Effect of sequential tillage practices and N levels on energy relations and use- efficiencies of irrigation water and N in maize (Zea mays)wheat (Triticum aestivum) cropping system

Abstract

Field experiments were conducted during 2009-10 and 2010-11 at New Delhi to evaluate the effect of four se- quential combinations of conventional tillage (CT) and zero tillage (ZT) practices in conjunction with N levels (0, 60, 120 and 180 kg N/ha) on energy relations and use-efficiencies of irrigation water (IWUE) and N (NUE) in maize (Zea mays L.)wheat {Triticum aestivum (L.) emend. Fiori & Paol} cropping system. ZT practices saved on an average 20 and 15 % input energy requirements over CT practices in maize and wheat, respectively. The maximum input energy requirement in maizewheat cropping system was recorded under CTCT tillage se- quence, whereas the minimum was recorded with ZTZT sequential tillage system. The gross and net output en- ergy productions by the maize-wheat cropping system were not influenced significantly due to different sequential tillage practices, however these were recorded maximum under CTZT sequential tillage system. Significantly maximum energy-use efficiency in maizewheat cropping system was recorded with ZTZT sequence, which was 29.76, 19.44 and 11.49 % higher than the CTCT, CTZT and ZTCT sequential tillage practices, respectively during the year 2010-11. ZT sown wheat based tillage sequences (CTZT and ZTZT) resulted 46 % higher IWUE than CT sown wheat based tillage sequences (CTCT and ZTCT). The energy relations, IWUE and NUE parameters of both the crops differed significantly due to various N levels. The input and output energy and IWUE increased significantly with each successive increase in levels of N from 0 to 120 kg N/ha, while reverse trends were observed with energy-use efficiency and NUE, which were decreased significantly from 0 to 180 kg N/ha. Consequently ZT involving sequential tillage practices in conjunction with application of 120 kg N/ha may be adopted to enhance resource-use efficiency in maizewheat cropping system.