ABSTRACT The quality of cherry tomato fruits is directly related to the management strategies used in the production system, such as irrigation and fertilization. This study aimed to assess the quality of cherry tomato fruits cultivated under water availability and potassium fertilization. The experiment was carried out in a greenhouse in pots of 12 dm3 of an Oxisol. The experimental design was a randomized block design in a 52 fractional factorial arrangement with five water availabilities in the soil (4, 14, 24, 34, and 44 -kPa), five potassium doses (0, 125, 250, 375, and 500 mg dm−3) and with four blocks. Irrigation was performed with a semi-automated drip irrigation system with soil moisture monitoring by the Diviner 2000® capacitance probe. The assessed variables in fruits were longitudinal and transversal diameter and pulp thickness, fruit shape index, total soluble solids (SS), titratable acidity (TA), the SS/TA ratio, and vitamin C. The data were submitted to statistical analyses at 5% probability error, with analysis of variance by the F-test and polynomial regression. Fruit size presents a reduction as water availability decreased. The total soluble solids have a higher concentration at a potassium dose of 326 mg dm−3. The quality of cherry tomato fruits cultivated in an Oxisol is influenced by water availability and potassium doses.

RESUMO Objetivou-se avaliar a produtividade e o uso da água do tomateiro cereja em ambiente protegido sob disponibilidades hídricas e doses de potássio. O experimento foi conduzido em casa de vegetação utilizando unidades experimentais de 12 dm3 de volume de solo e com delineamento experimental de blocos casualizados em esquema fatorial fracionado 52, com cinco disponibilidades hídricas e cinco doses de potássio, com 13 combinações (4-0; 4-250; 4-500; 14-125; 14-375; 24-0; 24-250; 24-500; 34-125; 34-375; 44-0; 44-250; 44-500) (kPa mg dm-3) e quatro repetições. Foi utilizado o sistema de irrigação por gotejamento com controle da irrigação semiautomatizado. As variáveis analisadas foram massa seca da parte aérea, número de frutos, produtividade, consumo e eficiência no uso da água. A partir dos modelos de regressão constatou-se que a maior produtividade do tomateiro cereja ocorre na tensão de água no solo de 24 kPa e na dose de potássio de 290 mg dm-3. A tensão de água no solo de 44 kPa e a dose de potássio de 290 mg dm-3 possibilitam maior eficiência no uso da água pelo tomateiro cereja. A produtividade e o uso da água do tomateiro cereja são influenciados pelas disponibilidades hídricas do solo e doses de potássio em ambiente protegido.

ABSTRACT The objective of this study was to evaluate the yield and water use of cherry tomatoes under soil water availability and potassium (K) doses in a greenhouse. The experiment was conducted in randomized blocks in a 52 fractional factorial design, corresponding to five levels of water availability and five K doses, with 13 combinations (4-0; 4-250; 4-500; 14-125; 14-375; 24-0; 24-250; 24-500; 34-125; 34-375; 44-0; 44-250; 44-500) (kPa-mg dm-3) and four replicates. A drip irrigation system with semi-automated irrigation control was used. The analyzed variables were shoot dry matter, number of fruits, yield, water consumption and water use efficiency. Highest cherry tomato yield occurs at soil water tension of 24 kPa and K dose of 290 mg dm-3. Soil water tension of 44 kPa and K dose of 290 mg dm-3 allow for higher water use efficiency in cherry tomato. Cherry tomato yield and water use are influenced by soil water availability and K doses in greenhouse.

J. M. G. Carvalho, E.M. Bonfim-Silva, T.J.A. Silva, Helon H.F. Sousa, S.L. Guimarães, and A.B. Pacheco. 2016. Nitrogen and potassium in production, nutrition and water use efficiency in wheat plants. Cien. Inv. Agr. 43(3):442-451. Wheat (Triticum aestivum L.) is a cereal used in food and feed for its nutritional properties. For nitrogen and potassium management, efficient use of water is required for greater availability and transportation of these nutrients. The objective of this study was to evaluate the effect of combinations of nitrogen and potassium doses in production, nutrition and water use efficiency in wheat. The experiment was held in a greenhouse with 8-dm³ pots using Oxisol collected at a depth of 0-0.2 m under Cerrado vegetation. Base saturation was raised to 60%. The experimental design was a randomized block in a 5x5 factorial arrangement with five doses of nitrogen (0, 100, 200, 300 and 400 mg dm-3) and potassium (0, 90, 180, 270, 360 mg dm-3) with four replications. Soil moisture was maintained by an auto-irrigation system (3 kPa pressure). The experiment was collected at 95 days after plant emergence. We evaluated the dry mass of ears, shoots and roots, the total dry matter, nitrogen and potassium in grains, and the consumption and efficiency in water use. An analysis of variance and regression test at 5% probability was conducted using SAS statistical software (SAS Institute, Inc., Cary, North Carolina). The nitrogen and potassium alone increased the dry mass of ears by 31.47% and 20.91%, respectively. There was an interaction of nutrients on the dry mass of the shoots and the total dry matter. Potassium increases the concentration of nitrogen. Nitrogen and potassium promote gains in production, nutrition and water use efficiency.

. M. G. Carvalho, E.M. Bonfim-Silva, T.J.A. Silva, H.H.F. Sousa, S.L. Guimarães y A.B. Pacheco. 2016. Nitrógeno y potasio en la producción, nutrición y eficiencia del uso de agua en plantas de trigo. Cien. Inv. Agr. 43(3):442-451. Trigo (Triticum aestivum L.) es un cereal utilizado en la alimentación humana y animal por sus propiedades nutritivas. En la gestión de nitrógeno y potasio, el uso eficiente del agua es necesaria para la mayor disponibilidad y el transporte de estos nutrientes. Este estudio tuvo como objetivo evaluar el efecto de las combinaciones de nitrógeno y potasio en la producción, la nutrición y la eficiencia en el uso del agua en trigo. El experimento se realizó en un invernadero con recipientes de 8 dm³. Usando Oxisol, recogido a una profundidad de 0-0,2 m de área bajo la vegetación del Cerrado. La saturación de bases se aumentó a 60%. El diseño experimental fue de bloques al azar en arreglo factorial 5x5 con cinco dosis de nitrógeno (0, 100, 200, 300 y 400 mg dm-3) y potasio (0, 90, 180, 270 y 360 mg dm-3) con cuatro repeticiones. La humedad del suelo se mantuvo con un sistema autoirrigante (mantenido en el potencial de -3 kPa). El experimento foe cosechó después de 95 días de la emergencia. Se evaluaron la materia seca de las espigas, brotes, raíces, y materia seca vegetal total; nitrógeno y potasio en granos; el consumo y la eficiencia en el uso del agua. Las variables se sometieron a análisis de varianza y prueba de regresión al 5% de probabilidad por el programa estadístico SAS. El nitrógeno y potasio, por separado, aumentaron el peso seco de las espigas, con incrementos de 31,47 y 20,91%, respectivamente. Hubo interacción de nutrientes a la masa seca de la parte aérea y total. El potasio aumenta la concentración de nitrógeno. El nitrógeno y el potasio promueven ganancias en la producción, la nutrición y la eficiencia en el uso del agua.

RESUMO Objetivou-se avaliar a produção e a nutrição mineral do capim piatã em função da adubação nitrogenada e potássica em Latossolo Vermelho coletado no Cerrado. Realizou-se o experimento em casa de vegetação, o delineamento experimental foi inteiramente casualizado em esquema fatorial de 5 x 5 sendo cinco doses de nitrogênio (0, 100, 200, 300 e 400 mg dm-3) e cinco doses de potássio (0, 90, 180, 270 e 360 mg dm-3), com quatro repetições. Realizaram-se três cortes da parte aérea a cada 30 dias. Foram avaliados o índice de clorofila, a massa seca da parte aérea e das raízes, a concentração de nitrogênio e de potássio, nas folhas. A massa seca da parte aérea apresentou interação entre o nitrogênio e o potássio nos três cortes sendo que no segundo e no terceiro apresentou máxima produção nas doses de nitrogênio e potássio, de 254 e 158 mg dm-3 no segundo e de 250 e 306 mg dm-3 no terceiro, respectivamente. As doses de nitrogênio e de potássio apresentaram interação significativa para a massa seca da parte aérea do capim piatã, nos três cortes. As concentrações de nitrogênio e potássio são influenciadas em função da adubação nitrogenada e potássica isolada por fator. A relação de nitrogênio e potássio no capim piatã é de 1:1.

ABSTRACT This study aimed to evaluate the production and mineral nutrition of Piatã grass as a function of nitrogen and potassium fertilization in Oxisol collected in the Cerrado. The experiment was carried out in a greenhouse, the experimental design was completely randomized, in a 5 x 5 factorial scheme, corresponding to five nitrogen doses (0, 100, 200, 300 and 400 mg dm-3 of N) and five potassium doses (0, 90, 180, 270 and 360 mg dm-3 of K2O), with four replicates. Three cuts of the shoots were performed every 30 days. Chlorophyll index, dry mass of shoots and roots, and nitrogen and potassium contents in the leaves were evaluated. The dry mass of shoots showed interaction between nitrogen and potassium in the three cuts; in the second and third cuts, it had maximum production at the nitrogen and potassium doses of 254 and 158 mg dm-3, in the second, and 250 and 306 mg dm-3 in the third, respectively. The nitrogen and potassium contents are influenced as a function of nitrogen and potassium fertilization isolated by factor. The nitrogen and potassium ratio in the Piatã grass crop was around 1:1.