【目的】青钱柳(Cyclocarya paliurus)是我国特有集药用、食用和材用等价值于一身的单种属植物。探究青钱柳-茶复合系统土壤养分、酶活性及植物叶片养分对生物炭与有机肥配施的响应,筛选出最适配施比例,为青钱柳-茶复合系统的经营管理提供有机栽培方案。【方法】针对青钱柳-茶复合系统,采用完全随机区组设计,设置CK(不施肥)、T1(100%有机肥,即4 500 kg/hm²)、T2[15%(质量占比,下同)生物炭+85%有机肥,即675 kg/hm²+3 825 kg/hm²]、T3(30%生物炭+70%有机肥,即1 350 kg/hm²+3 150 kg/hm²)、T4(50%生物炭+50%有机肥,即2 250 kg/hm²+2 250 kg/hm²)等5种不同生物炭与有机肥质量配施比例,探讨不同配施处理对复合经营系统不同层次([0,10)、[10,20)和[20,40)cm)土壤养分、酶活性及青钱柳和茶树叶片养分含量的影响。【结果】双因素方差分析表明,不同施肥处理和土层深度对土壤pH均有显著影响(P<0.05)。随着生物炭添加比例增加,表层[0,10)cm土壤pH显著提高(P<0.05)。与CK相比,T4处理下[0,10)cm土壤pH提高了12.89%,[10,20)cm提高了4.50%,[20,40)cm提高了3.13%;不同生物炭与有机肥配施显著影响土壤养分含量(P<0.05),与CK相比,生物炭与有机肥配施显著提高了土壤氮磷全量及速效养分含量(P<0.05),且随着生物炭施用比例的增加呈现先升后降的趋势;不同施肥处理和土层深度对土壤酶活性均有极显著影响(P<0.001)。生物炭与有机肥配施显著提高了表层[0,10)cm土壤的β-葡萄糖苷酶(βG)和酸性磷酸酶(ACP)活性(P<0.05),且均在T2处理达到最大值,分别比CK处理提高22.6%和47.0%。总体上,βG、β-N-乙酰氨基葡萄糖苷酸(NAG)和ACP活性呈现出随着生物炭添加量的增加而降低的趋势;不同生物炭与有机肥配施处理对青钱柳叶片氮磷养分含量有显著影响(P<0.05)。青钱柳叶片N含量在T3处理最高,比CK处理高12.4%;而青钱柳叶片P含量在T4处理最低,T1处理最高(约比T4处理高6%)。而茶树叶片的氮磷全量养分含量在不同处理间无显著影响(P>0.05),但整体上在T2处理下达到最大值。偏最小二乘法结构方程模型(PLSPM)分析结果显示,生物炭与有机肥配施对土壤pH和土壤酶活性的影响均为极显著正向调控(P<0.01),路径系数分别达0.899和0.752;生物炭与有机肥配施主要通过改善土壤pH和酶活性来提高土壤有效氮和有效磷的含量,且土壤速效养分对植物叶片养分吸收有显著正向影响。【结论】合理的生物炭与有机肥配施能显著提高土壤pH和土壤酶活性,加速土壤中养分转化,促进青钱柳和茶树的养分吸收利用。现有研究结果表明,以质量配比15%生物炭+85%有机肥配施效果最佳,但这种配施比例应根据立地条件和林分年龄的变化而不断调整。

【Objective】Wheel wingnut (Cyclocarya paliurus), native to China, is the sole species in its genus. Grown for its medicine food homologous and fine timber tree species as well as for an ornamental plant, there exists a great development and application prospect for C. paliurus resources. This study explores the responses of soil nutrients, soil enzymes activities and leaf nutrients to combined application of biochar and organic fertilizer in a compound system of C. paliurus and tea(Camellia sinensis), to select an optimal application mass ratio of biochar and organic fertilizer, and to provide organic cultivation scheme for the management of C. paliurus and tea compound system.【Method】A completely randomized block design was established in the compound system of C. paliurus and tea, comprising five treatments with different application mass ratios of biochar and organic fertilizer: CK (no fertilization), T1 (100% organic fertilizer, as 4 500 kg/hm²), T2 (15% biochar + 85% organic fertilizer, as 675 kg/hm²+3 825 kg/hm²), T3 (30% biochar + 70% organic fertilizer, as 1 350 kg/hm²+3 150 kg/hm²), and T4 (50% biochar + 50% organic fertilizer, as 2 250 kg/hm²+2 250 kg/hm²). The study examined the effects of these treatments on soil nutrients and enzyme activities across different soil layers ((0,10], (10,20], and (20,40] cm), as well as on the leaf nutrient content of both plant species.【Result】Two-way ANOVA indicates that both different fertilization treatments and soil layer depth have significant impacts on soil pH (P<0.05). With the increase of biochar application ratio, soil pH in the surface layer (0,10] cm significantly increases (P<0.05). Compared with CK treatment, the treatment with T4 increases the pH by 12.89%, 4.50% and 3.13% in the soils of (0,10], (10,20] and (20,40] cm respectively. Application of biochar combined with organic fertilizers significantly affects soil nutrients (P<0.05). Compared to the CK, the combined application of biochar and organic fertilizer significantly increases both the soil total and available nutrient contents of nitrogen and phosphorus in the soil (P<0.05), and shows a trend of first increasing and then decreasing with increasing biochar application ratio. Both fertilizer treatments and soil layer depth have a highly significant effect on soil enzyme activities (P<0.001). Combined application of biochar and organic fertilizer also significantly enhances the activities of β-glucoside (βG) and acid phosphatase (ACP) in the soil layers of (0,10] cm (P<0.05), which all reach the maximum values at the T2 treatment and significantly increase by 22.6% and 47.0% respectively when compared with CK treatment. In general, the activities of βG, NAG and ACP show a decreasing trend with the increase of biochar addition. Different treatments have significant effects on leaf nutrient contents of nitrogen and phosphorus in C. paliurus (P<0.05). The highest N content in C. paliurus leaves is observed under T3 treatment, with 12.4% greater than the CK, while the lowest P content is detected under T4 treatment and the highest P content is under T1 treatment (about 6% higher than T4 treatment). However, no significant effect on nutrient contents of nitrogen and phosphorus in tea leaves is detected among different treatments (P>0.05), with the maximum value appearing in the T2 treatment as a whole. The partial least squares path modeling (PLSPM) analysis results show that the effects of combined application of biochar and organic fertilizer on soil pH and soil enzyme activity are highly significant positive regulation (P<0.01), and the path coefficients reach 0.899 and 0.752 respectively. Meanwhile, a combined application of biochar and organic fertilizer can increase the content of available nitrogen and available phosphorus in soil by improving soil pH and soil enzyme activity, and soil available nutrients have a significant positive effect on the plant leaf nutrient uptake.【Conclusion】A reasonable combined application of biochar and organic fertilizer can significantly improve soil pH and soil enzyme activity, accelerate soil nutrient conversion, and promote nutrient uptake and utilization of C. paliurus and tea tree, while the application mass ratio of 15% biochar and 85% organic fertilizer can achieve the effect. However, the proportion of such combined application should be continuously improved based on the site conditions and stand ages.