title: Soybean yield in relation to distance from the Itaipu reservoir.
abstract: Crops close to small water bodies may exhibit changes in yield if the water mass causes significant changes in the microclimate of areas near the reservoir shoreline. The scientific literature describes this effect as occurring gradually, with higher intensity in the sites near the shoreline and decreasing intensity with distance from the reservoir. Experiments with two soybean cultivars were conducted during four crop seasons to evaluate soybean yield in relation to distance from the Itaipu reservoir and determine the effect of air temperature and water availability on soybean crop yield. Fifteen experimental sites were distributed in three transects perpendicular to the Itaipu reservoir, covering an area at approximately 10 km from the shoreline. The yield gradient between the site closest to the reservoir and the sites farther away in each transect did not show a consistent trend, but varied as a function of distance, crop season, and cultivar. This finding indicates that the Itaipu reservoir does not affect the yield of soybean plants grown within approximately 10 km from the shoreline. In addition, the variation in yield among the experimental sites was not attributed to thermal conditions because the temperature was similar within transects. However, the crop water availability was responsible for higher differences in yield among the neighboring experimental sites related to water stress caused by spatial variability in rainfall, especially during the soybean reproductive period in January and February.
authors.affiliation: Univ. Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, 14884-900, Brazil. rogeriofaria@fcav.unesp.br.
authors.forename: Rogério Teixeira
authors.initials: RT
authors.lastname: de Faria
authors.affiliation: Fapeagro, Rua Paranaguá, 1672, Londrina, PR, 86015-030, Brazil.
authors.forename: Ruy Casão
authors.initials: RC
authors.lastname: Junior
authors.affiliation: Epagri, Rua João José Godinho, S/N, Lages, SC, 88502970, Brazil.
authors.forename: Simone Silmara
authors.initials: SS
authors.lastname: Werner
authors.affiliation: Iapar, BR 163, km 188, Santa Tereza do Oeste, PR, 85825-000, Brazil.
authors.forename: Luiz Antônio Zanão
authors.initials: LA
authors.lastname: Junior
authors.affiliation: Washington State University, 24106 North Bunn Road, Prosser, WA, 99350-8694, USA.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Hoogenboom
mesh_terms: D001938:Brazil; D018556:Crops, Agricultural / Q000254:growth & development; D011891:Rain; D013025:Glycine max / Q000254:growth & development*; D013696:Temperature; D014881:Water Supply
keywords: Air temperature; Water balance; Water stress; Yield components