Micronutrients Uptake by Wheat as Affected by Genotypes, N and P.
Deepak Kumar, M.L. Dixit, and Kuldeep Singh. Dept of Soil Science, CCS Haryana Agricultural Univ, Hisar-125004, India
Increased crop yield results into greater uptake of nutrients. Crop species and genotypes differ in their nutrient uptake. Nitrogen is essential for stimulation of root growth, development and uptake of other nutrients. Phosphorus is a component of ADP and ATP and helps in energy transformation in plants. Field experiment was conducted in split plot design with three replication, at the research farm during rabi season of 1998-99. Treatment comprised of two wheat varieties (PBW-343 and WH-542), five levels of N (0, 50, 100, 1050 and 200 kg N ha-1) and four levels of P (0, 30, 60 and 90 kg P2O5 ha-1). Grain and straw samples were collected at maturity. Concentration of Zn, Cu, Fe and Mn were determined by AAS and uptake of each nutrient was computed. The performance of both the genotypes of wheat was almost similar in respect of micronutrients uptake, except Cu uptake in wheat straw which was significantly higher in genotype WH-542 than PBW-343. Application of 200 kg N ha-1 increased the uptake of Zn, Cu, Fe and Mn by 173, 225, 282 and 215 per cent, respectively over control in case of wheat grain, whereas this increase was 177, 181, 197 and 217 per cent over control in wheat straw. Uptake of Zn, Fe and Mn increased significant upto 150 kg N ha-1, whereas Cu-uptake increased significantly upto 200 kg N ha-1 in grain. In straw, uptake of Cu, Fe and Mn increased significantly with the application of N upto 200 kg N ha-1 and Zn uptake increased significantly upto 150 kg N ha-1 only. Application of 90 kg P2O5 ha-1 increased the uptake of Zn, Cu, Fe and Mn by 14, 18, 53 and 16 per cent, respectively over control in grain, whereas, this increase was 23, 26, 27 and 29 per cent over control in straw. The Fe and Mn uptake increased significantly with the application of 60 kg P2O5 ha-1, but differences were non-significant among 60 and 90 kg P2O5 ha-1. In wheat straw, Zn, Fe and Mn uptake was not influenced by the application of P. Application of 90 kg P2O5 ha-1 increased Cu uptake significantly over control and 30 kg P2O5 ha-1, but differences were non significant among 60 and 90 kg P2O5 ha-1. The uptake of Zn, Cu, Fe and Mn in grain and straw showed that much of these micronutrients (63-67, 65-72, 66-75 and 74-77 per cent) was retained in straw. Thus wheat residue can be a rich renewable source of micronutrient and its incorporation may help in sustaining the soil productivity.