Characteristic of soil moisture utilisation with different water-sensitive cultivars of summer maize in the North China Plain

Summer maize cultivars are differently sensitive to soil moisture. To better understand the differences in water productivity of summer maize cultivars with different water sensitivity, a field experiment was conducted from 2020 to 2022. Three different water-sensitive summer maize cultivars were selected, including TY808 (high watersensitive cultivar), DH605 (medium water-sensitive cultivar), and ZD958 (low water-sensitive cultivar). Soil water content (SWC), soil water storage (SWS), water consumption, water use efficiency, and grain yield were determined. The results showed that under rainfed conditions, the SWC of the medium water-sensitive cultivar DH605 in the deep soil layer was 2.1-18.2% lower than TY808 and ZD958, respectively, and the differences were significant in the 12th leaf stage (V12) and vegetative tassel stage (VT). The SWS of the high-water-sensitive cultivar TY808 was 0.7% to 6.4% higher than the other two water-sensitive cultivars from 2020 to 2022. The changes in SWS are related to the spatiotemporal distribution of precipitation. The water consumption of DH605 was higher than TY808 and ZD958 by 5.3% and 7.09% in 2020 and 2.9% and 2.8% in 2021; in 2022, DH605 is 2% higher than ZD958 and 2.8% lower than TY808, respectively. The yield of DH605 was 4.3-10.78% higher than the other two cultivars in the three-year experiment. Additionally, the 1 000-kernel weight of DH605 was the highest in TY808 and ZD958. DH605 has the highest water use efficiency, which was increased by 4.8-14.6% compared to TY808 and ZD958. Through path analysis, we found that the direct path coefficient of SWS in the VT stage on yield reached 0.999, indicating that soil moisture in the VT stage has the greatest impact on yield, followed by the blister stage (R2). In conclusion, our results suggest that the water consumption of summer maize during the VT stage is the highest, and the soil moisture condition in VT significantly affects the grain yield of summer. Planting DH605 in the North China Plain would harvest the maximum grain yield and water productivity.