Fertiliser and irrigation best management practices (BMPs) for optimal citrus production and water quality in sandy entisols of Florida

Abstract

In order to increase efficient use of applied fertiliser by citrus, economically feasible best irrigation and fertiliser management practices (BMPs) are necessary. A six year field study was conducted on a well-drained Tavares fine sand in Highlands county, Florida, USA, to evaluate the effects of N source, placement, and rate (112 to 280 kg ha−1yr−1) with optimum irrigation management on (i) the fruit yield, quality and leaf nutrient contents of bearing mature (25 + year old) ‘Hamlin’ orange trees on Cleopatra mandarin rootstock and (ii) changes in NO3-N status in soil solution collected from vadose zone below the rootzone and in surficial groundwater. Results of this study indicated that optimum fruit yield could be obtained at about 250 kg N ha−1, which supported optimum range of spring flush N concentration. Leaching of NO3-N accounted for only 22 to 34 kg ha−1yr−1 and the NO3-N concentration in soil solution in the vadose zone and in surficial groundwater remained below 10 mg L−1 under optimal irrigation and N management conditions used in this study.