It is known that use of natural reactive phosphate associated with humic substances will be able to increase phosphorus absorption the the efficiency of phosphate fertilization in the production of sugar cane.Objective of this study is to evaluate the effects of phosphorus levels in the absence and presence of enriched peat extract with humic substances. The study was conducted in a greenhouse in the municipality of Chapadinha, in the state of Maranhão, Brazil, in an entirely randomized 2x2x3+2 delineation with three repetitions in Quartzipsamment and Kandiudult, in the absence and presence of 520 L ha-1 of the peat extract, three doses of phosphorus (75, 150 and 300 mg dm-3) in the natural reactive phosphate form and two controls. The experimental unit consisted of a vase filled with 20kg of soil containing a RB867515 of sugar cane. The accumulation of phosphorus and dry matter on the aerial part of the sugar cane were evaluated, 180 days after planting and 120 days after the first cutting. The associated natural phosphate and humic substances demonstrated greater increments in the sugar cane for the two cycles and different soils compared to the isolated phosphate.