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Influence of silicate and lime on crop residue decomposition and nutrient availability to bean plants

Si made available by Ca silicate can increase polyphenol formation, which could increase the persistence of crop residues on the soil surface. The present study evaluated the effect of silicate and lime on decomposition of different crop residues and the nutrient release for the development of common bean plants. An experimental design in randomized blocks, arranged as a 3 x 5 factorial combination, was used with four replications. Treatments consisted of three cover plant species: millet (Pennisetum americanum), brachiaria (Brachiaria brizantha), and pigeon pea (Cajanus cajan L.), and five proportional Ca silicate levels: 0, 25, 50, 75, and 100 %, applied at increasing doses of 0, 2.31, 4.63, 6.96, and 9.27 g/pot, balanced with Ca carbonate and magnesium carbonate so that the Ca and Mg amounts in each treatment were identical, and calculated to achieve a soil base saturation of 70 %. The application of Ca silicate did not affect Brachiaria, pigeon pea, and millet crop residue decomposition. The available soil Mg content was reduced by Ca silicate applications, leading to lower Mg uptake by the cover plants and eventually becoming less available after residue decomposition. Bean growth benefited from the application of Ca silicate, and the efficiency was higher for doses varying from 25-75 % silicate in association with Brachiaria crop residues.

calcium silicate; brachiaria; millet; pigeon pea


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