The efficiency of subsurface acidity alleviation by surface liming in the presence of crop residues is controversial and more information is needed. The objective of this study was to quantify the contribution of cover crop residues, regarding their contents of low molar mass organic acids and soluble nutrients to mobilization in the soil profile of the reaction products of surface-applied lime. Two experiments were carried out under laboratory conditions using 30 cm high PVC cylinders filled with acid and clayey […]

Nitrogen fertilization applied as sidedressing in corn can be optimized by considering additional soil characteristics as complementary indicators of soil N availability. The objectives of this study were to evaluate the potential use, critical level and best sampling time of the soil nitrate (NO3–-N) concentration to predict soil N availability in corn, as well as to verify if the determination of the soil ammonium (NH4+-N) concentration, in addition to NO3–-N concentration, enhances the efficiency of N availability evaluation. A field […]

The objective of this work was to evaluate the effects of gross irrigation depths on the nutrient concentration of Eucalyptus grandis seedlings, produced in different substrates. The experiment was carried out in Camará – Mudas Florestais, in Ibaté, São Paulo, in a factorial 5 x 4, with five daily irrigation levels (6, 8, 10, 12 and 14 mm), applied three times a day (at 10 am, 13 pm and 16 pm), on four substrates (FB- coconut fiber; CPV- pine bark […]

Preconsolidation pressure (sp) is determined by a consolidation test method, based on the gradual transference of a load onto the soil until all porosity is compressed. The equipment used for this test is a consolidometer, which is not available in Brazil, while the models used abroad are very costly. In some cases this situation impairs the access of Brazilian researchers and farmers to data of Soil Load Support Capacity (SLCS). This study had the objective of developing and evaluating an […]

The increasing need for food, space and other conditions for human survival generate greater anthropic interferences with the environment. Intensively and improperly tilled soils are degraded and illegal civil construction in rural areas is causing problems. Different techniques are being used to ameliorate these soils, mainly by the addition of organic matter, but information on the time required for soil recovery, influence of the organic matter type and on indicators of soil alterations is still rare. Our study aimed to […]

Particle distribution in soil or sediments of coastal plains contributes to the understanding of the sedimentation processes in estuaries. It is an important attribute for applications in studies of palaeoenvironmental reconstruction, geochemical cycles and environmental pollution such as heavy metal and oil spill contamination, which are relatively common in these sites due to human impact. With the objective of characterizing the sedimentary environments according to the particle size and the process of quaternary evolution, 14 mangroves along the São Paulo […]

The addition of fertilizers to the soil increases P contents in many forms of different bond energies with soil colloids. This has been observed in the soil surface layer under no tillage system, however there is little information about the availability of these P forms to plants. The study aimed to evaluate the bioavailability of P forms of a soil under no tillage with P applications. Samples were collected (0-10 cm) in a Rhodic Hapludox that had been fertilized with […]

The integration of farming and cattle production activities in no-tillage system areas with winter cover crops can be an income supplement for summer grain farmers. However, many of them are afraid of adopting this integration system, because of possible negative effects of animal treading on soil attributes, mainly of those related to soil compaction. This study was conducted: (1) to determine the alterations in the soil physical attributes promoted by animal treading; (2) to verify if the alterations in soil […]

The soils, some those considered homogenous, show some spatial and temporal variability of its physical, chemical and biological atributes. To define this variability is very important to efficient soil management. This study had the objective of investigating the spatial variability of some physical attributes of an Red Latosol in Mossoró, state of Rio Grande do Norte, Brazil, to determine the best procedure for soil sampling. Soil samples were collected on a 100 x 100 m area, in 10 m grid […]

Knowledge about the proper management of not-burned sugar cane is still limited, particularly regarding nitrogen fertilization. A field experiment was carried out to evaluate sugar cane yield, the balance of 15N fertilizers in the soil-plant-residue system and ammonia loss by volatilization in sugarcane ratoon crop without straw burning prior to mechanical harvesting, comparing different locations of surface-applied nitrogen fertilizers. The sugar cane variety SP81-3250. Treatments were arranged in a complete randomized blocks, with four replicates. The treatments consisted of four […]