Potassium fertilization in the cultivation of colored cotton irrigated with saline water

Abstract

A B S T R A C TThe objective of this study was to evaluate growth, flowering and production components of the cotton cv. 'BRS Topázio' irrigated with water of different salinity levels and potassium (K) doses in the soil. The research was conducted in a greenhouse. The experiment was set in a randomized complete block design with four replicates, in 4 x 4 factorial arrangement with 4 levels of irrigation water salinity (1.5, 3.0, 4.5 and 6.0 dS m -1 ) and four K doses (50, 75, 100 and 125% of the recommendation); the dose of 100% corresponded to 150 mg K 2 O kg -1 of soil. Irrigation water salinity reduced stem diameter, plant height, number of leaves and leaf area of the cotton cv. 'BRS Topázio' . Leaf area at 53 DAS was the most affected variable. The highest K dose associated with increased salinity of the irrigation water caused a more deleterious effect on the number of leaves and leaf area at 108 DAS. Progressive increases in irrigation water salinity proportionally increased flower abortion rate and, consequently, reduced the total number of bolls and seed weight of cotton.Adubação potássica no cultivo do algodoeiro de fibra colorida irrigado com águas salinas R E S U M O Objetivou-se neste trabalho avaliar crescimento, floração e os componentes de produção do algodoeiro cv. BRS Topázio em função da irrigação com águas de diferentes níveis de salinidade e doses de potássio no solo. A pesquisa foi conduzida em casa de vegetação. O delineamento experimental utilizado foi o de blocos casualizados em arranjo fatorial 4 x 4, com três repetições cujos tratamentos consistiram de quatro níveis de condutividade elétrica da água de irrigação (1,5; 3,0; 4,5 e 6,0 dS m -1 ) e quatro doses de potássio (50; 75; 100 e 125% da recomendação), sendo a dose de 100% correspondente a 150 mg K 2 O kg -1 de solo. A salinidade da água de irrigação reduziu o diâmetro de caule, altura de plantas, número de folhas e área foliar do algodoeiro, sendo a área foliar aos 53 dias após a semeadura (DAS) a variável mais afetada. As maiores doses de potássio associadas ao aumento da salinidade da água de irrigação proporcionaram um efeito depressivo no número de folhas e na área foliar aos 108 DAS. Aumentos progressivos da salinidade da água de irrigação elevaram, de forma proporcional, a taxa de abortamento de flores e, consequentemente, reduziram o número de capulhos total e a massa de algodão em caroço.

Chloroplast pigments and photochemical efficiency of West Indian cherry under salt stress and potassium-phosphorus fertilization

“…Thus, it is clear that, under high salinity levels, the supply of 45/45% of K 2 O/P 2 O 5 had mitigating action on chlorophyll a synthesis, possibly because the increase in the supply of mineral fertilizers contributes to the increase in soil EC, given their salt indices, especially that of potassium chloride, compromising chlorophyll biosynthesis by crops. This situation has been observed in cowpea (Prazeres et al, 2015), colored cotton (A. R. Silva et al, 2017), and West Indian cherry (Dias et al, 2019) under water salinity conditions.…”

“…BRS 366 Jaburu. Sousa, Gheyi, Brito, Silva and Lima (2017), in a study with citrus under irrigation with saline water, found a reduction of 38.81% in carotenoid contents as salinity levels increased from 0.6 to 3.0 dS m -1 .…”

Growth and Post-Harvest Fruit Quality of West Indian Cherry Under Saline Water Irrigation and Potassium Fertilization

“…However, the salt concentrations that cause reduction in growth and post-harvest fruit quality of West Indian cherry may vary among species and cultivars, which exhibit different physiological behaviors regarding the effects of the stress caused by water and/or soil salinity. These effects depend on crop development stage, duration of exposure to stress, type of salt present in the medium, environmental conditions, cultural and irrigation managements, edaphoclimatic conditions and fertilization (SILVA et al, 2017).…”