|
|
|
| Registros recuperados: 12 | |
|
|
| Medeiros,Wilker Nunes; Valente,Domingos Sárvio Magalhães; Queiroz,Daniel Marçal de; Pinto,Francisco de Assis de Carvalho; Assis,Igor Rodrigues de. |
| ABSTRACT Mapping the apparent soil electrical conductivity (ECa) has become important for the characterization of the soil variability in precision agriculture systems. Could the ECa be used to locate the soil sampling points for mapping the chemical and physical soil attributes? The objective of this work was to examine the relations between ECa and soil attributes in two fields presenting different soil textures. In each field, 50 sampling points were chosen using a path that presented a high variability of ECa obtained from a preliminary ECa map. At each sampling point, the ECa was measured in soil depths of 0-20, 0-40 and 0-60 cm. In addition, at each point, soil samples were collected for the determination of physical and chemical attributes in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Management zones; Soil sampling. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902018000100043 |
| |
|
| |
|
| |
|
| |
|
|
| Guedes Filho,Osvaldo; Vieira,Sidney Rosa; Chiba,Marcio Koiti; Grego,Célia Regina. |
| It is known, for a long time, that crop yields are not uniform at the field. In some places, it is possible to distinguish sites with both low and high yields even within the same area. This work aimed to evaluate the spatial and temporal variability of some crop yields and to identify potential zones for site specific management in an area under no-tillage system for 23 years. Data were analyzed from a 3.42 ha long term experimental area at the Centro Experimental Central of the Instituto Agronômico, located in Campinas, Sao Paulo State, Brazil. The crop yield data evaluated included the following crops: soybean, maize, lablab and triticale, and all of them were cultivated since 1985 and sampled at a regular grid of 302 points. Data were normalized and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial variability; Cross semivariogram; Management zones. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052010000500003 |
| |
|
| |
|
|
| Bernardi,Alberto Carlos de Campos; Tupy,Oscar; Santos,Karoline Eduarda Lima; Mazzuco,Giulia Guillen; Bettiol,Giovana Maranhão; Rabello,Ladislau Marcelino; Inamasu,Ricardo Yassushi. |
| Abstract: The objective of this work was to evaluate the spatial and temporal variability of the dry matter yield of irrigated corn for silage, as well as its economic return. The study was conducted in an irrigated silage corn field of 18.9 ha in the municipality of São Carlos, in the state of São Paulo, Brazil. The spatial variability of the yield of three crop seasons, normalized yield indexes, production cost, profit, and soil electrical conductivity (EC) were modeled using semivariograms. Yield maps were obtained by kriging, and management zones were mapped based on average yield, normalized index, and EC. The results showed a structured spatial variability of corn yield, production cost, profit, and soil EC within the irrigated area. The adopted... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zea mays; Economic return; Management zones; Soil electrical conductivity; Temporal stability; Yield maps. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2018001201289 |
| |
|
| |
|
|
| Buss,Ricardo N.; Silva,Raimunda A.; Siqueira,Glécio M.; Leiva,Jairo O. R.; Oliveira,Osmann C. C.; França,Victor L.. |
| ABSTRACT The objective of this study was to evaluate the spatial variability of soybean yield, carbon stock, and soil physical attributes using multivariate and geostatistical techniques. The attributes were determined in Oxisols samples with clayey and cohesive textures collected from the municipality of Mata Roma, Maranhão state, Brazil. In the study area, 70 sampling points were demarcated, and soybean yield and soil attributes were evaluated at soil depths of 0-0.20 and 0.20-0.40 m. Data were analysed using multivariate analyses (principal component analysis, PCA) and geostatistical tools. The mean soybean yield was 3,370 kg ha-1. The semivariogram of productivity, organic carbon (OC), and carbon stock (Cst) at the 0-0.20 m layer were adjusted to the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Management zones; Geostatistics; Principal components. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662019000600446 |
| |
|
|
| Machado,Flavia Cristina; Montanari,Rafael; Shiratsuchi,Luciano Shozo; Lovera,Lenon Henrique; Lima,Elizeu de Souza. |
| Brazilian soils have natural high chemical variability; thus, apparent electrical conductivity (ECa) can assist interpretation of crop yield variations. We aimed to select soil chemical properties with the best linear and spatial correlations to explain ECa variation in the soil using a Profiler sensor (EMP-400). The study was carried out in Sidrolândia, MS, Brazil. We analyzed the following variables: electrical conductivity - EC (2, 7, and 15 kHz), organic matter, available K, base saturation, and cation exchange capacity (CEC). Soil ECa was measured with the aid of an all-terrain vehicle, which crossed the entire area in strips spaced at 0.45 m. Soil samples were collected at the 0-20 cm depth with a total of 36 samples within about 70 ha. Classical... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Precision agriculture; Electrical conductivity; Management zones. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832015000401112 |
| |
|
|
| Ribeiro,Felipe O.; Fernandes,Antonio R.; Matos,Gilson S. B. de; Lindolfo,Marcelo M.; Guedes,Rafael S.; Rodrigues,Graziele R.. |
| ABSTRACT This study aimed to define management zones (MZs) for fertirrigated açaí cultivation, based on spatial variability of the foliar nutrients and productivity data. The work was carried out in an area of 5.75 ha of a 7-year crop, with 80 georeferenced sample points. Fresh fruit productivity and nutrient (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn) contents were determined. The average contents of macronutrients were considered adequate for adult açaí plants, and their spatial dependence associated with fruit productivity allowed the representation of their distributions through maps of variability. Through multivariate analysis, three main components were highlighted. These components explained 51.5 % of the total variability of the data, where PC1... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amazon; Management zones; Multivariate analysis; Nutrient contents; Precision agriculture. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000600800 |
| |
|
| |
| Registros recuperados: 12 | |
|
|
|
