Citrus phosphorus uptake dynamics with glyphosate under greenhouse conditions

Phosphorus (P) is a vital macronutrient for continued growth and high fruit production. Glyphosate is the most commonly used herbicide in Florida citrus production for controlling weeds, which can proliferate with Florida's high temperature and precipitation. The focus of the study was to monitor P and orthophosphate bioavailability, uptake, and adsorption in citrus in selected Florida soils. The study was performed under greenhouse conditions using varying amounts of P and glyphosate treatments separately and in tandem to assess the bioavailability, uptake, and adsorption of P in the presence of glyphosate. There were 36 young Valencia citrus trees [Citrus sinensis (L.) Osb] for this experiment. There were nine different treatments with varying P and glyphosate rates and combinations with four replicates of each treatment. The P levels within the soil and the plant organs were measured. Significant differences within the plant tissue (p < .05) were observed that could suggest P was retained within the soil when glyphosate was applied with P. Results showed there was an additive effect when glyphosate and P were applied in tandem, moreover when P is applied with glyphosate, and did not inhibit citrus tree growth. This result could be used to establish effective rates of glyphosate and P when applied together in citrus production systems.