Productivity, resource-use efficiency and economics of maize (Zea mays)-wheat (Triticum aestivum)-greengram (Vigna radiata) cropping system under conservation agriculture in irrigated north-western Indo-Gangetic plains

A field experiment was conducted during 2011–12 and 2012–13 in New Delhi, to evaluate conservation agricultural practices on crop productivity, profitability and resource-use efficiency of maize (Zea mays L.)-wheat [Triticum aestivum (L.) emend. Fiori & Paol.]-greengram [Vigna radiata (L.) Wilczek] cropping system. Four main plots treatments, viz. conventional tillage with flat and raised bed planting (CTF and CTB) and zero tillage with flat and raised bed planting (ZTF and ZTB) were supplemented with 4 subplots treatments, viz. no residue control (CON), wheat residue in maize crop (WR), maize residue in wheat crop (MR) and wheat + maize residue (WMR) in both maize and wheat crops. Each residue was applied at 2.5 t/ha. The experiment was laid out in a split-plot design. Greengram was grown during summer under zero till condition and its residue was retained in all the plots except CON. The results of 2 year pooled data revealed that the system productivity (maize grain-equivalent yield, MGEY) was found comparable among ZTF, ZTB and CTB (13.0–13.2 t MGEY/ha). The ZTF incurred the least cost (73.4 thousand/ha), but fetched significantly higher net returns (94.1 thousand/ha) and benefit: cost (1.28) in the cropping system. Irrigation water productivity and energy productivity of the system were significantly higher with ZTB. The WMR increased the total cost by 16.5% in comparison to CON, however, showed the highest crop productivity, profitability and water productivity of the system. The WMR showed the least energy productivity. Overall, zero tillage with residue retention throughout crop cycle was more productive, remunerative and irrigation water-use efficient in the maize-wheat-greengram system.