Impact of sugarcane cultivation on the biological attributes of oxisol in the brazilian savannah

Resumo

Sugarcane is fundamental for the energy matrix in Brazil. The evaluation of biochemical attributes in different sugarcane production systems provides information on their environmental sustainability. Altogether, soil biochemical attributes are considered very sensitive indicators of changes in soil properties and of alterations caused by soil management and land-use systems. The aim of this work was to study the effect of organic and conventional sugarcane cultivation systems on microbial soil properties. Changes in carbon (C) and nitrogen (N) microbial and microbial activity were evaluated in a Cerrado Oxisol in the state of Goiás, Brazil, cultivated with sugarcane in three different production systems: organic (Organic Cane - OC), conventional with burning (Burned Cane - BC), and conventional without burning (Raw Cane - RC). The native Cerrado (NC) and other cultivated pasture (PT) were used as references. The soil samples were collected during the dry and rainy seasons from two depths: 0-10 and 10-20 cm. The chronological order of the implementation of the land-use (NC, PT and sugarcane) and cultivation (RC, BC, OC) systems were: NC, PT, RC/BC, OC. The microbial biomass C (C SMB ), microbial biomass N (N SMB ), basal respiration (Br), metabolic quotient (qCO 2 ) and the C SMB /C org , N SMB /N total and C SMB /N SMB ratios were determined. The different land-use and cultivation systems influenced microbial biomass and activity. The replacement of conventional tillage for organic system recovered C SMB and N SMB levels and improved recycling of nutrients in the microbial biomass (N SMB /N total ). The conventional tillage system with burning (BC) was less efficient in use of energy and carbon (high qCO 2 ), resulting in a loss of C-CO 2 to the atmosphere.

Descrição

Palavras-chave

Cerrado, Microbial C, Organic farming, Soil microbial biomass, Microbial N, qCO 2, Cerrado, Cultivo orgânico, Biomassa Microbiana do Solo, C Microbiano, N microbiano, qCO 2

Citação

BORGES, Lurdineide de Araújo Barbosa; RAMOS, Maria Lucrecia Gerosa; VIVALDI, Lúcio José; FERNANDES, Paulo Marçal; MADARI, Beata Emöke; SOARES, Rogério Augusto Bremm; FONTOURA, Patrícia Rezende. Impact of sugarcane cultivation on the biological attributes of oxisol in the brazilian savannah. Bioscience Journal, Uberlândia, v. 30, n. 5, p. 1459-1473, Sept./Oct. 2014.