HIGHLIGHTS:
Electrical conductivity of irrigation water above 2.1 dS m-1 reduces sunflower growth.
The use of mineral and organic fertilizers mitigates the deleterious effect of salts on sunflower crops.
Gas exchange is favored in the presence of organic or mineral fertilizers.
ABSTRACT
The frequent use of saline water for crop irrigation, under climatic conditions of semiarid region, can directly affect the physiological processes of plants. However, nutritional management of cultivated plants can influence responses to saline environments. Based on this, the objective of the present study was to evaluate the response of sunflower crops to different electrical conductivities of irrigation water in soil, with and without mineral and organic fertilizers. The experiment was conducted in the experimental area of Universidade Federal do Ceará, Fortaleza, Ceará, Brazil. The experimental design was completely randomized in a 5 × 3 factorial arrangement, with four replicates. The treatments consisted of five levels of electrical conductivity of irrigation water (ECw): 1.1, 2.1, 3.1, 4.1, and 5.1 dS m-1 and three forms of fertilization applied to the soil (M= mineral fertilizer based on NPK, B = goat biofertilizer, and CT = soil without fertilization). The salinity of irrigation water from 2.1 dS m-1 negatively affected plant height, leaf area, stem diameter, and leaf number of sunflower plants and increased leaf temperature. The use of mineral fertilization with NPK and organic goat biofertilizer positively favored growth in the height of plants and number of leaves in relation to the control. Mineral and organic fertilization attenuated the negative effect of saline water on stomatal conductance, transpiration, and the internal concentration of CO2 and provided the highest rate of CO2 assimilation.
Key words:
Helianthus annuus L.; morphophysiology; abiotic stress; organic input; mineral nutrition
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Thumbnail
** - Significant at p ≤ 0.01 by F test; ** - Significant at p ≤ 0.05 by F test
Means followed by the same letter do not indicate significant differences between them by Tukey’s test at p ≤ 0.05; M, mineral fertilization; B, goat biofertilizer; CT, no fertilization (control)
** - Significant at p ≤ 0.01 by F test
** - Significant at p ≤ 0.01; ** - Significant at p ≤ 0.05; Means followed by the same letter, indicate no significant differences between them by Tukey test at p ≤ 0.05; M - mineral fertilization ; B - goat biofertilizer ; CT- no fertilization (control)
** - Significant at p ≤ 0.01 by F test; ** - Significant at p ≤ 0.05 by F test; Means followed by the same letter do not indicate significant diffences between them by Tukey test at p ≤ 0.05; M - mineral fertilization; B - goat biofertilizer; CT - no fertilization (control)