Physiological Aspects of Yellow Passion Fruit With Use of Hydrogel and Mulching

Abstract

In the Brazilian semi-arid region, water deficit is one of the main factors that compromise the growth and productive yield of crops, including yellow passion fruit, due to the limitation of carbon assimilation by the photosynthetic activity of plants. Therefore, it is necessary to manage the soil with technologies that can reduce the loss of water in the soil and mitigate the effects of water deficit on yellow passion fruit plants cultivated under semi-arid conditions. The objective of this study was to evaluate the application of hydrogel doses and mulching to the soil on the physiological aspects of irrigated yellow passion fruit cultivation. The experiment was carried out in a randomized block design, in a 5 × 2 factorial scheme, referring to five doses of hydrogel (0.0, 0.5, 1.0, 1.5 and 2.0 g dm−3 of soil) in soil without and with mulching from signal grass (Brachiaria decumbens L.). The variables analyzed were chlorophyll indices, fluorescence (initial, maximum and variable) and gas exchange. The total chlorophyll index was increased with the application of 1.5 g dm−3 of hydrogel and the use of mulching; when applying hydrogel doses of 2.0 g dm−3 the photosynthetic rate of yellow passion fruit plants increased, whereas their transpiration rate increased with the use of mulching and doses of hydrogel; as a consequence, there was a reduction in water use efficiency.

Gas exchange and yield of yellow passion fruit under different irrigated depths, planting hole volumes, and hydroretentive polymer application

“…Hydro-absorbent polymers can absorb and retain a large amount of water and fluids, reducing nutrient losses by leaching, such as nitrogen, which is a constituent element of chlorophyll molecules (Felippe et al, 2016(Felippe et al, , 2020 and is present in fertilizers such as urea and organic matter. Comparable results were obtained by Araújo et al (2022) in yellow passion fruit cv. BRS GA1 irrigated in soil with mulching and hydrogel polymer; these authors found that applying 1.5 g dm -3 of the polymer increased leaf chlorophyll indices.…”

“…The larger planting hole volume has high interaction with increased irrigation depth due to the greater water supply provided by the irrigation depth in a larger volume of soil explored by the roots of yellow passion fruit plants, as roots are concentrated within the topmost soil layer up to 40 cm deep (Sousa et al, 2005;Lucas et al, 2012;Rosa et al, 2017). Araújo et al (2022) also found that the application of hydro-absorbent polymer doses associated with mulching increased leaf transpiration in yellow passion fruit plants irrigated with maximum water depth.…”

“…However, this result shows that combining increased irrigation depths with hydrogel polymer provides a larger wetted area near the root of yellow passion fruit plants, hence promoting favorable conditions for plant development and avoiding water stress (Testezlaf, 2017;Felippe et al, 2021). Under water deficit conditions, hydrogel polymer increases water retention in the soil, promoting a gradual release and availability of water to plants, and preventing stomatal limitation (Araújo et al, 2022).…”

“…In the Northeast, the primary production areas are located in semi-arid regions, which, despite ideal soil and climatic conditions for yellow passion fruit cultivation, face temporal and spatial limitations in rainfall and low availability of water in terms of quantity and quality in reservoirs, necessitating supplemental irrigation (Freire et al, 2014;Araújo et al, 2022). According to Uchoa et al (2021), inadequate water supply to yellow passion fruit is one of the most limiting factors for production and, in general, plants under water deficit conditions reduce their physiological processes, limiting gas exchange and carbon assimilation, thereby resulting in reduced yields (Cavalcante et al, 2020).…”

Water-Retaining Polymer and Planting Pit Size on Chlorophyll Index, Gas Exchange and Yield of Sour Passion Fruit with Deficit Irrigation

“…Passiculture has great socioeconomic importance for the semiarid region of the Brazilian Northeast; however, water in this region is the most limiting factor for obtaining high yields, due to high evaporative rates and irregular distribution of rainfall, making it necessary to use irrigation [ 4 , 5 ]. However, the use of water by agricultural crops is considered very low, as approximately 60% of the applied water, depending on the irrigation method, is lost by evaporation [ 6 ].…”