Influence of Saline Irrigation on Leaf Growth, Nutrient Accumulation, and Soil Properties in Coconut Seedlings

HistoryCoconut (Cocos nucifera L.) is a key tropical perennial crop with notable tolerance to moderate salinity, yet extreme saline conditions can impair growth and productivity.This study investigated the effects of saline irrigation on nutrient accumulation, leaf growth, and soil properties in Dua Ta coconut seedlings under greenhouse conditions.Five salinity levels (0.89, 6.25, 18.25, and 24.5dSm -1 ) were applied to five-month-old seedlings over 12 months.Leaf growth, biomass, leaflet formation, and nutrient concentrations in roots and leaves were measured, along with changes in soil physicochemical properties.Results indicated that increasing salinity reduced leaf number, length, width, biomass, and leaflet formation, with the most severe effects at 24.5dSm -1 .High salinity increased soil EC, TDS, and Na+/Clconcentrations while reducing organic carbon, nitrogen, phosphorus, calcium, and magnesium.Mild salinity (≤ 6.25dSm -1 ) had minimal effects, moderate salinity (12.0 -18.25dSm -1 ) partially inhibited growth, and extreme salinity (24.5dSm -1 ) severely disrupted physiological functions.The study highlights the interconnected pathway linking saline irrigation, soil nutrient availability, root nutrient uptake, and leaf growth, providing mechanistic insight to guide management strategies for sustaining coconut productivity under salinity stress.