The excess of heavy metals contaminating soils is responsible for a negative impact on microorganisms and toxicity on plants, hence turning revegetation and rehabilitation of areas degraded by these metals very difficult. In the present study, the effects of the isoflavonoid formononetin (7 hydroxy 4’methoxy isoflavona) on growth and metal uptake by corn (Zea mays L.) were studied in soil-mixes with increasing proportions of a contaminated soil with 16.904; 194; 219 and 836 mg dm-3 of soil of Zn, Cd, […]

Irrigation quality has been described by calculated parameters assuming that water storage capacity in soil is a constant. However, this property presents spatial variations. Concern with environmental and economic aspects has led to culture management in specific areas, a fact which requires knowledge of spatial distribution of soil properties. Geostatistics makes possible the identification of the spatial dependence structure and the mapping of a given soil property. The objective of this work was to identify sampling and block kriging intensities, […]

This experiment was conducted in leaching tubes filled with soils classified as Typic Quartzipsament (AQ), Typic Hapludox (LV) and Rhodic Typic (LE). Sewage sludge was periodically added and incorporated to the soils in a total amount corresponding to 156,0 t ha-1 (dry weight basis), for an incubation period of 310 days. The soils were then treated with water and the following salt solutions: 0.9 mol L-1 KCl; 0.9 mol L-1 KNO3; 0.3 mol L-1 K2SO4 and 0.3 mol L-1 Ca(NO3)2. […]

The most probable number (MPN) for soil bacteria and fungi was determined using a micro-assay technique, which was more economical and less tedious. This technique was compared with the conventional procedure for counting soil microorganisms in soil samples with different textures. The sensitivity of this method could be also verified when used to evaluate number of microorganisms from different sources of organic matter and chromium added to the soil.

The characterization and quantification of soil organic matter as water soluble carbon, labile carbon and light organic matter may be used to characterize the rehabilitation of degraded areas. Soil samples were thus collected on a hillside cut submitted to reclamation, presenting different types of vegetal covering during November 1994, in the district of Viçosa. The treatments consisted of areas of soils without vegetation, recovering areas with mainly legumes, recovering areas with mainly grass, soils under grass and soils under natural […]

Organic matter is considered the soil attribute most sensitive to the changes triggered by the management systems. The objective of this study was to evaluate the effect of nine years using three soil tillage systems -conventional tillage, reduced tillage and no tillage- on soil chemical characteristics of a Humic Cambisol in southern Brazil. Soil samples were collected in September 1996 at depths of 0-2, 2-5, 5-10, 10-15, and 15-20 cm, and analysed for C and N contents in total organic […]

The macronutrient removal by both cashew nut and apple was evaluated in orchards of two dwarf clones in a field without irrigation and fertilization on a Red-Yellow Podzolic at Pacajus Experimental Station (Centro Nacional de Pesquisa de Agroindústria Tropical (CNPAT/EMBRAPA)), in Pacajus, Ceará, Brazil, from March/94 to April/95. CCP-76 and CCP-09 cashew clones did not differ with regard to the macronutrient quantities removed by the cashew nut and cashew apple, except for Ca. This macronutrient was removed in greater quantity […]

This work was based on six experiments carried out in the northwestern region of the state of São Paulo, using six common varieties of sugarcane. The soil of each locality was classified and both deformed and undeformed samples of soils were collected in a 150 cm deep profile, by horizon, for chemical, physical and physico-hydric characterization. Data on climate and sugarcane plant-cane yield for the 96/97 harvest season were also collected. To determine which factors were better correlated with productivity, […]

Through profile morphology and physical analysis (texture, bulk and particle densities, pore size distribution, water storage and retention, and field capacity determined “in situ”), the behavior of a yellow Latosol located in Cruz das Almas (BA), Brazil, was studied when subjected to irrigation. The results made showed that the AB and BA horizons were hard (cohesion), mainly when dry, becoming a strong mechanic impediment fot root growth , aeration and water movement; due to the presence of the hard layer, […]

Shoot growth, phosphorus uptake (PC) and utilization efficiency (PUE) of Eucalyptus grandis seedlings associated to Glomus etunicatum (Ge) and, or, Pisolithus tinctorius (Pt), in different P rates and soil water potentials (ψ), were evaluated in a greenhouse experiment with two geminated pots, using a split-root technique. One of the pots in the geminated set contained the treatments, arranged in a factorial scheme of two P rates (P60 and P120, corresponding to additions of 60 and 120 mg dm-3 soil), three […]