Biomass and Nutrient Content by Sugarcane as Affected by Fertilizer Nitrogen Sources

Knowing the right fertilizer N source is a key management practice for improving nutrient use and productivity for sugarcane (Saccharum spp.). Therefore, this study evaluated the effect of fertilizer N sources on aboveground biomass (BM) and nutrient (N, P, K, Ca, Mg, and S) content for sugarcane ratoon. Two field trials under highly weathered tropical soils (Site 1, Typic Hapludox; Site 2, Typic Eutrustox) were conducted in the southeast region of Brazil. Five fertilizer N sources (organomineral fertilizer [OMF], ammonium chloride [AC], ammonium nitrate [AN], calcium ammonium nitrate [CAN], and urea) were applied on sugarcane at a rate of 100 kg N ha−1. A control treatment was also included in the randomized complete block design. At harvest, total BM varied from 24.4 Mg ha−1 (control and AC) at Site 1 to 44.2 Mg ha−1 (CAN) at Site 2, total K content varied from 185 kg ha−1 (AC) at Site 2 to 747 kg ha−1 (OMF) at Site 1, and total N content ranged from 92 kg ha−1 (AC) at Site 2 to 165 kg ha−1 (AN) at Site 1. Use of CAN and OMF resulted in comparable or superior BM and nutrient content relative to the other N fertilizers. In contrast, AC did not increase BM and nutrient content (except for N and Mg at Site 1), but also decreased by 33% total N content than control at Site 2. Use of more efficient fertilizer N sources (e.g., CAN and OMF) could increase productivity and nutrient use for sugarcane ratoon systems.