Role of Yield Potential and Yield-Gap Analyses on Resource-Use Efficiency Improvement

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A systems approach is used to show the effect of genotypic, environmental, and management factors on the potential yield of rice and maize and the role yield potential and yield-gap analyses play in fertilizer recommendations. Examples from Myanmar are presented for determining yield potential, conducting yield-gap analyses, and identifying appropriate management strategies taking into consideration climatic, soil, and management inputs. CERES-Rice and CERES-Maize models were used to simulate yield potential and N response using site-specific weather and soil data from 18 locations in Myanmar. Planting dates typical for the wet and dry seasons were used for each of the locations. To capture the effect of weather variations, 18 weather years (1997-2015) for each location were used in the simulation study. The wet season rainfed potential production yield, which was the same as the potential production yield, varied from 6.5-7.3 tons per hectare (tha) in the Delta Region to 9.4-10.3 t/ha in the Central Dry Zone and Shan State for high-yielding hybrid rice. Similar differences for maize were also observed with the wet season rainfed maize potential production yield of 4.0-4.9 t/ha in the Delta Region and 6.8-7.2 t/ha in the Central Dry Zone and Shan State for the improved maize variety. The potential production yield for irrigated dry season rice was an average of 11.1 tha for the 18 locations. The irrigated maize yield potential for the dry season ranged from 6.9-7.6 tha in the Delta Region to 7.0-8.6 t/ha in the Central Dry Zone and Shan State. The lower yields in the Delta Region compared to others, particularly during the wet season, were attributed to lower solar radiation. Nitrogen (N) response varied with season, yield potential, and indigenous N supply. Due to these differences, optimum N rates varied from 40 to 120 kilograms (kg) N per ha for rice during the wet season. The optimum agronomic N rates during the dry season were much higher at 120-180 kg N/ha for irrigated hybrid rice. The effects of varieties, indigenous N supply, and method of N application on N recommendations were also simulated.
Singh, U., M. Aung, and J. Fugice. 2018. “Role of Yield Potential and Yield-Gap Analyses on Resource-Use Efficiency Improvement,” IN Myanmar Soil Fertility and Fertilizer Management Conference Proceedings, pp. 22-37, IFDC and DAR, Nay Pyi Taw, Myanmar