Nutritional Evaluation of Millet Plants Grown in Soils Fertilized With Organic Wastes From Different Sources

The losses of essential elements to crops make necessary to correct soil fertility to meet the nutritional requirements of plants, which can be achieved by increasing soil organic matter. The objective of this work was to evaluate the leaf nutritional conditions of millet plants grown in soils fertilized with organic wastes from different sources at different rates. Organic matter can make the soil more productive and suitable to agricultural crops. A randomized block experimental design with a 4 × 2 factorial arrangement was used with four replications, consisting of 32 experimental units. The treatments consisted of four organic matter sources (swine manure, sewage sludge, bovine manure, and poultry litter), and two organic matter rates (20% and 40% of the pot volume). Boron extraction was performed by dry digestion—the organic matter of the plant tissue was incinerated in an electric muffle furnace at 450-550 ºC, and the inorganic residue (ash) was dissolved in a dilute acid solution. N, K, Ca, Mg, S, Fe, Cu, Mn, and Zn was extracted through wet digestion—the organic matter of the leaf tissue was oxidized by concentrated mineral acids and by heat. N, P, S, B, Ca, Mg, Cu, Fe, Mn, and Zn was determined by spectrophotometry. K was determined by flame photometry. All macro and micronutrient contents in the millet leaves, and biometric parameters of the millet panicle were affected by the organic matter sources, organic matter rates, and the interaction between them.