Produção e qualidade comercial de alface fertirrigada com nitrogênio e potássio em ambiente protegido

Abstract

Produção e qualidade comercial de alface fertirrigada com nitrogênio e potássio em ambiente protegidoA adubação orgânica pode fornecer grande parte dos nutrientes necessários à cultura da alface. No entanto, a taxa de mineralização de nutrientes pode ser limitante à absorção, sendo que outras formas de adubação complementares com fertilizantes solúveis podem ser utilizadas, como a fertirrigação. O objetivo deste trabalho foi avaliar o efeito da fertirrigação por gotejamento, com nitrogênio e potássio, aliada à adubação de plantio, no crescimento da alface Vera, cultivada em ambiente protegido. O experimento foi realizado entre agosto e outubro de 2012 (inverno e primavera; 67 dias). O delineamento experimental foi inteiramente aleatorizado, com três repetições. Os tratamentos foram formados pela matriz Plan Puebla III, isto é, da combinação entre cinco doses de nitrogênio (N) (9; 54; 90; 126 e 171 kg ha -1 ) e cinco doses de potássio (1,15; 6,90; 11,50; 16,10 e 21,85 kg ha -1 ), além da testemunha, que não recebeu fertirrigação. Concluiuse que a fertirrigação pode ser utilizada para o crescimento da cultura mesmo com adubação orgânica de plantio. As maiores doses de N e de K 2 O resultaram no maior número de folhas comerciais por planta. Os aumentos das doses de N e de K 2 O promoveram incrementos da matéria fresca não comercial da parte aérea, sem prejuízo à qualidade comercial. Palavras Production and commercial quality of lettuce fertirrigated with nitrogen and potassium in greenhouseOrganic fertilization can provide most of the nutrients needed to grow lettuce crop. However, the rate of nutrient mineralization may be limiting to absorption, once complementary forms of fertilization with soluble fertilizers can be used, such as fertirrigation. The objective of this work was to evaluate the effect of the drip fertirrigation with nitrogen and potassium with organic fertilization in the production and commercial quality of the Vera lettuce cultivated in greenhouse. The cultivation period used for the experiment was between August and October 2012 (winter and spring; 67 days). The experimental design was completely randomized with three replications, in which ten treatments were evaluated, with nine of them formed by the Plan Puebla III matrix, that is, from the combination among five N (9, 54, 90, 126, and 171 kg ha -1 ) and five K doses (1. 15, 6.90, 11.50, 16.10, and 21.85 kg ha -1 ), applied in topdressing, and one of them as control, which did not receive fertirrigation. The best answer to the shoot commercial fresh mass took place with the maximum dose of Si and K 2 O and in the zero dose of N. The commercial leaf number per plant showed their higher values in the maximum doses of N and Si and K 2 O. The shoot noncommercial fresh mass increment, both with the increase in N doses and with the increase in Si and K 2 O doses, did not harm the commercial quality.

Research Article Yield components of lettuce cultivars submitted to different phosphate sources

“…The SPT propitiated an increase of 4% in CLN, although being necessary the addition of 647 kg of P 2 O 5 ha -1 (Figure 2δ). Similar results were reported by Rezende et al (2017) and Nascimento et al (2017), with averages of 22 and 20 leaves per plant, respectively. This character is directly related to yield, since, besides the number, the expansion of leaf area potentiate the crop fresh matter.…”

Potassium Fertirrigation on Iceberg Lettuce

“…In the study performed by Rezende et al (2017), both nitrogen and potassium fertigation have significantly influenced the number of commercial leaves per plant, with an increase in the N dose and an increase in the K 2 O dose causing an increasing linear response of this variable. The same authors showed that for the increase of one commercial leaf per plant, 65.6 kg ha -1 of N was necessary, whereas for K 2 O the addition was 8.32 kg ha -1 .…”

“…Among the various functions that potassium exerts in plants, we can highlight better water use efficiency, as a result of controlling the opening and closing of stomata, greater translocation of carbohydrates produced in leaves to the other organs of the plant, greater enzymatic efficiency and improvement of the commercial quality of the plant (FILGUEIRA, 2003). In addition to the nutritional aspect, it is a culture of great importance from a socioeconomic point of view, being a source of income for farmers (SOUZA et al, 2017).…”

Cultivo De Rúcula Em Fibra De Coco Utilizando Solução Nutritiva Salinizada Enriquecida Com Nitrato De Potássio

“…Assim, verifica-se que, apesar da solução S4 apresentar maior condutividade elétrica, o aumento no número de folhas deve-se ao efeito positivo do nitrogênio e do potássio sobre a emissão foliar, conforme observado por (REZENDE et al, 2017).…”