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A Growth-Focused Spatial Econometric Model of Agricultural Land Development in the Northeast AgEcon
Hailu, Yohannes G.; Brown, Cheryl.
Using county data for West Virginia, Maryland, and Pennsylvania, estimation of a system of simultaneous equations shows that population growth, higher taxes, high farmland value, and high initial per capita income accelerate farmland development, but return on farmland, government assistance to farmers, farmland conservation, and farming agglomeration reduce development pressure.
Tipo: Conference Paper or Presentation Palavras-chave: Farmland; Development; Regional growth; Policy; Equilibrium model; Spatial autocorrelation; Land Economics/Use.
Ano: 2005 URL: http://purl.umn.edu/19488
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Agriculture, habitat loss and spatial patterns of human occupation in a biodiversity hotspot Scientia Agricola
Diniz-Filho,José Alexandre Felizola; Oliveira,Guilherme de; Lobo,Fábio; Ferreira,Laerte Guimarães; Bini,Luis Mauricio; Rangel,Thiago Fernando Lopes Valle Brito.
The Cerrado biome, the second largest biome in Neotropical region, consists of a mosaic of different habitat types, ranging from open grasslands to dense woodlands and dry forests. An intensive recent occupation process has transformed it into the most important region for cattle ranching and intensive commodity crops in Brazil. In this study, a macroecological approach was used to evaluate broad-scale spatial patterns of habitat loss in the Brazilian Cerrado, applying a series of spatial autocorrelation and partial regression analyses to understand how the proportion of remaining natural habitats is correlated with socio-economic variables, expressing different dimensions of human occupation and climatic variation. On average, 59% of the area is occupied...
Tipo: Info:eu-repo/semantics/article Palavras-chave: MODIS; Brazilian Cerrado; Spatial autocorrelation.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162009000600007
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Assessing the influence of neighborhood effects on the adoption of improved agricultural technologies in developing agriculture AgEcon
Langyintuo, Augustine S.; Mekuria, Mulugetta.
Researchers generally assume spatial homogeneity when assessing the factors that influence farmers to adopt improved agricultural technologies. However, the potential for spatial heterogeneity is high due to, for example, neighborhood effects such as farmers sharing information about new technology. Ignoring spatial heterogeneity can result in biased or inefficient regression estimates and make inferences based on t and F statistics misleading. Using data collected from 300 randomly selected farmers in three districts of Mozambique during the 2003/04 crop season, a spatial Tobit model was specified to estimate which factors determined the adoption of improved maize varieties, after an initial diagnostic test rejected the null hypothesis of spatial...
Tipo: Journal Article Palavras-chave: Spatial Tobit model; Spatial heterogeneity; Spatial autocorrelation; Neighborhood effects; Maize farmers; Mozambique; Research and Development/Tech Change/Emerging Technologies.
Ano: 2008 URL: http://purl.umn.edu/56960
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Autocorrelação espacial das freqüências alélicas em subpopulações de cagaiteira (Eugenia dysenterica DC., Myrtaceae) no sudeste de Goiás Rev. Bras. Bot.
TELLES,MARIANA P. DE C.; DINIZ-FILHO,JOSÉ ALEXANDRE F.; COELHO,ALEXANDRE S.G.; CHAVES,LÁZARO J..
Dentre as diversas árvores frutíferas nativas dos cerrados, a cagaiteira (Eugenia dysenterica DC.) merece destaque pelo seu amplo potencial econômico. A fim de fornecer algumas informações relativas ao padrão espacial da variabilidade genética desta espécie, foram realizadas análises de autocorrelação espacial das freqüências alélicas em dez subpopulações locais da região sudeste do Estado de Goiás. Foram utilizados marcadores isoenzimáticos, em um total de seis sistemas enzimáticos (SKDH, 6-PGD, alfa-EST, MDH, PGI e PGM), com oito locos polimórficos. Foi realizada uma análise de autocorrelação espacial, utilizando índices I de Moran estimados em quatro classes de distância geográfica. Os correlogramas mostraram que, de fato, a divergência genética está...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Eugenia dysenterica; Isozymes; Neutral evolution; Spatial autocorrelation.
Ano: 2001 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042001000200003
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Density and fertility of Byrsonima pachyphylla A. Juss. (Malpighiaceae) in small fragments of the Brazilian Cerrado Acta Botanica
Melo,Marina da Silva; Oliveira,Danilo Elias de; Franceschinelli,Edivani Villaron.
Habitat fragmentation is one of the main threats to the biodiversity of the planet. This study was conducted in nine fragments of the Brazilian cerrado (savanna) sensu stricto. We assessed the effects that fragment size and distance between fragments has on the density and fertility of populations of Byrsonima pachyphylla A. Juss. (Malpighiaceae), known in Brazil as "murici". In each of the nine fragments, we evaluated seven individuals. We quantified the B. pachyphylla density within a 20-m radius around each individual. Fertility in each fragment was estimated by determining the ratio between the number of flowers and the number of fruits produced. We carried out linear regression analyses between mean B. pachyphylla density and fragment size, as well as...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Habitat fragmentation; Productivity; Spatial autocorrelation.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062014000200012
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Determinants of Iowa Cropland Cash Rental Rates: Testing Ricardian Rent Theory AgEcon
Du, Xiaodong; Hennessy, David A.; Edwards, William M..
Based on the Ricardian rent theory, this study employs the variable profit function to analyze the determinants of Iowa cropland cash rental rates using county-level panel data from 1987 to 2005. Accounting for spatial and temporal autocorrelations, responses of local cash rental rates to changes in output prices and other exogenous variables are estimated. We find that Iowa cash rental rates are largely determined by output/input prices, soil quality, relative location, and other county-specific factors. Cash rents go up by $79 for a $1 increase in corn price in the short run. The marginal value of cropland quality, as represented by row-crop corn suitability rating index, is about $1.05. Ethanol plants are not found to have a significant local effect on...
Tipo: Working or Discussion Paper Palavras-chave: Bargaining; Basis; Ethanol; Land quality shadow price; Rate of adjustment; Spatial autocorrelation; Land Economics/Use.
Ano: 2007 URL: http://purl.umn.edu/7700
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Distribuição espacial da variabilidade genética intrapopulacional de Dipteryx alata. Repositório Alice
SOARES, T.N.; CHAVES, L.J.; TELLES, M.P. de C.; DINIZ-FILHO, J.A.F.; RESENDE, L.V..
O objetivo deste trabalho foi avaliar o padrão espacial da variabilidade genética entre plantas, dentro de três populações naturais de barueiro (Dipteryx alata Vogel), pela genotipagem por RAPD e técnicas de autocorrelação espacial. Os cinco iniciadores RAPD permitiram a codificação de 45 locos, utilizados nas análises de diversidade, estrutura e distribuição espacial da variabilidade genética entre populações. As populações apresentaram diversidade genética (Hs) com valor médio 0,314. Verificou-se que 12% da variação total se encontra entre as populações, o que indica que estas mantêm um considerável nível de variabilidade genética. Foi observada tendência de autocorrelação espacial positiva nas primeiras classes de distâncias, nas três populações, o que...
Tipo: Artigo em periódico indexado (ALICE) Palavras-chave: Autocorrelação espacial; Conservação; Estrutura familiar; Fluxo gênico; RAPD; Spatial autocorrelation; Baru; Conservation; Familiar structure; Genetic flow.
Ano: 2008 URL: http://www.alice.cnptia.embrapa.br/handle/doc/122170
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Floristic units and their predictors unveiled in part of the Atlantic Forest hotspot: implications for conservation planning Anais da ABC (AABC)
SAITER,FELIPE Z.; EISENLOHR,PEDRO V.; FRANÇA,GLAUCO S.; STEHMANN,JOÃO R.; THOMAS,WILLIAM W.; OLIVEIRA-FILHO,ARY T. DE.
ABSTRACT We submitted tree species occurrence and geoclimatic data from 59 sites in a river basin in the Atlantic Forest of southeastern Brazil to ordination, ANOVA, and cluster analyses with the goals of investigating the causes of phytogeographic patterns and determining whether the six recognized subregions represent distinct floristic units. We found that both climate and space were significantly (p ≤ 0.05) important in the explanation of phytogeographic patterns. Floristic variations follow thermal gradients linked to elevation in both coastal and inland subregions. A gradient of precipitation seasonality was found to be related to floristic variation up to 100 km inland from the ocean. The temperature of the warmest quarter and the precipitation...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Phytogeographic patterns; Environmental gradients; Spatial autocorrelation; Doce River basin.
Ano: 2015 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000502031
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Heterogeneous genetic structure in a natural population of Raulí (Nothofagus nervosa) Ciencia e Investigación Agraria
Carrasco,Basilio; Eaton,Lafayette; Letelier,Luis; Díaz,Carole; García-Gonzáles,Rolando.
Heterozygote deficiencies in natural populations of outbreeding tree species are common and thought to be due mainly to biparental inbreeding. Inbreeding is believed to be caused by family structure within populations, a product of limited seed dispersal and probably limited pollen dispersal. Although both theory and simulation studies predict that structure should be apparent where trees are isolated by distance, most studies of structure in natural populations have detected only a weak spatial genetic structuring. In this contribution, we compare the use of spatial autocorrelation methodology and F statistics with the concept of relatedness to examine the spatial genetic structure in the natural population of a native southern beech and to explore the...
Tipo: Journal article Palavras-chave: Genetic structure; Spatial structure; Raulí; Spatial autocorrelation.
Ano: 2011 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202011000300014
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Impacts of Population and Income Growth Rates on Threatened Mammals and Birds AgEcon
Pandit, Ram; Laband, David N..
Per capita income and human population levels in a country have direct influences on its environmental outcomes. Countries with same level of income may have different rate of income growth and vice versa, suggesting that the influence of the rate of income growth on environmental outcomes could be different than that of income level. Similarly, the rate of population growth might have different impact in addition to the impacts of sheer number of population. We explore this empirical question using country-level data on threatened species published by IUCN for the year 2007. Controlling for other factors, our model estimates the influences of the rate of population and income growth on threatened mammals and birds across 113 continental countries. The...
Tipo: Conference Paper or Presentation Palavras-chave: Income; Population; Spatial models; Spatial autocorrelation; Endemic species; Biodiversity; Environmental Economics and Policy; C21; Q57.
Ano: 2011 URL: http://purl.umn.edu/101404
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Regression models for prediction of corn yield in the state of Paraná (Brazil) from 2012 to 2014 Agronomy
Seffrin, Rodolfo; Araújo, Everton Coimbra De; Bazzi, Claudio Leones.
This study aimed to identify areas that showed spatial autocorrelation for corn yield and its predictive variables (i.e., average air temperature, rainfall, solar radiation, soil agricultural potential and altitude) and to determine the most appropriate spatial regression model to explain this culture. The study was conducted using data from the municipalities of the state of Paraná relating to the summer harvests in 2011/2012, 2012/2013, and 2013/2014. The statistical diagnostic of the OLS (Ordinary Least Square regression model) was employed to determine the most suitable regression model to predict corn yield. The SAR (Spatial Lag Model) was recommended for all crop years; however, the Spatial Error Model (CAR) was recommended only for the 2013/2014...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Autoregressive spatial model; Moran’s index; Spatial autocorrelation; Spatial error model; Spatial regression.; Produção de Cultura; Geomática.
Ano: 2018 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/36494
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Regression models for prediction of corn yield in the state of Paraná (Brazil) from 2012 to 2014 Agronomy
Seffrin, Rodolfo; Araújo, Everton Coimbra De; Bazzi, Claudio Leones.
This study aimed to identify areas that showed spatial autocorrelation for corn yield and its predictive variables (i.e., average air temperature, rainfall, solar radiation, soil agricultural potential and altitude) and to determine the most appropriate spatial regression model to explain this culture. The study was conducted using data from the municipalities of the state of Paraná relating to the summer harvests in 2011/2012, 2012/2013, and 2013/2014. The statistical diagnostic of the OLS (Ordinary Least Square regression model) was employed to determine the most suitable regression model to predict corn yield. The SAR (Spatial Lag Model) was recommended for all crop years; however, the Spatial Error Model (CAR) was recommended only for the 2013/2014...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Produção de Cultura; Geomática autoregressive spatial model; Moran’s index; Spatial autocorrelation; Spatial error model; Spatial regression. Produção de Cultura; Geomática.
Ano: 2018 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/36494
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Relationships between structure of the tree component and environmental variables in a subtropical seasonal forest in the upper Uruguay River valley, Brazil Acta Botanica
Mélo,Máida Ariane de; Budke,Jean Carlos; Henke-Oliveira,Carlos.
This study aimed to analyze relationships among the structure of the tree component, edaphic variables and canopy discontinuity along a toposequence in a seasonal upland (hillside) forest in southern Brazil. Soil and vegetation were sampled in 25 plots of 20 × 20 m each. We described the vegetation in terms of structure, richness and diversity, as well as by species distribution patterns. We evaluated canopy continuity, determined sloping and calculated spatial coordinates. We applied partial canonical correspondence analysis (pCCA) to determine whether species distribution correlated with environmental and spatial variables. We identified 1201 individuals belonging to 76 species within 30 families. The species with highest density and frequency were...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Sloping; Soil drainage; Spatial autocorrelation; Toposequence.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000400015
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Spatial genetic structure within natural populations of Machaerium villosum Vog. (Leguminosae) at Moji-Guaçu region, SP, Brazil Rev. Bras. Bot.
GIUDICE NETO,JOÃO DEL; KAGEYAMA,PAULO YOSHIO.
A spatial autocorrelation study of enzyme loci detected by starch gel electrophoresis was performed to verify the occurrence of spatial genetic structure within two natural populations of Machaerium villosum Vog. The sampled populations were termed "Antropic Model (MA)" and "Natural Model (MN)" and they are situated in Campininha Farm areas, at Moji-Guaçu municipality, 22°10'43''-22°18'19'' S and 47°8'5"-47°11'34" W, in the state of São Paulo. Ten polymorphic loci in the MA population and nine polymorphic loci in the MN population were assessed by Moran's I autocorrelation statistic. No spatial autocorrelation was detected among individuals within sampled populations. Results are in line with other studies in woody species from tropical rain forest.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Machaerium villosum; Allozymes; Spatial autocorrelation.
Ano: 2000 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042000000200010
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Variabilidade espacial da condutividade hidráulica e da infiltração da água no solo - DOI: 10.4025/actasciagron.v32i1.959 Agronomy
Scherpinski, Clementina; UNIOESTE; Uribe Opazo, Miguel Angel; UNIOESTE; Vilas Boas, Marcio Antonio; UNIOESTE; Sampaio, Silvio César; UNIOESTE; Johann, Jerry Adriani; UNIOESTE.
Quando as áreas cultivadas são utilizadas com intensa produção agrícola, o solo apresenta alterações espaciais e temporais em seus atributos físico-hídricos de modo que a viabilidade econômica da produção agrícola depende desses atributos, requerendo, consequentemente, estudos detalhados sobre a variabilidade espacial do solo. Desse modo, o objetivo do trabalho foi avaliar a variabilidade espacial da condutividade hidráulica saturada e da infiltração da água no solo, em uma área de 20 ha, caracterizada pela intensa produção de grãos, foi usado uma grade de 50 x 50 m, utilizando o permeâmetro de Guelph. Nas análises da variabilidade espacial, utilizaram-se os métodos geoestatísticos. Concluiu-se que os atributos físico-hídricos estudados apresentaram...
Tipo: Foram seguidos os métodos da Embrapa Palavras-chave: 5.01.00.00-9 Agronomia permeâmetro de Guelph; Geoestatística; Autocorrelação espacial Ciências do Solo; Física do Solo Guelph permeameter; Geostatistics; Spatial autocorrelation.
Ano: 2010 URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/959
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