The recent shift in soil tillage from conventional to no-tillage systems in Brazil alters the soil system dynamics. In soils cultivated under the no-tillage system the relations are established and preserved over the course of time, which increases the functional complexity of the system, while under the conventional system often destroys these relationships. Some questions have risen about the reliability of sampling the so-called “arable soil layer” (0-20 cm) for soil acidity quantification in the no-tillage system due to the […]

The soil acidity and associated variables are very important on soil management, especially at tropical and subtropical regions. In order to study some soil acidity variables and verify the influence of clay mineralogy on the relationship between pH and base saturation degree (V%), soil samples were collected from B and C horizons of different soil classes in Paraná State: Acric Red-Yellow Latossol (LBw-1), Dystric Red-Yellow Latossol (LBw-2), Dusky Red Latosol (LVdf), Alumic Cambisol (CXa) and Dystric Cambisol (CHd). The clay […]

Despite the chemical differences in soils under the fertilizer bands and inter-rows in orange orchards, no criterion to determine the need of liming in the two areas is yet known. The objective of this study was to quantify the temporary chemical alterations in fertilizer bands and inter-rows of a “Pêra” orange orchard as well as nutrition and fruit yield after surface liming, in a Typic Paleudults, in northwestern Paraná, Brazil. The soil surface was limed four times between 1996 and […]

No-tillage systems can change the ratio between soil acidity components and crop yields over the course of time. High crop yields are not seldom observed in highly acid soils. The liming criteria established for conventional tillage soils are likely to be unsuitable for no-tillage soils. The objective of this report was to define liming criteria, based on the yield response to different soil acidity levels and layers in no-tillage systems. Six plantations were sampled in the Planalto region of the […]

Cattle ranching is one of the main economic activities in the agrosystem of Itapetinga, state of Bahia, Brazil. This activity is known to cause direct impacts on soil, subsoil and vegetation. This study aimed at verifying changes in soil chemical characteristics and texture under different vegetation covers in the cattle ranching region of Itapetinga by sampling soils in a primary forest-secondary forest-pasture sequence. Soil samples were collected along a transect with 36 small trenches, 60 cm deep, spaced 5 m apart (12 […]

Alterations in soil chemical properties after liming depend on the frequency of soil sampling and rainfall. This study evaluated such alterations in a Typic Haplorthox (Rhodic Ferralsol) with a sandy-loam superficial layer. The experiment had a completely randomized block design, with four dolomitic lime rates (0, 2.4, 4.8, and 7.2 t ha-1) and three replicates. The experiment was carried out in Alto Parana in northwestern Parana state (southern Brazil). Lime was broadcast on the soil surface over Brachiaria decumbens grass residues in-between […]

A greenhouse experiment was carried out to evaluate the effect of the Ca/Mg ratio in the cation exchange capacity on common bean growth. Samples of a typic ferric aluminum Red Latosol (LVat) and a psamitic dystrophic Red Latosol (LVdp), both Haplortox (U.S. Soil Taxonomy) in pots containing 3.5 dm3 of soil were treated with Ca:Mg ratios of 1/2, 1, 2, 4, 6 and 8. The experiment was arranged in a completely randomized block design with six replications. Three replications were harvested […]

Calcium silicate slag, as a soil acidity corrective material with long-lasting residual effects, can benefit long-cycle cultures like sugar cane, thus minimizing production drops during the productive cycle. This study evaluated different base saturation levels, comparing calcitic limestone to basic slag as a soil corrective agent, in relation to alterations of some chemical soil properties, as well as to the response of sugar cane rattoon. Sugar cane of the SP 80-1842 type, during the third and fourth cut in the agricultural […]

High acidity predominates in southeastern and midwestern Brazilian soils, where the largest area of sugar cane plantations is concentrated. Large amounts of slag, a steel-industry residue containing nutrients such as calcium and magnesium and acting as acidity corrective agents, are also present in the region. This study aimed to evaluate different base saturation levels using slag as a soil corrective agent. This material was compared to calcitic limestone to analyze acidity neutralization and certain chemical soil properties, as well as […]

The efficiency of surface application of lime under a no-tillage system is doubtful, particularly with regard to subsoil acidity and to methods of lime requirement determination. A field experiment was carried out on a dystrophic Dark Red Latosol (Haplortox) from Ponta Grossa, Paraná, Brazil, from 1993 to 1998, to evaluate the extent of downward movement of lime applied on the surface under a no-tillage system, and the effect on crop rotation grain yields. A randomized complete block design was used, […]