Pedro Antonio Martins Auler

Produção de laranja com plantas de cobertura permanente na entrelinha

The objective of this work was to evaluate water status, physiological parameters and fruit yield of the Pear orange on Rangpur lime rootstock, as well as soil water content in different orchard floor vegetation management. Field experiment was set up in 1993, at Alto Parana, northwest of the state of Parana, Brazil. The soil is a Typic Paleudults. Three treatments were evaluated: bahiagrass (Paspalum notatum), legume (Arachis pintoi), and spontaneous vegetation plus herbicide. The experimental design was in random blocks with three replicates. From 1999 to 2003, the following measurements were made: photosynthesis rates, stomatal conductance, leaf water potential, fruit yield and soil water content. Legume keeping in the interrows causes higher stress to orange plants. Bahiagrass assures better water and metabolic relations to Pear orange tree. Fruit yield orange is not influenced by orchard floor vegetation management.

Produção de frutos de laranjeira pêra e teores de nutrientes nas folhas e no solo, em Latossolo Vermelho-Escuro do Noroeste do Paraná

A cobertura vegetal das entrelinhas dos pomares citricos e uma pratica necessaria nos solos arenosos originarios da formacao geologica do arenito Caiua do Parana. O estudo foi realizado em um experimento de laranjeira pera sobre o porta-enxerto limao-cravo instalado no campo em 1993, no municipio de Alto Parana, em um Latossolo Vermelho-Escuro, onde estavam sendo avaliados seis diferentes sistemas de manejo do solo das entrelinhas do pomar. Na safra agricola de 1995/96, foram coletadas amostras de folha e solo nas entrelinhas e faixas de adubacao nas camadas de 0-20 e 20-40 cm e avaliados a producao e o numero de frutos. A producao e o numero de frutos correlacionaram-se, positivamente, com as caracteristicas quimicas do solo Ca, Mg, pH e V das entrelinhas do pomar e, negativamente, com Al e H + Al. Os teores foliares de Ca correlacionaram-se, positivamente, com a producao e o numero de frutos. O nivel critico de Ca nas folhas foi de 29,72 g kg-1.

Effect of tillage systems and permanent groundcover intercropped with orange trees on soil enzyme activities

The objective of this study was to evaluate the effect of different soil tillage systems and groundcover crops intercropped with orange trees on soil enzyme activities. The experiment was performed in an Ultisol soil in northwestern Parana State. Two soil tillage systems were evaluated [conventional tillage (CT) across the entire area and strip tillage (ST) with a 2-m strip width] in combination with various groundcover vegetation management systems. Soil samples were collected after five years of experimental management at a depth of 0-15 cm under the tree canopy and in the inter-row space in the following treatments: (1) CT-Calopogonium mucunoides; (2) CT-Arachis pintoi; (3) CT-Bahiagrass; (4) CT-Brachiaria humidicola; and (5) ST-B. humidicola. The soil tillage systems and groundcover crops influenced the soil enzyme activities both under the tree canopy and in the inter-row space. The cultivation of B. humidicola provided higher amylase, arylsulfatase, acid phosphatase and alkaline phosphatase than other groundcover species. Strip tillage increased enzyme activities compared to the conventional tillage system.

Relations among Valencia orange yields with soil and leaf nutrients in Northwestern Paraná, Brazil

The Valencia orange orchards established on soils of low fertility in the Northwest region of Parana State, Brazil, have showed symptoms of Mg deficiency and reduced fruit yields. The objective of this study was to verify the relationship between yield with soil and leaf nutrients during 1996/97 growing season. Two sites of low and high productivity were selected in seven orchards. Leaf and soil samples (fertilized rows and interrows) were collected in 1996. The results showed that the citrus yields were negatively related with soil Mg/K and Ca+Mg/K ratios in the fertilized rows, and fruit weight positively correlated with leaf Zn in the low productivity orchards. The fruit weight was positively related with leaf Ca and soil Ca in the fertilized rows of the high productivity orchards. The results suggested an adequate lime and K fertilization managements in the fertilized rows, as well as an adequate Zn supply.

Influência das frações de areia na retenção e disponibilidade de água em solos das formações Caiuá e Paranavaí

Tem sido verificado que a adocao das tecnicas de uso e manejo para solos derivados do arenito Caiua no noroeste do Parana nem sempre corresponde as expectativas de producao das culturas. Nessa regiao ocorrem duas Formacoes desse arenito: a Caiua e a Paranavai, com diferencas na granulometria dos solos. A hipotese e de que os solos da Formacao Caiua tenham menor retencao e disponibilidade de agua para a producao agricola, em razao da maior proporcao da fracao de areia grossa do que solos da Formacao Paranavai. O objetivo deste trabalho foi caracterizar a retencao e disponibilidade de agua do solo em integracao lavoura-pecuaria e cultivado com abacaxi em solos do arenito das Formacoes Caiua e Paranavai, no noroeste do Parana. Em 2010, foram realizadas duas amostragens de solo em quatro areas agricolas comerciais de integracao lavoura-pecuaria e producao de abacaxi, que apresentaram textura arenosa na camada de 0-40 cm; nessas havia evidencias de que, mesmo com a utilizacao das melhores tecnicas agronomicas de manejo de solo, as produtividades de soja, pastagem e de abacaxi eram muito baixas nos solos da Formacao Caiua. Coletas de amostras de solo deformadas e indeformadas nas camadas de 0-10, 11-20 e 21-40 cm foram realizadas para caracterizar a granulometria (argila, silte, areia fina e areia grossa), o carbono orgânico e a retencao de agua no solo. Os solos da Formacao Caiua tem granulometria mais grosseira, poros de maior diâmetro e menor disponibilidade de agua do que os da Paranavai. Os riscos de deficiencia hidrica sao maiores em solos da Formacao Caiua do que os da Paranavai.