TY - JOUR

T1 - Sugarcane straw preservation results in limited immobilization and improves crop N-fertilizer recovery

AU - Castro, Saulo Augusto Quassi de

AU - Otto, Rafael

AU - Sánchez, Camilo Ernesto Bohórquez

AU - Tenelli, Sarah

AU - Sermarini, Renata Alcarde

AU - Trivelin, Paulo Cesar Ocheuze

PY - 2021/1

Y1 - 2021/1

N2 - Current knowledge indicates that sugarcane straw is a short-term sink of fertilizer nitrogen (N) due to N immobilization during the decomposition process. This study aimed to determine whether sugarcane straw removal from the field benefits the N-fertilizer recovery by plant (NRP), and if legume cultivation will further improve NRP. Half of a field was planted with sunn hemp (Crotalaria spectabilis) and half was left fallow. In the second ratoon, treatments with 0, 50, and 100% of sugarcane straw maintenance levels were installed, receiving 120 kg ha−1 N over straw. A microplot of ammonium nitrate labeled with 1.99% atoms 15N was included. NRP was quantified at 92, 164, and 264 days after fertilization (DAF). At harvest (264 DAF), soil samples and straw (<4 mm and >4 mm fractions) were collected to determine N-fertilizer recovery in the soil (NRS) and in the straw (NRSt). Maintaining 50 and 100% of straw improved NRP over the sugarcane cycle. NRP was not improved by crop rotation cultivation and NRS averaged 50% in the entire soil profile. NRSt at harvest averaged 1–3% in the 50% and 100% straw levels. Contrary to the current view, N-fertilizer immobilization in the straw was negligible and keeping straw could improve NRP. The findings indicate that increasing N rates in green cane trash blanket system to compensate for the N-fertilizer immobilization is not necessary, and that straw removal for bioenergy production will change the short-term demand for N-fertilizer.

AB - Current knowledge indicates that sugarcane straw is a short-term sink of fertilizer nitrogen (N) due to N immobilization during the decomposition process. This study aimed to determine whether sugarcane straw removal from the field benefits the N-fertilizer recovery by plant (NRP), and if legume cultivation will further improve NRP. Half of a field was planted with sunn hemp (Crotalaria spectabilis) and half was left fallow. In the second ratoon, treatments with 0, 50, and 100% of sugarcane straw maintenance levels were installed, receiving 120 kg ha−1 N over straw. A microplot of ammonium nitrate labeled with 1.99% atoms 15N was included. NRP was quantified at 92, 164, and 264 days after fertilization (DAF). At harvest (264 DAF), soil samples and straw (<4 mm and >4 mm fractions) were collected to determine N-fertilizer recovery in the soil (NRS) and in the straw (NRSt). Maintaining 50 and 100% of straw improved NRP over the sugarcane cycle. NRP was not improved by crop rotation cultivation and NRS averaged 50% in the entire soil profile. NRSt at harvest averaged 1–3% in the 50% and 100% straw levels. Contrary to the current view, N-fertilizer immobilization in the straw was negligible and keeping straw could improve NRP. The findings indicate that increasing N rates in green cane trash blanket system to compensate for the N-fertilizer immobilization is not necessary, and that straw removal for bioenergy production will change the short-term demand for N-fertilizer.

UR - https://doi.org/10.1016/j.biombioe.2020.105889

U2 - 10.1016/j.biombioe.2020.105889

DO - 10.1016/j.biombioe.2020.105889

M3 - Journal article

JO - Biomass & Bioenergy

JF - Biomass & Bioenergy

SN - 0961-9534

ER -