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	Provedor de dados AgEcon (4) REA (1) PAB (1) Rev. Bras. Ciênc. Solo (1) Autor English, Burton C. (3) Roberts, Roland K. (3) Larson, James A. (2) Mahajanashetti, S.B. (2) Amado,Telmo Jorge Carneiro (1) Amaral,Lucas R. do (1) Babcock, Bruce A. (1) Baron,Felipe Arthur (1) Bragagnolo,Jardes (1) Corassa,Geomar Mateus (1) Fiez, Timothy E. (1) Fioresi,Dejales (1) Flora,Diandra Pinto Della (1) Hennessy, David A. (1) Jasper,Joerg (1) Justina,Diego D. Della (1) Kunz,Junior (1) Mooney, Daniel F. (1) Nicoloso,Rodrigo da Silveira (1) Reimche,Geovane Boschmann (1) Mais... Palavra-chave Site-specific management (7) Precision agriculture (3) Crop Production/Industries (2) Farm Management (2) Precision farming (2) Soil fertility (2) Soil sampling (2) Spatial variability (2) Variable rate technology (2) Capital budgeting (1) Corn (1) Data interpolation (1) Decision aid (1) Environment (1) Farm management (1) Geostatistics (1) Management zones (1) Map-based (1) Meta-response functions (1) Negative externality (1) Mais... Tipo do documento Info:eu-repo/semantics/article (3) Journal Article (2) Conference Paper or Presentation (1) Working or Discussion Paper (1) Ano 2019 (1) 2018 (1) 2013 (1) 2009 (1) 2002 (1) 2001 (1) 1996 (1) Mais... País United States (4) Brazil (3) Idioma Inglês (7)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 7 Primeira ... 1 ... Última SPATIAL DEPENDENCE DEGREE AND SAMPLING NEIGHBORHOOD INFLUENCE ON INTERPOLATION PROCESS FOR FERTILIZER PRESCRIPTION MAPS REA Amaral,Lucas R. do; Justina,Diego D. Della. ABSTRACT Data interpolation is widely required in precision agriculture. However, its effectiveness is a function of the characteristics of the dataset, being necessary for the evaluation of several parameters. This study aimed to identify how the spatial interpolators, Kriging, and Inverse Distance Weighting, are influenced by the degree of spatial dependence of the variables analyzed and the number of neighbors considered in the interpolation process (sampling neighborhood). Soil samples were collected from three sugarcane fields. By the optimization process, we verified that the sampling neighborhood influences the accuracy of interpolations, but there is not a standard recommendation to follow. Thus, the best sampling neighborhood must ever be... Tipo: Info:eu-repo/semantics/article Palavras-chave: Data interpolation; Soil sampling; Geostatistics; Site-specific management. Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162019000800085 Soil chemical attributes restricting grain yield in Oxisols under no-tillage system PAB Corassa,Geomar Mateus; Santi,Antônio Luís; Silva,Vanderlei Rodrigues da; Baron,Felipe Arthur; Reimche,Geovane Boschmann; Fioresi,Dejales; Flora,Diandra Pinto Della. Abstract: The objective of this work was to identify soil chemical attributes restricting grain yield in Oxisols under the no-tillage system, using directed soil sampling. High, medium, and low yield zones were defined in two agricultural fields using historical yield data of several crops. The yield zones were defined based on the harvest maps of the following crops: corn in 2008/2009, white oat in 2009, and corn in 2012/2013 in field I, with 117.70 ha; and corn in 2009/2010, soybean in 2010/2011, and wheat in 2012 in field II, with 107.30 ha. Soil sampling points were georeferenced in each yield zone, where samples were collected at eight soil depths, spaced 0.05 m apart, totaling 80 variables. Low yields were associated with low cation exchange... Tipo: Info:eu-repo/semantics/article Palavras-chave: Organic matter; Precision agriculture; Site-specific management; Soil fertility; Soil sampling; Yield zones. Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018001101203 VARIABLE RATE NITROGEN APPLICATION ON CORN FIELDS: THE ROLE OF SPATIAL VARIABILITY AND WEATHER AgEcon Roberts, Roland K.; Mahajanashetti, S.B.; English, Burton C.; Larson, James A.; Tyler, Donald D.. Meta-response functions for corn yields and nitrogen losses were estimated from EPIC-generated data for three soil types and three weather scenarios. These metamodels were used to evaluate variable rate (VRT) versus uniform rate (URT) nitrogen application technologies for alternative weather scenarios and policy option. Except under very dry conditions, returns per acre for VRT were higher than for URT and the economic advantage of VRT increased as realized rainfall decreased from expected average rainfall. Nitrogen losses to the environment from VRT were lower for all situation examined, except on fields with little spatial variability. Tipo: Journal Article Palavras-chave: Corn; Environment; Meta-response functions; Nitrogen restriction; Precision farming; Site-specific management; Spatial variability; Weather variability; Crop Production/Industries. Ano: 2002 URL: http://purl.umn.edu/15512 ASSESSING SPATIAL BREAK-EVEN VARIABILITY IN FIELDS WITH TWO OR MORE MANAGEMENT ZONES AgEcon English, Burton C.; Mahajanashetti, S.B.; Roberts, Roland K.. Farmers are interested in knowing whether applying inputs at variable rates across a field is economically viable. The answer depends on the crop, the input, their prices, the cost of variable rate technology (VRT) versus uninform rate technology (URT), and the spatial and yield response variability within each field. Methods were investigated for determining the range of spatial variability over which the return to VRT covers its additional cost compared with URT in fields with multiple management zones. Models developed in this article, or variants thereof, could be used to help farmers make the VRT adoption decision. Tipo: Journal Article Palavras-chave: Management zones; Nitrogen; Precision farming; Site-specific management; Spatial break-even variability proportions; Spatial variability; Variable rate technology; Yield response variability; Farm Management. Ano: 2001 URL: http://purl.umn.edu/15450 Effects of Site-Specific Management on the Application of Agricultural Inputs AgEcon Hennessy, David A.; Babcock, Bruce A.; Fiez, Timothy E.. Site-specific management of inputs in agricultural production is receiving increasing attention because of new technologies and concerns about excessive input use. This paper provides a microeconomic analysis of its implications. It shows that profit decreases with an increase in the variability of input requirements, but that the input and production effects can be quite complicated. The effects of moving from uncertainty about input requirements to variable requirements are also identified. An empirical study of nitrogen fertilization suggests that sitespecific management may reduce input use substantially, but the production and profitability impacts may not be large. Tipo: Working or Discussion Paper Palavras-chave: Negative externality; Site-specific management; Uncertainty; Variability; Crop Production/Industries. Ano: 1996 URL: http://purl.umn.edu/18521 Economics of the Variable Rate Technology Investment Decision for Agricultural Sprayers AgEcon Mooney, Daniel F.; Larson, James A.; Roberts, Roland K.; English, Burton C.. Producers lack information about the profitability of variable rate technology (VRT) for agricultural sprayers. An economic framework was developed to evaluate the returns required to pay for VRT investments. Payback variables included input savings, yield gains, and reduced application costs. We illustrate the framework with two example investment scenarios. Tipo: Conference Paper or Presentation Palavras-chave: Capital budgeting; Decision aid; Farm management; Precision agriculture; Map-based; Sensor-based; Site-specific management; Variable rate technology; Farm Management; Q10; Q16. Ano: 2009 URL: http://purl.umn.edu/46860 Optical crop sensor for variable-rate nitrogen fertilization in corn: i - plant nutrition and dry matter production Rev. Bras. Ciênc. Solo Bragagnolo,Jardes; Amado,Telmo Jorge Carneiro; Nicoloso,Rodrigo da Silveira; Jasper,Joerg; Kunz,Junior; Teixeira,Tiago de Gregori. 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 experiments were conducted at different locations in Southern Brazil, in the growing seasons 2008/09 and 2010/11. The following crop properties were evaluated: above-ground dry matter production, nitrogen... Tipo: Info:eu-repo/semantics/article Palavras-chave: Site-specific management; Optical spectrometry; Precision agriculture; Soil fertility. Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000500018 Registros recuperados: 7 Primeira ... 1 ... Última

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