Waste‐derived fertilizers can increase phosphorus uptake by sugarcane and availability in a tropical soil #

Background The use of highly water‐soluble phosphorus (P) fertilizers can lead to P fixation in the soil, reducing fertilization efficiency. Waste‐derived, low water‐solubility sources can potentially increase sugarcane's P uptake compared to triple superphosphate by reducing adsorption to the soil. Aims We aimed to test struvite, hazenite, and AshDec ® for their agronomic potential as recycled fertilizers for sugarcane production in a typical tropical soil. We hypothesize that these sources can reduce P fixation in the soil, increasing its availability and sugarcane's absorption. Methods In a greenhouse pot experiment, two consecutive sugarcane cycles, 90 days each, were conducted in a Ferralsol. The recovered sources struvite, hazenite, AshDec ® , and the conventional triple superphosphate were mixed in the soil in three P doses (30, 60, and 90 mg kg –1 ), aside a control (nil‐P). At both harvests, sugarcane number of sprouts, plant height, stem diameter, dry mass yield, shoot phosphorus, and soil P fractionation were investigated. Results At 90 days, struvite and hazenite performed better for dry mass yield (70.7 and 68.3 g pot –1 , respectively) than AshDec ® and triple superphosphate (59.8 and 57.4 g pot –1 , respectively) and for shoot P, with 98.1, 91.6, 75.6, and 66.3 mg pot –1 , respectively. At 180 days, struvite outperformed all treatments for dry mass yield (95.3 g pot –1 ) and AshDec ® (75.5 mg pot –1 ) for shoot P. Struvite was 38% and hazenite 21% more efficient than triple superphosphate in P uptake, while AshDec ® was 6% less efficient. Soil had higher labile P under struvite, hazenite, and AshDec ® than triple superphosphate by the end of the first cycle, while only the later increased nonlabile P by the end of the experiment (180 days). Conclusions Waste‐derived P sources were more efficient in supplying P for sugarcane and delivering labile P in 180 days than triple superphosphate.