International Journal of Agricultural Engineering

Subhas Balaganvi ¹, P. Balakrishnan ², M. V. Ranghaswami ³, D. Tamilmani ⁴

Affiliations
1 Department of Soil and Water Engineering, College of Agricultural Engineering, Raichur karnataka, IN
2 College of Agricultural Engineering, University of Agricultural Sciences, Raichur karnataka, IN
3 Department of Soil and Water Conservation Engineering, Agricultural Engineering College and Research Institute, (T.N.A.U.) Coimbatore T.N., IN
4 Department of Soil and Water Conservation Engineering, Agricultural Engineering College and Research Institute, (T.N.A.U.) Coimbatore T.N.

Abstract

The study was conducted at the Agricultural Research Station, Gangavati, University of Agricultural Sciences, Gangavathi in northern Karnataka, India during Rabi/summer, 2007-08 and 2008-09 with beetischolar_main (Beta vulgaris) as the test crop. Under the drip irrigation, the soil moisture content was the highest and maintained almost steadily near the field capacity throughout the cropping period at all distances away from the dripper. The maximum moisture content near the dripper was reduced to the extent of 15 and 19 per cent at a distance of 60 cm away horizontally and vertically downwards, respectively, from the dripper during 2007-08 in case of drip irrigation at 0.6 ET in salinity level-I, against16 and 20 per cent during 2008-09. The soil moisture content at particular distance from the point of application increased with increase in depth of applied water and it decreased with distance from the point of application (R2= 0.83 to 0.92). The maximum water use efficiency of 6.74 and 6.23 kg m-3 was achieved in drip irrigation at 0.6 ET under salinity level-I and the lowest water use efficiency of 2.78 and 2.40 kg m-3 was recorded in drip irrigation at 1.4 ETin salinity level-III during 2007-08 and 2008-09, respectively. Among the surface irrigation levels, the highest water use efficiency of 4.25 kg m-3 at 1.0 ET and 3.32 kg m-3 in 0.8 ET was recorded in salinity level-I during 2007-08 and 2008-09, respectively.

Keywords

Drip, Surface Irrigation, Irrigation, Vegetable, Beetischolar_main, Soil Salinity, Moisture Distribution, Water Use Efficiency

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M. Manikandan ¹, D. Tamilmani ²

Affiliations
1 Department of Soil and Water Conservation Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore T.N., IN
2 Department of Soil and Water Conservation Engineering, Agricultural Engineering College and Research Institute, Tamil Nadu Agricultural University, Coimbatore T.N., IN

Abstract

The identification and characterization of droughts are of great importance in water resources planning and management. In the present study, the standardized precipitation index (SPI) was employed to investigate the spatial characteristics of meteorological drought in the Parambikulam-Aliyar basin, Tamil Nadu. The basin was divided into 97 grid-cells of 5×5 km and monthly rainfall data for the period 1972-2011 from 28 rain gauge stations were used for spatial interpolation of rainfall using the ArcGIS. Occurrence of drought categories and cumulative drought severity were then assessed from the estimated gridded SPI values calculated from gridded rainfall at each grid and maps of spatial variation of drought characteristics were developed. The analysis of the SPI suggests that the basin had suffered severe and extreme drought in the 1970s and 1980s. The spatial extent of drought category showed that moderate and severe drought was more in the central and northern parts of the basin; while extreme drought was high in the southern parts of the basin. Drought severity map at 5 year return period indicated that the annual cumulative drought severity was high in the southern and northern parts of the basin. The results of this study can be used for identifying drought vulnerable areas, developing drought preparedness plan and mitigation strategies within the basin.

Keywords

Drought Severity, GIS, Rainfall, Return Period, SPI

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