59 results

Soil phosphorus availability and soybean response to phosphorus starter fertilizer

Ciro Antonio Rosolem, Alexandre Merlin

01/Oct/2014

Phosphorus fixation in tropical soils may decrease under no-till. In this case, P fertilizer could be surface-spread, which would improve farm operations by decreasing the time spend in reloading the planter with fertilizers. In the long term, less soluble P sources could be viable. In this experiment, the effect of surface-broadcast P fertilization with both soluble and reactive phosphates on soil P forms and availability to soybean was studied with or without fertilization with soluble P in the planting furrow […]

Soil chemical atributes associated with wheat yield in a plot with different yield potentials

Luiz Fernando Machado Kramer, Marcelo Marques Lopes Müller, Cassio Antônio Tormena, Aline Marques Genú, Leandro Michalovicz, Marcelo Vicensi

01/Aug/2014

Different yield potentials between plots and within them have been verified in areas managed under no-till (NT). Precision farming (PF) techniques can help in identifying these distinct areas, but for efficient soil fertility management in areas under long-term NT, there must be representative sampling. The aim of this study was to evaluate the influence of soil chemical properties on wheat yield in accordance with the sampling layer or depth in an area under long-term NT using zones of a plot […]

Efficiency of nitrogen fertilizer applied at corn sowing in contrasting growing seasons in Paraguay

Telmo Jorge Carneiro Amado, Enrique Oswin Hahn Villalba, Rafael Pivotto Bortolotto, Antônio Luis Santi, Enrique Asterio Benítez León, Dorothy Menefee, [...]

01/Dec/2013

In order to select soil management practices that increase the nitrogen-use efficiency (NUE) in agro-ecosystems, the different indices of agronomic fertilizer efficiency must be evaluated under varied weather conditions. This study assessed the NUE indices in no-till corn in southern Paraguay. Nitrogen fertilizer rates from 0 to 180 kg ha-1 were applied in a single application at corn sowing and the crop response investigated in two growing seasons (2010 and 2011). The experimental design was a randomized block with three […]

Optical crop sensor for variable-rate nitrogen fertilization in corn: i – plant nutrition and dry matter production

Jardes Bragagnolo, Telmo Jorge Carneiro Amado, Rodrigo da Silveira Nicoloso, Joerg Jasper, Junior Kunz, Tiago de Gregori Teixeira

01/Oct/2013

Variable-rate nitrogen fertilization (VRF) based on optical spectrometry sensors of crops is a technological innovation capable of improving the nutrient use efficiency (NUE) and mitigate environmental impacts. However, studies addressing fertilization based on crop sensors are still scarce in Brazilian agriculture. This study aims to evaluate the efficiency of an optical crop sensor to assess the nutritional status of corn and compare VRF with the standard strategy of traditional single-rate N fertilization (TSF) used by farmers. With this purpose, three […]

Chemical properties and mineralogy of soils with plinthite and petroplinthite in Iranduba (AM), Brazil

Cira Hortensia Pérez Garcia, Hedinaldo Narciso Lima, Francisco Weliton Rocha Silva, Afrânio Ferreira Neves Junior, Wenceslau Geraldes Teixeira, Rodrigo Santana Macedo, [...]

01/Aug/2013

Large areas of Plinthosols with ferruginous materials such as plinthite and/or petroplinthite are fairly common in the Brazilian Amazon basin. This work was carried out to investigate the chemical behavior, mineralogical composition and weathering stage of four representative soil profiles with plinthite and petroplinthite, in Iranduba, AM (Central Amazon). Three well-drained soil profiles at high elevations were studied (P1, Plinthic Vetic Ferralsol; P2 and P3, Vetic Endopetric Plinthosol) and a contrasting poorly drained soil (P4 Haplic Plinthosol), located at low […]

Strategy of specification of management areas: rice grain yield as related to soil fertility

Flávio Carlos Dalchiavon, Morel de Passos e Carvalho, Rafael Montanari, Marcelo Andreotti

01/Feb/2013

It is well-known nowadays that soil variability can influence crop yields. Therefore, to determine specific areas of soil management, we studied the Pearson and spatial correlations of rice grain yield with organic matter content and pH of an Oxisol (Typic Acrustox) under no- tillage, in the 2009/10 growing season, in Selvíria, State of Mato Grosso do Sul, in the Brazilian Cerrado (longitude 51º24′ 21” W, latitude 20º20′ 56” S). The upland rice cultivar IAC 202 was used as test plant. […]

Characterization of soil chemical properties of strawberry fields using principal component analysis

Gláucia Oliveira Islabão, Marília Alves Brito Pinto, Lisiane Priscila Roldão Selau, Ledemar Carlos Vahl, Luís Carlos Timm

01/Feb/2013

One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS) is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component […]

Potential acidity estimated by SMP pH in soils of the state of Pará

Marcos André Piedade Gama, Gilson Sergio Bastos de Matos, George Rodrigues da Silva, Edilson Carvalho Brasil, Otiniel Ferreira Nunes

01/Feb/2013

The use of SMP pH to estimate the potential acidity (H + Al) is more practical than the method of 0.5 mol L-1 calcium acetate for routine laboratory analyses. The objective was to fit an equation to estimate the H + Al from SMP pH values of soils of the State of Pará. From various regions of the state, 177 soil samples were collected, in which the SMP pH was determined in 0.01 mol L-1 CaCl2 solution and H + […]

Liming criteria and critical levels of phosphorus and potassium in oxisoils under no-till system of the south-central region of Paraná state, Brazil

Renan Costa Beber Vieira, Cimélio Bayer, Sandra Mara Vieira Fontoura, Ibanor Anghinoni, Paulo Roberto Ernani, Renato Paulo de Moraes

01/Feb/2013

When conventional tillage is replaced by no-tillage (NT) changes occur in the dynamics of soil nutrients and acidity, which may influence the soil-plant relationships and consequently, the criteria for soil fertility management. This study determined the criteria for liming as well as the soil critical levels for P and K in a crop rotation of soybean, maize, wheat, barley, and white oat, widely used in the South-Central region of the State of Parana, in Southern Brazil. The study involved 13 […]

Sulfur in agriculture

Adriano Reis Lucheta, Marcio Rodrigues Lambais

01/Nov/2012

Sulfur (S) deficiency in soils is becoming increasingly common in many areas of the world as a result of agronomic practices, high biomass exportation and reduced S emissions to the atmosphere. In this review, the incidence and commercial exploitation of S pools in nature are discussed, as well as the importance of S for plants and the organic and inorganic S forms in soil and their transformations, especially the process of microbiological oxidation of elemental sulfur (S0) as an alternative […]

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