Volume 33, Number 5, 2009

Nutrient balance in tropical forest allows an evaluation of eventual differences due to management practices and conclusions on forest sustainability. The aim of this study was to evaluate the nutrient concentration in native species and quantify biomass production and C and nutrient balance in tropical montane Atlantic Forest fragments (Dense Montane Ombrophile Forest) in the North of Rio de Janeiro State, from May 1999 to April 2001. Two sites were selected in the State Park of Desengano, at 900 and […]

Rhizoctonia-like mycorrhizal fungi Epulorhiza spp. have been isolated from orchids of the genus Epidendrum and have been used to promote the symbiotic germination of orchid seeds. Epidendrum secundum is a widely distributed orchid in campo de altitude (high elevation grassy vegetation) regions of the State Park of Serra do Brigadeiro (PESB), Minas Gerais, Brazil, and little is known about the mycorrhizal relationships of this species in the park. The objective of this study was to evaluate the morphological diversity of […]

The nitrogen source applied to crops may alter some soil properties such as pH, resulting in changes in the soil nutrient availability and plant nutrient uptake. Manganese (Mn), which can influence the plant susceptibility to diseases, may even affect host-pathogen relationships. The objective of this study was to evaluate the effect of soil application of two N sources and five Mn doses on the severity of the wheat spot blotch disease. Additionally, shoot and root dry matter production, plant Mn […]

Compaction is one of the most destructive factors of soil quality, however the effects on the microbial community and enzyme activity have not been investigated in detail so far. The objective of this study was to evaluate the effects of soil compaction caused by the traffic of agricultural machines on the soil microbial community and its enzyme activity. Six compaction levels were induced by tractors with different weights driving over a Eutrustox soil and the final density was measured. Soil […]

The biodiversity of rhizobium in soils of the São Francisco Valley is unknown and can be studied using cowpea as trap plants. The objective of this study was to verify the diversity of diazotrophic bacteria that nodulate cowpea in soils of the lower half of the São Francisco River Valley by morphological and genotypic characterization. Seven soil samples (A1, A2, A3, A4, C1, C2 and MC) were collected to capture bacteria associated to five cowpea cultivars (IPA 206, BRS Pujante, […]

In the last decades, the use of plant growth-promoting rhizobacteria has become an alternative to improve crop production. Rhizobium leguminosarum biovar trifolii is one of the most promising rhizobacteria and is even used with non-legume plants. This study investigated in vitro the occurrence of plant growth-promoting characteristics in several indigenous R. leguminosarum biovar trifolii isolated from soils in the State of Rio Grande do Sul, Brazil. Isolates were obtained at 11 locations and evaluated for indoleacetic acid and siderophore production […]

Soil and fertilizer management during cultivation can affect crop productivity and profitability. Long-term experiments are therefore necessary to determine the dynamics of nutrient and root distribution as related to soil profile, as well as the effects on nutrient uptake and crop growth. An 18-year experiment was conducted at the Federal University of Rio Grande do Sul State (UFRGS), in Eldorado do Sul, Brazil, on Rhodic Paleudult soil. Black oat and vetch were planted in the winter and corn in the […]

There are several regions of the world where soil N analysis and/or N budgets are not used to determine how much N to apply, resulting in higher than needed N inputs, especially when manure is used. One such region is the North Central “La Comarca Lagunera”, one of the most important dairy production areas of Mexico. We conducted a unique controlled greenhouse study using 15N fertilizer and 15N isotopic-labeled manure that was labeled under local conditions to monitor N cycling […]

The deficiency or excess of micronutrients has been determined by analyses of soil and plant tissue. In Brazil, the lack of studies that would define and standardize extraction and determination methods, as well as lack of correlation and calibration studies, makes it difficult to establish limits of concentration classes for analysis interpretation and fertilizer recommendations for crops. A specific extractor for soil analysis is sometimes chosen due to the ease of use in the laboratory and not in view of […]

The nutritional demand of pineapple plants is higher than for other crops and IT depends on cultivar, fruit weight, production destination and planting density and cultivation system. However, the variation in these factors is not always taken into account in fertilization tables. The purpose of this study was to propose a fertilizer and lime recommendation system for pineapple designated FERTCALC-Abacaxi, based on systematization and modeling of literature data and the current knowledge concerning fertilization and mineral nutrition of the crop. […]