ENERGY PRODUCTIVITY OF SORGHUM (SORGHUM-BICOLOR) WHEAT (TRITICUM-AESTIVUM) SEQUENCE THROUGH LONG-TERM USE OF CHEMICAL FERTILIZERS

A long-term field experiment was conducted during 1977-78 to 1990-91 o n medium black soil to evaluate the effect of continuous sorghum [Sorg hum bicolor (L.) Moench]-wheat (Triticum aestivum L. emend. Fiori and Paol.) cropping and manuring on sustainability. The yield of both the crops, energy output and net returns increased with an increase in lev el of each nutrient during all the years. The response per unit nutrie nt applied and benefit :cost ratio drastically declined with increased levels of nutrients. The total energy-use efficiency and energy produ ctivity increased only up to an 80 kg N/ha. However, energy intensiven ess showed the reverse trend. Application of P and K decreased the ene rgy-use efficiency and energy productivity but increased the energy in tensiveness.