Optimization of phosphorus and potassium use efficiency of rice (Oryza sativa L) under different flood depths within the Everglades Agricultural Area

Rice cultivation in South Florida, especially within crop rotation systems, presents a promising avenue for mitigating phosphorus (P) levels in drainage water by optimizing nutrient absorption across varying flooding conditions. This study aimed to assess the impacts of different flooding depths on rice growth and nutrient efficiency while exploring the interrelationships among these factors. Conducted over a two-year period, the field study involved planting a single rice variety (Diamond: 95 kg ha-1, long-grain, short-season) at four distinct flooding depths (5, 10, 15, and 20 cm) without fertilizer application. Results revealed minimal effects of flooding depths on root and shoot length or dry matter accumulation. Additionally, concentrations of total P and potassium (K) in both shoot and root tissues remained consistent across the different flooding depths. Despite the absence of P and K fertilizer inputs, no significant changes were observed in P use efficiency (PUE), K use efficiency (KUE), or water use efficiency (WUE). Cultivating rice under optimal flood depths of 5 cm within the Everglades Agricultural Area (EAA) demonstrated potential for conserving water and essential nutrients such as P and K. These findings highlight the feasibility of rice cultivation in fertile soils as a means to decrease nutrient (P and K) concentrations in drainage water, thereby promoting sustainable agricultural practices in the region.