Transformation of cationic micronutrients in lowland rice soils as affected by seasons, sources and methods of nitrogen application.

摘要

Field experiments were conducted during the kharif [monsoon] and rabi [winter] seasons on an Inceptisol in Kalyani, Karnataka, India to study the effect of different sources and methods of nitrogen application on the availability of four cationic micronutrients in soils growing rice. There was a marked increase in the DTPA-extractable Fe and Mn, while Cu and Zn content in soils decreased from their initial contents. However, the increases in Fe and Mn content, and decreases in Zn content were higher during the rabi season. Copper content in soil was higher in the rabi than in the kharif season. Application of N especially through integrated use of urea and green manure at 1:1 proportion to rice crop improved the availability of these cationic micronutrients in soil.