3312 results

Correlation between characteristics of latosols from Minas Gerais State, Brazil, and parameters of adsorption equations of copper and zinc

C. W. A. Nascimento, R. L. F. Fontes

01/Dec/2004

Copper and zinc adsorption is one of the main phenomena controlling the availability of these metals to plants. As a consequence, studies on the adsorption of such elements in soils may be useful tools to understand the relationship between soil characteristics and retention of these micronutrients. The present study examined the adsorption of copper and zinc in six Latosols (Oxisols) with a wide range of chemical properties. Solutions containing different Cu and Zn concentrations (0, 10, 20, 40, 60, 80, […]

Water erosion on an Hapludox submitted to different soil managements under simulated rainfall. I – Soil and water losses

D. Leite, I. Bertol, J. C. Guadagnin, E. J. Santos, S. R. Ritter

01/Dec/2004

Soil management influences surface cover and roughness, and it is the major factor that affects water erosion. A rotating-boom rainfall simulator operated at a constant rainfall intensity of 64 mm h-1 and 0.2083 MJ ha-1 mm-1 kinetic energy was used to investigate water erosion and related parameters in six management systems of corn and bean crops. The experiments were carried out on a clayey loam structured soil (Hapludox) with 0.165 m m-1 average slope, on the Southern Plateau of Santa Catarina State, Brazil, from March […]

Assessment of spatial variability of soil attributes as a basis for the adoption of precision agriculture in sugarcane plantations

J. E. Corá, A. V. Araujo, G. T. Pereira, J. M. G. Beraldo

01/Dec/2004

The spatial variability of physical and chemical attributes of Latosols (Oxisols) cultivated with sugarcane was assessed. The study was carried out in a 90 ha area in the surroundings of Jaboticabal, São Paulo State, Brazil (21 º 15 ‘ S and 48 º 18 ‘ W). A 50 m regular grid was projected onto the experimental area. Soil samples were obtained at each 50 m grid point (421 points) from the 0 to 0.20 m and from the 0.60-0.80 m soil layers. Organic matter, pH, P, K+, Ca2+, Mg2+, H + Al, CEC, soil […]

Viability of soybean inoculation with Bradyrhizobium strains in flooded soil

D. Scholles, L. K. Vargas

01/Dec/2004

Soybean can be a viable alternative crop for lowlands. However, soybean relies on biological nitrogen fixation, a process that is normally affected by soil flooding, depending on the macrosymbiont genotype. Moreover, the behavior of different bradyrhizobia strains in flooded soil is yet unknown. The present research aimed to evaluate the efficiency of Bradyrhizobium elkanii and Bradyrhizobium japonicum strains recommended for soybean in comparison to mineral nitrogen fertilization, in flooded soil. The experiment was carried out in a greenhouse, where soybean […]

Peach palm growth and heart-of-palm yield responses to liming

M. L. A. Bovi, S. H. Spiering, L. A. Saes

01/Dec/2004

The effects of liming rates on growth and heart-of-palm yield of peach palm plants (Bactris gasipaes Kunth) were studied in a two-year field experiment conducted in Pariquera-Açu, State of Sao Paulo, Brazil. Soils in this region are allic (sub group Ultic Haplorthox), with base saturation ranging from 15 to 26 % of the cation exchange capacity (CEC). A randomized complete block design, with five rates of dolomitic limestone (0, 0.7, 4.7, 8.7, and 14.6 Mg ha-1) and five replications was utilized. Individual plots were […]

Soil compressibility under non-irrigated and irrigated short duration grazing systems

C. L. R. Lima, A. P. Silva, S. Imhoff, T. P. Leão

01/Dec/2004

Increment in pasture productivity has been associated with the understanding of the soil behavior under compression. The objective of this research was to quantify (a) the compression curves and (b) the preconsolidation pressure of the soils under non-irrigated and irrigated short duration grazing systems. Ninety-six undisturbed soil samples were taken from the four successive pasture cycles of Tanzania grass (Panicum maximum Jacq.) in a Hapludalf. The samples were saturated in water and equilibrated at the matrix potential (y): -10 kPa and then […]

Comparison of methods for determining microbial biomass in two soils

M. M. Andréa, M. J. Moreno Hollweg

01/Dec/2004

The potential of soil microbial biomass measurements as indicators of soil bioactivity and interferences in this environment can be verified by the amount of published papers on the subject. Nevertheless, a comparison among data from different authors, regions, and soils is only possible when the methodology employed in the determinations is the same. Several papers, however, propose different methodologies and calculations. This study evaluated the results of microbial carbon determination by different extraction and digestion methodologies in two distinct soils. […]

Phosphorus adsorption, specific surface, and mineralogical attributes of soils developed from volcanic rocks from the Upper Paranaíba, MG (Brazil)

F. C. Rolim Neto, C. E. G. R. Schaefer, L. M. Costa, M. M. Corrêa, E. I. Fernandes Filho, M. M. Ibraimo

01/Dec/2004

Despite relatively high levels of total P, most deeply-weathered tropical soils have very low levels of available P due to the low solubility of most P forms found in these soils. In this research we studied P adsorption of soils, some of which were rich in apatite, developed from basic to ultrabasic volcanic rocks in the Upper Paranaíba region of Minas Gerais State, in relation to the specific surface and clay mineralogy. Samples of eleven B horizons from representative Latosols […]

Morphology of soil aggregates evaluated by images analysis

N. Olszevski, L. M. Costa, E. I. Fernandes Filho, H. A. Ruiz, R. C. Alvarenga, J. C. Cruz

01/Oct/2004

The intensive soil use together with inadequate management practices contribute to the deterioration of soil physical properties, mainly due to modifications in the soil structure pattern. Once the structural changes could affect the morphology aggregates in different ways, the search for new methods of studying soil macro-morphological characteristics must be prioritized to allow the observation of modified characteristics in cultivated soils. Therefore, this study was carried out to adapt and test a digital method for a qualitative macro-morphological analysis of […]

Implications of soil management and compaction state on soil physical properties and soybean yield

D. Secco, D. J. Reinert, J. M. Reichert, C. O. da Ros

01/Oct/2004

Agricultural machinery traffic may lead to a restrictive state of soil compaction for crop yields in no-tillage systems. This study was conducted at the University of Cruz Alta, in Cruz Alta, State of Rio de Janeiro, Brazil. The main objective was to evaluate the effects of soil management systems and compaction states on selected soil physical properties and on yield of six soybean cultivars. The experiment was conducted on an Oxisol with 427 g kg-1 of clay, prior under no-tillage. The experimental […]

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