Effect of wood ash on soil fertility and on sorption behaviour of imazethapyr in acid soils

Author(s)

Bruna Botin Nascimento

• Document type: Master's Dissertation
• Press: Piracicaba.
• Institution: Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC)
• Defense date: 2013-11-14

Examining board members

Jussara Borges Regitano; Luis Reynaldo Ferracciú Alleoni; Moacir Rossi Forim

• Advisor: Jussara Borges Regitano

Abstract

The pulp and paper industries generate huge amounts of wood ash every year. The ashes disposals in landfills used to be a common practice, but their use in agricultural and forest soils deserves special attention due to their potential to neutralize acidity and to fertilize soils, thus decreasing pressure about their environmental disposal. However, the use of this residue may directly impact the dynamic of pesticides as well as add heavy metals to the soils. Therefore, this study evaluated the effects of three wood ashes (C-1 , C-11, and C-27 ) in the fertility and sorption of imazethapyr in three soils (RQd, LVd, LVAd), with contrasting physical-chemical attributes. Besides the ashes, lime and control treatments were added, all of them incubated for three months. Afterwards, batch sorption isotherms for imazethapyr were performed for all treatments. The C-11 and C-27 enhanced soil-pH and macroelement contents, but decreased cationic microelement contents. The C-1 was a good source of K to the soils. There is little risk of contamination by heavy metals. Overall, imazethapyr sorption was low in all soils and their respective treatments (Kd < 1,8 L kg-1). The C-11 and the C-27 decreased whereas C-1 enhanced sorption of imazethapyr to the soils, most likely due to changes in soil-pH. Sorption was slightly higher in the soil with higher clay and organic carbon contents (LVd) whereas desorption was higher in the soil with intermediate values (LVAd). There was hysteresis, suggesting irreversibility during sorption/desorption processes. (AU)

• FAPESP's process: 11/16324-4 - WOOD ASH AS A CORRECTIVE ACIDITY AND ITS EFFECTS ON SORPTION OF IMAZETHAPYR IN SOIL
• Grantee: Bruna Botin Nascimento
• Support Opportunities: Scholarships in Brazil - Master