Abstract
Dry direct-seeded rice has been shown to save irrigation water and labor. Nonetheless, irrigation management in dry direct-seeded rice has received very little attention. Here, we examined the potential of different irrigation regimes: aerobic rice (AR), alternate wetting and drying (AWD) and continuous flooding (CF) in dry direct-seeded rice cultivation on two rice cultivars (Pride-1 (hybrid indica) and NB-1 (inbred indica)). Growth, yield attributes, grain yield, total water input, water productivity and benefit cost ratio were measured. Our results showed that AR saved 11.22 and 28.40%, and 5.72 and 32.98% water compared with AWD and CF during 2018 and 2020, respectively. There was a significant difference in grain yield among treatments and cultivars. AWD and CF produced statistically same total dry weight and grain yield, while AR reduced the total dry weight by 31.34% and 38.04% and grain yield by 34.82% and 38.16% in comparison to AWD and CF, respectively, across the years. Except for 1000-grain weight and harvest index in AWD and CF, further differences in total dry weight and grain yield among irrigation treatments were primarily correlated with variations in yield attributes. Among the cultivars, hybrid rice performed better than inbred rice. Over the two-year period, hybrid rice increased total dry weight, grain yield, and water productivity by 9.28%, 13.05%, and 14.28%, respectively, as compared to inbred rice. Regarding water productivity (WP), the maximum percentage (40.90 and 26.53%) was recorded for AWD compared to AR and CF. Among cultivars, more water productivity (14.28%) was calculated for hybrid rice than inbred one. Chlorophyll and carotenoid contents, leaf area index and crop growth rate contributed to higher grain yield of hybrid rice under AWD and CF. In contrast to WP, the maximum benefit cost ratio was estimated to be higher for CF than that of AR and AWD. For the cultivars, the maximum value (2.26 in 2018 and 2.32 in 2020) was calculated for hybrid rice compared with the inbred one. In conclusion, these results suggests that AWD with maximum WP and CF with maximum BCR could be more efficient approaches than AR. Under CF, hybrid rice cultivars with higher yield and yield-related attributes, WP and BCR performed better.
Highlights
Rice (Oryza sativa L.), is an important staple cereal crop and fulfills the dietary requirement for more than of half population globally [1]
Direct seeded rice (DSR; both wet direct-seeded rice and dry direct-seeded rice) has been proposed as an efficient planting method to attain the high-water productivity under water scarce conditions
In the past few years, different studies were conducted on the yield and water productivity of dry DSR, and reported variable response depending upon cultivar and location [10,11]
Summary
Rice (Oryza sativa L.), is an important staple cereal crop and fulfills the dietary requirement for more than of half population globally [1]. In China prior to 2000 the rice crop was commonly planted by puddled transplanting method but, in 2015 about. Direct seeded rice (DSR; both wet direct-seeded rice and dry direct-seeded rice) has been proposed as an efficient planting method to attain the high-water productivity under water scarce conditions. Dry direct-seeded rice cultivation has been identified as a more water- and labor-saving technique under DSR, as it cuts water and labor requirements by 50% [8]. Under dry DSR cultivation, seeds are sown in unsaturated soil or non-puddled soil. In the past few years, different studies were conducted on the yield and water productivity of dry DSR, and reported variable response depending upon cultivar and location [10,11]. Dong et al [12] and Kato et al [13] reported more than 11 t ha−1 yield in dry DSR
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