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| Registros recuperados: 46 | |
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| Vieira,Sidney Rosa; Paz Gonzalez,Antonio. |
| The objective of this study was to assess spatial variability of soil properties and crop yield under no tillage as a function of time, in two soil/climate conditions in São Paulo State, Brazil. The two sites measured approximately one hectare each and were cultivated with crop sequences which included corn, soybean, cotton, oats, black oats, wheat, rye, rice and green manure. Soil fertility, soil physical properties and crop yield were measured in a 10-m grid. The soils were a Dusky Red Latossol (Oxisol) and a Red Yellow Latossol (Ultisol). Soil sampling was performed in each field every two years after harvesting of the summer crop. Crop yield was measured at the end of each crop cycle, in 2 x 2.5 m sub plots. Data were analysed using semivariogram... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spatial variability; Kriging; Yield map; Semivariogram. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052003000100016 |
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| Chiba,Marcio Koiti; Vieira,Sidney Rosa; González,Antonio Paz; Dechen,Sonia Carmela Falci; Maria,Isabella Clerici de. |
| This study was carried out in order to assess the spatial variability of some soil properties after adoption of no tillage system (NTS). A 19,200 m² plot was marked with a 20 x 20 m spacing grid. Crop yield and soil attributes, at 0-0.2 m deep layer, were measured in 63 points in 1985, 1987 and 1988. The spatial variability was assessed by semivariogram calculation using geostatistics. Soil base saturation index (BS) was interpolated by kriging and also, using a bivariate geostatistical method, the collocated cokriging (CLCK) using terrain elevation as ancillary data. Although, the coefficient of variation (Cv) for soil organic matter content decreased from 1985 (20.4%) to 1988 (10.7%), its mean value increased 32% in the same period. The soil fertility in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Geostatistics; Kriging; Cokriging. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052010000500005 |
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| Camacho-Tamayo,Jesús H; Luengas,Carlos A; Leiva,Fabio R. |
| Growing demand for food exerts pressure on natural resources and may lead to the expansion of agricultural frontiers in developing countries. Most of this pressure appears in tropical zones, in native savannahs, with naturally infertile soils prone to degradation. Crop management in these regions is based on generalized estimates, leaving aside the inherent soil variability, leading to low production efficiency and high risk of environmental damage. This study aims at determining the spatial variability of some chemical properties, including organic carbon, pH, exchangeable acidity, exchangeable aluminum, P, Ca, Mg, K and Na for two Oxisols with different levels of agricultural intervention, in Puerto Lopez, Colombia, in order to identify guidelines for... |
| Tipo: Journal article |
Palavras-chave: Geostatistics; Kriging; Soil management; Precision agriculture; Kriging. |
| Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392008000100005 |
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| Morais,Vinícus Augusto; Mello,José Marcio de; Mello,Carlos Rogério de; Silva,Carlos Alberto; Scolforo,José Roberto Soares. |
| ABSTRACT Litter corresponds to the layer of decomposing dead organic matter present on the soil surface. This layer is very important for nutrient cycling and contributes with organic matter accumulation in the soil, besides the carbon stock. The objective herein was to quantify the carbon biomass, both content and stock, and map the litter C-stock in the Cerrado biome, which is formed by Savanna Grassland (SG), Cerrado Stricto Sensu (CE) and Forest Savanna (FS), in Minas Gerais state, southeastern Brazil. The data were collected in 26 fragments in Minas Gerais state, totaling 210 sampling locations. A variographic study was conducted and, for mapping, the ordinary kriging method was used for delimitation of homogeneous zones. It was possible to detect... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Climate change; Kriging; Mapping procedures; Accumulated biomass.. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542017000500580 |
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| Aquino,Regimeire Freitas; Silva,Marx Leandro Naves; Freitas,Diego Antonio França de; Curi,Nilton; Mello,Carlos Rogério de; Avanzi,Junior Cesar. |
| Rainfall erosivity and its spatial variability were studied for 54 pluviometric stations in Southern Minas Gerais State (48º00' - 44º00'W; 23º50' - 20º00'S), aiming to plan the land-use strategies. Therefore, erosivity factor was determined for the pluviometric stations, using long-term rainfall data sets obtained along with the Brazilian National Water Agency- ANA, which varied from 15 to 40 years. The monthly and annual erosivity indexes were generated using Fournier equation for Lavras, MG and the spatial distribution of rainfall erosivity was studied on the basis of geostatistical approaches considering only the distance which separates them, developing the isotropic experimental semivariogram. The semivariogram adjustment was done based on the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Erosive potential; Soil sustainability; Kriging. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542012000500006 |
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| Registros recuperados: 46 | |
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