R. N. Adhikari , M. S. Rama Mohan Rao , A. K. Singh , K. K. Reddy

Abstract

Vegetative measures for soil & water conservation are preferred due to their efficacy and cost effectiveness. A study conducted during 1996-2000 in black soil semi-arid region showed that among the commonly occurring grasses, Cenchrus ciliaris, Dichanthium annulatum and Cymbopogon martini were most effective in reducing surface runoff which ranged from 9 to 12%, while sediment loss varied from 500 - 1000 kg/ha and was below permissible limits of 5 t/ha/year. Cymbopogon has drought resistance and capability to withstand limited grazing. It also gives comparatively more (1.7 to 2.4 times) biomass production with aromatic uses. Thus, from a holistic perspective Cymbopogon is recommended for conservation and production. By artificial seeding on large scale, Cymbopogon, Ciliaris and Dichanthium can replace the Sehima species which has currently failed to survive due to changed environment.

Keywords

Grass Species, Run-off, Soil Loss, Semi-arid, Black Soil

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R. N. Adhikari , M. S. Rama Mohan Rao , V. Husenappa

Abstract

The rainfall simulator is an useful tool to generate quick and satisfactory information on runoff and soil loss under different surface conditions, involving much less cost and time. The results show that sorghum stover mulch reduced runoff and soil loss considerably. It is also observed that runoff and soil loss increase with increase in degree of slope. Simple application of mulch material on the surface upto 2% slope of the field, involving almost no cost, can act as good inter-terrace soil and water conservation treatment in the black soil region, apart from improving in-situ moisture condition to increase crop production. The results show that mulched plot reduced runoff by 10 to 20% in comparison to bare plot and for individual storm, soilless is reduced from 0.5 t/ha to 0.1 t/ha (for 1% slope) and 0.8 t/ha to 0.2 t/ha (for 2% slope). Attempt has also been made to have effect on runoff and soil loss under steep slopes having stone barrier using mini rainfall simulator. It is observed that stone barrier reduced sediment density by about 50%. From discharge simulation studies it is observed that grass cover reduced runoff and the peak rate of runoff by 20 to 30%. The study shows that simple and cheap technology like surface mulch, grass cover and stone barrier can act as a good soil conservation treatment in arable and non-arable land.

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S. K. N. Math , S. L. Patil , R. N. Adhikari , Vasudev K. Lamani

Abstract

The field studies were conducted at Research Farm of Central Soil and Water Conservation Research and Training Institute, Research Centre, Bellary and in the farmer's fields in Joladarasi and Chellagurki watersheds of Bellary district of Karnataka during 2000-2003. Survival per cent, height, collar diameter and canopy spread of all the bio-fence species evaluated were higher in ridge planting over flat planting. Among the bio-fence species, Agave sisilana survived better and recorded higher collar diameter over other species. Lower runoff and soil loss was observed in ridge planting than flat planting. Ridge planting reduced runoff by 56.9% and soil loss by 87.4% over flat planting. Agave sisilana and Euphorbia tirucalli were found more efficient in reducing runoff by 34.6% and 31%, soil loss by 61.9 and 48.4% and conserving 16.4 and 12.4% higher soil moisture over control respectively. At research farm, sorghum yield was higher by 37% when planted with Agave sisilana and bengalgram yield was higher by 23% when planted with Euphorbia tirucalli. Grain yield of sorghum, sunflower and bengalgram crops were higher by 22, 42 and 11% respectively in ridge method over flat method of planting. Sorghum, sunflower and bengalgram crops when planted away from bio-fence species (2-4 m) recorded 7.1%, 4.8% and 6.7% higher yields as compared to near to bio-fence (<2 m) species. The performance of Agave sisilana and Euphorbia tirucalli planted in ridge method of planting was better with minimum effect on crop yields with better soil and water conservation.

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R. N. Adhikari , M. S. Rama Mohan Rao , I. P. Pradhan , M. Padmaiah

Abstract

The loss of soil, which constitutes one of the most important life supporting systems, results in lowering productivity and if unchecked may even threaten the very existence of life. Apart from reduction in productivity and destruction of valuable forests, it also reduces basin retention capacity causing floods in the down stream side and siltation of multipurpose reservoirs should be considered as non renewable and hence need to be protected on priority. It is therefore, essential to adopt proper conservation measures which are most effective and 1east expensive. Accordingly, studies were initiated since 1986, in two mine areas, namely (a) Navalutti Mines near Sandur (60 km from Bellary) under lease of M/s H.R.. Gaviappa & Co., and (b) Metriki Forest (Karnataka Forest Department). Vithalapuram Mine situated at 30 km on the south-west direction from Bellary.

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