o manejo de plantas daninhas ? uma pr?tica indispens?vel na abacaxicultura, visto que as esp?cies competidoras apresentam r?pido crescimento e interferem negativamente no crescimento da planta. Entre os m?todos de controle, a aplica??o de herbicidas tem sido o mais utilizado, por se tratar de uma pr?tica eficiente e que n?o danifica o sistema radicular da cultura. Diante disso, esta pesquisa foi realizada com objetivo de avaliar a associa??o do fungo Piriformospora indica com mudas de abacaxizeiro micropropagadas em cultivo com a aplica??o de herbicidas em pr?-emerg?ncia e determinar o crescimento e a absor??o de nutrientes das mudas micorrizadas. Avaliou-se o crescimento in vitro de fungo P. indica em meio de cultura com aplica??o dos herbicidas ametryn, diuron e sulfentrazone. Posteriormente, as mudas micropropagadas de abacaxizeiro foram inoculadas com fungo P. indica e plantadas em substrato tratado com os herbicidas ametryn, diuron e sulfentrazone. Avaliaram-se a coloniza??o micorr?zica, a fluoresc?ncia da clorofila a, os teores de nutrientes foliares e o crescimento das mudas. Os dados foram submetidos ? an?lise de vari?ncia, regress?o polinomial e compara??o de m?dias, a 5% de probabilidade. No cultivo in vitro, o diuron inibiu o crescimento do fungo P. indica em todas as doses testadas. O ametryn, at? a dose equivalente a 2,48 L ha-1 e o sulfentrazone, at? a dose 1,6 L ha-1, n?o interferiram no crescimento do fungo P. indica. Foi observada a associa??o do P. indica com as mudas de abacaxizeiro ?Imperial? com a aplica??o de todos os herbicidas. As mudas associadas com o fungo apresentaram maiores teores de nutrientes e crescimento. A aplica??o dos herbicidas em doses elevadas interferiu no crescimento e na absor??o de nutrientes pelas mudas de abacaxizeiro micorrizadas.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes)Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013.ABSTRACT Glycerin is a residue of the biodiesel industry, output from the process of vegetable oil transesterification of triglycerides in basic catalyst that will lead to economic, social and environmental impacts due to increased production of biodiesel in Brazil. The objective of this study was to evaluate the application of glycerin, a biodiesel industry waste, came from vegetable oil transesterification of triglycerides by potassium hydroxide catalyst (KOH) as a source of potassium ("K glycerin") on productivity and nutrition of soybeans and on chemical and microbiological characteristics of the soil. Two experiments were conducted under field conditions in a Oxisol (Typic) soil type, at Curvelo, Minas Gerais state, Brazil, and another in the village of Diamantina, Minas Gerais state in a sand soil type (NQ). The experimental design was randomized blocks with four replications. The treatments were three doses of "glycerin K 'corresponding to 50, 100 and 200% of recommended dose of Potassium for soybean and 100% of the dose recommended in the form of KCl and K2SO4 and a treatment without application of K. The recommended dose of K2O were 120 and 80 kg ha -1 for NQ and Oxisoil, respectively. There has been carried out chemical analysis of soil (pH, P, K, Ca, Mg, Al, Al + H, CO, SO4-2) in the soybean harvest and microbiological analysis (microbial basal respiration (BR), microbial biomass carbon (CBM) and metabolic quotient (OKQ (2)) soil at two times (early emergence and soybean harvest) and soybean yield and foliar concentrations of nutrients in the flowering of soybeans. Soybean yield increased with the application of "glycerin K" when the availability of K in the soil was limited, and although lower than the mineral sources of K, it supplied in part the soybeans need for K. The soil microbiota tended to balance at the end of the cycle of soybeans with application of "glycerin K", thus not causing adverse effects on crop and soil. The "glycerin K" does not cause environmental problems to the place where it was applied, but studies are needed to evaluate its long-term use to better understand the dynamics of soil and crop productivity