Greenhouse crisphead lettuce grown with mulching and under different soil water tensions

Abstract

ABSTRACT:Proper irrigation management is important both to enable adequate water supply and to minimize problems with diseases, nutrient leaching and unnecessary water and power wastes. Thus, this study aimed at improving irrigation management in greenhouses. For that reason, we assessed the effect of various water tensions on yield performance of crisphead lettuce, Raider-Plus cv., grown with mulching. KEYWORDS:Lactuta sativa, irrigation management, protected environment, soil covering. PRODUÇÃO DE ALFACE-AMERICANA EM CULTIVO PROTEGIDO UTILIZANDO MULCHING, SOB DIFERENTES TENSÕES DE ÁGUA NO SOLORESUMO: O manejo correto da irrigação é importante não apenas por possibilitar que a irrigação supra adequadamente as necessidades hídricas das plantas e por minimizar problemas com doenças e lixiviação de nutrientes, mas também como gastos desnecessários com água e energia. Visando a definir critérios para o manejo da irrigação, este trabalho teve como objetivo avaliar o efeito de diferentes tensões de água no solo sobre o co mportamento produtivo da alface-americana, cv. Raider-Plus, em ambiente protegido, com uso de mulching. O experimento foi conduzido em casa de vegetação na Universidade Federal de Lavras. Os tratamentos foram constituídos de cinco tensões de água no solo: 12; 25; 35; 45 e 70 kPa. Os resultados permitiram concluir que, para a obtenção de valores máximos de produtividade total e comercial, 66 e 50 t ha -1 , a reposição da lâmina evaporada deve ser realizada quando a tensão de água no solo atingir 12 kPa, representando consumo total de 167,25 mm. As variáveis altura de plantas e circunferência da cabeça comercial tiveram valores máximos alcançados quando se utilizou a tensão de 12 kPa. A eficiência no uso da água apresentou resposta quadrática aos tratamentos, sendo que a maior eficiência no consumo de água foi verificada nos tratamentos intermediários (35 e 45 kPa), atingindo valores de 579,87 e 471,71 kg ha -1 mm -1 , respectivamente.

Head lettuce production and nutrition in relation to nutrient solution flow

“…Bandeira et al (2011) reported that this can be explained by the decrease in leaf water potential, stomatal conductance and CO 2 flow, resulting in an adverse impact on accumulations of photoassimilate compounds and as a consequence, reduction in crop production. Water deficit effect causes changes in stomatal responses, osmotic adjustment and important movement of photoassimilates to the roots, metabolic energy consumption and affects crop production anywhere in the plant as well as its commercial quality (Geisenhoff et al, 2016). According to Soares (2007), plants submitted to increasing salinity were less tender, showing more coriaceous leaves: these characteristics were also observed in this study.…”

Productivity of Irrigated Jambu Under Soil-Water Stresses and Nitrogen Doses

“…The treatment with 12 kPa favored the use of nitrogen fertilization by jambu plants, which responded with maximum productivity at the highest dose. The treatment with soil-water stress of 12 kPa maintained the soil close to field capacity, demonstrating behavior similar to the results found by Geisenhoff et al (2016) with lettuce and Lima Junior et al (2012) with carrots, who performed irrigation management based on the soil and obtained maximum productivity at stresses close to field capacity. Jambu production is benefited by the stress that maintains soil moisture close to field capacity.…”

“…Water depths applied before and after treatment differentiation, as well as precipitations during the experimental period, total water supplied to the crop until harvest, number of irrigations, mean irrigation frequency, and daily water demand during treatment differentiation are shown in Table 2. The data in Table 3 showed a linear behavior in relation to water consumption per treatment, similar to that observed by Geisenhoff et al (2016) in an experiment with drip-irrigated lettuce with different stresses, in which the total applied depth decreased as the soil-water stress increased.…”

“…2020 respectively, submitted to different irrigation depths and observed maximum production values close to the replacement factor of 100% of the evapotranspiration. Geisenhoff et al (2016) also studied lettuce productivity subjected to different soil-water stresses and found a maximum productivity value at a stress of 12 kPa, but with higher water use efficiency with intermediate stresses of 34 and 45 kPa, reaching 579.87 and 471.71 kg ha −1 mm −1 , respectively.…”

Productivity of jambu (Acmella oleracea) using different soil water tensions and nitrogen rates under greenhouse condition

“…Additionally, an adequate irrigation allows a vigorous growth of the plant, causing less susceptibility to the attack of pathogens. With the object of finding optimal water blade and satisfactory overall production, Geisenhoff et al (2016) evaluated the crisphead lettuce yield subjected to different water tensions in the soil. Regarding the results, they reached maximum productivity in the tension of 12 kPa.…”