Trocas gasosas e produtividade de meloeiro com diferentes espaçamentos e arranjos espaciais de plantas.

Abstract

The planting spacing and spatial distribution of plants in the area is one of the main factors that influence the physiology and growth of the melon tree (Cucumis melo). Therefore, the objective was to evaluate gas exchange and productivity of melon fruits with different planting spacings and spatial arrangements of plants. The experiment was carried out between September and November 2022, with plants of the melon hybrid “Bazuca F1”, at the Experimental Farm of the Federal University of Campina Grande (UFCG), in São Domingos – PB. The treatments were distributed in a randomized block design in 2 x 3 split plots, with 4 replications per treatment. The plot was two spacings between plants in the row (0.3 and 0.5 m) and the subplots were three spatial arrangements of plants (single row, quadrangular double row and triangular double row). The photosynthesis rate (A), leaf transpiration (E), stomatal conductance (gs), intracellular CO2 concentration (Ci), photosynthetically active photon flux density (DFFAT) and leaf temperature (Tf) were evaluated. Using the values of Ci, A and E, water use efficiency and carboxylation efficiency were calculated, defined by the ratios A/E and A/Ci, respectively, and finally, crop productivity. The smaller number of plants in the area provided by the 0.5 m row spacing resulted in less shading of the leaves, increasing the plant's photosynthetic rate and the internal concentration of CO2 in the leaves. In variables related to photosynthesis, the spatial arrangement of plants only influenced the photosynthetically active flux density with a greater value in single row cultivation with plants spaced 0.3 m apart. The increase in the number of plants provided by the spatial arrangement of a double quadrangular row resulted in greater total crop productivity, especially when spacing the planting row with 0.3 m. Productivity was higher when the melon was in conditions of greater density at 0.3 m. However, in this spacing in the planting line, the type of market will define whether the producer will adopt quadrangular double row cultivation (smaller fruit size) or single row (larger fruit size).