Effect of 31 years of continuous cropping and fertilizer use on soil properties and uptake of micronutrients by maize (Zea mays)-wheat (Triticum aestivum) system

A study was conducted during 2002-06, to assess the changes in soil properties and micronutrient uptake by maize-wheat system after 31 years of fertilizer use, at Indian Agricultural Research Institute, New Delhi. The soil pH, electrical conductivity and CaCO3 content of the soil varied from 8.28 to 8.53, 0.40 to 0.43 dS/m and 0.92 to 1.05% respectively. DTPA extractable Fe, Mn and Cu in soil did not differ significantly among the treatments but DTPA-Zn was highest under Zn-treated plots. Organic carbon content ranged from 0.38 under control to 0.67% under 100% NPK+farmyard manure. Build-up of Olsen's available P was observed under all the treatments except control. Neutral ammonium acetate extractable K content in soil varied from 219 to 326 kg/ha under the various treatments. The highest grain (2.43 tonnes/ha) and stover (2.48 tonnes/ha) yield of maize was obtained under integrated use optimal NPK and farmyard manure (100% NPK+FYM), followed by 100% NPK+Zn. But in case of wheat, grain and straw yields under 100% NPK+FYM and 100 NPK+Zn were at par and higher as compared to other treatments. Total uptake of Zn, Fe, Mn and Cu ranged from 119.5 to 268.6, 278.3 to 504.6, 51.6 to 108.3 and 17.0 to 37.5 g/ha respectively by maize and from 134.0 to 324.7, 1030.8 to 2540.2, 219.4 to 466.3 and 60.8 to 149.3 g/ha by wheat under different treatments.