Frequency of irrigation with saline water in sugar-apple seedlings produced on substrate with polymer

Abstract

The objective of this work was to evaluate the growth of sugar-apple seedlings under irrigation management with saline water in a substrate with soil amendment. Treatments were obtained from the arrangement between polymer doses (0, 0.2, 0.6, 1.0 and 1.2 g dm-3) and levels of irrigation water electrical conductivity (0.3, 1.1, 2.7, 4.3 and 5.0 dS m-1), associated with irrigation frequencies (daily and every alternate day), and two additional treatments to evaluate container volume (1.30 and 0.75 dm3), using a randomized complete block design, with four replicates. At 120 days after sowing, the variables substrate salinity, stem diameter, plant height, number of leaves and Dickson quality index were determined. Data were submitted to analyses of variance, regression and contrast. Substrate salinity increased with the increase in irrigation water electrical conductivity and polymer doses. Growth and quality of the seedlings were reduced with increasing irrigation water salinity, and highest values of the variables were obtained in seedlings under daily irrigation. Container with larger volume led to higher growth. The use of hydrated polymer at the adopted levels had no effect on growth and quality of seedlings, requiring further studies. To produce sugar-apple seedlings with better quality, irrigation frequency should be daily and water electrical conductivity should be lower than 2 dS m-1.

Allometry and morphophysiology of papaya seedlings in a substrate with polymer under irrigation with saline water

“…In passion fruit seedlings, the use of polymer reduced the leaf area ratio (Carvalho et al, 2013;Fagundes et al, 2015 constituting a global parameter that better reflects the seedling quality. As observed in this work, the increase in electrical conductivity resulted in the reduction of quality (DQI) in the papaya seedlings, results also corroborated in seedlings of sweet apple (Silva et al, 2018a) and yellow passion fruit (Medeiros et al, 2016;Bezerra et al, 2019). It is then highlighted that the irrigation frequency modifies the effects of salinities, which are intensified under a lower frequency, probably due to the effect of lower salt dilution.…”

“…The increase in the electrical conductivity of the irrigation water also reduced the ratio between stem height and diameter since the elevation in the salt content reduces water availability and increases the absorption of toxic ions (Taiz et al, 2017). There is a growth reduction both in height and diameter in the seedlings due to salinity, as already observed for papaya (Sá et al, 2013a, b) and sugar apple (Silva et al, 2018a), with a more pronounced decrease in height; however, the intensity may be related with the age of the plant. In this sense, Santos et al (2015), studying papaya, observed a growth reduction caused by the electrical conductivity of the irrigation water, observing the greatest impact in height compared to the diameter at 60 days after sowing, whereas at 90 and 120 days the effect of salinity was more intense on diameter.…”

“…In seedlings of yellow passion fruit (Passiflora edulis Sims.) (Carvalho et al, 2013) and sugar apple (Annona squamosa L.) (Silva et al, 2018a), the reduction in the irrigation frequency reduced the stem growth both in height and diameter.…”

“…Seedling production with saline water considerably increases the concentration of salts (Sá et al, 2013b;Bezerra et al, 2014;Silva et al, 2018a) and toxic ions in the substrate, such as sodium (Sá et al, 2015). In a saline environment, there is less absorption of water by plant roots, besides increasing the absorption and accumulation of toxic ions, promoting a nutritional imbalance (Taiz et al, 2017).…”

Curva de retenção de água em substrato de fibra de coco para cultivos em vasos em ambiente protegido

“…A irrigação é a única maneira de fornecer água para as plantas em ambiente protegido (BEZERRA et al, 2019;ZHANG et al, 2021), e a agricultura consome cerca de 70% da água doce do mundo, com os sistemas de irrigação tendo eficiência de aproximadamente 56% (CIRELLI et al, 2009;SOUSA et al, 2020). Em regiões semiáridas, o uso da irrigação é imprescindível devido à baixa disponibilidade de água de boa qualidade e a salinização do solo provocado pelas secas e distribuição irregular das chuvas que limitam a produtividade agrícola e causam graves problemas econômicos, sociais e ambientais (SILVA et al, 2018;GRUDA, 2019).…”