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Jaya , P. C. Srivastava , A. K. Agnihotri , D. Ghosh

Abstract

Using batch technique, the effect of some factors like adsorbate concentration, equilibrium pH, temperature and ionic strength on adsorption-desorption of fulvic acid on goethite (α-FeOOH) was studied. The adsorption isotherms were predominantly of S-type and confirmed to Freundlich equation. The calculated value of adsorption capacity (log K) decreased while slope factor (l/n) increased with the increase in equilibrium pH from 5.0 to 6.0. An increase in temperature from 5° to 20°C increased the adsorption of fulvic acid by many folds but further increase in temperature from 20° to 30°C either decreased the adsorption or did not affect it. An increase in ionic strength decreased the adsorption of fulvic acid. In the case of all factors, the desorption of adsorbed fulvic acid has an inverse relationship with the adsorbed amount. Infra-red spectral evidence indicated that COO and phenolic (OH) moieties of fulvic acid interact with goethite.

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Ravi Kiran , A. K. Agnihotri

Abstract

The experiment was conducted to see the effect of modified microclimatic conditions on the yield and yield attributes of wheat at G.B. Pant University of Agriculture and Technology, Pantnagar, during Rabi season 1996-97. Wheat cv. PBW-226 was intercropped with Dalbergia sissoo (Roxb.) (planted in March, 1989). There were fifteen treatments of the orientation of the tree rows; starting from North in anticlock wise direction. The angle between the two adjacent tree rows was 24°. Tree rows were pruned 0%, 30%, 45%, 60% and 90%, respectively, in anticlock wise direction. Total number of trees were 105. Area per tree was 30 m². Net radiation, yield and yield attributes were recorded below tree canopies and control. Net radiation available during grain filling and maturity stages ranged 70-75% and 58-77% of control during crop growing period. Grain yield and biological yield was found reduced below tree canopies and ranged 71.58-88.90% and 69.24-79.86% of control, respectively. Higher harvest index and yield attributes were observed in some of the treatments below tree canopies.

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