SANTOS, Raquel Ferreira dos.
Resumo:
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).