Effect of Long Term Fertilization on Soil Nutrient Status and Yield of Hybrid Maize under Finger Millet-Maize Cropping Sequence in an Irrigated Inceptisol

An investigation was undertaken to evaluate the effect of long term application of inorganic fertilizers and organic manure on soil available nutrients, organic carbon and yield of hybrid maize during 2013-14 under finger millet-maize cropping sequence at TNAU, Coimbatore. The experimental results showed that the performance of hybrid maize in terms of both grain and straw yield was highest in the treatment receiving 100% NPK along with FYM (10t ha-1) recording an increase in grain yield of 12.6 % over 100% NPK. Similarly the different soil fertility parameters viz., available nutrients (N, P and Zn) and organic carbon content in soil showed significant improvement with integrated application of inorganic fertilizers in combination with FYM compared to control treatment. A declining trend (471 to 605 kg ha-1) from its initial level (810 kg ha-1) of available K status was observed which shows a considerable mining of soil K under intensive cropping. However, the decline of K was of lower magnitude with 100% NPK + FYM (25.3%) and 150% NPK (27.9%) treatments indicating the need to raise the level of K fertilizer application to meet demand of crops. The fertility of the soil appears to be adversely affected due to imbalanced use of fertilizers viz., NP or N alone. Thus, balanced fertilization in combination with organic manure is necessary for sustain soil fertility and productivity of crops.