Soil water balance, land and water productivity of direct seeded rice-wheat and maize-wheat system in relation to differential tillage and irrigation regimes
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Date
2018
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Punjab Agricultural University, Ludhiana
Abstract
The field experiments were carried out during 2016-18 in a sandy loam soil to assess the role of differential tillage and irrigation regime on crop performance, land productivity, soil water balance and water productivity of direct seeded rice (DSR)-wheat and maize-wheat system. First experiment consisted of DSR-wheat with two irrigation regimes in main plots [4-days (4-d) and 8-days (8-d) interval in DSR; IW/PAN-E=1.0 (I1.0) and 0.5 (I0.5) in wheat] and six differential tillage in sub-plots viz. DSRDT2-CTW: Deep tillage (DT) before DSR in both season + Conventional tilled (CT) wheat, DSRCT-WDT2 : CT-DSR + DT before wheat in both season, DSRDT1-WCT: DT before DSR in first season + CT wheat, DSRCT-WDT1 :CT-DSR + DT before wheat in first season, DSRCT-WCT: CT- DSR + CT wheat, DSRCT-WZT: CT- DSR + Zero tilled wheat with residue retention). The land productivity was significantly higher under frequently irrigated conditions (4-d/I1.0) during both the years but the difference was statistically significant during 2016-17. It was significantly higher under DSRDT1-WCT, DSRCT-WZT, DSRCT-WDT1 than DSRCT-WCT during 2016-17. The DT during second year did not resulted in significant increase in land productivity of the system. The Evapotranspiration (ET) losses were higher under frequently irrigated (4d/I1.0) as compared to less frequently irrigated (8d/I0.5) conditions. Among different tillage practices the ET losses were comparable for the system as a whole. The water productivities (total input, irrigation and ET-based) of the rice-wheat system were higher in plots irrigated less frequently. The DT helped in increasing the water productivities of the rice-wheat as compared to CT plots during both the years. Second experiment consisted of maize-wheat system with two irrigation regimes in main plots (IW/PAN-E=1.2 (I1.2) and 0.8 (I0.8) in maize; IW/PAN-E=1.0 (I1.0) and 0.5 (I0.5) in wheat). There were five differential tillage treatments in sub plots viz. MDT2-WCT: DT before maize in both season + CT wheat, MCT- WDT2: CT maize + DT before wheat in both seasons, MDT1-CTW: DT before maize in first season + CT wheat, MCT- WDT1: CT maize + DT before wheat in first season, MCT-WCT: CT maize + CT wheat. The land productivity of the maize-wheat system was significantly higher under frequently irrigated conditions during both the years. It was higher by 9.5 and 11.4 percent under I1.2/I1.0 than I0.8/I0.5 during 2016-17 and 2017-18, respectively. It was higher under DT than CT during both the years, like DSR-wheat system, the DT during second years did not result in significant increase in land productivity. The ET losses were higher under frequently irrigated (I1.2/I1.0) than less frequently irrigated (I0.8/I0.5) conditions. The water productivities of maize-wheat system were higher in plots irrigated less frequently the difference being significant during 2017-18. And they were significantly higher under DT than CT during both the years.