A curva característica de água no solo é um importante fator para descrever o comportamento físico-hídrico dos solos pois é de grande importância na agricultura, por apresentar aplicações científicas, técnicas e práticas. Desta forma, a estimativa da mesma pode ser feita através de diversos métodos, sendo o mais utilizado o método da câmara de Richards. Assim, o objetivo desse trabalho foi avaliar o modelo proposto por Arya e Paris, para estimar a umidade volumétrica para duas classes de solo, com base na análise textural. Foram selecionados na literatura solos oriundos de duas classes texturais e três locais de origem, onde foram utilizados os dados texturais para realizar a estimativa da curva de retenção de água no solo através dos parâmetros de Van Genuchten gerados através do programa Qualisolo e comparar com a curva gerada pelo método direto. Os resultados obtidos mostraram uma subestimação dos valores de umidades estimadas para os solos analisados, apresentaram coeficiente de determinação superiores a 0,87 relatando uma boa correlação entre as umidades observadas e estimadas. Portanto, conclui-se que os resultados mostraram uma boa alternativa de uso do método proposto por Arya e Paris para gerar a curva de retenção de água no solo de maneira satisfatória.

The objective of this work was to evaluate the effect of raised seedbeds associated with irrigation on the yield of soybean (Glycine max) rotated with rice (Oryza sativa) in lowland conditions in Southern Brazil. Field experiments were conducted in two crop seasons (2014/2015 and 2015/2016), with two planting systems (raised seedbed and flat planting) and two irrigation managements (irrigated and nonirrigated). Water use, biological nitrogen fixation, and yield were evaluated. The water used for raised seedbeds was 14% (151 m3 ha-1) and 27% (163 m3 ha-1) lower than that for flat planting in the first and second crop seasons, respectively. Irrigation increased nodule number per plant, nodule dry weight, and biological nitrogen fixation. The average grain yield of the raised seedbed system was 10% (529 kg ha-1) and 9% (362 kg ha-1) higher than that of flat planting in 2014/2015 and 2015/2016, respectively. Irrigation improved yield by 5% (203 kg ha-1) and 7% (265 kg ha-1) in each crop year. The use of raised seedbeds associated with irrigation improves the yield of soybean grown in rotation with rice in lowland in Southern Brazil.

O objetivo do presente trabalho foi avaliar e calibrar diferentes modelos de estimativa da radiação solar global para três municípios da região Fronteira Oeste do Rio Grande do Sul. Para isso, foram utilizados dados médios diários de temperatura máxima e mínima do ar e radiação solar, de estações automáticas do Instituto Nacional de Meteorologia (INMET), localizadas nos municípios de Alegrete, Uruguaiana e São Borja. A radiação solar global estimada foi obtida através da utilização de dez modelos baseados na amplitude térmica diária e destes, quatro foram calibrados a partir da série histórica de dados para cada município. A análise de regressão linear simples e outros parâmetros de desempenho foram utilizados para a avaliação dos modelos. Os modelos de Ball et al. (2004) e Chen et al. (2004), com os coeficientes calibrados nesse estudo, apresentaram a melhor estimativa da radiação solar global para a região Fronteira Oeste do Rio Grande do Sul, seguidos pelos modelos de Annandale et al. (2002) e

The amount of available water in the substrate is one of the most important factors for the growth and development of potted ornamental species. The aim of the present study was to determine the water consumption of Alstroemeria x hybrid variety Firenze when submitted to different irrigation levels and to assess their effects on production factors. The experiment was carried out under controlled conditions of temperature at Colégio Politécnico of Universidade Federal de Santa Maria, in the state of Rio Grande do Sul, Brazil. Rhizomes of Alstroemeria x hybrid variety Firenze were transplanted into 20 liters rigid black plastic pots filled with substrate. Five treatments (90%, 75%, 60%, 45%, and 30% of container capacity) with 10 repetitions were arranged in a completely randomized design. The production components height and flowering stem diameter, number of flowers per stem, and stem fresh and dry matter content were evaluated over a year of production. Our results demonstrated an increase in water consumption as water availability increased, interfering with the production parameters, except for the number of flowers per stem and flower stems diameter.

The use of crop rotation in hydromorphic soils has been intensified in the state of Rio Grande do Sul, Brazil. Due to the difficult management of these soils, the use of irrigation is fundamental to increase the reliability of these production ecosystems. The present study aimed to evaluate the growth and yield components of corn under different managements of furrow irrigation. The study was conducted in Alegrete/RS in the experimental area of the Farroupilha Federal Institute during the 2017/2018 season. Two factors were evaluated: five managements of furrow irrigation, with a control (not irrigated) and 0, 25, 50 and 100% of the time required to replace the irrigation depth up to field capacity, and the influence of plant position relative to the total length of the furrow, at 0, 25 and 50 meters from its beginning. During the growth stage of corn, its LAI showed better performance for the three collections, at 34, 54 and 76 DAS, and plant height and shoot dry matter showed differences at 76 DAS in treatments that received irrigation. Yield components such as number of grains per ear, harvest index and grain yield were influenced by the use of irrigation, whereas water use efficiency did not differ between the use of irrigation and the control treatment. Lastly, best performances of application efficiency were found in treatments with 0% and 25% of the time required to replace the irrigation depth.