Nutritional efficiency in sunflower cultivars under dosages of potassium in semiarid region

Potassium (K) participates in critical processes in sunflower cultivation, such as osmotic regulation and translocation of photosynthesis. However, the absorption or accumulation of this nutrient occurs differently owing to edaphoclimatic factors or between cultivars. The objective of this study was to evaluate the nutritional efficiency of sunflower cultivars as a function of different dosage K dosages in a semiarid region. To this end, two experiments were conducted in 2016 and 2017. The treatments consisted of five dosages of K at 0, 30, 60, 90, and 120 kg ha-1 K2O and four sunflower cultivars, Aguará 6, Altis 99, Multissol, and BRS 122. The experimental design was a randomized block with four replications and subdivided plots. The characteristics evaluated were agronomic efficiency, physiological efficiency, recovery efficiency, utilization efficiency, and accumulation of total K in the plant. Sunflower cultivars responded to K dosages in the two crops, with variations in efficiency parameters. Crop 2 showed better nutritional efficiency compared to crop 1. Aguará 6 showed greater nutritional efficiency than the other two crops. The use of dosages between 75 and 91 kg ha-1 of K2O provided better efficiency in K usage for the cultivars.

Genetic divergence between pumpkin accessions for morphoagronomic characters

The objective of this work was to evaluate the diversity between accessions of Cucurbita moschata from the Northeast of Brazil and preserved at the Universidade Federal Rural do Semi-Árido (UFERSA) in Mossoró-RN. The experiment was carried out in complete randomized blocks, with two replications and three plants per plot. The treatments consisted of 51 accessions of C. moschata Duch and a commercial cultivar of Cucurbita maximum Duch. After ripening, the fruits were harvested (one fruit per plant) and evaluated for morpho-agronomic descriptors. Univariate and multivariate variance analyzes were performed. From the dissimilarity matrices, accessions were hierarchically grouped by the UPGMA method. The relative contribution of quantitative characters to the divergence was also estimated. There was an effect of accessions (p <0.01 or p <0.05) for all characters in univariate analyzes, indicating that there is heterogeneity between the accessions evaluated. Considering the quantitative descriptors, the accessions formed eight groups and for the qualitative six groups. When considering the two sets of descriptors, the accessions were distributed in eight groups but presenting a greater distribution of accessions. The descriptors that most contributed to the discrimination of accessions were the firmness of the pulp and the length of the fruit.

Efficiency of nitrogen use by sesame genotypes under brazilian semi-arid conditions

Nitrogen (N) is an essential macronutrient for plant growth and rate applications can influence the performance of sesame, and when applied in excess can cause nitrogen loss in the environment, and consequently make the cost of production more costly to the producer. Therefore, the objective of this work was to evaluate the efficiency of nitrogen use by different cultivars of irrigated sesame seeds under the edaphoclimatic conditions of the northeastern semi-arid region in two harvests. The experiments were carried out from February to May (1st harvest) and from July to October (2nd harvest) in 2016. The treatments were arranged in a split plot scheme, in which the plots were the five nitrogen doses (0, 30, 60, 90 and 120 kg ha-1), and in the subplots, the four sesame genotypes (CNPA G2, CNPA G3, CNPA G4 and BRS Seda), the design was in randomized complete blocks with four replications. The nitrogen use efficiency assessments evaluated were: agronomic efficiency (AE), physiological efficiency (PE), agrophysiological efficiency (APE), recovery efficiency (RE) and efficiency of use (EU). The rate that provided the greatest efficiency of use was 30 kg ha-1 of N applied. The cultivar BRS Seda had greater efficiency of use in relation to the other cultivars studied. The crop that had better efficiency of use was the 2nd agricultural harvest.

Agro-economic profitability of sweet potato cultivars as a function of the harvest age and times of cultivation in the semi-arid / Rentabilidade de cultivares de batata-doce em função da idade de colheita e épocas de cultivo no semiárido

The objective of this work was to evaluate the profitability of sweet potato cultivars, harvested at different ages and cultivated in different periods (rainy and dry) in the municipality of Mossoró, semi-arid region of Rio Grande do Norte. The experimental design was a randomized complete block design with four replications and treatments arranged in split plots scheme. The plots were composed of three sweet potato cultivars (ESAM 1, Paraná and Mother of Family) and the subplots for five harvest ages (90 , 105, 120, 135 and 150 days after transplanting - DAT). Productivity of commercial roots and production costs was evaluated, as well as the economic indicators: gross income, net income, rate of return and profit margin. Independently of the growing periods, the productivity of commercial roots increased with the later harvest of the crop and differentiated the cultivars. Production costs averaged R$ 6,087.97 ha-1 in the rainy season and R$ 6,181.42 ha-1 in the dry period. Labor expenditures were the most impacting of total expenditures. The cultivars ESAM 1 and Paraná presented higher productivities of commercial roots and profitability when cultivated in the rainy season, while Paraná cultivar was superior to the other cultivars in the crop in the dry season. In both growing periods, the harvest age of 150 DAT promoted higher productivities of commercial roots and profitability to sweet potato production.

Este trabalho teve como objetivo avaliar a rentabilidade de cultivares de batata-doce, colhidas em diferentes idades e cultivadas em períodos distintos (chuvoso e seco) no município de Mossoró, semiárido do Rio Grande do Norte. O delineamento experimental foi em blocos ao acaso, com quatro repetições e tratamentos arranjados em parcelas subdivididas, sendo as parcelas formadas por três cultivares de batata-doce (ESAM 1, Paraná e Mãe de Família) e as subparcelas por cinco idades de colheita (90, 105, 120, 135 e 150 dias após o transplantio ­ DAT). Avaliaram-se produtividade de raízes comerciais e custos de produção, assim como os indicadores econômicos: renda bruta, renda líquida, taxa de retorno e índice de lucratividade. Independentemente dos períodos de cultivo, a produtividade de raízes comerciais aumentou com a colheita mais tardia da cultura e diferenciou as cultivares. Os custos de produção foram em média da ordem de R$ 6.087,97 ha-1 no período chuvoso e R$ 6.181,42 ha-1 no período seco. As despesas com mão de obra foram as mais impactantes nas despesas totais. As cultivares ESAM 1 e Paraná apresentaram maiores produtividades de raízes comerciais e lucratividades quando cultivadas no período chuvoso, enquanto a Paraná foi superior as demais cultivares no cultivo na época seca. Em ambas as épocas de cultivo, a idade de colheita de 150 DAT promoveu maiores produtividades de raízes comerciais e rentabilidade à produção de batata-doce.