Meager information is available on the use of Sesbania in conjunction with-crop residue and N-dose in maize-wheat cropping system. Therefore, an attempt was made to substitute the fertilizer N through organic sources in maize-wheat cropping sequence. Hence a field experiment was conducted for 2 year from 2006-2008, on maize ( Zea mays L)-wheat ( Triticum aestivum L. emend. Fiori & Paol) system to evaluate the influence of four organic sources (control, Sesbania green manure (SGM), wheat straw; and the combination of SGM and wheat straw), and three fertilizer N levels (0, 60 and 120 kg/ha) on maize. The residual effect of above treatments and response of wheat to direct N application (0, 40, 80 and 120 kg/ha) were also assessed. The highest plant height, dry matter accumulation, leaf area index, yield attributes, yield (4.48 and 4.86 t/ha during each year) and N uptake by maize were recorded with the application of SGM in combination with wheat straw closely followed by SGM alone. Maize responded significantly to fertilizer N up to 120 kg/ha (4.63 and 4.96 t/ha grain yield during each year) and the residual effect of that also affected significantly the growth and yields of succeeding wheat. Statistically higher plant height, dry matter accumulation, leaf area index, effective tillers, test weight, yields and N uptake by wheat were recorded under residual fertility of organic sources. Under the influence of residual fertility of N, wheat growth and yield parameters responded significantly up to 120 kg N/ha. Wheat also responded significantly to direct N application with respect to all growth and yield parameters and N uptake by wheat. SGM and SGM+wheat straw treatments resulted in gain of N content. Regarding the effect of N levels, N gain was found with all N levels. It was concluded that conjoin use of organic and inorganic sources of N was essential for higher productivity of maize-wheat cropping sequence.
