1 Introduction

Atractylodes macrocephala Koidz. is a perennial medicinal herb whose dried rhizome is the medicinal part used as Baizhu, and its long-standing clinical importance has made stable cultivation and quality improvement major production goals (Yang et al., 2021; Luo et al., 2024). The species has substantial medicinal value because its rhizome contains bioactive sesquiterpenoids, polysaccharides, and polyacetylenes that support anti-inflammatory, gastrointestinal, immunomodulatory, and other pharmacological activities. This medicinal relevance has increased demand for cultivated raw material, while the scarcity of wild resources and the need for consistent quality have made agronomic regulation increasingly important in commercial production. Rhizome quality in A. macrocephala is not determined only by yield, but also by the accumulation of characteristic compounds and by morphological development associated with superior medicinal value (Cui et al., 2025). Environmental analyses further indicate that rhizome biomass and phytochemical composition are partly decoupled, so cultivation practices aimed only at increasing output may not necessarily optimize chemical quality (Lee et al., 2025). For this reason, studies on A. macrocephala need to treat rhizome growth, nutrient acquisition, and quality formation as related but distinct processes that should be co-regulated in production systems.

Fertilization management is one of the most direct agronomic tools for regulating medicinal plant growth, nutrient use efficiency, and secondary metabolite accumulation. Across medicinal crops, fertilizer application is used not only to raise biomass and yield but also to enhance the concentration of pharmacologically active constituents, although the response depends strongly on fertilizer type, rate, and balance. Moderate nitrogen supply generally benefits yield and phytometabolite accumulation, whereas excessive nitrogen can reduce quality and create environmental and soil-management problems, indicating that fertilizer effects are inherently nonlinear (Hao et al., 2024). Evidence from medicinal-plant meta-analysis also shows that both inorganic and organic fertilizers can increase bioactive compounds, but each has trade-offs: inorganic inputs can promote active-compound accumulation while long-term overuse risks soil degradation, whereas organic fertilizers improve the soil environment but may not fully satisfy crop nutrient demand on their own (Lv et al., 2025). As a result, balanced fertilization and formula fertilization are increasingly viewed as the most rational strategies for simultaneously improving nutrient uptake, yield, soil quality, and medicinal quality in cultivated medicinal plants (Sun et al., 2022). This broader evidence base strongly suggests that nutrient regulation in A. macrocephala should be evaluated through integrated indicators, including biomass production, nutrient absorption, nutrient partitioning, and rhizome quality traits, rather than by fertilizer input alone.

Research directly focused on A. macrocephala already indicates that fertilizer regulation can substantially alter rhizome yield, nutrient uptake, and nutrient distribution. Field evidence showed that phosphorus, potassium, boron, and zinc application increased the rhizome yield of large-headed Atractylodes in grey clayey soil by 15.1%, 34.7%, 9.1%, and 5.7%, respectively, and that balanced fertilization improved the distribution ratio of phosphorus, potassium, and zinc to the medicinal rhizome portion. Nutrient-absorption studies further showed that budding stage and rhizome swelling stage are key periods of rapid nutrient uptake in one-year-old plants, while flowering stage is critical in two-year-old plants, with nutrient allocation shifting toward the rhizome in older plants. The same work quantified average nutrient demand per 100 kg rhizome product in two-year-old A. macrocephala at 2.65 kg N, 0.91 kg P₂O₅, and 2.16 kg K₂O, and recommended topdressing during specific developmental stages in addition to base fertilization. Fertilizer-rate experiments also found that the response of aboveground and underground growth to N, P, and K differs, with one study estimating 6-4-6 kg/10a as an optimum N-P-K level for highest yield from one-year-old rhizomes. Organic fertilization has likewise shown practical value in A. macrocephala, as selected compost treatments increased yield and raised atractylenolide I content relative to conventional fertilization in Korean production trials.

Even so, current knowledge remains fragmented, because existing studies have often examined individual nutrients, selected fertilizer sources, or single production targets, rather than systematically linking fertilization regimes with both nutrient uptake dynamics and rhizome quality formation in A. macrocephala. Related work in Atractylodes chinensis has shown that different NPK combinations significantly changed growth traits and rhizome concentrations of major pharmacodynamic components, and that specific nutrient ratios could selectively enhance certain compounds while improving overall yield and quality. In that species, a high-phosphorus treatment achieved the highest comprehensive score for high yield and high quality, supporting the view that formula fertilization can regulate not only biomass production but also metabolite biosynthesis through key metabolic enzymes (Sun et al., 2022). For A. macrocephala, however, a comparable integrated framework that connects fertilizer regime, nutrient absorption, nutrient allocation, and rhizome quality indicators is still needed. Therefore, the objective of this study is to evaluate how different fertilization regimes influence nutrient uptake characteristics and rhizome quality in A. macrocephala, and to identify fertilization patterns that can better coordinate productive performance with medicinal quality (Lee et al., 2025). Such work should provide a more practical basis for precision fertilization, sustainable cultivation, and the production of high-quality A. macrocephala germplasm and raw medicinal materials.

2 Nutrient Requirements and Fertilization Characteristics of A. macrocephala

2.1 Nutrient absorption characteristics and critical nutrient requirements during different growth stages

Nutrient absorption in A. macrocephala changes markedly with developmental stage, so fertilization cannot be optimized with a single uniform schedule across the crop cycle. Field measurements showed that in one-year-old plants, the budding stage and rhizome swelling stage were the main periods of rapid nutrient absorption, and the absorbed nutrients were allocated primarily to the aerial parts at that time. In two-year-old plants, the flowering stage became the key period of rapid nutrient uptake, and assimilated nutrients were directed mainly to the rhizome, indicating a developmental shift from canopy construction toward underground medicinal-organ filling.

These stage-dependent patterns agree with broader medicinal-plant evidence showing that nutrient demand fluctuates across the growth cycle and that the relative importance of N, P, and K changes with biomass accumulation and metabolite formation. In Epimedium pubescens, nutrient demand followed the order N > K > P, and the effects of NPK on biomass and flavonoid accumulation differed by stage, leading to a stage-specific fertilization strategy rather than constant nutrient supply. Similar logic was demonstrated in Atractylodes chinensis, where base fertilizer at the seedling stage followed by topdressing during vegetative and later reproductive development promoted growth more effectively, supporting the view that A. macrocephala should also be managed according to critical uptake windows rather than calendar-based fertilization alone (Sun et al., 2022).

2.2 Roles of nitrogen, phosphorus, potassium, and micronutrients in plant development and rhizome formation

Nitrogen, phosphorus, and potassium contribute differently to plant development and rhizome formation in A. macrocephala, and their effects are not interchangeable. Nitrogen is central to medicinal-plant productivity because it supports growth and supplies precursors for amino acids, terpenoids, polysaccharides, phenolics, and related specialized metabolites, but excessive N can reduce quality rather than improve it (Hao et al., 2024). In A. macrocephala, fertilizer-rate trials showed that increasing N and K tended to suppress aboveground growth while phosphorus promoted it, and different NPK combinations favored aerial growth, underground growth, and final yield differently, indicating strong nutrient-specific regulation of plant architecture and rhizome production.

Phosphorus appears especially important for rhizome yield and quality formation, while potassium and micronutrients support nutrient accumulation and partitioning into the medicinal organ. In field-grown large-headed Atractylodes, phosphorus, potassium, boron, and zinc all increased rhizome yield in grey clayey soil, and phosphorus application promoted N, P, K, and B uptake, whereas potassium, boron, and zinc increased the uptake of multiple nutrients and improved allocation of P, K, and Zn to the rhizome. Evidence from the related medicinal species A. chinensis further showed that a high-phosphorus fertilization scheme produced the best combined outcome for yield and quality and promoted the accumulation of sesquiterpene and polyacetylene constituents, suggesting that phosphorus supply can influence both rhizome enlargement and pharmacodynamic component biosynthesis in Atractylodes crops (Sun et al., 2022).

2.3 Relationship between soil nutrient availability, fertilizer supply, and nutrient use efficiency

The effectiveness of fertilizer supply in A. macrocephala depends not only on the amount applied but also on the capacity of the soil to deliver nutrients to roots and sustain uptake efficiency. Across plant systems, nutrient uptake requires movement through the soil-plant continuum, transfer across the root surface, and subsequent use or transport within the plant, while the maximum nutrient demand during rapid biomass accumulation often exceeds instantaneous supply from the soil solution alone. This helps explain why medicinal crops often require well-timed fertilization and why fertilizer use efficiency is constrained by soil physical and chemical factors, particularly for nutrients such as ammonium, potassium, and orthophosphate that diffuse much more slowly than nitrate in soil.

For medicinal plants, rational fertilization therefore requires matching fertilizer source and dose to soil fertility, crop demand, and desired quality traits. Reviews of medicinal-crop nutrition show that species differ substantially in N demand according to production environment and soil fertility, and that moderate fertilization generally improves yield and phytometabolite accumulation whereas excessive input reduces efficiency and can damage the soil system (Hao et al., 2024). In A. macrocephala, rhizosphere evidence showed that moderate foliar Se indirectly improved parts of the soil nutrient environment by increasing soil organic matter and, at suitable rates, increasing available N, P, or K, while broader field analyses indicated that phytochemical composition is strongly associated with soil properties even when rhizome growth itself is less tightly coupled to environmental variation (Zhou et al., 2020; Lee et al., 2025).

3 Effects of Different Fertilization Regimes on Plant Growth and Nutrient Uptake

3.1 Effects of organic, inorganic, and integrated fertilization on biomass accumulation and growth traits

Different fertilization regimes can markedly change biomass accumulation and growth traits in medicinal plants, and the response is usually strongest under balanced rather than excessive nutrient supply. In Atractylodes chinensis, combined NPK regulation improved growth and medicinal quality, with the T6 treatment giving the highest comprehensive score for high yield and high quality, while in chrysanthemum the N3P2K1 combination increased plant height, leaf fresh weight, root dry weight, and shoot dry weight relative to the unfertilized control (Fang et al., 2023). These findings support the view that, for A. macrocephala, inorganic fertilization should be evaluated by nutrient balance rather than by single-element addition, because both deficiency and excess can reduce plant performance and quality formation (Sun et al., 2022).

Evidence directly from A. macrocephala also indicates that organic inputs can sustain or improve rhizome production and may favor quality-associated traits. Basal application of organic fertilizer increased rhizome yield, with the HA treatment reaching 184.6 kg per 10 a and a 2.0-fold rate reaching 203.0 kg per 10 a, while integrated organic-inorganic fertilization in rice increased total biomass and improved leaf physiological activity relative to chemical fertilizer alone. More broadly, integrated low-rate inorganic-organic fertilization increased growth rate and yield in pakchoi, indicating that mixed nutrient sources can alleviate the common yield-quality trade-off by improving rhizosphere function rather than simply increasing nutrient dose (Figure 1) (Lin et al., 2026).

Figure 1 Conceptual effects of inorganic nutrient balance on the growth and development of Atractylodes macrocephala

3.2 Regulation of root development and nutrient acquisition capacity under different fertilization strategies

Fertilization strategy affects nutrient uptake not only through nutrient supply itself but also through its control over root development and rhizosphere activity. Localized fertilization promotes root foraging for heterogeneously distributed nutrients by increasing absorption area, strengthening nutrient mobilization, and stimulating beneficial belowground microbial interactions, which together improve nutrient-use efficiency and crop productivity. This principle is consistent with broader rhizosphere evidence showing that nutrient availability in the rhizosphere directly regulates plant growth and is often enhanced relative to bulk soil through higher microbial nitrogen cycling activity, although phosphorus can remain strongly competed for under high demand (Liu et al., 2025).

Root architecture and nutrient acquisition capacity are also shaped by biological interactions that respond to fertilization regime. Root enhancement in tobacco increased nutrient accumulation through rhizosphere mediation, with soil hydrolyzable nitrogen explaining most of the effect of root activity and root surface area on total plant nitrogen accumulation, while improved root traits also promoted dry weight via higher available phosphorus (Yu et al., 2026). In medicinal plants, mycorrhizal and rhizosphere processes appear especially relevant: AMF can strongly support phosphorus acquisition and water uptake, and rhizosphere microbial communities are recognized as central mediators of nutrient acquisition and plant vigor in medicinal cropping systems.

3.3 Changes in nitrogen, phosphorus, and potassium uptake, translocation, and utilization efficiency

In A. macrocephala, different fertilizer inputs alter not only total N, P, and K uptake but also their distribution among plant organs and their eventual allocation to the rhizome. Field studies showed that phosphorus application promoted N, P, K, and B uptake in large-headed Atractylodes, while potassium, boron, and zinc increased the uptake of multiple nutrients, and the distribution ratio of phosphorus, potassium, and zinc in the medicinal rhizome was improved by balanced fertilization (Yu et al., 2026). Developmental timing further matters because one-year-old plants absorbed nutrients rapidly during budding and rhizome swelling, whereas two-year-old plants showed their key uptake period at flowering, when absorbed nutrients were mainly allocated to the rhizome.

Across medicinal plants, nutrient use efficiency depends on both fertilizer rate and nutrient interaction. In Sideritis cypria, an intermediate NPK regime improved nutritional value, whereas high N increased mineral accumulation and nutrient-use efficiency and high K induced oxidative stress, showing that stronger uptake does not always translate to better physiological performance. Likewise, studies on N-K interaction emphasize that balanced N and K management is necessary because nitrogen drives photosynthetic and biosynthetic capacity, potassium supports osmotic regulation and transport processes, and their coordination is central to improving yield, quality, and fertilizer-use efficiency under field conditions.

4 Influence of Fertilization Regimes on Rhizome Yield and Quality Formation

4.1 Effects of fertilizer management on rhizome expansion, dry matter accumulation, and yield formation

Fertilizer management affects rhizome expansion and final yield in A. macrocephala primarily by altering dry matter production and the timing of nutrient supply to the underground organ. Stage-analysis of nutrient accumulation showed that dry matter and N, P, and K uptake vary across development, with one-year-old plants relying especially on the budding and rhizome swelling stages and two-year-old plants shifting stronger nutrient allocation to the rhizome at flowering, indicating that rhizome enlargement depends on matching fertilizer application to these critical demand periods. Direct fertilizer trials further showed that yield responded to nutrient regime rather than simple fertilizer presence alone, with one NPK study estimating 6-4-6 kg/10a as an optimum combination for one-year-old rhizomes, supporting the view that balanced supply promotes underground biomass formation more effectively than unstructured input.

Organic fertilization also promotes rhizome yield, but its effect depends on compost type and application rate. In field-grown A. macrocephala, the HA organic treatment produced 184.6 kg/10a, and increasing the same fertilizer to 2.0 times raised yield to 203.0 kg/10a, both exceeding conventional fertilization in that trial. A parallel growth regulator study showed that maleic hydrazide increased yield and rhizome weight while also elevating starch and water-soluble polysaccharides, indicating that practices that stimulate storage-product accumulation can increase rhizome mass even when their effects on medicinal quality are less favorable (Cui et al., 2026).

4.2 Regulation of bioactive compounds, including atractylenolides, polysaccharides, and volatile components

Fertilization regimes influence rhizome quality not only through yield but also through differential regulation of major active compounds. In A. macrocephala, selected organic fertilizer treatments increased atractylenolide I, with the HA treatment reaching 0.036% compared with 0.023% under customary fertilization, showing that nutrient source can improve both yield and a key sesquiterpenoid marker. By contrast, maleic hydrazide increased starch and water-soluble polysaccharides but significantly decreased atractylenolide I, atractylone, and chlorogenic acid, showing that stronger biomass accumulation can coincide with deterioration of several recognized quality constituents (Cui et al., 2026).

Evidence from related medicinal systems further indicates that NPK balance can selectively regulate volatile and terpenoid profiles. In Atractylodes chinensis, the T6 fertilization regime significantly promoted the synthesis and accumulation of atractylenolide II and atractylodin, and more broadly enhanced sesquiterpene and polyacetylene volatile oils in rhizomes (Sun et al., 2022). More generally, nutrient supplementation in medicinal plants can alter secondary-metabolite profiles in an organ-specific manner, as shown in medical cannabis where enhanced NPK changed cannabinoid composition differently across tissues, reinforcing that nutrient regulation acts on phytochemical partitioning as well as total accumulation.

4.3 Relationship between nutrient supply, secondary metabolism, and medicinal quality improvement

The relationship between nutrient supply and medicinal quality in A. macrocephala appears to depend on how fertilization redistributes carbon and metabolic flux between primary growth and secondary metabolism. Broad work in medicinal plants shows that increasing N, P, or K usually enhances assimilation and yield up to a threshold, but high single-nutrient availability can depress growth or shift allocation away from target metabolites, consistent with a growth-quality trade-off rather than a universally positive fertilizer effect. A transcriptomic-physiological study in Epimedium pubescens reached a similar conclusion, showing that moderate nitrogen optimized both biomass and flavonoid production, whereas deficiency or excess impaired photosynthesis, carbon-nitrogen balance, and medicinal metabolite biosynthesis (Liu et al., 2025).

For A. macrocephala specifically, soil nutrient context helps explain why fertilization does not affect all quality traits in parallel. Across cultivation sites, rhizome growth and phytochemical composition were regulated by largely independent environmental networks, while atractylenolide content was strongly associated with soil texture, cation exchange capacity, temperature, and humidity, indicating that nutrient effects on quality are filtered through the local soil environment rather than expressed uniformly (Lee et al., 2025). Rhizosphere studies also showed that available N, P, and K and organic matter were positively associated with active-compound accumulation, whereas pH showed the opposite pattern, supporting the idea that medicinal quality improvement requires coordinated regulation of fertilizer supply, soil condition, and belowground biological processes.

5 Physiological and Biochemical Mechanisms Regulating Fertilizer-Induced Quality Improvement

5.1 Effects of nutrient availability on photosynthesis, carbon assimilation, and assimilate allocation

Nutrient availability regulates quality formation first by shaping photosynthetic capacity and the balance between carbon fixation and nitrogen assimilation. Broad evidence shows that nitrogen status directly affects carbon fixation because N is a core component of the photosynthetic machinery, while suboptimal C/N balance disrupts growth and development at the whole-plant level. In medicinal plants, this balance appears especially important for quality traits: in Epimedium pubescens, moderate nitrogen simultaneously supported higher biomass and maximal flavonoid production, whereas nitrogen deficiency or excess reduced photosynthetic efficiency and hindered carbon reallocation needed for secondary metabolism (Liu et al., 2025). These findings indicate that optimized fertilization improves rhizome quality not simply by increasing nutrient supply, but by sustaining a physiological state in which photosynthesis, carbon skeleton production, and nitrogen metabolism remain coordinated. Under such conditions, more assimilated carbon can be directed toward both structural growth and the biosynthesis of medicinal constituents rather than being trapped in stress compensation.

Carbon allocation after assimilation is equally important, because fertilizer regime influences whether photosynthate is retained in leaves, diverted to roots, or invested in storage organs. Under low nitrogen in maize, soluble sugars and starch accumulated while root biomass increased at the expense of shoot biomass, indicating a higher root-to-shoot assimilate allocation and stronger competition for carbon in sink tissues (Amoah et al., 2025). A root-focused maize analysis reached the same conclusion mechanistically, showing that low N enhanced carbon transport to roots, increased sugar and starch reserves there, and remodeled root architecture to improve nutrient capture. In A. macrocephala, a related framework is supported by rhizosphere evidence showing that direct soil nutrient supply, microbiome-mediated C/N metabolism remodeling, and resource reallocation jointly drive bioactive compound accumulation. This suggests that fertilizer-induced quality improvement in the rhizome depends on maintaining efficient source-sink transport so that assimilates produced by photosynthesis are effectively transferred to the underground medicinal organ and incorporated into storage compounds and secondary metabolites.

5.2 Regulation of antioxidant metabolism and physiological stability under optimized fertilization

A second mechanism involves the stabilization of cellular redox status under appropriate nutrient supply. In medicinal and aromatic plants, intermediate fertilization rather than maximal fertilization often gives the best biochemical outcome: in Sideritis cypria, an intermediate NPK regime increased phenols, flavonoids, and antioxidant activity, whereas the NPK and very high K treatment caused oxidative stress accompanied by elevated lipid peroxidation and antioxidant-enzyme activation. Similar optimization was reported under abiotic stress, where a specific NPK combination in West Indian cherry modulated SOD and APX activity and helped preserve redox homeostasis under salinity. These results support the interpretation that fertilizer-induced quality improvement partly reflects reduced oxidative burden, because moderate and balanced nutrient supply lowers the need for emergency stress responses and preserves metabolic energy for growth and biosynthesis.

Organic and biofertilizer inputs can reinforce this physiological stability by supporting antioxidant defenses through rhizosphere and enzyme-mediated pathways. In basil under water limitation, fertilizer application, especially partial chemical fertilizer combined with bacterial biofertilizer, alleviated drought damage by improving physiological traits and antioxidant activity across irrigation regimes. In medicinal pumpkin, biofertilizers protected plants from drought-induced oxidative stress mainly by increasing ROS-scavenging enzymes such as CAT, APX, GPX, and GR, thereby helping maintain cellular homeostasis under stress (Najafi et al., 2021). Comparable trends appear in chemically fertilized systems as well: optimized NPK increased chlorophyll and soluble protein while decreasing MDA and proline in Solanum nigrum, indicating improved physiological stability rather than mere stress tolerance. For A. macrocephala, this implies that well-designed fertilization regimes likely improve rhizome quality by protecting photosynthetic tissues and roots from oxidative disruption, thereby sustaining assimilate production and metabolic continuity during rhizome filling.

5.3 Interaction between nutrient metabolism, hormone signaling, and rhizome development

Fertilizer-induced quality formation also depends on the interaction between nutrient metabolism and hormone signaling, especially pathways controlling storage-organ initiation and enlargement. Across plants, nutrient signals interact with hormones to reprogram growth, and sugar signaling in particular acts together with auxin to regulate gene expression, carbon partitioning, and root system architecture (Mishra et al., 2021). Auxin is central in this process because it regulates plant growth, responds to environmental inputs, and interacts with cytokinin, gibberellin, abscisic acid, and ethylene to maintain developmental homeostasis under changing conditions. This broader evidence makes it plausible that fertilizer regimes in A. macrocephala influence rhizome development not only through mineral nutrition, but also through nutrient-sensitive hormonal networks that determine sink strength, cell division, and storage-organ differentiation.

Work on belowground storage organs supports this interpretation directly. Auxin has been shown to induce tuber initiation and growth, and its crosstalk with gibberellin and strigolactone contributes to belowground storage-organ yield across tuber and storage-root crops (Kondhare et al., 2021). More broadly, rhizome studies indicate that initiation, elongation, and storage-related carbohydrate metabolism are regulated by context-dependent interactions among auxin, cytokinin, gibberellin, abscisic acid, and environmental cues rather than by isolated single pathways. In Atractylodes chinensis, precise NPK regulation altered the activity and expression of ACC, HMGR, and FPPS, and a high-phosphorus regime increased both yield and accumulation of polyacetylene and sesquiterpene volatile oils, providing a close medicinal-plant analogue for how fertilization can connect nutrient status with developmental and metabolic signaling (Sun et al., 2022). Taken together, the most likely mechanism in A. macrocephala is that optimized fertilization strengthens rhizome sink development through coordinated C/N metabolism and hormone-regulated developmental programs, while simultaneously promoting biosynthetic pathways responsible for medicinal quality.

6 Case Study: Comparative Evaluation of Different Fertilization Strategies on Nutrient Uptake and Rhizome Quality of Atractylodes macrocephala

6.1 Experimental design comparing conventional fertilization, organic fertilization, and integrated nutrient management

A suitable experimental design for A. macrocephala is a field trial with at least three fertilizer regimes: conventional chemical fertilization, organic fertilization, and integrated nutrient management combining reduced chemical fertilizer with organic inputs. Direct precedent exists for comparing chemical fertilizer with vermicompost in a field experiment focused on rhizome quality and soil traits, while broader rhizome-crop work shows that integrated systems can combine NPK fertilizer, manure, and growth regulators within a randomized replicated design to evaluate yield, quality, and soil fertility simultaneously. Such a framework allows the test of whether partial substitution of inorganic fertilizer can maintain nutrient supply while improving rhizosphere conditions and medicinal quality, which is the core agronomic question for this crop (Sun et al., 2024).

Treatment structure should also reflect the developmental biology of A. macrocephala, because nutrient demand changes with growth stage and organ sink strength. Field evidence in A. macrocephala shows that one-year-old plants absorb nutrients rapidly during the budding and rhizome swelling stages, whereas two-year-old plants show their critical uptake period at flowering, which supports a design using uniform basal fertilization followed by stage-specific topdressing across all regimes. Related work in A. chinensis further supports this schedule, showing that basal fertilizer at the seedling stage combined with topdressing at vegetative and later reproductive stages improved growth and provided a basis for comparing NPK combinations under controlled field conditions (Sun et al., 2022).

6.2 Assessment of plant growth, nutrient absorption characteristics, fertilizer use efficiency, and rhizome yield

Assessment should include plant height, branch number, root length, rhizome fresh and dry weight, and organ-specific N, P, and K accumulation across major growth stages, because these traits capture both source growth and medicinal-organ filling. In A. macrocephala, nutrient absorption and distribution have already been quantified by measuring dry matter and NPK contents in different plant parts over time, and in analogous rhizome crops such as turmeric, stage-specific tracking of biomass and multi-element accumulation has been used to identify critical demand periods and align fertilization with underground yield formation. This approach is preferable to single harvest measurements because it distinguishes transient vegetative responses from sustained improvements in nutrient capture and rhizome deposition (Liao et al., 2025).

Fertilizer use efficiency should be evaluated together with yield, not as a separate endpoint, using indices such as nutrient uptake efficiency, partial factor productivity, and agronomic efficiency. Reviews of fertilizer-use methodology emphasize that indices such as PFPN, uptake efficiency, and utilization efficiency are appropriate for judging whether optimized fertilization reduces nutrient input without sacrificing yield or NPK uptake, while integrated fertilizer trials in wheat show that combining organic and chemical fertilizers can increase nitrogen and phosphorus utilization rates and maintain or raise yield through greater dry matter and plant nutrient accumulation (Barłóg, 2023). For A. macrocephala, yield comparison among regimes should therefore be interpreted together with nutrient recovery and allocation to the rhizome, because high biomass under inefficient fertilization is less useful than stable rhizome production under improved nutrient-use efficiency (Figure 2) (Chang et al., 2024).

Figure 2 Experimental design and fertilizer-treatment structure for evaluating the effects of inorganic, organic, and integrated nutrient management on Atractylodes macrocephala growth, rhizome development, and soil properties

6.3 Identification of key physiological and biochemical indicators associated with high-quality rhizome production

High-quality rhizome production should be identified using both phytochemical and physiological indicators rather than yield alone. In A. macrocephala, organic fertilizer increased atractylenolide I relative to customary fertilization, while maleic hydrazide increased rhizome weight and water-soluble polysaccharides but reduced atractylenolide I, atractylone, and chlorogenic acid, showing that larger rhizomes do not necessarily indicate better medicinal quality. A robust case study should therefore include atractylenolides, polysaccharides, volatile components, and dry matter content as primary quality outputs, with yield treated as only one dimension of performance (Cui et al., 2026).

The most informative supporting indicators are those linking soil nutrient supply to metabolic quality formation, especially available P and K, soil enzymes, antioxidant status, and rhizosphere biological activity. Vermicompost in an Atractylodes system increased available phosphorus and soil enzyme activity while also raising volatile-quality components and yield, and medium-element fertilization in A. chinensis enhanced SOD, POD, and CAT alongside greater pharmacologically active components and stronger primary and secondary metabolism (Sun et al., 2024). Rhizome-quality assessment can be sharpened further by incorporating polysaccharide-related indicators, because Atractylodis Macrocephalae Rhizoma polysaccharides are important for immunomodulatory quality control and vary in structural features associated with activity (Li et al., 2026).

Taken together, this case-study framework supports a side-by-side comparison of conventional, organic, and integrated fertilization in A. macrocephala using common timing, stage-specific sampling, and a combined endpoint of nutrient uptake, fertilizer efficiency, rhizome yield, and medicinal quality. The most informative conclusion will be the regime that best coordinates rhizome productivity with active-compound accumulation, rather than the one that simply produces the largest biomass.

7 Integrated Mechanisms of Fertilization Regulation in Atractylodes macrocephala Production

7.1 Coupling mechanisms between soil nutrient supply, root nutrient uptake, and plant growth

Fertilization regulation in A. macrocephala should be understood as a coupled soil-root-plant process rather than a simple linear response to fertilizer input. An integrated nutrition framework shows that root absorption capacity is feed-back regulated by whole-plant growth, nutrient availability depends on interactions among multiple elements, and the plant itself modifies nutrient dynamics through rhizosphere microbial processes. In A. macrocephala, this systems view is directly supported by evidence that direct soil nutrient supply, microbiome-mediated C/N metabolism remodeling, and resource reallocation jointly drive growth and bioactive compound accumulation.

At the crop level, this coupling changes across development because nutrient uptake and organ allocation are stage dependent. One-year-old A. macrocephala absorbs nutrients most rapidly during the budding and rhizome swelling stages, whereas two-year-old plants show their main uptake pulse at flowering, when nutrient allocation shifts more strongly to the rhizome. The root-mediated side of this coupling is reinforced by broader evidence that localized nutrient supply increases root proliferation and nutrient capture efficiency, with larger root length density and stronger root physiological activity tightly associated with improved shoot growth and nutrient accumulation (Zhang et al., 2023).

7.2 Optimization strategies for balancing yield formation and medicinal compound accumulation

Balancing yield and medicinal quality in A. macrocephala requires moving beyond maximum biomass as the only target, because the environmental controls of rhizome growth and phytochemical accumulation are partly decoupled. Across cultivation sites, rhizome growth showed weak environmental correlations, while atractylenolide content was strongly associated with soil texture, cation exchange capacity, temperature, and humidity. This means that fertilization strategies that maximize yield will not automatically maximize medicinal quality, and quality-oriented nutrient management must be aligned with the soil conditions that favor secondary metabolite accumulation (Lee et al., 2025).

The most effective optimization strategy therefore appears to be balanced and targeted nutrient supply, especially where phosphorus and other supporting elements are coordinated with plant developmental demand. In Atractylodes chinensis, a high-phosphorus NPK regime produced the best combined outcome for yield and quality and promoted sesquiterpene and polyacetylene accumulation through higher ACC and FPPS expression (Sun et al., 2022). In A. macrocephala, moderate foliar selenium increased yield below 10.0 mg/m² but had little effect on atractylenolide concentration, while total atractylenolide was negatively correlated with available nitrogen, indicating that some nutrient interventions promote growth more readily than quality and that excess N can work against phytochemical accumulation (Zhou et al., 2020).

7.3 Development of precision fertilization approaches for sustainable A. macrocephala cultivation

Precision fertilization for A. macrocephala should combine stage-specific nutrient scheduling with spatially explicit diagnosis of soil variability. Work on medicinal crops shows that tracking phenology, dry matter allocation, and nutrient dynamics across growth stages provides the basis for synchronizing nutrient supply with physiological demand, thereby improving yield, quality, and resource-use efficiency while reducing losses (Liao et al., 2025). At the field scale, site-specific management depends on identifying within-field variation in water-holding capacity and nutrient retention, and robust variable-rate fertilization requires soil mapping to be integrated with canopy-level diagnostics.

Sustainable precision management should also integrate biological inputs and species-specific nutrient thresholds rather than relying on uniform synthetic fertilizer programs. Reviews of medicinal plant cultivation show that moderate N application generally improves yield and phytometabolite content but excessive N has the opposite effect, so nutrient formulas must be set case by case with reference to local soil fertility and crop response (Hao et al., 2024). Emerging smart-farming frameworks extend this principle by combining precision irrigation, AI-driven nutrient management, and soil health monitoring to improve nutrient uptake, stress regulation, phytochemical production, and sustainability in medicinal crops.

8 Conclusions and Future Perspectives

Different fertilization regimes regulate A. macrocephala production through coordinated effects on nutrient absorption, dry matter allocation, and medicinal compound accumulation. Field evidence shows that nutrient uptake is strongly stage dependent, with one-year-old plants absorbing N, P, and K most rapidly during the budding and rhizome swelling stages, whereas in two-year-old plants the flowering stage is the key period and absorbed nutrients are preferentially allocated to the rhizome. At the same time, fertilizer source changes quality formation: organic fertilization increased rhizome yield and raised atractylenolide I relative to customary fertilization, indicating that nutrient management can improve both productivity and pharmacologically relevant constituents. The overall evidence indicates that quality improvement does not arise from nutrient input alone, but from its interaction with soil properties and rhizosphere processes. In A. macrocephala, direct soil nutrient supply, microbiome-mediated C/N metabolism remodeling, and resource reallocation collectively drive growth and geo-authentic quality formation, while broader site analysis shows that environmental controls of rhizome growth and atractylenolide accumulation are partly independent. This helps explain why fertilization strategies that maximize biomass do not always maximize medicinal quality, and why soil texture, cation exchange capacity, temperature, and humidity can modify phytochemical outcomes even when growth responses are modest.

In practice, efficient fertilizer management for medicinal plants should prioritize balanced, stage-specific, and site-adapted application rather than uniformly increasing fertilizer rates. Reviews across medicinal crops show that moderate nitrogen application generally increases yield and phytometabolite content, whereas excessive nitrogen often reduces both, so fertilizer formulas should be planned case by case according to species demand and local soil fertility. Parallel work in Atractylodes chinensis supports the same principle, showing that formula fertilization improves nutrient utilization, soil quality, yield, and pharmacodynamic quality, and that a defined NPK ratio can outperform non-targeted input. Organic substitution and integrated nutrient management appear especially promising for sustainable medicinal plant production because they improve soil function while maintaining or increasing product quality. In Epimedium pubescens, organic substitution increased yield by 32.56%-59.70% and total flavonoid glycosides by 8.12%-18.79%, with soil quality improvement identified as the core driver of system sustainability. In an Atractylodes system, vermicompost increased atractylenolide II, β-eudesmol, atractylenol, and atractylenolone while also raising yield by 70%, and it improved available phosphorus and soil enzyme activity, showing that bio-organic fertilization can couple nutrient efficiency with medicinal quality enhancement.

Future research should move from describing fertilizer responses to resolving the sensing and regulatory networks that connect soil nutrients, root uptake, and secondary metabolism. Rhizosphere studies show that microorganisms not only increase soil nutrient content but also assist nutrient absorption, promote element cycling, and maintain soil homeostasis, while plant developmental stage strongly shapes rhizosphere community succession and function. This makes nutrient sensing in A. macrocephala a root-microbiome system trait rather than a purely plant-intrinsic process, and supports targeted work on beneficial taxa involved in nitrogen transformation, phosphorus mobilization, hormone production, and metabolite regulation. A second priority is the development of intelligent fertilization systems that integrate microbiome engineering, sensing technologies, and predictive analytics for field-scale decision support. PGPR-based biofertilizers and microbiome engineering appear promising for improving nutrient availability and input efficiency, but their field performance remains inconsistent and will require standardized protocols, omics-guided design, and field-realistic validation. At the same time, smart farming and AI-based rhizosphere analysis are becoming practical tools for medicinal plant cultivation, because they can link soil, microbial, and plant phenotypic data to predict nutrient uptake, yield, and quality, although current models still face limitations in data integration, standardization, and scalability.

Acknowledgments

I extend my sincere gratitude to the anonymous reviewers for their valuable and insightful comments, which have greatly strengthened this paper.

Conflict of Interest Disclosure

The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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