Maneesh Kumar

Assessing a suitable extractant and critical limits of nickel in soil and plant for predicting the response of barley (Hordeum vulgare L.) to nickel grown in Inceptisols

ABSTRACT Nickel (Ni) is an essential element for plants. Abundant information exists on Ni toxicity in soil–plant system but not much is available on its critical level of deficiency (CLD) in soils and plants. Five chemical extractants were evaluated to find a suitable extractant for Ni in Inceptisol. Twenty-one soils having low to high levels of Ni were used to grow barley (Hordeum vulgare L). The amount of Ni extracted was correlated with Ni concentration and uptake by barley. The diethylene triamine penta acetic acid-calcium chloride (0.005 M DTPA-CaC12) was identified as the most promising soil extractant for Ni. The CLD of Ni for 0.005 M DTPA-CaC12 in soil was 0.22 mg kg−1 whereas in barley plant it was 2.14 mg kg−1. Application of 7.5 mg kg−1 Ni in soil caused a significant increase in Ni concentration in the shoot of barley in all the soils irrespective of the initial Ni status.

Effect of Integrated Nutrient Management on Physico-chemical Soil Properties Under Rice Crop in Hot Sub Humid Ecoregion of Middle Gangetic Plains of India

A field experiment was conducted during Kharif season (2010) to find out the effect of integrated use of urea, zinc, poultry manure and Azotobacter on physico-chemical properties, available NPKS content of soil under rice crop (Oryza sativa L.). The experiment was laid out in Randomized Block Design (RBD) during kharif seasons with seven treatments and three replications. The details of various treatments applied to rice crop are as follows: T1 (Control); T2 (100% RDF); T3(100% RDF+ Zn); T4 (50 % RDF + 50 % N through urea); T5 (50 % N through poultry manure + 50 % N through urea + Zn); T6 (50 % N through poultry manure + 25 % N through urea+ Azotobacter); T7 (50 % N through poultry manure + 25 % N through urea + Azotobacter + Zn). The integrated use of poultry manure along with urea, zinc and Azotobacter were found to build up in organic carbon, available N, P, K and S content of soil under rice plants significantly over the sole use of chemical fertilizer. The plots which had received poultry manure and chemical fertilizers with Azotobacter showed significant improvement in residual soil fertility. It could also be concluded that the application of poultry manure with Azotobacter has good performance over sole application of manure.