基于产量、水肥利用效率和温室气体排放的滴灌葡萄水肥用量优选

Environmental challenges can often stem from the inefficient use of water and fertilizers in vineyards located in the Guanzhong Plain of Shaanxi, China. It is highly required for effective irrigation and fertilizer management in the area. This study aims to optimize the irrigation and fertilizer, in order to balance the grape growth, nutrient retention, yield factors, and greenhouse gas emissions. A three-year field trial was conducted from 2019 to 2021. 'Hutai 8' was also taken as the test variety. A combination design was employed to feature three irrigation levels: W3 (100% of the irrigation quota, M), W2 (75% of M), and W1 (50% of M), along with four rates of fertilizer: F3 (648 kg/hm²), F2 (486 kg/hm²), F1 (324 kg/hm²), and F0 (0 kg/hm²). A systematic investigation was implemented to explore the impacts of irrigation and fertilization on grape growth, soil water and fertilizer distribution, greenhouse gas emissions, and yield components. The TOPSIS method was applied to identify the optimal irrigation and fertilizer amounts for grape cultivation. The results indicated that the fertilization shared a predominant impact on the leaf area index, SPAD value, leaf nitrogen content, leaf phosphorus content, and leaf potassium content, compared with the irrigation. These index values rose significantly, as the amount of fertilization increased from F0 to F2 treatments. By contrast, irrigation shared a notable influence on the soil moisture levels up to 60 cm deep in the soil. The content of residual nutrients in the F1 and F0 treatments declined each year, while there was an increase in the F3 treatment. Proper application of potassium fertilizer effectively reduced the nutrient levels of residual soil among the three types of soil. Compared with irrigation, fertilization was the main influencing factor on the cumulative greenhouse gas emissions from the soil. The cumulative emissions of N₂O rose significantly, as the fertilization increased, while the cumulative emissions of CO₂ declined gradually. Additionally, the cumulative emissions of CH₄ were mostly negative over the last two years. It infers that the soil absorbed CH₄ gas. The F2 treatment was achieved in the highest grape yield, water use efficiency, and fertilizer agronomic use efficiency. The best strategies of irrigation and fertilization were determined using the TOPSIS method. The grapevine growth, yield components, and soil conditions were also considered during optimization. The optimal combination was achieved in the W2F2 (225 m³/hm² of irrigation and 486 kg/hm² of fertilization) during wet years and W3F2 (465 m³/hm² of irrigation and 486 kg/hm² of fertilization) during dry years. A theoretical framework was offered to maximize the growth and yield of grapevines. The effective usage of water and fertilizer was also combined for the decision-making in the vineyards.