Sugarcane straw preservation results in limited immobilization and improves crop N-fertilizer recovery. (January 2021)

• Record Type: Journal Article
• Authors: Quassi de Castro, Saulo Augusto; Otto, Rafael; Bohórquez Sánchez, Camilo Ernesto; Tenelli, Sarah; Sermarini, Renata Alcarde; Trivelin, Paulo Cesar Ocheuze
• Is Part Of: Biomass and bioenergy. Volume 144(2021)
• Publication Date: 2021-01
• Subjects: No-tillage -- Sunn hemp -- Crop rotation -- Labeled N -- N use efficiency; Biomass energy -- Periodicals; Biomass -- Periodicals; Energy-Generating Resources -- Periodicals; Bioénergie -- Périodiques; 333.9539
• DOI: 10.1016/j.biombioe.2020.105889
• Languages: English
• ISSNs: 0961-9534

Abstract

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 15 N 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. Highlights: Previous studies indicate sugarcane straw as a sink for N-fertilizer. Sugarcane straw increases N recovery by plant at initial growth stages. N-fertilizer immobilization in straw reaches only 2.8% at harvest time. Crop rotation did not improve recovery of N-fertilizer by sugarcane. Straw removal for bioenergy production will have implications in N-fertilizer demand.