The availability of nitrogen from sugarcane trash on contrasting soils in the wet tropics of North Queensland

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

“…The favorable climatic condition (higher rates of evapotranspiration) that took place during plant cane and fist ratoon development may have enhanced N mineralization of crop residues as well as increased crop yield (Figure 2). Meier et al (2006) verified lower recoveries of N from fertilizer (6 %) and trash (5 %) in sites located in northeastern of Australia, which was attributed to the higher intensity of rainfall and occasional waterlogging in sugarcane fields.…”

“…As aforementioned, the low degradability of sugarcane trash is also related to its high C:N ratio, varying from 70:1 to 120:1 (Gava et al, 2005;Meier et al, 2006;Oliveira et al, 2002;Robertson and Thorburn, 2007ab) while Spain and Hodgen (1994) reported 170:1, one of the highest values in literature. Therein, lower rates of net mineralization of green harvest residues are expected in short-term, although the N supplied by fertilization LSD = least significant difference; CV % = coefficient of variation.…”

“…This composition affords intense N immobilization by the soil microbial biomass and a slow net mineralization of C and N. Likewise, the recovery rates of N from crop residues incorporated into the soil varied from 2 % to 15 % of the total N contained in such residues (Ambrosano et al, 2005;Basanta et al, 2003;Chapman et al, 1992;Gava et al, 2005;Meier et al, 2006;Ng Kee Kwong et al, 1987;Trivelin et al, 2002;Vitti et al, 2010).…”

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

“…trash consists of dry leaves, tops and variable amounts of cane stalks, varying from 10 to 20 t ha -1 of dry matter, presents high C to N ratio (80 to 110:1) and contains 30 to 80 kg ha -1 of N (Basanta et al, 2003;Fortes et al, 2012;Gava et al, 2003;Robertson and Thorburn, 2007a;Thorburn et al, 2005;Trivelin et al, 1995;Vitti et al, 2011). 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.…”