Soil sampling and analysis

Soil sampling was carried out at depth of 0–30 cm prior to the initiation of the experiment in both the “Sars” and after harvesting of each crop in both kharif and rabi seasons. i.e., in the months of April/May and October/November, respectively. Soil was sampled from five random locations in each of the three replicate plots. Samples from each plot were mixed thoroughly to obtain one composite sample per plot. Soil pH was measured following Jackson (2005). Soil organic carbon content was determined by the method of Walkley and Black (1934). Organic carbon free soil samples were used to determine total N, K, Ca, Mg, Na and available P. The digestions were carried out using Kjeldhal apparatus (Anderson and Ingram 1989). Total N was estimated by micro- Kjeldhal method (Allen 1974). Available phosphorous was measured at 880 nm wavelength using ammonium molybdate blue menthod (Systronics 160). Total calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K) were estimated using the same filtrate by atomic absorption spectrophotometry (AA 6300 Shimadzu, Japan).