Micronutrient status in soybean (Glycine max)-wheat (Triticum aestivum) cropping system in Kumaon region of Uttaranchal

A study was conducted during 1993-99 to assess the yield response to farmya rd manure application and its fate on build up/depletion in soil and uptake of Fe, Mn, Zn and Cu in soybean [Glycine max (L.) Merr.]-wheat (Triticum a estivum L. emend. Fiori and Paol.) rotation in a long-term field experiment s. Yield response curve showed sharp increase in response to farmyard manur e application in soybean and succeeding wheat crop. Change in micronutrient showed that zinc levels were below the critical level in NPK treatment (< 0.6 ppm) which is alarming in intensive agriculture. Iron content increased in NPK treatment clue to increase in soil acidity. Farmyard manure decreas ed the Fe and Mn content but increased the Zn content and maintained the Cu level in the soil. Micronutrients content in soybean and wheat were found to be present above the critical limits in all the treatments except Zn in NPK treatment and contents were significantly higher in treatments receivin g farmyard manure after 26 years of cropping.