Planting legume cover crop as a strategy to replace synthetic N fertilizer applied for sugarcane production

Author(s)

Otto, Rafael ^[1] ; Pereira, Greice Leal ^{[1, 2]} ; Tenelli, Sarah ^{[1, 3]} ; Nunes Carvalho, Joao Luis ^[4] ; Lavres, Jose ^[5] ; Quassi de Castro, Saulo Augusto ^[1] ; Lisboa, Izaias Pinheiro ^[1] ; Sermarini, Renata Alcarde ^[1]

Affiliation

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

^[2] Univ Fed Vicosa, Ave Peter Henry Rolfs S-N, Campus Univ, BR-36570900 Vicosa, MG - Brazil

^[3] Univ Estadual Campinas, Grad Program Bioenergy, Rua Monteiro Lobato, 80 Cidade Univ Zeferino Vaz, BR-13083862 Campinas, SP - Brazil

^[4] CTBE CNPEM Brazilian Ctr Res Energy & Mat, Rua Giuseppe Maximo Scolfaro 10-000, BR-13083970 Campinas, SP - Brazil

^[5] Univ Sao Paulo, Ctr Nucl Energy Agr, Av Centenario 303, BR-13416000 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: INDUSTRIAL CROPS AND PRODUCTS; v. 156, NOV 15 2020.
• Web of Science Citations: 0

Abstract

Planting cover crops as a strategy to enhance soil quality has been long adopted in several agroecosystem worldwide. Among the cover crops, some legume species are must chosen due to their abilities to fix atmospheric nitrogen (N) into the soil, which increases soil N availability for the cash crop planted subsequently. Our hypothesis was that planting a legume within the sugarcane (Saccharum spp.) renewal period can be adopted as a strategy to supply the N required for the sugarcane at planting. The hypothesis was tested through an experiment set up within Southeast Brazil into two adjacent areas: in an area sunn hemp (Crotalaria junceae L.) was planted within the sugarcane renewal period (rotation system), whereas the another area was left in fallow (fallow system). Five N-fertilizer rates: 0, 130, 260, 390, and 520 kg N ha(-1) were arranged in a randomized block design with four replications within both systems. The N amounts were divided throughout the plant cane, first and second racoons cycles. Plant parameters evaluated included: tillering, stalk yield and stalk industrial quality. The N content on leaves as well as the inorganic N dynamic on soil were also evaluated. Overall, sunn hemp cropped within the sugarcane renewal period potentially replaces 60 kg ha(-1) of N at sugarcane planting. Moreover, the rotation system enhanced stalk yield in 20 Mg ha(-1) over both racoon cycles, whereas the N amount required for each Mg of stalk harvested is reduced by 12.5%, indicating augmented the nitrogen recovering (NUE). The sucrose content and sugar yield are both enhanced under rotation system. However, soil N inorganic dynamic, the N content on leaves and amounts removed on plant components were little sensitive to the rotation system. Our findings highlight the rotation system as a feasible alternative to replace part of the N required by the sugarcane, which improves the NUE for the crop. Conclusions from this study indicate that legume rotation system adoption increases the sustainability of bioenergy from sugarcane by reducing the dependency on synthetic N fertilizers. (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