关键词: 谷子, 垄沟集雨种植, 氮素利用, 产量, 黄土高原

Abstract:

【Objective】To explore the response of foxtail millet growth and yield to nitrogen fertilizer under ridge-furrow rainwater harvesting planting model, in order to provide a theoretical basis for high yield and efficient production of foxtail millet in the semi-arid regions of the Loess Plateau. 【Method】Shaan-Yugu No. 3 variety was selected for field experiments from 2022 to 2023, and split plot design was adopted. The main plot were different planting models (Ridge-furrow rainwater harvesting planting model, R; Traditional plain planting model, T), and the sub-plot were different nitrogen application levels (0 kg·hm^-2, N0; 60 kg·hm^-2, N1; 135 kg·hm^-2, N2; 210 kg·hm^-2, N3). The net photosynthetic rate and chlorophyll content of flag leaves of foxtail millet, dry matter accumulation and nitrogen accumulation of aboveground population at different growth stages, agronomic traits and yield at maturity stage, and nitrogen utilization rate were measured under different planting models. 【Result】Under the same nitrogen application rate, compared with the traditional plain planting model, the net photosynthetic rate and chlorophyll content of flag leaves under the ridge-furrow rainwater harvesting planting model increased only at the filling stage in 2022 with more rainfall and increased at the heading, flowering, and filling stages in 2023 with less rainfall. The ridge-furrow rainwater harvesting planting model enhanced the photosynthetic capacity of foxtail millet in the middle and later stages of growth and delayed leaf senescence during the two years. The dry matter accumulation and nitrogen accumulation of the aboveground population of foxtail millet increased during the jointing, filling, and maturity stages in 2022, and increased at all growth stages in 2023. There was no significant difference between N1, N2, and N3, and the aboveground dry matter accumulation and nitrogen accumulation increased by 0.6% to 39.5% and 0.9% to 51.1%, respectively. The grain nitrogen accumulation, post-flowering nitrogen accumulation, and post-flowering nitrogen contribution rate to grain have significantly increased over the past two years, meeting the nutrient needs of foxtail millet throughout its entire growth stage and improving insufficient nitrogen supply in the later growth stage of foxtail millet under traditional plain planting model. Nitrogen partial productivity increased between two years, increasing by 3.7% to 14.3% and 2.8% to 27.6%, respectively. Nitrogen agronomic efficiency slightly decreased at a nitrogen application rate of 210 kg·hm^-2 in 2022, while the nitrogen agronomic efficiency and nitrogen use efficiency both decreased when the nitrogen application rate exceeded 135 kg·hm^-2 in 2023. Meanwhile, nitrogen partial productivity, nitrogen agronomic efficiency, and nitrogen use efficiency decreased with the increase in nitrogen application rate. The ear diameter and single ear weight of foxtail millet increased between two years, while the ear length decreased. The yield has significantly increased between two years, increasing by 3.7% to 14.3% and 2.8% to 27.6%, respectively. The yield increase effect was more significant in 2023 with less rainfall, and there was no significant increase in yield when the nitrogen application rate exceeded 60 kg·hm^-2. 【Conclusion】In the semi-arid regions of the Loess Plateau, the ridge-furrow rainwater harvesting planting model combined with 60 to 135 kg·hm^-2 nitrogen fertilizer is more beneficial to the nitrogen utilization and yield formation of foxtail millet.

Key words: foxtail millet, the ridge-furrow rainwater harvesting planting model, nitrogen utilization, yield, Loess Plateau