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A study was conducted to characterize soil salinity and sodicity of Ghataprabha Left Bank Canal command area of Mudhol taluk (Bagalkot District). Bulk Electrical conductivity of salt affected soils was determined by using electromagnetic induction (EM 38). The pHs of surface and sub-surface soil layers ranged from 7.4 to 8.7 and 7.7 to 8.6, respectively. Electrical conductivity of saturated extract of surface and sub-surface soils ranged from 4.2 to 59.9 dSm -1 and 4.2 to 57.0 dSm -1 . Majority of soil samples were found to be saline as sodium absorption ratio (SAR) ranged between 0.3 to 10.8 and 0.5 to 10.9 for surface and sub-surface soil, respectively. Among the analysed surface soil samples, 26 per cent were saline, 18 per cent sodic and 56 per cent were saline-sodic. On the other hand, 26, 20 and 54 per cent of soils were categorized into saline, sodic and saline-sodic, respectively. Among the water soluble cations, Na + (10.9 to 73.4 cmol (P + ) kg -1 ) pre-dominated in surface and sub-surface horizons (10.9 to 65.2 cmol (P + ) kg -1 ). Among water soluble anions, Cl -dominated both in surface (2.0 to 60 me L -1 ) and sub-surface (2.0 to 59.0 me L -1 ).

With a view to study the effects of irrigation scheduling on the water use efficiency and physiological response and molecular basis of maize hybrids of different maturity groups, a field experiment was conducted at Water Management Research Center (WMRC), Belvatagi, University of Agricultural Sciences, Dharwad, India during 2010-2011 rabi season in Malaprabha Command Area'. The experiment was laid out in split plot design with three replications. The main plot comprised four irrigation levels (0.4. 0.6 and 0.8 irrigation water/cumulative pan evaporation (IW/CPE) ratio and irrigation at critical growth stages of maize) and subplots were three maize hybrids [PEEHM-5 (extra early), PEHM-2 (early) and 900 M gold (full season)] were tested. The results reveal that significantly higher grain yield (P<0.05) was at 0.8 IW/CPE ratio followed by irrigation at critical growth sages of maize. Among the maize genotypes tested, full season 900 M Gold recorded significantly greater grain yield (84.61 q ha-1) over PEHM-2 (early) and PEEHM-5 (extra-early). The moisture stress due to 0.4 IW/CPE ratio prolonged the days which reached 50% anthesis and 50% silking thus widening the anthesis-silking interval. Significant positive correlations (P<0.05) of maize grain yield with 100 seed weight (r=0.81), cob length (r=0.83), harvest index (r=0.82) and water-use efficiency (WUE; r=0.61) were found. The RWC decreased significantly (P<0.05) from 82.53 to 75.24% with increasing moisture stress on account of variations in the availability of soil moisture in the crop root zone. WUE was significantly low (P<0.05) in 0.8 IW/CPE ratio, despite providing more amount of water which could be attributed to a greater use of water with relatively lesser increase in yield. The present investigation shows that providing four irrigations at critical growth stages of maize hybrids followed by either three or five irrigations seem to have higher WUE. This approach could save water up to 29% with slight reduction of grain yield by 12% over providing full irrigation. Molecular analysis of three hybrids revealed the possibility of introgressing the yield enhancing traits from full season hybrid into early and extra-early hybrids, the latter clustered distinctly with each other. This strategy besides saving water helps tail-end farmers in choosing additional crop for double cropping in the command areas.

Morphometric analysis reveals the development of land surface processes and provides an insight into hydrologic behaviour of watershed. A morphometric analysis of landforms on basalt, granite gneiss and schist in north Karnataka was conducted with the objective of comparing various morphometric parameters among them. A sub-watershed each was selected to represent landform on basalt, granite gneiss and schist. The stream length was highest in sub-watershed on basalt and was least on schist with one on granite gneiss being intermediate. The stream number was highest in basalt and its values were similar in granite gneiss and schist. Total relief, relief ratio and ruggedness number were distinctly high in subwatershed on schist compared to the other two. The low mean bifurcation ratios in all three sub-watersheds suggested stability of the landforms. Drainage density was relatively coarser in the sub-watershed on granite-gneiss compared to the other two. The drainage network was dendritic in the sub-watershed on basalt, sub-dendritic on granite gneiss and sub-trelis on schist. The drainage texture and texture ratio were slightly higher, overland flow values were lower in sub-watersheds on basalt and schist compared to that on granite-gneiss. All three subwatersheds exhibited similar elongation ratio, form factor and circularity ratio.

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