Arbuscular mycorrhizal fungi in an oxisol under managements and uses in cerrado
01/Feb/2012
The alterations in the communities of arbuscular mycorrhizal fungi (AMF) induced by changes in land use and different agricultural uses are still insufficiently studied, particularly in the Cerrado biome. This study evaluated how human interference by management and land use change affect the AMF density and diversity in a Cerrado Oxisol. The study evaluated five areas: Riparian Forest (MC), Riparian Forest Edge (BM), Pasture (Past), no-till monoculture (PD) and Riparian Deforested Area (AD). In each area, 20 plots of 250 […]
Variability of nutrient harvest indices in common bean genotypes and their relationship with grain yield
01/Feb/2012
The use of genotypes with high biomass and nutrient accumulation but low nutrient harvest indices (ratio between nutrient amount in grains and in shoots) could reduce nutrient removal by harvesting and improve agricultural sustainability. The low variability found in the harvest indices in common bean (Phaseolus vulgaris L.) calls for the evaluation of a wide range of genotypes. This study evaluated the variability of nutrient harvest indices and their relationship with grain yield in common bean genotypes. A field experiment […]
Deficiency symptoms and uptake of micronutrients by castor bean grown in nutrient solution
01/Feb/2012
Castor bean is a nutrient-demanding species, but there is still little information on its micronutrient requirements. The objectives of this study were to evaluate the effects of levels of B (2.5, 12.5 and 25.0 µmol L-1), Cu (0.05, 0.25 and 0.50 µmol L-1), Mn (0.2, 1.0 and 2.0 µmol L-1) and Zn (0.2, 1.0 and 2.0 µmol L-1) in a nutrient solution on plant B, Cu, Mn and Zn concentrations and uptake, vegetative growth and fruit yield of castor bean […]
Mycorrhizal effectiveness on physic nut as influenced by phosphate fertilization levels
01/Feb/2012
In recent years, physic nut (Jatropha curcas L.) has attracted attention because of its potential for biofuel production. Although it is adapted to low-fertility soils, physic nut requires soil acidity corrections and addition of a considerable amount of fertilizer for high productivity. The objective of this research was to evaluate the effectiveness of arbuscular mycorrhizal fungi (AMF) (control without AMF inoculation, Gigaspora margarita inoculation or Glomus clarum inoculation) on increasing growth and yield of physic nut seedlings under different rates […]
Normal nutrient ranges by the ChM, DRIS and CND methods and critical level by method of the reduced normal distribution for orange-pera
01/Feb/2012
The use of nutritional diagnoses methods to define ideal and critical nutrient concentrations in plant tissues has proved promising, provided the limits are known. This study determined the normal nutrient ranges for an orange pear population, using the methods mathematical chance (MCh), Integrated Diagnosis and Recommendation (DRIS) and Compositional Nutrient Diagnosis (CND), in addition to the critical level by the reduced normal distribution method. The study was conducted in Bebedouro, São Paulo state, at the Experimental Station of Bebedouro. The […]
Physical properties of an Alfisol and no-till soybean yield
01/Feb/2012
It is known that any kind of soil management causes changes in the soil physical characteristics and can affect agricultural yield. The purpose of this study was to evaluate soil properties of an Alfisol and soybean yield under different management systems for no-tillage annual crops, no-tillage with chiseling and no-tillage crop rotation. The 11-year experiment was initiated in the 1998/99 growing season, on 100 x 30 m plots (11 % slope). Soil samples (5 per management system) were systematically collected […]
Dris interpretation criteria for cupuassu orchards
01/Feb/2012
The productivity of cupuassu orchards in the Amazon region has been gradually declining, probably due to the reduction in soil fertility, calling for fertilization. In the absence of technical recommendations to calculate the nutrient demand of an orchard, the use of the Integrated Diagnosis and Recommendation (DRIS) may represent an alternative to fill this gap. The purpose of this study was to evaluate the diagnoses based on different formulas and criteria of interpretation of DRIS indices of cupuassu orchards. The […]
Kinetic parameters of silicon uptake by rice cultivars
01/Feb/2012
Silicon is considered an important chemical element for rice, because it can improve tolerance to biotic and abiotic stress. However, in many situations no positive effect of silicon was observed, probably due to genetic factors. The objective of this research was to monitor Si uptake kinetics and identify responses of rice cultivars in terms of Si uptake capacity and use. The experiment was carried out in a greenhouse of the São Paulo State University (UNESP), Brazil. The experiment was arranged […]
Microbial indicators of soil quality in different management systems
01/Feb/2012
Agricultural activity, by the application of different soil management practices, can cause impacts on soil production capacity that need to be assessed. In this study, different microbiological parameters were evaluated, to assess the relation of soil quality with different tillage practices and crop systems, in comparison to a natural reference soil. The activities of β-glucosidase, urease, acid phosphatase and arylsulphatase were evaluated, as well as soil microbial respiratory activity and microbial biomass. Conventional tillage (CT) and no-tillage (NT) were evaluated […]
Modelling of soil penetration resistance for an oxisol under no-tillage
01/Feb/2012
Soil penetration resistance is an important property that affects root growth and elongation and water movement in the soil. Since no-till systems tend to increase organic matter in the soil, the purpose of this study was to evaluate the efficiency with which soil penetration resistance is estimated using a proposed model based on moisture content, density and organic matter content in an Oxisol containing 665, 221 and 114 g kg-1 of clay, silt and sand respectively under annual no-till cropping, […]
