Management of Zinc Fertilizer under Pearl Millet-Wheat Cropping System in a Typic Ustipsamment

摘要

Field experiments were conducted with pearl millet-wheat cropping system on a Typic Ustipsamment to assess the direct, residual and cumulative effect of Zn application on crops with or without use of organic manure. The residual effect of 10 kg Zn ha~(-1) applied to first crop on grain yields was noted up to the sixth crop. Better yields were obtained with the application of 10 kg Zn ha~(-1) every year or at least in alternate years. Combined application of 2.5 kg Zn + 5 t FYM ha~(-1) in alternate years gave significantly higher concentration of Zn in flag leaf, its uptake by crops and higher content of DTPA-extractable Zn in soil at the end of three years' cycle. Apparent Zn fertilizer use efficiency under combined application of 2.5 kg Zn + 5 t FYM ha~(-1) applied in 1st and 2nd years or 1st and 3nd years was about ten-fold higher than application of 10 kg Zn as ZnSO_4ha~(-1) in 1st and 2ndor in 1stand 3nd years.