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G. Gururaja Rao , Ravender Singh , G. P. Bhargava

Abstract

The salt affected soils which are widespread in inland and coastal areas of Gujarat State, either remain barren or serve as poor grazing grounds. A survey was undertaken to catalogue the native species growing on saline soils and to evaluate their economic importance with a view to identify species suitable for further exploitation. The study indicated that only very few species like Salvodora persica, Prosopsis juliflora, Tamarix ericoides, Kochia prostrata and Cressa cretica exist on very highly saline soils having EC₂ values in the order of 25.0-38.0 dS m^-1. The number of species increased several fold with decreasing salinity. Based on the soil salinity status, some salt tolerant species which are economically useful have been suggested for further introduction on the saline soils. The plant species catalogued at different salinity levels are proposed for growing on different saline soils.

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Ravender Singh , R. K. Singh , Kalyan Singh

Abstract

Effect of different plant cavers on pbysico-chemical properties of soil was evaluated in Doon Valley environmental conditions. Amount of organic carbon, total nitrogen, available phosphorus and potash, exchangeable magnesium and cation exchange capacity was highest in soils under Eucalyptus hybrid plantations, and lowest in soils under agriculture landuse except the lowest values of available phospborus and potash in soils under Chir (Pinus roxburghii). Available nitrogen in agricultural soils and exchangeable calcium in soils under Teak (Teeona grandis) were highest in amount while these nutrients were lowest in soils under Sal (Shorea robusla) and agriculture, respectively. Other species exhibited different patterns of soil characteristics. The highest C:N ratio in soil. Under Subabul and lowest in soils under Chir iniicated bigbest production of decomposable leaf litter is oils under Subabul and lowest in soils under Chir. The surface soil (0-10 cm deep) contained bighest amount of mineral nutrients. Seasonally, mineralization of nutrients was found to be highest in the month of February and lowest in June.

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Pratap Narain , Ravender Singh , Kalyan Singh

Abstract

Studies were conducted on soil nutrient status, their dynamics and physico-chemical characteristics of soil under Sal. Eucalyptus and Brushwood forests in Doon valley. Annual return of nutrients through leaf fall was maximum under Sal forest followed by Brushwood and Eucalyptus. The understorey biomass and nutrients contained therein were however bighest in Eucalyptus followed by Brushwood and Sal forest. Organic carbon, total nitrogen, available rotash and exchangeable calcium and magnesium in soil were maximum in Brushwood forest allowed by Eucalyptus and Sal but available phosphorus was more under Sal. Accumulation of nutrients was conspicuous in surface soil while lower depths (90-210 cm) did not show much hange in nutrient status. The 0-10 cm layer was the richest in respect to all the nutrients due to their recycling through leaf-fall or understorey. Site quality was estimated to be II under Eucalyptus and Sal forests. Soil bulk density increased and correspondingly porespace percentage decreased with increasing soil depth. Lower bulk density and higher porespace percentage was found under Brushwood forest, followed by Eucalyptus and then Sal forests. Soil moisture retention curves showed higher water retention and available water under Brushwood followed by Eucalyptus and then Sal. Infiltration rates and cumulative infiltration rates were also higher under Brushwood followed by Eucalyptus and then Sal. These physical characteristics are due to higher organic carbon content in Brushwood, followed by Eucalyptus and then in Sal watersheds. Hydraulic conductivity was found to increase with moisture content. Generally, Brushwood and Eucalyptus watershed showed higher hydraulic conductivity in surface layer. In sub-surface layer Sal also revealed higher value due to low clay content. Organic matter and clay content are major determinant factors for hydraulic conductivity.

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Pratap Narain , Ravender Singh

Abstract

In a study conducted on three forest watersheds namely Sal' Eucalyptus and Brushwood on an agricultural land in Doon valley' higher nitrates were observed upto 20 cm soil depth' which decreased in deeper layers. Agricultural land revealed much higher levels of nitrates than forest land users' particularly in 0-10 cm depth. Thus agricultural fields when dressed with heavy doses of nitrogen fertilizer pose a serious threat to nitrate contamination. Amongst the forest watersheds' higher nitrates were recorded under Sal followed by Eucalyptus and then brushwood. Maximum amount of nitrates were observed in February sampling followed by September and June sampling. Nitrate contents was found to bear direct relationship between ph' organic carbon and moisture status in surface layers. The correlation coefficients and regression equations have been reported.

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K. K. Bandyopadhyay ¹, R. N. Sahoo ¹, Ravender Singh ¹, S. Pradhan ¹, S. Singh ¹, Gopal Krishna ¹, S. Pargal ¹, S. K. Mahapatra ²

Affiliations
1 Division of Agricultural Physics, Indian Agricultural Research Institute, New Delhi 110 012, IN
2 National Bureau of Soil Survey and Land Use Planning, Delhi Centre, New Delhi 110 012, IN

Abstract

Rice is the principal crop during kharif (rainy) season in eastern India, which occupies 26.8 M ha accounting for 63.3% of the total rice-growing areas of the country. However, this area is not fully utilized for crop production in the subsequent rabi (post-rainy) season and kept fallow due to a number of biotic, abiotic and socio-economic constraints. If this rabi fallow area can be effectively utilized, it will help in improving the economy of this region, which is yet to be benefited from the green revolution. The objectives of the present study include: (i) delineation of rabi fallow areas of eastern India using remote sensing and GIS technique; (ii) characterization of soil resources of the rabi fallow regions, and (iii) suggesting site-specific crop planning for this region. It was estimated that about 12.54 M ha area in the rabi season is left fallow in eastern India. The soil properties like soil texture, soil moisture retention at field capacity and permanent wilting point, saturated hydraulic conductivity, soil pH, electrical conductivity, soil organic carbon, etc. were determined at the representative profiles distributed in different agro-ecological sub-regions (AESRs) of this region and mapped in a GIS environment. Using water balance studies, site-specific crop planning based on available residual soil moisture has been suggested. In most of the AESRs, pulses and oilseeds like green gram, black gram, Sesamum and mustard can be grown successfully on residual soil moisture content. Crops which suffer from water deficit during maturity stages can also be grown during rabi season with one or two supplemental irrigations, wherever possible. If the site-specific constraints to crop production can be alleviated and these fallow lands can be brought under cultivation through proper crop planning as suggested, poverty in this resourceful region can be eradicated to a great extent.

Keywords

Crop Planning, Rabi Fallow, Remote Sensing and GIS, Water Balance.

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