干湿交替灌溉下施氮模式对水稻光合产物和氮转运的影响

【目的】采用大田小区试验，研究不同灌溉模式下氮肥施用模式对水稻产量、光合生理特性、非结构性碳水化合物和氮素利用效率的影响，以期为当地稻田灌溉和施氮模式优化管理提供理论依据。【方法】以中浙优1号为供试材料，设常规淹灌和干湿交替2种灌溉模式，以及不施氮(N₀)、常规施氮(PUN₁₀₀)、减氮20%(PUN₈₀)、缓控释复合肥减氮20%+生物炭(CRFN₈₀-BC)和稳定性复合肥减氮20%+生物炭(SFN₈₀-BC) 5种施氮模式。【结果】不同灌溉和施氮模式显著影响水稻产量和氮素利用率，且二者存在显著交互作用。与常规淹灌相比，干湿交替灌溉下CRFN₈₀-BC和SFN₈₀-BC处理显著提高了水稻齐穗期净光合速率，增加了叶面积，促进了叶片非结构性碳水化合物累积及其向籽粒的转移，进而提高了水稻有效穗数和每穗粒数，其2年平均产量分别为9656.5 kg/hm²和10033 kg/hm²，较PUN₁₀₀处理分别提高了6.8%和10.4%。同时，干湿交替灌溉提高了CRFN₈₀-BC和SFN₈₀-BC处理下齐穗至灌浆期水稻茎鞘和叶片氮转运量和氮转运贡献率，进而显著提高水稻氮利用效率。与PUN₈₀处理相比，干湿交替灌溉下CRFN₈₀-BC和SFN₈₀-BC处理氮肥回收效率、氮肥农学利用率、氮肥偏生产力分别显著提高37.8%和58.4%、56.6%和71.1%、15.2%和19.3%。【结论】干湿交替灌溉模式下稳定性复合肥或缓控释复合肥减氮20%(144 kg/hm²)配施生物炭处理显著提高了水稻营养生长期叶片光合速率，促进了非结构性碳水化合物和氮素累积和转运，二者协同提高水稻产量和氮利用效率，可作为适宜当地水稻绿色高效栽培的最佳水氮管理模式。

Effects of Different Nitrogen Application Regimes on Translocation of Rice Photosynthetic Products and Nitrogen Under Alternate Wetting and Drying Irrigation

【Objective】Field plot experiments were conducted to study the effects of different irrigation and nitrogen application regimes on yield, photosynthetic physiological characteristics, non-structural carbohydrate and nitrogen use efficiency of rice, so as to lay a theoretical basis for scientific and reasonable irrigation and nitrogen management in local paddy fields. 【Method】With Zhongzheyou 1 as material, a field experiment was carried out under two irrigation regimes of flooding irrigation (FI) and alternate wetting and drying (AWD), as well as five nitrogen application regimes of zero nitrogen (N₀), conventional nitrogen application (PUN₁₀₀), 20% nitrogen reduction (PUN₈₀), 20% nitrogen reduction of slow-release compound fertilizer with biochar (CRFN₈₀-BC) and 20% nitrogen reduction of stable compound fertilizer with biochar (SFN₈₀-BC). 【Result】Different irrigation and nitrogen application regimes significantly affected the grain yield and nitrogen use efficiency, and the two factors showed significant interaction. Compared with FI, CRFN₈₀-BC and SFN₈₀-BC treatments significantly increased the net photosynthetic rate and leaf area index of rice at full heading stage, leaf non-structural carbohydrate accumulation and its transfer to grains under AWD, and finally increased the number of effective panicles and grains per panicle of rice. Compared with PUN₁₀₀, the yield increased by 6.8% and 10.4%, and the average yield in two years was 9656.5 kg/hm² and 10033 kg/hm², respectively. AWD also increased the amount of N translocation and the contribution rate of N translocation of stem and leaves from heading to filling stages under CRFN₈₀-BC and SFN₈₀-BC treatments, and then significantly increased rice nitrogen use efficiencies. Compared with PUN₈₀, CRFN₈₀-BC and SFN₈₀-BC under AWD significantly increased N recovery efficiency, N agronomic efficiency and N partial productivity, by 37.8% and 58.4%, 56.6% and 71.1%, 15.2% and 19.3%, respectively. 【Conclusion】Under AWD regimes, 20% (144 kg/hm²) N reduction of the stable compound fertilizer or slow-release compound fertilizer combined with biochar treatment significantly promote the leaf photosynthetic rate, non-structural carbohydrate and nitrogen accumulation at the vegetative growth period of rice, as well as their transportation to panicles at the reproductive growth period, which jointly improve rice yield and nitrogen use efficiency. It can serve as the suitable water and nitrogen management regimes for the green and efficient rice cultivation at the local area.