Nitrogen fertilization to attenuate the damages caused by salinity on yellow passion fruit seedlings

Abstract

The study aimed to evaluate the mitigating effect of nitrogen (N) on the damages caused by irrigation water salinity, in the production of yellow passion fruit seedlings. A randomized block design in split plots was used, with five levels of irrigation water salinity (plot) (0.3, 1.0, 1.7, 2.4 and 3.1 dS m-1) and five doses of N fertilization (sub-plot) (180, 240, 300, 360 and 420 mg of N dm-3), with five replicates, totaling 125 experimental units, with one plant per plot. The seedlings were produced in 3.780 mL tubes, used as drainage lysimeter, which received a daily irrigation depth based on water balance. Growth and contents of chlorophyll and carotenoids were evaluated at 85 days after sowing. The increase in irrigation water salinity reduced stem diameter, plant height, number of leaves, chlorophyll a, chlorophyll b and total chlorophyll; increasing N doses also led to linear decline in stem diameter and plant height. Application of increasing doses of N did not attenuate the effect of salinity on growth and pigment contents.