Contribution of nitrogen from sugarcane harvest residues and urea for crop nutrition

Abstract

Sugarcane (Saccharum spp.) harvested without burning provides a substantial amount of remains (trash) on soil profiles which can be decomposed and release nutrients contributing to reduce fertilizer needs. The contribution of nitrogen (N) from sugarcane plant residues and fertilizer in sugarcane nutrition was assessed. Plant cane treatments were micro plots of 15 Nlabeled urea, sugarcane trash and root system; the last two to simulate the previous crop residues incorporated into the soil after crop renewal.

Impact of sugarcane trash on fertilizer requirements for São Paulo, Brazil

“…Fortes et al (2013) found recovery of trash-N accumulated over a three year period, of 16.9 % and 30.7 % in plots without N fertilizer and plots with 150 kg ha -1 N over the trash, respectively. Based on this result, we adopted a factor of 1.82 (30.7/16.9) to consider the effect of N fertilization in increasing the recovery of trash-N.…”

“…Recovery of N from previous crop residues (RN-PCR): Fortes et al (2013) studied the recovery of N from aboveground and belowground sugarcane residues by the subsequent sugarcane crop up to four years after residues were applied. Using the data of Fortes et al (2013) and considering aboveground components account for 70 % of the total sugarcane residues and belowground Franco et al (2007).…”

“…Using the data of Fortes et al (2013) and considering aboveground components account for 70 % of the total sugarcane residues and belowground Franco et al (2007). t1 to t5 refer to first through fifth crop cycle.…”

“…The high C/N ratio of trash results in significant N immobilization due to increased microbiological activity caused by energy input into the soil, leading to slow rates of N release in the short term (Meier et al, 2006). N recovery by sugarcane from crop residues was assessed using 15 N tracer techniques and was found to vary from 3 to 15 % (Basanta et al, 2003;Fortes et al, 2013;Gava et al, 2003;Ng Kee Kwong et al, 1987;Vitti et al, 2010;Vitti et al, 2011).…”

“…Fortes et al (2013) obtained trash-15 N recovery accumulated in a 3-yr period varying from 17 % to 31 %, whereas Basanta et al (2003) found 6 % after two seasons. Since most of the trash-derived N stays in the soil N pool (Meier et al, 2006;Fortes et al, 2013), the differences observed can be explained, at least in part, by variations on weather conditions favoring plant growth and uptake of trash-N mineralized.…”