SERAPAN N DAN P TANAMAN KANGKUNG (Ipomoea Aquatica) AKIBAT PERLAKUAN PUPUK KANDANG DAN UREA DI LAHAN SAWAH NARMADA LOMBOK BARAT

Water spinach (Ipomoea aquatica) in an important horticultural commodity in West Nusa Tenggara (NTB); however, its productivity has declined due to land conversion, climatic factors, and suboptimal fertilization management. This study aimed to evaluate the effects of urea and manure application on the growth, yield, and nitrogen (N) and phosphorus (P) uptake of water spinach cultivated under flooded conditions. The research was conducted from July to September in Grimax Village, Narmada District, West Lombok Regency, using a Randomized Block Design (RBD) consisting of four treatments: P0 (control/no fertilizer), P1 (urea at 300 kg ha⁻¹), P2 (manure at 1 ton ha⁻¹), and P3 (combination of urea and manure), with three replications. Observed parameters included soil chemical properties, N and P uptake, plant growth, and yield. The results showed that fertilization treatments had no significant effect on soil pH, organic C, total N, available P, and available K, but significantly affected N uptake, stem length, number of shoots, fresh weight, total yield, and plant biomass. The highest N uptake was observed in treatment P3 (urea + manure), reaching 28.4 mg plant⁻¹, while the highest P uptake was also recorded in treatment P3 at 6.5 mg plant⁻¹. The greatest stem length and number of shoots were obtained in treatment P1 (urea at 300 kg ha⁻¹), with stem length reaching 575.16 cm and the number of shoots reaching 377 at 60 days after planting (DAP). The highest total yield was obtained in treatment P1 at 27.65 kg, while the highest total biomass was also recorded in treatment P1 at 91.27 kg.
Keywords: water spinach, urea fertilizer, manure, nitrogen, phosphorus.