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To mitigate environmental stresses, use of aminocyclopropane-1-carboxylic acid (ACC)-deaminase containing plant growth promoting rhizobacteria (PGPR) as agricultural inputs for improved crop production is required. A total of 47 bacterial isolates from different rhizospheric soils of chickpea from Punjab were biochemically characterized and found to be representatives of genus Bacillus (25) and Pseudomonas (22). Ten (10) of the isolates were able to utilize ACC as a sole source of nitrogen, maximum growth (in terms of optical density λ600) being recorded with Bacillus isolate 23-B (0.463) followed by Pseudomonas 6-P (0.317). Three isolates were P-solubilizers and their relative Psolubilization efficiency ranged from 14.6 to 21.6 mg/100 ml culture broth. All the isolates produced Indole-3-acetic acid (IAA) (4.4-22.8 µg/ml). Two PGPR's 23-B and 6-P alone and in combination with recommended (for Punjab state) Mesorhizobium ciceris, were evaluated for water stress mitigation and plant growth promotion under axenic conditions on Cicer arietinum varieties (Kabuli L-552 and Desi GPF-2). Both the rhizobacteria significantly improved germination, root and shoot length and fresh weight of chickpea seedlings under osmotic potential of up to 0.4 MPa over uninoculated control. Proline content was considerably higher in PGPR treated varieties of chickpea under water stress. Coinoculation of 23-B with Mesorhizobium enhanced all growth parameters under water stress.

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all soils were considered, total Cu content ranged from 7 to 37 mg kg −1 , while DTPA-extractable and soil solution plus exchangeable Cu contents ranged from 0.30 to 3.26 mg kg −1 and from 0.02 to 0.43 mg kg −1 , respectively. Copper adsorbed onto inorganic sites ranged from 0.62 to 2.6 mg kg −1 and that onto oxide surfaces ranged from 2.0 to 13.2 mg kg −1 . The Cu bound by organic sites ranged from 1.2 to 12.2 mg kg −1 . The magnitudes of different forms of Cu in soils did not exhibit any consistent pattern of distribution. Organic matter and size fractions (clay and silt) had a strong influence on the distribution of different forms of Cu. The content of all forms of Cu was generally greater in the fine-textured Alfisols and Inceptisols than coarse-textured Entisols. Soil solution plus exchangeable Cu, Cu held onto organic sites, and and Cu adsorbed onto inorganic sites (crystalline) had significant positive correlations with organic carbon and silt contents.The DTPA Cu was positively correlated with organic carbon, silt, and clay contents. Total Cu content strongly correlated with silt and clay contents of soils. Among the forms, Cu held on the organic site, water soluble + exchangeable Cu, and Cu adsorbed onto oxide surface were positively correlated with DTPA-extractable Cu. The DTPA-extractable Cu and soil solution plus exchangeable Cu seems to be good indices of Cu availability in soils and can be used for correction of Cu deficiency in the soils of the region. The uptake of Cu was greater in fine-textured Inceptisols and Alfisols than coarse-textured Entisols. Among the different forms only DTPA-extractable Cu was positively correlated with total uptake of Cu.

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The knowledge of profile distribution of soil organic carbon (SOC) in long-term agricultural systems could help to store atmospheric carbon in the soil. We investigated profile distribution of easily oxidisable Walkley-Black SOC pool (SOC WB ) under long-term ricewheat (R-W) and maize-wheat (M-W) cropping systems under soils of different pedogenesis. The soil samples were collected from the characteristic genetic horizons and analysed for carbon fractions. The SOC WB was the highest in soils under R-W systems in both Alfisols and Inceptisols. The SOC WB stock in the deeper profile horizons under R-W system was significantly (p < 0·05) higher than that under M-W system especially in Typic Hapludalfs. Long-term R-W system could store on average 3·55 Mg ha À1 more SOC WB than M-W system in the Ap horizon. The SOC WB stock in the Ap horizon of all pedons was significantly (p < 0·05) higher in Alfisols than that in Inceptisols. About 60-90% of the total profile SOC WB stock was contributed by B-horizon because of its greater extent. Considering the whole profile, clay was negatively correlated with SOC fractions; however, the SOC fractions were closely related to each other. This study reveals that the distribution of SOC WB is different in long-term R-W and M-W systems not only in surface but also in the deeper horizons and the magnitude of the variation is influenced by the specific pedogenic processes. This indicates the significance of profile SOC WB stock instead of topsoil SOC WB stock in quantifying carbon retention potential of the long-term management practices.

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