Eficiência de escórias de siderurgia na cultura do feijoeiro em sistema de semeadura direta

Abstract

No sistema de semeadura direta (SSD), a prática da correção da acidez do solo se restringe ao uso do calcário, havendo poucas informações em relação às escórias de siderurgia. O trabalho objetivou avaliar as alterações em propriedades químicas do solo, rendimento e absorção de nutrientes do feijoeiro, em função das formas de aplicação de escórias de siderurgia, comparadas ao calcário, na implantação do sistema de semeadura direta. O experimento foi conduzido na área experimental da Faculdade de Ciências Agronômicas de Botucatu (SP), no período de dezembro de 2010 a maio de 2011. Os tratamentos foram duas formas de aplicação de sete corretivos da acidez do solo: escórias de aciaria, de alto forno, de forno de panela, do aço inox (agrosilício), wollastonita, calcário dolomítico e calcário dolomítico calcinado, além de uma testemunha sem aplicação de corretivo. A dose aplicada de cada corretivo foi calculada para elevar a saturação por bases do solo a 70. A acidez do solo foi neutralizada até a camada de 20cm com os calcários, enquanto a wollastonita e escória de forno de panela atingiram a camada de 10cm; para as escórias de aciaria, alto forno e o agrosilício, o efeito corretivo ficou restrito aos primeiros 5cm. O rendimento do feijoeiro aumentou com a aplicação de corretivos da acidez do solo, sem diferença entre o modo de aplicação.

Steel slag to correct soil acidity and as silicon source in coffee plants

“…Rise in the soil´s pH due to corrective agents increases silicon availability caused by decrease of the element´s adsorption caused by the soil´s inorganic colloids (Silva and Coelho, 2010). Korndörfer et al (1999), Camargo et al (2007), Silva and Coelho (2010) and Deus and Büll (2013) reported similar results and detected increase in c rate in the soil when silicate slag was applied. There were no changes in the nutrients concentrations in the leaf tissue of the coffee plant when stainless steel slag and limestone were applied.…”

“…Silva et al (2004) also reported the correction of acidic soil at 0 to 0.1 m layer with surface application of limestone in coffee crops and they insisted that correction at the sub-surface layers of the soil only occurred 34 months after the first application of the corrective agent and 13 months after the second one. Deus and Büll (2013) registered that in an area with bean tillage system, the corrective effect of stainless steel slag was limited to a depth of 5 cm whereas limestone neutralized soil acidity at the 0 to 0.2 m layer sixty days after their application on the soil surface. In an assay with coffee crops, Melo and Sartori (2013) showed that industrial slag behaved similarly to limestone when correcting soil acidity at a depth of 0 to 0.1 m. However, the two corrective agents did not correct acidity at a depth of 0.1 to 0.2 m after 90 days of application on the soil surface.…”

“…Certain industrial slags, such as iron and steel industry slag, may be used in agriculture to replace liming (Prado et al, 2003;Oliveira et al, 2010). Iron and steel industry slag derive from high temperature processing within the limestone and silicon (SiO 2 ) reaction are present in the mineral iron (Deus and Büll, 2013). Approximately 6.25 million tons of slags are annually produced in Brazil but their use in agriculture is still fledging (Deus, 2014).…”

“…Since steel slags are more soluble than limestone, they may correct soil acidity faster and deeper when applied at the soil´s surface (Deus and Büll, 2013). These material contain silicon whose effects have been the object of several assays in rice (Artigiani et al, 2014), potato (Pultz et al, 2008), tomato (Marodin et al, 2014), bean (Deus and Büll, 2013), soy and corn (Castro and Crusciol, 2013) and sugarcane (Reis et al, 2013).…”

“…These material contain silicon whose effects have been the object of several assays in rice (Artigiani et al, 2014), potato (Pultz et al, 2008), tomato (Marodin et al, 2014), bean (Deus and Büll, 2013), soy and corn (Castro and Crusciol, 2013) and sugarcane (Reis et al, 2013). However, the use of steel slag in agriculture is still rare in Brazil.…”