Potassium fertilizer management for sugar cane
01/Aug/2010
Brazil is the largest sugar cane producer in the world and, due to the increasing interest in renewable energy sources, the cultivated area is expanding. Sugar cane is usually planted in soil with low nutrient levels, which can limit the yield. In sugar cane, potassium is basically applied in the furrow, which can decrease the K use efficiency due to leaching or salinizaton to plant roots. The goal of this study was to evaluate stalk yield and technological properties of […]
Liming influence on soil chemical properties, nutritional status and yield of alfalfa grown in acid soil
01/Aug/2010
Alfalfa is an important forage crop with high nutritive value, although highly susceptible to soil acidity. Liming is one of the most efficient and prevailing practices to correct soil acidity and improve alfalfa yield. The objective of this study was to evaluate response to liming of alfalfa grown in a greenhouse on a Typic Quartzipsamment soil. The treatments consisted of four lime rates (0, 3.8, 6.6 and 10.3 Mg ha-1) and two cuts. Alfalfa dry matter increased quadratically with increasing lime rates. […]
Coffea arabica L. nutritional status survey based on dris, in the Upper Paranaíba region – Minas Gerais
01/Aug/2010
A striking characteristic of soils under savanna vegetation is the low natural fertility, as in soils in the Upper Paranaíba region – MG. This characteristic is aggravated by the use of low fertilizer quantities, which may cause nutritional imbalance in plants. The objective of this study was to evaluate the nutritional status of coffee plants in the Upper Paranaíba region – MG, using the integrated system for diagnose and recommendation (DRIS) to interpret leaf analyses and apply the fertilization response […]
Attributes of irrigated rice and soil solution as affected by salinity levels of the water layer
01/Aug/2010
In the State of Rio Grande do Sul, Brazil, flooded rice fields using Patos Lagoon as the source of water for irrigation are subject to be damaged by salinity, since this source is bound to the sea on its southern end. The sensitivity of rice is variable during plant development, being higher in the seedling and reproductive periods. However, there is not enough information about the behavior of plants under salt stress during the course of its development, especially in […]
Restoration of the soil structure by crop sequences established in no-till, as related to water erosion in distinct surface physical conditions
01/Aug/2010
Soil structure plays a prominent role in plant growth and erosion control, and consequently in food production and soil and water conservation. This research was developed with the objective of implementing and accompanying the restoration process of the structure of a degraded soil, by planting crop sequences under no-tillage (autumn-winter and spring-summer, grass and legume, in single and intercropped systems), and later verifying the relations with water and soil losses caused by rainfall erosion, under distinct surface physical conditions (untilled […]
Diversity and efficiency of bradyrhizobium strains isolated from soil samples collected from around sesbania virgata roots using cowpea as trap species
01/Aug/2010
The genetic diversity of ten Bradyrhizobium strains was evaluated for tolerance to high temperatures, to different salinity levels and for the efficiency of symbiosis with cowpea plants (Vigna unguiculata (L.) Walp.). Eight of these strains were isolated from nodules that appeared on cowpea after inoculation with suspensions of soil sampled from around the root system of Sesbania virgata (wand riverhemp) in ecosystems of South Minas Gerais. The other two strains used in our analyses as references, were from the Amazon […]
Soil shear strength under non-irrigated and irrigated short duration grazing systems
01/Jun/2010
Pasture productivity can drop due to soil compaction caused by animal trampling. Physical and mechanical alterations are therefore extremely important indicators for pasture management. The objective of this research was to: draw and evaluate the Mohr failure line of a Red Yellow Latossol under different pasture cycles and natural forest; calculate apparent cohesion; observe possible physical alterations in this soil; and propose a correction factor for stocking rates based on shear strength properties. This study was conducted between March/2006 and […]
Relationship between the soil water content and root penetration resistance of a dystrocohesive yellow argissol
01/Jun/2010
Soil resistance to root penetration is the main parameter to express the soil compaction degree and the facilities that it offers to root penetration. The purpose of this study was to characterize the ratio of the soil water content and root penetration resistance of a DystrocohesiveYellow Argissol in the Recôncavo Baiano (Bahia, Brazil). The study was carried out in a commercial citrus orchard with ‘Pera’ sweet orange (Citrus sinensis Osb.) grafted on ‘Rangpur’ lime (Citrus limonia Osbeck) with a green […]
Soil spectral library and its use in soil classification
01/Jun/2010
Soil science has sought to develop better techniques for the classification of soils, one of which is the use of remote sensing applications. The use of ground sensors to obtain soil spectral data has enabled the characterization of these data and the advancement of techniques for the quantification of soil attributes. In order to do this, the creation of a soil spectral library is necessary. A spectral library should be representative of the variability of the soils in a region. […]
Dielectric constant obtained from TDR and volumetric moisture of soils in southern Brazil
01/Jun/2010
Soil moisture is the property which most greatly influences the soil dielectric constant, which is also influenced by soil mineralogy. The aim of this study was to determine mathematical models for soil moisture and the dielectric constant (Ka) for a Hapludalf, two clayey Hapludox and a very clayey Hapludox and test the reliability of universal models, such as those proposed by Topp and Ledieu and their co-workers in the 80’s, and specific models to estimate soil moisture with a TDR. […]
