Effect of NPK fertigation schedule on growth and yield of capsicum under polyhouse

Abstract:

Capsicum grown under protected structures rarely receives the fertigation attention that its high nutrient demand warrants. This research assessed four NPK fertigation levels 75, 100, 125, and 150% of the Recommended Dose of Fertiliser (RDF) against a soil-applied control on growth, yield, and nutrient uptake of capsicum (Capsicum annuum L. cv. Kapija) inside a naturally ventilated polyhouse at the Antalya Mediterranean Agricultural University, Antalya during the rabi season of 2022-23. The experiment followed a randomised block design with four replications. Plant height, number of branches, days to first flowering, fruit length, fruit diameter, individual fruit weight, number of fruits per plant, and marketable yield were recorded. Fertigation at 125% RDF produced the tallest plants (78.4 cm), the highest single-fruit weight (148.3 g), and the greatest marketable yield (61.8 t ha⁻¹), which was 22.6% above the 100% RDF treatment and 151% above the control. Raising the dose to 150% RDF did not improve yield further; instead, it caused a slight decline, possibly because of salt build-up in the root zone. Nitrogen, phosphorus, and potassium uptake peaked at 125% RDF. These data suggest that moderate over-fertilisation through drip fertigation can push capsicum yields well beyond conventional soil-applied programmes, though exceeding 125% RDF appears counterproductive.