Soil heterogeneity is known to cause variability of soil-water storage. Thus intensive sampling is required to characterize its spatial pattern. For irrigation management, it is necessary to measure the soil water content between irrigations. The objectives of this paper are to identify whether spatial patterns of soil water content in sprinkler irrigated area present temporal stability and whether this property presents spatial dependence. Temporal stability of spatial dependence structures and spatial correlation with clay content were studied. A 180 m long […]

Bulk density is a soil parameter that can be easily measured, associated to other intrinsic soil properties such as texture and organic matter. Pore size distribution, soil resistance to root penetration, and available water are also related with bulk density. When comparing tillage systems, bulk density is frequently used. However, tillage and plant effects on bulk density variability have not been addressed. Bulk density variability is caused by traffic, wetting and drying processes, as well as root system activity. The […]

The suitability of four extraction methods (acetic acid 0.5 mol L-1, buffer pH 4.0, calcium chloride 0.0025 mol L-1 and water) for estimating the amount of available Si in soil for upland rice was determined. Four soil types corresponding to the following classes were used: Typic Acrustox – isohyperthermic (LEa), Typic Acrustox – isohyperthermic (LVa), Rhodic Acrustox – isohyperthermic (LRd) and Ustoxic Quartzipsammentic – isohyperthermic (AQa), all of them from the Triângulo Mineiro region in Minas Gerais, Brazil. Five Si levels were created in each […]

Two axial experiments were carried out in two soils of the Northeast of Brazil from 1987 to 1992 to study the response of coconut to urea, simple superphosphate and potassium chloride. Nitrogen was found to affect the number of fruit in the Quartz Sand Soil. The critical level for nitrogen in leaf 14 was 17.18 g kg-1 which was reached when 1.538 kg of N was applied per plant/year. In the same soil, simple superphosphate did not influence the number of fruit while […]

Different methods for quantification of active extraradicular mycelium (AEM) and total extraradicular mycelium (TEM) of arbuscular mycorrhizal fungi (AMF) were examined by conducting an experiment under greenhouse conditions, with a completely randomized factorial design and five replicates per treatment. The experiment was arranged in a 4 x 6 x 2 design and the factors were: 3 species of AMF (Glomus intraradices, G. etunicatum and G. clarum) and one control without AMF x 6 levels of P (0, 50, 100, 150, 200 and 250 mg kg-1) x 2 citrus species (Citrus reshni and […]

This study was conducted to characterize the morphology, physics, chemistry, mineralogy and pedography of soil profiles with Mollic horizon at Nazaré da Mata, Pernambuco, Brazil, 1995. Three soil profiles involving Litosol, Reddish Brunizém and Red Yellow Podzolic were morphologically described. Samples were taken from each horizon to determine the physical, chemical (including humic fraction quantification), mineralogical and pedographycal properties. Based on soil properties and environmental conditions, it could be assumed that the surface horizons were developed from climate – vegetation […]

The objective of this experiment was to quantify variations in maize canopy of plants submitted to two water managements (irrigated and terminal soil water deficit) in clayey, loamy and sandy soils. The experiment was conducted at the experimental area of the Rural Engineering Department of the Federal University of Santa Maria during the 1995/1996 growing season. A set of 12 drainage lysimeters was used. These were 156 cm long, 100 cm wide and 80 cm deep and were placed under a shelter to avoid […]

Six calcareous soil profiles (P1, P2, P3, P4, P5 and P6) were investigated with regard to their main characteristics of soil organic matter related to structural organization. The effect of degrading processes on these soils was also considered, mainly under intensive cultivation. Based on morphological in situ observation and analytical data, the profiles P1 e P2 showed organic matter with an advanced level of evolution presenting reasonable amounts of low polymerized materials (fulvic acids). Conversely, profiles P3, P4, P5 e […]

Total and soluble boron contents were evailable by means of three extractors, used as plant availability indexes, in order to study their relationships with soil properties in representative mapping units of the state of Ceará, Brazil. Composite soil samples from the surface soil layers (0-20 cm) of Quartz Sands (AQd), Alluvium (Ae), Planosol (PL), Bruno non Calcic (NC), Cambisol (Ce), Red-Yellow Podzol (PV), Red-Yellow Latosol (LV) and Littosol (Re) were used. Total boron was determined after fusion with sodium carbonate […]

Simple linear correlations among runoff and rainfall erosivity parameters and soil losses caused by erosivity rainfall in Haplargids were studied. Data related to 1986-1990 were obtained in the Experimental Station at Sumé-Brazil. The rainfall erosivity parameters were the following: a) total height of the rainfall (P) in mm; b) maximum intensity (In): I5; I10; I15; I20; I25; I30; I35; I40; I45; I50; I55; I60 and I120 minutes in mm h-1, respectively; c) total kinetic energy by the Wischmeier & Smith’s […]