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

Author(s)

Quassi de Castro, Saulo Augusto ^[1] ; Otto, Rafael ^[1] ; Bohorquez Sanchez, Camilo Ernesto ^[1] ; Tenelli, Sarah ^{[1, 2]} ; Sermarini, Renata Alcarde ^[1] ; Ocheuze Trivelin, Paulo Cesar ^[3]

Affiliation

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Av Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Brazilian Ctr Energy & Mat Res CNPEM, Brazilian Biorenewables Natl Lab LNBR, Av Giuseppe Maximo Scolfaro 10000, BR-13083100 Campinas, SP - Brazil

^[3] Univ Sao Paulo, Ctr Nucl Energy Agr, Av Centenario 303, BR-13416000 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: BIOMASS & BIOENERGY; v. 144, JAN 2021.
• Web of Science Citations: 0

Abstract

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 N-15 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. (AU)

• FAPESP's process: 14/05591-0 - Effect of Crotalaria rotation and trash removal in soil N transformations and sugarcane response to N fertilization
• Grantee: Rafael Otto
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 15/25151-7 - Nitrogen fertilizer in sugarcane due to crop rotation, straw removal and nitrogen rates
• Grantee: Saulo Augusto Quassi de Castro
• Support Opportunities: Scholarships in Brazil - Master