SLAG EFFICACY AS A LIME AND SILICON SOURCE FOR RICE CROPS THROUGH THE BIOLOGICAL METHOD

Abstract

There is little information about the best silicon (Si) sources for agricultural use, and yet some products have already been marketed as sources of this element. One of these products is slag, which is used as a source for Si and lime. This study evaluated the silicon supply availability and efficacy of different silicate slag types for rice crops. The experiment was conducted in a greenhouse, used Entisol Quatzipsamment soil and was set up in randomized blocks with three replications. Si source reactivity was evaluated using five metallurgic slag types and Wollastonite, which is considered a standard in Si studies. Doses of each Si source were 1000 and 2000 mg dm⁻³ of Si and a control (additional treatment). Soil data [soluble Si, calcium (Ca²⁺), magnesium (Mg²⁺) and pH] and rice growth and yield were recorded. Data were evaluated by analysis of variance and contrasts were made for comparisons between each slag type and the additional treatment. Averages were compared by the Scott Knott test at 5% with the statistics program SISVAR. The efficacy of the slag types in supplying Si for the plants (ESSi) and in increasing Si availability in the soil (ESiA) was determined from the values of contrast estimates. Slag E3 and Wollastonite were effective in increasing soil silicon availability and, consequently, the efficacy of supplying silicon for the plants, while the other slag types had low efficacy.

Keywords:

• slag
• silicon
• rice

ACKNOWLEDGMENTS

The authors would like to express gratitude for the support of FAPEMIG and CNPq as well as to the HOLCIM cement company for their financial support and for supplying the material (slag) used in this study.

Notes

¹Determined according to the methods described by Korndörfer et al. (2004).

²Determined according to the methods described by EMBRAPA (1999).

¹Averages followed by the same letter, lowercase in the column and capital in the line, are not significantly different by the Scott Knott test at 5%. ² CV: coefficient of variance.

¹Averages followed by the same letter are not significantly different by the Scott Knott test at 5%.

¹Averages followed by the same letter, lower case in the column and capital in the line, are not significantly different by the Scott Knott test at 5%. ² CV: coefficient of variance.

¹Averages followed by the same letter are not significantly different by the Scott Knott test at 5%.