REGULATED DEFICIT IRRIGATION AND DIFFERENT MULCH TYPES ON FRUIT QUALITY AND YIELD OF WATERMELON

ABSTRACT The objective of this work was to assess the pulp resistance, soluble solids and yield of watermelon fruits grown under different irrigation managements (determined by the ISAREG model) and mulches, and their interactions. After a survey carried out on local producers, two experiments were conducted, using a completely randomized block design in split-plot arrangement with four replications, in the Teaching, Research and Extension Unit (UEPE) of the Federal Institute of Ceara (IFCE), Jaguaribe-Apodi Irrigation District (DIJA), State of Ceara, Brazil. The treatments consisted of four irrigation managements in the plots, M1 (100% of the available-water capacity (AWC) of the soil), M2 (80%), M3 (60%) and M4 (average water depth used by local producers) and four mulch types in the sub-plots, without mulching (C0) with rice husk (C1), white plastic (C2) and black plastic (C3) as mulches. The results were subjected to analysis of variance, and significant results were subjected to regression (irrigation managements), average test (mulches) and trend graphs (interaction between the factors). The irrigation management practiced during the watermelon crop cycle by the local producers of the Irrigation District of Jaguaribe-Apodi (DIJA) in the State of Ceara, Brazil, is not appropriated, since they usually apply more water than the highest water depth determined by the ISAREG model (100% of the AWC). The plants grown under irrigation water depth of 365.20 mm (M1) and soils with mulches of rice husk or white plastic had the highest yields and fruits with better quality of soluble solids and pulp resistance. RESUMO Objetivou-se avaliar a resistência de polpa e os sólidos solúveis dos frutos, e a produtividade da melancieira, sob diferentes proposições de irrigação (geradas pelo ISAREG) e condições de cobertura do solo; e seus efeitos de interação. Após pesquisa de campo junto aos irrigantes foram realizados dois experimentos na UEPE (Unidade de Ensino, Pesquisa e Extensão) do IFCE, no Distrito de irrigação Jaguaribe -Apodi, DIJA, sob delineamento em blocos completos ao acaso, com parcelas subdivididas e quatro repetições. Os tratamentos consistiram da combinação de quatro proposições de irrigação (M1 - manutenção de 100% da capacidade de água disponível no solo (CAD); M2 - 80 %; M3 - 60%; e M4 - lâmina modal dos irrigantes) nas parcelas, e quatro sub-parcelas, compostas por três condições de cobertura no solo (coberturas com casca de arroz, com “mulching” bra