Corrective and maintenance P fertilization on sugarcane yield in multi-sites of south-central Brazil

ABSTRACT Corrective phosphate is a usual practice in poor soils to improve P levels and yield potential. However, the broadcast P application in soils with high P fixing capacity may have low efficiency. This study evaluated sugarcane yield response to corrective phosphate (broadcast application and incorporated) and in planting maintenance phosphate application in four sugarcane sites during three crop cycles in South-Central Brazil. The experimental design was a factorial 2 × 5: presence or absence of corrective phosphate and five rates of P 2 O 5 as maintenance , with four repetitions. A reactive phosphate rock (Bayovar, 29 % of total P 2 O 5 , 14 % soluble in citric acid 2 %) was broadcast applied at a rate of 150 kg ha -1 P 2 O 5 , while monoammonium phosphate was used in planting furrow in rates varying from 0 to 200 kg ha -1 P 2 O 5 . Sugarcane stalk yield, total recoverable sugar, and sugar yield were evaluated in each site for three consecutive harvests with no re-application of P. Corrective phosphate fertilization combined with maintenance P statistically improved sugarcane yields in 4 of 12 sites-years, showing a yield gain of 4.2 Mg ha -1 compared to control. On the average of the literature review, corrective phosphate combined with maintenance P improved sugarcane yield of 7.8 Mg ha -1 . In addition, the corrective P had a positive isolated effect in the other two ratoon cycles and a negative in one. maintenance P application isolated (rates of 100-200 kg ha -1 P 2 O 5 ) improved sugarcane stalk yield in an average of three harvest, with a mean yield gain of 6.5 Mg ha -1 . On average, of all cycles, the CP combined with maintenance P or the isolated practices (at the same rate) increased sugarcane yield from 92 Mg ha -1 of control to 97-98 Mg ha -1 . Phosphorus fertilization slightly improved total recoverable sugar, so sugar yield improvement was most associated with yield enhancement. Corrective P combined with maintenance P can be a strategy for improving the sustainability of P usage in sugarcane production, including a potential reduction in P input in the cane-plant cycle, aligned to a positive residual effect on the ratoons.