AGRO-climatic indices of fodder maize (Zea mays L.) under varying levels of nitrogen and farm yard manure

An experiment on fodder maize was conducted at Punjab Agricultural University, Ludhiana, India in the kharif (summer) season of 2011 and 2012. Study comprising of twelve treatment combinations viz; three farmyard manure levels(FYM) (0, 12.5 and 25 t/ha) in main plot and four nitrogen levels (0, 40, 80 and 120 kg/ha) in sub plot was laid out in spilt plot design with four replications. Crop, which received the highest level of N and FYM took minimum days for attainment of all development stages and consequently for completion of life cycle. Increase in the level of organic or inorganic source reduced the span of life of crop, which resulted in low heat requirement. Conversely on the over hand, lowest level of N and FYM resulted in consumption of highest number of heat units. Fodder yield was dependent on the level of crop nutrition. Results revealed that heat requirement was inversely related with N and FYM level, indicating that heat requirement of a crop can be modified by nutrition.