-The aim of this study was to evaluate the spatial dependence between chemical properties of the soil and yield components in the soybean using precision farming techniques. Samples of the soil and plants were taken from georeferenced points to determine the chemical properties of the soil and the yield components. The results were submitted to Pearson correlation analysis, descriptive statistics and geostatistics. The coefficient of variation showed a wide range of distribution for the chemical attributes of the soil, with the highest indices being found for the levels of available phosphorus (102%) and potassium (72.65%). Soil pH and organic matter showed a coefficient of variation of 5.96 and 15.93% respectively. Semivariogram analysis of the yield components (productivity, 1,000-seed weight and number of seeds) and the chemical properties of the soil (organic matter, pH, phosphorus, potassium, calcium, magnesium, boron, manganese and zinc) fitted the spherical model with moderate spatial dependence, with values ranging from 200 to 700 m. Spatial distribution by means of map interpolation was efficient in evaluating spatial variability, allowing the identification and quantification of regions of low and high productivity in the production area, together with the distribution of soil attributes and their respective levels of availability to the soybean plants.Key words: Precision farming. Soil fertility. Spatial distribution. Seed yield.RESUMO -O objetivo deste trabalho foi avaliar a dependência espacial entre os atributos químicos do solo e os componentes do rendimento de soja, por meio de técnicas de agricultura de precisão. Realizaram-se amostragens de solo e de plantas, em pontos georreferenciados, para determinação dos atributos químicos do solo e componentes do rendimento. Os resultados foram submetidos às analises de correlação linear de Pearson, estatística descritiva e geoestati stica. O coeficiente de variação apresentou ampla faixa de distribuição nos atributos químicos do solo, sendo os maiores índices obtidos para os teores disponíveis de fósforo (102%) e potássio (72,65%). O pH do solo e a matéria orgânica apresentaram coeficientes de variação de 5,96 e 15,93%, respectivamente. A análise dos semivariogramas, para os componentes do rendimento (produtividade, massa de mil sementes e número de sementes) e atributos químicos do solo (matéria orgânica, pH em água, fósforo, potássio, cálcio, magnésio, boro, manganês e zinco), ajustaram-se ao modelo esférico, com dependência espacial moderada, e valores para o alcance da dependência espacial distribuídos entre 200 a 700 m. A espacialização por meio de mapas de interpolação foi eficiente na avaliação da variabilidade espacial, permitindo a identificação e a quantificação na área de produção de regiões com baixa e alta produtividade, associado à distribuição dos atributos do solo e respectivos níveis de disponibilidade para a planta de soja.Palavras-chave: Agricultura de precisão. Fertilidade do solo. Distribuição espacial. Rendimento de sementes.

-The high quality is a factor that must be assured in a corn seed production system. In order to achieve this, seeds are harvested with high moisture content, and then artificially dried. However, the costs of this operation are high and may reduce the profits. The objective of the present study was to evaluate, through the physiological quality, the possibility of using intermittence periods for drying corn seeds on the cob in a stationary system. The seeds were harvested on the cob, close to the physiological maturity stage, with an average moisture content of 35%. The treatments consisted of four periods of intermittence (3, 6 and 9 hours) and one period without intermittence. The seeds were stored for six months. To evaluate the physiological quality of the seeds, germination, first germination, electrical conductivity, and the cold tests were performed. The experimental design was completely randomized, in split plots. In a stationary drying system, periods of intermittence of up to 6 hours per day helped to preserve the physiological quality of the corn seeds. The use of intermittence periods in the drying process provides corn seeds with higher physiological quality and greater storage potential, in comparison with the continuous drying.

Short‐statured, high yielding rice (Oryza sativa L.) varieties grown extensively in northern Peru require extremely high rates of conventional N sources to achieve maximum yields. The recovery of applied N is extremely low due to the use of intermittent flooding. This water management system results in heavy N losses even with properly timed split applications. In search of simpler and more efficient methods of N management, eight field experiments were conducted in the region to evaluate sulfur‐coated urea (SCU), an experimental, slow‐release N sources supplied by the Tennessee Valley Authority. Rice yields were increased an average of 59% more by pretransplant‐incorporated SCU than by urea or ammonium sulfate applied in the same manner. SCU produced an average of 20% higher grain yield response than topdressed applications of urea or ammonium sulfate. SCU applications increased panicle production, N uptake at harvest, and the apparent recovery of added N. Beneficial effects of SCU were more pronounced in sites where check yields were low, especially less than about 4.8 ton/ha. In sites with high N supplying capacity, SCU produced excessive vegetative growth which resulted in yield reductions at high N rates.Regardless of an assumed 48%‐higher unit N cost in SCU, the overall benefits of pretransplant‐incorporated applications of SCU were favorable since there was a decrease of 40% in the optimum rate of N and the need for precise timing of application was eliminated.

Soybean is one of the leading commodities in Brazilian agribusiness. Its cultivation is widespread in different seed-producing regions of the country, where it generates income and local development. In this context, the soybean seed is a fundamental input, as its quality strongly influences the success of the crop. However, the period after the achievement of physiological maturity is critical for the maintenance of seed quality. For that reason, this study aimed at evaluating the effect of harvest delay on both the initial and final qualities of soybean seeds. The research consisted of four harvest times, in which the initial quality was assessed through tests of first germination count, germination, accelerated aging and tetrazolium. After 120 days of storage, the germination and accelerated aging tests were once again conducted. The experiment complied with a completely randomized block design with eight replications. The rainfall was monitored during the pre-harvest phase. All variables experienced negative impacts due to the delay in harvesting. Also, the seeds suffered more damage as the delay progressed, and the variables germination and seed vigor decreased after the storage period.

Temperatura de secagem e qualidade de sementes de arroz drying temperature and rice seed quality

The objective of this study was to identify the spatial distribution of the physiological quality of soybean seeds during storage from a production field of 39 hectares using geostatistical techniques in the 2012/2013 harvest. Seeds were sampled at geo-referenced points for the determination of physiological quality and spatial dependence analysis. The results were submitted to analysis of descriptive statistics, Pearson's linear correlation and geostatistics. The grid of one point per hectare and a georeferenced sampling mesh with spacing of 100 meters between points was efficient in the evaluation of the spatial variability. It was verified the existence of a negative correlation between the variable protein content and bed bug attack and a significant correlation between the intensity of bed bug damage and the protein content with the variables related to seed quality. Physiological quality is not uniform, particularly in relation to vigor, providing better diagnosis through interpolation maps. Precision agriculture, coupled with the monitoring of seed quality during storage, indicated spatial variability of quality from harvest to the end of storage. Areas with high rates of bedbug and unit damage presented low quality physiology and reduced protein levels. The geostatistics allows to determine the spatial distribution of the physiological quality of soybean seeds in the area of seed production, facilitating the decision making, regarding the areas to be harvested. DISTRIBUIÇÃO ESPACIAL DO POTENCIAL DE ARMAZENAMENTO DE SEMENTES DE SOJARESUMO -Objetivou-se identificar a distribuição espacial da qualidade fisiológica de sementes de soja durante o armazenamento, provenientes de campo de produção de 39 hectares por meio de técnicas de geoestatística na safra 2012/2013. Realizou-se amostragem de sementes em pontos georreferenciados, para a determinação da qualidade fisiológica e análise da dependência espacial. Os resultados foram submetidos às análises de estatística descritiva, correlação linear de Pearson e geoestatística. O grid de um ponto por hectare e uma malha de amostragem georreferenciada com espaçamento de 100 metros entre pontos foi eficiente na avaliação da variabilidade espacial. Constatou-se a existência de correlação negativa entre a variável teor de proteína e ataque de percevejos e correlação significativa entre a intensidade de dano por percevejo e o teor de proteína com as variáveis relacionadas a qualidade de sementes. A qualidade fisiológica não é uniforme, particularmente em relação ao vigor, proporcionando melhor diagnóstico por meio de mapas de interpolação. A agricultura de precisão, associada ao monitoramento da qualidade de sementes durante o armazenamento, indicou variabilidade espacial da qualidade desde a colheita até o fim do armazenamento. Áreas com altos índices de danos por percevejo e unidade apresentaram baixa qualidade fisiologia e reduzidos teores de proteína. A geoestatística possibilita determinar a distribuição espacial da qualidade fisiológica de sementes de soja em área ...

The objective of the present study was to describe the morphological characteristics that allow the differentiation of cultivars and to evaluate the agronomic characteristics that can determine the yield of Chenopodium quinoa cultivated in the southern part of Rio Grande do Sul. Quinoa is a pseudocereal that it is originally from the Andes region; it is consumed throughout the world due to its nutritional characteristics. Its introduction and production in Brazil are recent, so studies that make possible the increase of growing are of great importance. We evaluated the stem, leaf and inflorescence characteristics, number of seeds per branch, number of branches and mass of one thousand seeds, thus obtaining the agronomic characteristics. We calculated the yield of the cultivars using the adjusted formula for estimated yield. It was observed that the characteristics of the leaf could be used to differentiate the cultivars. It is possible to calculate the yield of the crop using the adjusted formula for estimated yield.

Quinoa (Chenopodium quinoa Willd) an annual grain crop belonging to the Amaranthacea family is the only vegetable food that contains all essential amino acids, micronutrients and vitamins. The study aimed to evaluate the performance, growth and seed physiological quality of two genotypes of quinoa in Southern Rio Grande do Sul region. The cultivar BRS Piabiru and one breeding line were grown at green house. The design was completely randomized with four replications and five harvest times during the vegetative stage of the crop. The variables were shoot length, number of leaves, leaf area index, dry matter of aerial parts, dry matter of root and total dry matter of plant. It was concluded that the line and BRS Piabiru have slow initial growth in the first 30 days and strong growth up to 120 days. The breeding line and commercial cultivar showed the same potential for seed production in the temperate climate of this region.