| To quantify the water demand and the water deficit of drought-alkali wheat in Hebei. We utilized meteorological observation data from the drought alkali wheat areas. By adopting the Pearson III curve, the precipitation frequency thresholds for 25%, 50%, 75% were respectively determined to be Wet, Average, Dry and Very dry years, along with the corresponding effective precipitation. Using the Penman-Monteith model, combined with the crop coefficient method and soil correction coefficient method. We calculated the water demand, water deficit and irrigation demand index characteristics and their spatiotemporal distribution under four hydrological year types. The results: From 1988 to 2022, the water demand for drought alkali wheat's entire growth period significantly increased, and precipitation, effective precipitation and water deficit increased. Across different hydrological year types, the water deficit and irrigation demand index significantly increased with the decrease in annual precipitation, being 97.7, 106.5, 126.2, 149.7 mm and 0.56, 0.60, 0.70, 0.79 for the four types, respectively. The variance in water demand was relatively minor, with an average of 181.0 mm. Spatially, water requiremen was higher in the north and lower in the south, while water deficit was more significant in the northwest than in the southeast. The water requiremen characteristics differed significantly between growth periods, with the greening to grain filling period requiring more water and experiencing more severe water deficits. The greening period faced the most severe deficit, with water requiremen, water deficit and irrigation demand index at 48.1, 38.7 mm and 0.80, respectively. In summary, adjusting irrigation for drought alkali wheat based on the proportion of different hydrological year types can save irrigation costs and ensure stable and high yields of drought alkali wheat. The focus should be on expanding to the southern regions of Mengcun, Yanshan and Haixing counties, which could effectively increase the sowing area of drought-alkali wheat and enhance the comprehensive utilization of saline-alkali land. |
基本信息
