Emissão de óxido nitroso e atributos físicos, químicos e biológicos de um argissolo com histórico de adubação com composto de pó de tabaco

Abstract

Tobacco powder compost produced by solid-state fermentation (SSF) of waste generated in the tobacco industry has been used in agricultural crops in southern Brazil. However, as this is a recent practice, there are few studies on the use of tobacco powder compost. In addition, the existing studies deal only with its use as an agricultural fertilizer, and no reports were found on the impacts of compost on soil attributes and environmental quality. The aim of this study was to evaluate the effect of successive applications of different doses of tobacco dust compost and mineral fertilizer (NPK) on crop production, nitrous oxide (N2O) emissions and the physical, chemical and biological attributes of the soil. The study consisted of a wheat/maize/oats succession planted after three successive applications of three different doses of tobacco dust compost and mineral fertilizer (NPK). For wheat and maize, the treatments consisted of reapplying the three doses of compost and NPK and the residual effect of these treatments, as well as a control treatment and a treatment with the first application of compost. The doses were calculated to provide the equivalent of 50, 100 and 200% of the N supplied with urea in the NPK treatment. Wheat and maize yields, N accumulation and N2O emissions were assessed. After harvesting the maize, which had received the fifth application of compost and NPK, the following were evaluated physical, chemical and biological attributes of the soil in the 0 to 5 and 5 to 10 cm depths, and the production and accumulation of N in black oats. In wheat, grain yield did not differ between reapplications of the three doses of compost. In corn, yield and accumulated N increased as the dose of compost reapplied increased. The yields of the two crops did not differ when the 100% dose of compost and NPK was reapplied. Unlike NPK, compost at the highest doses (100 and 200%) had a positive residual effect on grain yield and accumulated N in the two crops. Re-application of compost increased N2O emissions compared to mineral fertilization and the increase was related to the dose applied: however, the emission factor (EF) and emission on a yield scale were generally similar between the two doses. The compost residual did not increase N2O emissions; therefore, it had no impact on the N2O FE. Successive additions of the two highest compost doses (72 and 144 Mg ha-1) increased C and N stocks, soil fertility, biological activity, aggregation, porosity, saturated hydraulic conductivity and water infiltration rate, attributes that correlated positively with production and N accumulation in black oats.