Effect of integrated nitrogen management on yield and nitrogen nutrition of irrigated, rice (Oryza sativa)

Field experiments were conducted in rainy (kharif) season of 1999 and 2000 to study the effect of 3 integrated N management options using farmyard manure, green manure and wheat straw incorporation on yield and N nutrition of rice (Oryza saliva L.). Total above ground biomass and plant N uptake at different growth stages of rice crop were significantly affected by various N sources used alone and in combination with urea-N comparing to state fertilizer N recommendation for rice, i e 120 kg N/ha, optimum N dose calculated from the response curve were higher in both the years of study. Grain and straw yields of rice were significantly increased by various sources ofN. Use of green manure in combination with urea gave the same yield of rice grain and straw as farmyard manure or wheat straw incorporated in conjunction with urea-N at 150 kg/ha. These 3 integrated nitrogen management options were found at par with urea-N alone at 150 kg/ha in grain yield. Incorporation of wheat straw 4 weeks before rice planting did not show any adverse effect on rice growth. Green manure in conjunction with urea gave higher total N uptake than urea alone at 150 kg N/ha. Integrated use of urea with organic sources has shown increased nitrogen use efficiency in rice.