【目的】研究滴灌施肥条件下1年生‘龙脑香樟’幼苗的施肥效应,以获得最佳氮磷钾使用浓度和配比方案。【方法】在浙江余杭西北部的径山丘陵区,开展了不同N、P、K施肥配比试验,通过测定‘龙脑香樟’苗高、地径、生物量等生长指标和净光合速率(P_n)、蒸腾速率(T_r)等生理指标,比较滴灌施肥和常规施肥对‘龙脑香樟’生长的影响。【结果】①滴灌施肥显著增加了‘龙脑香樟’幼林苗高和地径年生长量、生物量,且均在N、P、K分别为26.0、2.6、16.9 g/株处理时达到最大值,分别比常规施肥增加了20.36%、55.15%、79.44%;②全年滴灌施肥和常规施肥苗高、地径生长一致,各处理苗高均在9月达到增长峰值,而地径则分别在6月、9月出现并达到增长峰值,苗高和地径全年生长差值最大均出现在8月和9月;③滴灌施肥显著提高了1年生‘龙脑香樟’的叶片净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)等生理指标,它们的变化趋势基本一致,即一定范围内随着施肥量增加而增加,过量施肥反而使其降低。相比常规施肥,滴灌施肥显著提高了1年生‘龙脑香樟’叶片的光饱和点(LSP)和表观量子效率(AQY),降低了光补偿点(LCP)和暗呼吸速率(Rd),使得‘龙脑香樟’叶片光合时效延长,这有利于‘龙脑香樟’叶片光合产物的积累,促进‘龙脑香樟’的生长。【结论】滴灌栽培1年生‘龙脑香樟’幼林最佳N、P、K施肥配比为N肥26.0 g/株、P肥2.6 g/株、K肥16.9 g/株,由此制定出滴灌栽培1年生‘龙脑香樟’幼林的优化施肥制度。

【Objective】In order to study the effects of different N, P and K concentrations on 1-year-old Cinnamomum longepaniculatum ‘Longnao Xiangzhang’ steckling and estimate the best N, P and K concentrations and ratios under drip fertilization, we conducted a fertilization experiment with different N, P and K concentrations in the hills of Jingshan, northwestern Yuhang, Zhejiang Province. 【Method】 By measuring growth indices such as tree height, ground diameter and biomass, as well as physiological indices, we compared the effects of drip fertilization and conventional fertilization on the growth of a juvenile ‘Longnao Xiangzhang’ plantation. 【Result】 ① The annual stecklings height, ground diameter, and biomass per tree were significantly higher under drip fertilization, and these parameters all reached their maximum values in the 26.0 g/plant N, 2.6 g/plant R, 16.9 g/plant K, treatment, increasing by 20.36%, 55.15% and 79.44%, respectively, compared with conventional fertilization. ② The trees were consistent in height and ground diameter under drip fertilization and conventional fertilization throughout the year. The height of each treatment tree reached its peak in September, while the ground diameters reached their peaks in June and September, respectively. The maximum differences in annual growth between the drip-fertilized and conventionally fertilized trees occurred in August and September. ③ Physiological indices, such as the net photosynthetic rate, stomatal conductance, and transpiration rate of the 1-year-old ‘Longnao Xiangzhang’ trees were significantly higher under drip fertilization with a similar model of variation; their value increased as the amount of fertilization increased within a certain range and then decreased with excessive fertilization. Compared to conventional fertilization, drip fertilization resulted in a higher light saturation point and apparent quantum efficiency, and a lower light compensation point and dark respiration rate in the leaves of ‘Longnao Xiangzhang’ trees. Hence, the photosynthetic aging of the leaves was extended, which is conducive to the accumulation of photosynthate in the leaves and, subsequently, the growth of ‘Longnao Xiangzhang’. 【Conclusion】As above, the best annual growth of juvenile ‘Longnao Xiangzhang’ plantations can be achieved under drip fertilization with 26.0 per individual of N, 2.6 per individual of P, and 16.9 per individual of K. According to this information, an optimized fertilization scheme for 1-year-old ‘Longnao Xiangzhang’ plantations under drip irrigation can be developed.