Status of secondary nutrients vis-à-vis soil site-characteristics of vegetable growing soils of Varanasi

Abstract

A study was conducted to assess the status of available secondary nutrients (Ca, Mg and S) along with physico-chemical properties of soils under continuous vegetable based cropping systems at the Central Research Farm of Indian Institute of Vegetable Research, Varanasi situated at 82.52°E longitude and 25.10°N latitude in the alluvial belt of Indo-Gangetic Plains (IGP) of Eastern Uttar Pradesh. The soils at this farm have been under continuous vegetable cultivation with the exception of intermittent cultivation of paddy in some blocks for the last 15 years. The experimental farm has a total area of 45 ha spread over 16 blocks. The analysis of soil samples collected from different blocks for various physico-chemical properties and status of secondary nutrients revealed that the soils of the research farm were neutral to slightly alkaline in reaction having pH in the range of 6.61 to 7.82 with a mean value of 7.29. Electrical conductivity was found within the normal limits (ranged from 0.09 to 0.76 dSm-1 with a mean value of 0.28 dSm-1). Twenty two per cent soil samples of the research farm were found low, 73 per cent medium and rest 5 per cent high in organic carbon content. Water retention at field capacity and permanent wilting points was 25.6 and 6.3 per cent, respectively, and available water content was estimated to be 19.4 per cent. The soils of the entire farm were found to be silt loam in texture. Among the secondary nutrients, available Ca ranged from 1206 to 2302 ppm, whereas, available Mg ranged from 164 to 723 ppm, which indicated that these soils are sufficient in calcium and magnesium. With regard to the status of available sulfur, 3 per cent soils were found to be in low, 13 per cent in medium and 84 per cent in high range.