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Article

Magnetized and Aerated Irrigation Promotes Nitrogen Dynamics and Metabolite Accumulation in Salvia miltiorrhiza

by
Yaofang Fan
1,2,
Weixin Zhao
1,2,
Yixin Zhang
1,
Xiangnian Zhu
1,
Ai-Bosheng Aerdake
1 and
Tong Heng
1,2,*
1
College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, Urumqi 830052, China
2
Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention, Urumqi 830052, China
*
Author to whom correspondence should be addressed.
Agriculture 2025, 15(21), 2243; https://doi.org/10.3390/agriculture15212243
Submission received: 15 September 2025 / Revised: 10 October 2025 / Accepted: 20 October 2025 / Published: 28 October 2025
(This article belongs to the Section Agricultural Systems and Management)
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Abstract

The cultivation of Salvia miltiorrhiza in arid regions is challenged by limited water availability and suboptimal soil aeration, which constrain nitrogen uptake and the accumulation of secondary metabolites. This study evaluated the integrated effects of magnetized and aerated irrigation on mitigating these constraints. Results indicated that the combined magnetized and aerated irrigation treatment demonstrated remarkable efficacy, achieving a 25.2% increase in soil nitrate nitrogen availability and 36.1% enhancement in root dry matter weight. Crucially, this optimized rhizosphere environment preferentially boosted the biosynthesis of salvianolic acid B and key tanshinones (T. IIA, Cryptotanshinone, T. I), with content increases exceeding 22% compared to conventional irrigation, representing substantial improvements in the herb’s therapeutic value. Water terminal magnetization proved superior to water source positioning, while aerated irrigation enhanced soil nitrification more effectively than magnetization alone. By concurrently improving rhizosphere oxygenation and creating favorable conditions for nutrient uptake, this strategy offers a sustainable approach for improving the quality and biomass of Salvia miltiorrhiza in water-limited environments.

1. Introduction

Water scarcity and low irrigation water use efficiency critically constrain agricultural productivity in arid regions [1]. Currently, the efficiency of irrigation water use in arid regions is limited, ranging from 0.4 to 0.55, with crop yields declining by an average of 1.5% annually under drought stress, ultimately leading to progressive land fallowing [2]. Bossolani et al. [3] proved through long-term lime amendment experiments that the interaction of irrigation water, oxygen, and soil nutrients can enhance soybean chlorophyll index by 35.0% and increase root dry matter accumulation by over 28.0%. Consequently, gaseous and soil nutrients are pivotal drivers of crop growth and development [4]. Hypoxic conditions impair root absorption capacity, resulting in significant reductions in nitrogen and phosphorus concentrations in root tissues [5]. Nutrient deficiencies hinder the accumulation of crop dry matter, decrease chlorophyll synthesis, and disrupt normal physiological functions in crops [6]. Research by Zahra et al. [7] confirmed that hypoxic conditions inhibit effective nutrient uptake by root systems from soil, resulting in K+ efflux and impaired NO3− absorption, which exacerbates nutritional imbalance and severely affects crop growth while reducing crop quality. Therefore, it is imperative to implement efficient irrigation management strategies to alleviate the adverse effects of water and gas deficiency on crop growth and soil nutrient uptake.
Salvia miltiorrhiza Bunge (S. miltiorrhiza) is a traditional Chinese medicinal herb whose root-derived metabolites are utilized for treating various diseases, exhibiting antioxidant and anti-inflammatory properties, and serving as a core therapeutic agent for cardiovascular and cerebrovascular disorders [8,9]. Due to water scarcity and soil infertility in arid regions, there is an urgent need for irrigation management strategies that enable the cultivation of high-yielding, high-quality S. miltiorrhiza [10]. Irrigation management regimes and soil nutrients significantly influenced root growth responses in S. miltiorrhiza, while conventional irrigation measures failed to ensure stable yield production. Li et al. [11] proved through pot experiments with S. miltiorrhiza that water deficit (45.0% of field capacity) combined with nutrient deficiency resulted in a 38.1% reduction in taproot length, a 53.2% decrease in root dry matter weight, and a 25.0% decline in root yield. Irrigation management measures not only affect the yield and quality of S. miltiorrhiza but also result in insufficient oxygen supply within the soil, severely inhibiting root development and the accumulation of metabolites [12,13].
Magnetized irrigation is an innovative technology in agricultural systems that enhances water conservation while maintaining stable crop yields [14,15]. This technique involves the application of a magnetic field to irrigation water through an external permanent magnetic magnetizer, which induces the restructuring of water molecular clusters and alters the hydrogen bonding configuration and surface tension of the irrigation water, ultimately enhancing crop growth and root development [16,17,18]. According to El-Zawily et al. [19], the implementation of magnetized irrigation resulted in annual increases in tomato dry matter weight and yield by 12.2% and 8.0%, respectively. In addition to magnetized irrigation, aerated irrigation represents another physical enhancement technique for ensuring high and stable crop yields, which utilizes irrigation water as a carrier to deliver dissolved oxygen to the rhizosphere soil, thereby promoting crop growth and maintaining root vitality [20,21,22]. Li et al. [23] proved that aerated irrigation promotes root development in melon plants, resulting in a 47.0% increase in dry matter weight accumulation and a 21.5% improvement in yield. However, in contrast to crops such as tomato and melon, S. miltiorrhiza exhibits more complex rhizosphere structure and developmental processes, and current research has not yet reported the effects of magnetized irrigation or aerated irrigation on the growth and metabolites of S. miltiorrhiza [24]. Furthermore, the mechanisms by which magnetized and aerated irrigation on soil nutrient accumulation remain poorly understood. Further investigation is required to determine whether the combined application of these treatments can enhance the yield of S. miltiorrhiza.
The metabolites of S. miltiorrhiza primarily comprise two major categories: liposoluble tanshinone diterpenoids and hydrophilic phenolic acids. These compounds play essential roles in alleviating drought stress and maintaining growth stability in S. miltiorrhiza [25,26]. Enhancing the accumulation of metabolites has emerged as a significant research focus in contemporary studies [27,28,29]. Ren et al. [30] enhanced the contents of salvianolic acid B (Sal. B) and total tanshinones by 22.3% and 44.1%, respectively, through the application of nanoparticles such as silicon dioxide. Liu et al. [31] proved that the application of traditional Chinese medicine residues significantly increased soil organic matter (SOM) content by 23.0–40.9% during S. miltiorrhiza cultivation, consequently resulting in tanshinone IIA (T. IIA) and cryptotanshinone (Cry.) contents of 42 and 59 mg plant−1, respectively. This confirms that field agronomic practices are crucial for enhancing the metabolites content in S. miltiorrhiza. Conversely, these metabolites improve soil nutrient availability by improving the rhizosphere environment [32,33,34]. The investigation conducted by Lu et al. [35] revealed that tanshinone diterpenoid compounds reduced soil N2O emissions by an average of 41.0%, effectively mitigating nitrogen nutrient losses and maintaining soil nutrient availability. Current research has largely concentrated on enhancing S. miltiorrhiza through agronomic interventions, with a conspicuous scarcity of empirical studies investigating the effects of irrigation management strategies on the metabolites of this species.
Previous studies have primarily explored the influence of agronomic practices on the growth of S. miltiorrhiza growth and soil nutrient dynamics. However, the mechanisms by which irrigation management strategies influence soil nutrients, S. miltiorrhiza development, and metabolite production remain poorly understood, particularly regarding the synergistic effects of magnetized and aerated irrigation on the physiological growth of S. miltiorrhiza. We hypothesize that the combination of magnetization and aerated irrigation will synergistically enhance the rhizosphere oxygen environment and nitrogen transformation efficiency, thereby more effectively promoting the growth of Salvia miltiorrhiza and the synthesis of secondary metabolites compared to any individual treatment. Based on this hypothesis, the main research objective of this study is to: (1) elucidate the mechanisms underlying the effects of magnetized and aerated irrigation on the growth and nutrient dynamics of S. miltiorrhiza; (2) to investigate the regulatory mechanisms of irrigation management measures on the biosynthesis of key bioactive compounds, specifically tanshinones and salvianolic acid B, in S. miltiorrhiz. The research comprehensively evaluated the interactive effects of magnetized and aerated irrigation measures on soil nutrients and the physiological growth of S. miltiorrhiza. The findings of this study contribute significantly to the development of the S. miltiorrhiza industry and the advancement of irrigation practices in arid regions.

2. Materials and Methods

2.1. Study Sites and Field Experiment Design

Field experiments were conducted during 2023–2024 in the endorheic region of the Junggar Basin within the inland river basin of Central Asia (43°58′12″ N, 87°42′36″ E; elevation 446 m; Figure 1a). The region is characterized by a temperate continental arid climate, with a mean annual temperature of 5.7 °C and mean annual sunshine duration of 2707 h. Precipitation is scarce and evaporation is intense, with mean annual precipitation of only 201.6 mm, whereas evaporation reaches 2180.4 mm (Figure 1f). The soil texture was classified as medium loam according to USDA textural classification (sand: 42.3%, silt: 35.8%, clay: 21.9%); with soil pH ranging from 7.8 to 8.5 (1:2.5 soil:water ratio). Soil water retention properties were determined using pressure plate apparatus: field capacity (FC, −33 kPa) was 24.8 ± 1.4% (v/v), permanent wilting point (PWP, −1500 kPa) was 11.2 ± 0.8%, resulting in plant-available water content of 13.6%. Irrigation scheduling-maintained soil moisture between 70–85% of FC throughout the growing season to avoid both water stress and hypoxia conditions. The groundwater table depth varying between 1.5 and 3.0 m. Patterns during the study period (2023–2024), error bars represent the variability of climate data in 2024.
This investigation was designed with two irrigation measures: magnetized and aerated. The magnetized irrigation measures included water source magnetized (P1), water terminal magnetized (P2), and non-magnetized (P3). The P1 treatment involved installing the magnetized irrigation devices (Tianlu-MNB300, Tianlu, Quanzhou, China, Figure 1b) at the pump house, while the P2 treatment involved installing the magnetized irrigation devices at the field lateral outlet (Diameter: 110 mm PVC). To enhance root development and water uptake, two irrigation measures were established: aerated irrigation (M1) and non-aerated irrigation (M2). The aerated measure employed a micro-nano bubble generator (SB-125, SPG Technology, Sumida, Japan, Figure 1d), which was installed at the field lateral outlets and continuously produced monodisperse nanobubbles with particle sizes ranging from 100 to 300 nm. A total of six experimental treatments were implemented, with three replicates for each treatment. Consequently, the 18 experimental plots were established with uniform dimensions (15 × 11 m, Figure 1c).
On April 10 of 2023 and 2024, the magnetized and aerated irrigation devices were synchronously installed during the annual sowing of Salvia miltiorrhiza (S. miltiorrhiza). The magnetizer was connected to the drip irrigation system via pipes (DN 110 PVC, China United Plastics, Foshan China). The 200-mesh disc filter (4SK-4, ARKAL, Kibbutz Beit Kama, Israel) was installed upstream of the magnetized irrigation devices inlet to prevent metallic elements or suspended particles in the water from interfering with the magnetization efficiency. To ensure stable operation of the magnetized irrigation devices, the pump power and pipeline pressure at the head unit were maintained constant throughout the experimental period, thereby ensuring uniform magnetization effects when water flowed through the magnetized irrigation devices. A gas flow meter (TG05, Ritter, Bochum, Germany) was simultaneously installed at the field lateral outlets to precisely control the generation flux of micro-nanobubbles. Following the installation of the magnetized irrigation devices and micro-nano bubble generator, three trial runs were conducted on the irrigation system to calibrate the magnetic intensity (0.35 T) and aeration rate (50–100 L h−1), with each calibration lasting no less than 8 h.
S. miltiorrhiza seedlings were transplanted annually on 10 April and harvested on 2 November, with a total growth period of 207 days. The tested cultivar of S. miltiorrhiza was “Zhongdan No. 1”, with seedlings obtained from the Chinese Academy of Medical Sciences. S. miltiorrhiza was cultivated using ridge planting with plastic film mulching, with plant spacing and row spacing of 0.25 and 0.75 m, respectively, resulting in a planting density of 22,600 plants ha−1. The experimental plots were irrigated using inline drip tape with an emitter spacing of 25 cm and an emitter discharge rate of 1.6 L h−1. S. miltiorrhiza was irrigated 12 times throughout the entire growth period (Table 1), with irrigation and fertilization timing synchronized across all plots. The irrigation water was sourced from a deep groundwater well (depth: 120 m) and exhibited the following physicochemical properties: pH 7.6 ± 0.2, electrical conductivity (EC) 0.68 ± 0.05 dS m−1, total dissolved solids (TDS) 435 ± 32 mg L−1. Water hardness was 292 mg L−1 CaCO3 equivalent, classified as moderately hard. Major ionic composition included Ca2+ (78 mg L−1), Na+ (45 mg L−1), and Cl− (68 mg L−1). The sodium adsorption ratio (SAR) was 0.97, indicating low sodicity risk. Composted sheep manure and diammonium phosphate (18% N, 46% P2O5) were applied as basal fertilizers one month before transplanting S. miltiorrhiza seedlings, at rates of 3000 kg ha−1 and 150 kg ha−1, respectively. Additionally, 240 kg ha−1 of urea (CH4N2O) and 108 kg ha−1 of potassium sulfate (50% K2O) were applied through fertigation during the S. miltiorrhiza growing season.

2.2. Methods of Soil and Plant Sampling

The soil core samples were collected at a depth of 5–15 cm, along with stem, roots, and leaves tissue samples from S. miltiorrhiza. Sampling was conducted 24 h following the final irrigation event for S. miltiorrhiza (1 October 2023 and 1 October 2024). To avoid damage to the main root system, sampling points were selected at a horizontal distance of 10 cm from the S. miltiorrhiza rhizome. Three replicate samples were collected from each experimental plot following a V-shaped sampling pattern (Figure 1e).
During sampling, a ring knife (70 mm inner diameter, 100 mm height) was vertically pressed into the 5–15 cm soil layer with uniform pressure. The ring knife was carefully extracted intact using a spade, excess soil at both ends was precisely trimmed flush with its edges, and finally secured with top and bottom covers. Fresh soil core samples were immediately placed in sterile resealable bags with excess air expelled, labeled with sampling information, and temporarily stored in a 50 L portable dry ice cooler (PF4025, Prima, Bristol, UK) before being transported to the laboratory. The soil core samples were air-dried in a shaded indoor area at 15 °C, then ground and passed through a 2 mm sieve for subsequent determination of soil nutrients and organic matter.
The stem, roots and leaves tissue samples of S. miltiorrhiza were collected during the harvest period (2 November 2023 and 2 November 2024). Three S. miltiorrhiza organ samples were selected from each experimental plot at the soil core sampling locations for analysis. Specifically, stems and leaves were harvested by cutting the plant at the base, near the soil surface, to obtain complete aboveground biomass samples. Intact root systems of S. miltiorrhiza were precisely harvested layer by layer from the soil surface downward, then placed on level ground and rinsed with clean water. After finishing field collection, all S. miltiorrhiza organ samples were sorted into sterilized kraft paper bags, temporarily stored in dry ice containers, and transported to the laboratory, where dry matter weight was determined after indoor processing. Following data acquisition, the S. miltiorrhiza root samples were ground using a ball mill (Pulverisette 14, Fritsch GmbH, Idar-Oberstein, Germany) and sieved through a 250 μm mesh to obtain homogeneous powder. The powder was sealed in sterile self-sealing bags for subsequent determination of tanshinone I (T. I), tanshinone IIA (T. IIA), cryptotanshinone (Cry.), and salvianolic acid B (Sal. B) contents.

2.3. Soil Nutrient Status

Soil nitrate nitrogen and ammonium nitrogen (AN) contents (mg kg−1) were determined using a continuous flow analyzer (Futura, AMS Alliance, Frépillon, France). Initially, 1 g of ground soil sample was precisely weighed using an analytical balance with 0.001 g precision, transferred to a 30 mL conical flask, and 10 mL of 1 mol L−1 KCl solution was added. The mixture was shaken at 200 rpm for 60 min using a reciprocating shaker (HS 260, IKA, Staufen, Germany), followed by filtration through a conical funnel to obtain the extract, which was subsequently used for instrumental analysis of soil nitrate nitrogen and AN.
Total soil nitrogen content (TN, g kg−1) was determined by the Kjeldahl method using an automatic Kjeldahl analyzer (Kjeltec 9, FOSS, Hilleroed, Denmark). Precisely 0.5 g of ground soil sample was weighed into a digestion tube, to which 2.0 g of catalyst mixture (containing K2SO4 and CuSO4) and 8.0 mL of concentrated sulfuric acid (H2SO4, 98%) were sequentially added. Digestion was performed using a microwave digestion system (Speed wave Xpert, Berghof, Eningen, Germany). After cooling and dilution to a fixed volume, the samples were subjected to instrumental analysis.
Soil organic matter content (SOM, g kg−1) was determined by spectrophotometric method using a UV-visible spectrophotometer (UV-1800, Shimadzu, Tokyo, Japan). Precisely 0.4 g of ground soil sample was weighed and mixed with 2.0 mL of potassium dichromate-sulfuric acid solution (K2Cr2O7-H2SO4, 1:5), then heated in a boiling water bath for 30 min. After cooling, the solution was transferred to a 50 mL volumetric flask and diluted to volume. An aliquot of 5.0 mL was mixed with 2.0 mL of 0.5% diphenylamine chromogenic reagent and allowed to stand for subsequent spectrophotometric analysis of SOM.

2.4. Metabolites of Salvia miltiorrhiza

Tanshinone compounds in root samples (Cry., T. I, and T. IIA, mg g−1) were quantified by high-performance liquid chromatography (HPLC). Precisely 0.2 g of sieved S. miltiorrhiza root sample was weighed and extracted with 20 mL of 85% methanol (MeOH), ultrasonicated for 30 min using an ultrasonic bath (RM 110 UH, Bandelin, Berlin, Germany), and filtered through a 0.45 μm organic membrane filter. The filtrate was subsequently analyzed for tanshinone constituents using a high-performance liquid chromatograph (1290 Infinity, Agilent, CA, USA).
The determination of Sal. B contents (mg g−1) followed a similar procedure to that of tanshinones. A 0.25 g aliquot of S. miltiorrhiza root sample was extracted with 7.5 mL of methanol solution (70% MeOH containing 0.1% formic acid), ultrasonicated for 40 min, filtered through a 0.22 μm nylon membrane filter, and subjected to instrumental analysis.

2.5. Plant Dry Matter Weight and Leaf Chlorophyll Index

The leaf chlorophyll index of S. miltiorrhiza was measured at full bloom stage using a SPAD-502 meter (Konica Minolta, Osaka, Japan). Measurements were taken at the same locations where plant samples were collected, with three fully expanded leaves of different orientations selected from each treatment.
After collecting S. miltiorrhiza organ samples at harvest, dry matter weight (g) was determined in the laboratory. The specific processing procedure was as follows: (1) samples were subjected to enzyme deactivation at 105 °C for 30 min in a forced-air oven (FD115, Binder, Tuttlingen, Germany); (2) dried at 70 °C for 24 h until constant weight was achieved; (3) weighed precisely using an analytical balance (0.001 g precision, PS360/C/1, Radwag, Radom, Poland).

2.6. Statistical Analyses

All statistical analyses and visualizations were performed using SPSS v27.0 (IBM Corporation, Chicago, IL, USA) and the R statistical computing environment (v4.2.3, RStudio Inc., Boston, MA, USA) with associated packages including car (v3.1.2) and ggplot2 (v3.4.0). Shapiro–Wilks test of normality and normal Q-Q plots were used to perform normality testing. Bartlett’s test was used to check the homogeneity of variance in these data. The correlation between the secondary metabolites of S. miltiorrhiza was quantified using Pearson’s correlation coefficient, and the p-value was corrected using the Bonferroni method. Effect sizes were represented as weighted standardized mean differences (SMD) along with 95% confidence intervals (CI). A one-way analysis of variance was applied to investigate the effects of magnetization or aerated irrigation on soil nutrient indicators and S. miltiorrhiza growth indicators.
Tukey’s HSD test facilitated post hoc pairwise comparisons to identify significant differences among treatment means, with statistical significance determined at α = 0.05. Different lowercase letters in figures denote significant differences among treatments (p < 0.05). Principal component analysis (PCA) of the main components of soil nutrient indicators, the metabolites and growth indicators of S. miltiorrhiza, the variables were standardized using Z-scores.

3. Results

3.1. Soil Nutrient Dynamic

3.1.1. Soil Available Nitrogen

The coprocessing of different magnetized irrigation types and aerated irrigation significantly enhanced soil nutrients. In 2023, soil nitrate nitrogen and soil AN content remained at high levels under M2P1, M1P2, and M2P2 treatments, with soil nitrate nitrogen content reaching a peak value of 110.8 mg kg−1 under M2P1 treatment, which was 29.2% higher than that under M2P3 treatment. Soil AN reached a peak of 42.9 mg kg−1 under M2P1 treatment, exceeding M2P2, M1P2, and M2P3 treatments by 13.2%, 16.9%, and 20.0%, respectively. The M2P1, M1P2, and M2P2 treatments yielded similarly elevated soil nitrate nitrogen content in 2024. Notably, the concentration under M2P1 reached a peak of 124.9 mg kg−1, which was 25.8% greater than that under M2P2. Soil AN content exhibited high values under M2P1, M2P2, and M2P3 treatments. The peak value of 46.5 mg kg−1 occurred under M2P1 treatment, surpassing M2P2, M1P1, and M2P3 treatments by 12.5%, 33.7%, and 3.3%, respectively (Figure 2).
Under water source magnetized (P1) measures, the M1P1 treatment exhibited SOM and soil AN content that were 16.3% and 25.2% lower than those of the M2P1 treatment in 2023–2024, respectively. Under water terminal magnetized (P2) measures, the M1P2 treatment exhibited soil nitrate nitrogen content that was 19.1% higher than M2P2 and soil AN content that was 0.5% lower than M2P2 throughout 2023–2024, while the soil nitrate nitrogen and soil AN contents under M1P2 treatment were 13.1% and 18.1% higher than those under M1P1, respectively, indicating that water terminal magnetized confirm superior efficacy compared to water source magnetized under identical aerated irrigation (M1) measures. Under aerated irrigation (M1) measures, the M1P2 treatment exhibited 27.2% and 1.4% higher soil nitrate nitrogen and soil AN content, respectively, compared to M1P3 during 2023–2024, and showed 35.4% higher soil nitrate nitrogen content but 8.6% lower soil AN content compared to the non-aerated and non-magnetized irrigation treatment (M2P3).

3.1.2. Soil Organic Matter and Total Nitrogen

In 2023, soil TN and SOM remained at high levels under M1P2, M2P2, and M1P1 treatments. Soil TN and SOM reached their peak values of 6.2 g kg−1 and 36.0 g kg−1, respectively under the M1P2 treatment. Under aerated irrigation (M1) measures, the M1P2 treatment compared to the M1P1 treatment exhibited 1.4% and 10.9% higher soil TN and SOM, respectively. Under water terminal magnetized (P2) measures, the M1P2 treatment showed 1.1% and 5.5% higher soil TN and SOM, respectively, compared to the M2P2 treatment. Under water source magnetized (P1) measures, the M1P1 treatment confirm 2.9% and 23.5% higher soil TN and SOM, respectively, compared to the M2P1 treatment. By 2024, under aerated irrigation (M1), SOM under M1P2 surpassed that under M1P1 by 6.3 g kg−1. Under water terminal magnetized (P2) conditions, M1P2 resulted in a modest increase of 0.08 g kg−1 in TN compared to M2P2. Peak soil TN and SOM levels occurred under water terminal magnetized treatments (M1P2, M2P2), with values reaching 6.2 g kg−1 and 36.0 g kg−1, respectively, in 2023. Under water source magnetized conditions, aerated irrigation (M1P1) resulted in 23.5% higher SOM compared to non-aerated treatment (M2P1).
Throughout the experimental period (2023–2024), the M1P1 treatment maintained 0.05 g kg−1 higher soil TN content compared to the M2P1 treatment. The M1P2 treatment-maintained SOM levels 2.6% and 15.0% higher than M2P2 and M1P1 treatments, respectively, throughout the experimental period.

3.2. Growth Performance of Salvia miltiorrhiza

3.2.1. Dry Matter Weight

Magnetized and aerated irrigation substantially enhanced dry matter accumulation in S. miltiorrhiza organs (Figure 3). Root dry matter weight, the primary indicator of medicinal yield, reached maximum values under all aerated irrigation treatments (M1P1, M1P2, M1P3), with M1P2 achieving the highest average of 130.2 g plant−1 across both years, representing a 36.1% increase over the M2P3 control (95.6 g plant−1). Treatment effects varied by magnetization position: under water terminal magnetization conditions (P2), aerated irrigation (M1P2) increased root dry matter weight by 24.7 g plant−1 compared to non-aerated irrigation (M2P2), while under water source magnetization (P1), aerated irrigation (M1P1) enhanced root dry matter weight by 23.3 g plant−1 relative to non-aerated treatment (M2P1). Among aerated treatments, water terminal magnetization (M1P2) produced 3.0% and 19.3% higher root dry matter weight than water source magnetization (M1P1) and non-magnetization (M1P3), respectively, averaged across the experimental period. Stem and leaf dry matter weights exhibited similar response patterns, with M1P2 treatment achieving 34.8 g plant−1 and 28.6 g plant−1, respectively, both representing the highest values among all treatments. The M1P2 treatment consistently produced the highest biomass values across all plant organs during both experimental years (Figure 3).

3.2.2. Leaf Chlorophyll Index

The combination of magnetized and aerated irrigation significantly increased the leaf chlorophyll index in S. miltiorrhiza. In 2023, under aerated irrigation (M1) measures, magnetized irrigation at the water terminal magnetized (M1P2) increased the leaf chlorophyll index of S. miltiorrhiza by 1.9 and 4.8 compared to water source magnetized (M1P1) and non-magnetized (M1P3) treatments, respectively. Under magnetized irrigation at the water terminal magnetized (P2), aerated irrigation (M1P2) substantially enhanced the leaf chlorophyll index of S. miltiorrhiza by 6.2 compared to non-aerated irrigation (M2P2). In 2024, under water source magnetized (P1), aerated irrigation (M1P1) increased the root dry weight of S. miltiorrhiza by 5.5 mg L−1 compared to non-aerated irrigation (M2P1) under water source magnetized (P1). Under magnetized irrigation at the water terminal magnetized (P2), aerated irrigation (M1P2) increased the root dry weight of S. miltiorrhiza by 5.0 mg g−1 compared to non-aerated irrigation (M2P2). Throughout the experimental period (2023–2024), the leaf chlorophyll index of S. miltiorrhiza consistently reached its peak under the M1P2 treatment. Under water terminal magnetized (P2), the leaf chlorophyll index of S. miltiorrhiza in the M1P2 treatment was 15.8% higher than that in M2P2 in 2023–2024. Under aerated irrigation (M1), the leaf chlorophyll index of S. miltiorrhiza in the M1P2 treatment increased by 2.8% and 11.1% compared with M1P1 and M1P3 treatments, respectively. Throughout the root thickening stage of S. miltiorrhiza, the M1P2 treatment maintained the highest leaf chlorophyll index values, averaging 27.1% higher than M2P3 treatment across the 2023–2024 experimental period. (Figure 4).

3.3. Bioactive Compound of Salvia miltiorrhiza and Their Correlations

3.3.1. Tanshinone Composition

Magnetized and aerated irrigation synergistically promoted the accumulation of tanshinone II A (T. II A), cryptotanshinone (Cry.), and tanshinone I (T. I) in S. miltiorrhiza roots. In 2023, tanshinone content exhibited high values under M1P2 treatment, with T. II A, Cry., and T. I content reaching 6.10 mg g−1, 6.11 mg g−1, and 1.26 mg g−1, respectively, representing increases of 14.9–20.6% compared to the control group (M2P3). Under magnetic treatment measures at the water terminal (P2), the tanshinone content in M1P2 was significantly higher than that in M2P2 treatment, with T. II A showing the highest increase of 10.9%. Under aerated irrigation (M1) measures, the tanshinone content in M1P2 treatment was 0.08 mg g−1 and 0.81 mg g−1 higher than that in M1P1 and M1P3 treatments, respectively. In 2024, the contents of Cry. and T. I showed significant differences under M1P2 treatment, yet both compounds maintained high concentrations of 6.78 mg g−1 and 1.32 mg g−1, respectively, representing increases of 1.05 mg g−1 and 0.33 mg g−1 compared to the M2P3 treatment in the same year. Under aerated irrigation conditions, Cry. content in M1P2 was 4.0% higher than M1P1 treatment (p < 0.05), while T. IIA and T. I showed the greatest concentration differences between magnetized positions at the water terminal (P2) versus water source (P1, Figure 5).

3.3.2. Salvianolic Acids and Metabolite Intercorrelations

Over the 2023–2024 period, the coprocessing of magnetized and aerated irrigation most directly promoted the accumulation of salvianolic acid B (Sal. B). In 2023, the M1P2 treatment achieved 186.45 mg g−1, outperforming all other treatments, while M2P3 yielded 151.89 mg g−1, representing a relatively low level. Magnetized treatments exhibited higher Sal. B content compared to non-magnetized treatments, particularly under water terminal magnetized (P2) measures where the maximum increase reached 34.56 mg g−1. Under aerated irrigation (M1) measures, the Sal. B content under M1P2 treatment was higher than that under M1P1 and M1P3 treatments, being 1.8% and 15.6% higher, respectively. In 2024, Sal. B content proved continuous enhancement, with the M1P2 treatment reaching 187.19 mg g−1, followed by M1P1 (185.86 mg g−1) and M2P1 (171.45 mg g−1). Under aerated irrigation (M1) measures, the disparity range among different magnetized treatments diminished by 3.2%, indicating that aerated irrigation measures promote salvianolic acid metabolism and reduce the gap in Sal. B content among different magnetized treatments.
Correlation analysis of salvianolic acid and tanshinone components revealed significant differences in correlation between different metabolites. T. II A showed a positive correlation with Sal. B (r = 0.31), while T. I exhibited a significant positive correlation with Sal. B (r = 0.59), with increases in both components under M1P2 treatment outpacing other treatments. Heatmap analysis revealed that the synergistic effect between T. II A and T. I (r = 0.7, p < 0.01) more effectively promoted root growth of S. miltiorrhiza compared to the correlation between T. II A and Cry. (r = 0.3, p < 0.05). The M1P2 treatment showed the highest increases in both Sal. B and T. I content compared to all other treatments, with the correlation coefficient between these two metabolites reaching 0.59 (p < 0.05).

3.4. Principal Component Analysis of Growth-Metabolite Relationships

The principal component analysis (PCA) loading plot of S. miltiorrhiza root, stem, and leaf growth indicators and metabolite profiles revealed that the variance contribution rates of the first two principal components (PC1 and PC2) were 37.1% and 20.6%, respectively, with a cumulative contribution rate of 57.7%. Sal. B, T. I, T. IIA, and Cry. exhibited strong correlation with S. miltiorrhiza root development across all treatments (p < 0.01), indicating their more pronounced contributions to root development in promoting the growth of S. miltiorrhiza. The M2P2 and M2P3 treatments exhibited high similarity, whereas the M1P2 and M2P3 treatments prove higher differentiation. Leaf dry matter weight, leaf chlorophyll index, and SOM content exhibited the strongest positive correlation with Sal. B content across all treatments (p < 0.05), with M1P2 and M2P3 treatments showing the greatest differentiation in the PCA biplot (Figure 6).

4. Discussion

4.1. Soil Nitrogen Availability and SOM Dynamics Under Irrigation Measures

The substantial increase in soil nitrate nitrogen (25.2%) under combined magnetized and aerated irrigation (M1P2) reflects synergistic effects on nitrogen transformation processes. Liu et al. [36] conducted greenhouse tomato trials under aerated irrigation, the results indicated that aerated irrigation reduced soil AN content by 43.6% while increasing nitrate nitrogen content by 26.6%. In field experiments with cotton under magnetized irrigation conducted by Lin et al. [37], nitrate nitrogen content increased by 18.7%. Our study combined magnetized and aerated irrigation measures (M1P2), resulting in a 25.2% increase in soil nitrate nitrogen content and a 3.3% increase in soil AN content (Figure 2), which were slightly higher than the findings reported by Liu et al. [36]. This study implemented magnetized irrigation treatments at both water terminal and water source locations, further confirming that magnetized irrigation at the water terminal location confirmed superior enhancement of soil available nitrogen compared to water source positioning. Yu et al. [38] found that magnetized irrigation reduced water surface tension by 25%, thereby improving soil infiltration uniformity and reducing evaporative water loss. While aerated irrigation increased dissolved gas levels in irrigation water, promoting soil nitrification [39]. The combined action of both factors disrupted the antagonistic relationship between soil nitrogen content and gas availability, reduced the risk of available nitrogen loss, and ultimately enhanced nutrient use efficiency.
The SOM is a critical carrier for nutrient accumulation, directly influences nutrient storage efficiency under irrigation measures for S. miltiorrhiza cultivation [40]. Lin et al. [37] conducted a two-year magnetized irrigation experiment on cotton, showing an average annual increase of 18.3% in SOM. Yu et al. [41] found that aerated irrigation combined with straw incorporation achieved a 20% increase in SOM and a 20–25% improvement in maize yield. The present study integrated magnetized and aerated irrigation treatments (M1P1), resulting in a 23.5% increase in SOM, which exceeded the aforementioned research findings (Figure 2). In contrast to the studies by Lin et al. [37] and Yu et al. [41], which relied on exogenous nutrient supplementation, the present study employed a combination of magnetized and aerated irrigation measures, achieving an additional 3.5–5.2% enhancement in SOM. This difference stemmed from the magnetized irrigation treatment reducing water surface viscosity, which facilitated the movement of organic carbon sources toward the root zone, minimized SOM leaching [42], and enhanced the mutual reinforcement between SOM and nitrogen content [43].

4.2. Effects of Magnetized and Aerated Irrigation on S. miltiorrhiza Growth

The root dry matter weight of S. miltiorrhiza represents a critical indicator of medicinal yield and is predominantly influenced by irrigation management and related agronomic measures. Khosrojerdi et al. [44] employed water source magnetized (P1), achieving a 15.2% increase in root dry matter weight of S. miltiorrhiza. This finding is consistent with the research by Li et al. [21], who confirmed that optimized nutrient management under drought stress conditions yielded a comparable 10.7% increase in S. miltiorrhiza root dry matter weight. These findings suggest that water source magnetized confers an additional yield enhancement of approximately 4.5% beyond that achieved through nutrient management alone. The present study implemented combined magnetized and aerated irrigation (M1P2), which increased S. miltiorrhiza root dry matter weight by 36.1% compared to the conventional treatment (M2P3), exceeding the results reported by Khosrojerdi et al. [44] by 20.9% (Figure 3). This substantial improvement is primarily attributed to the combined effect of magnetized and aerated irrigation. The magnetized irrigation weakens hydrogen bonds between water molecules, enhancing capillary infiltration rates into the root zone, thereby enabling S. miltiorrhiza to access higher growth resources under identical moisture measures and consequently promoting root expansion [45]. By delivering oxygen directly to the root zone, aerated irrigation maintains aerobic metabolism, ensuring sufficient ATP for growth and metabolite biosynthesis [46].
The chlorophyll index dominates the conversion efficiency from light energy to chemical energy and represents a critical indicator for regulating the accumulation of plant mass and the production of metabolites of S. miltiorrhiza. Guo et al. [47] found that the magnetized irrigation treatment increased cotton chlorophyll index values by 4.6% and 7.1%, respectively. Hou et al. [48] proved through pot experiments that adequate root oxygenation increased rice chlorophyll index values by 5.0–8.0%. In contrast to the single irrigation approaches employed by Guo et al. [47] and Hou et al. [48], this study integrated magnetized and aerated irrigation treatments, which further enhanced S. miltiorrhiza leaf dry matter weight and chlorophyll index by 7.0% (Figure 4). Magnetized irrigation treatment maintains leaf water status and enhances stomatal conductance, thereby facilitating chlorophyll accumulation and photosynthetic capacity improvement in S. miltiorrhiza leaves [49]. The mechanism underlying aerated irrigation lies in the improvement of rhizosphere gas environment, where adequate gas supply maintains root redox balance, reduces toxic substance accumulation, and enhances the transport capacity of water and mineral nutrients in the root zone, consequently promoting chlorophyll accumulation in aerial parts [50,51].

4.3. Interactions Among Metabolites of S. miltiorrhiza Revealed by Multivariate Analysis

Enhancement of tanshinone and salvianolic acid contents is crucial for improving the medicinal value of S. miltiorrhiza. Magnetized and aerated irrigation primarily improve energy metabolism and enzyme activity in S. miltiorrhiza through physical modification of water properties or rhizosphere environment [52]. This study employed magnetized and aerated irrigation treatment (M1P2), which achieved T. IIA, Sal. B, and Cry. contents of 6.10 mg g−1, 6.11 mg g−1, and 186.45 mg g−1, respectively, representing a 20.6% increase in tanshinones and 22.8% increase in Sal. B compared to the control treatment (M2P3) (Figure 5a–c). Lu et al. [53] found that hydroponic cultivation yielded T. IIA, Sal. B, and Cry. contents of 1.11 mg g−1, 0.62 mg g−1, and 52.50 mg g−1, respectively, representing increases of 35.4%, 50.5%, and 52.2% over field cultivation. Xu et al. [54] investigated the cellular biological effects of short-term magnetized irrigation on fresh-cut young ginger, revealing that magnetized irrigation treatment increased total phenolic and total flavonoid contents by 29.5% and 18.9%, respectively, compared to the control, confirming that magnetized irrigation significantly influences plant growth, development, and metabolite production. This study implemented magnetized and aerated irrigation treatment, achieving increases of 4.99 mg g−1, 5.49 mg g−1 and 133.95 mg g−1 in T. IIA, Sal. B, and Cry. Contents, respectively, compared to the hydroponic system reported by Lu et al. [53]. Notably, this study was conducted under field measures that closely approximate actual production settings, where the M1P2 treatment achieved significant increases exceeding 20.5% in tanshinone and salvianolic acid contents under conventional field cultivation, indicating the excellent field adaptability and practicability of magnetized and aerated irrigation, thereby providing higher theoretical value for advancing scientific cultivation techniques of S. miltiorrhiza.
However, several research gaps require attention before widespread adoption. Although this study indicated that magnetized and aerated irrigation enhances soil nitrogen availability, promotes plant growth, and accumulates metabolites, it is crucial to acknowledge its limitations. Our experimental design did not directly compare the drought or low-oxygen stress treatment groups with the well-watered and well-aerated control groups. While the inference of “alleviating drought and low-oxygen stress” based on the improved soil environment has some merit, but it lacks direct quantitative evidence from specific plant physiological stress indicators, such as proline or antioxidant enzyme activities. Khan et al. [55] found that exogenous proline significantly enhances maize drought tolerance by improving growth parameters, strengthening the antioxidant defense system, maintaining osmotic balance, and enhancing nutrient retention capacity, thereby alleviating oxidative damage and maintaining physiological stability under water-deficient conditions. Similarly, comprehensive assessment of stress responses would require measurements of endogenous proline accumulation, malondialdehyde content, activities of antioxidant enzymes (superoxide dismutase, catalase, peroxidase), relative water content, and stress-responsive gene expression patterns. Future research that combines explicit stress gradients with physiological assessments is essential for accurately elucidating the mechanisms by which these irrigation measures alleviate stress and for quantifying their efficacy under defined adverse conditions.

5. Conclusions

This study provides compelling evidence that magnetized and aerated irrigation (M1P2) represents a highly effective strategy for optimizing the growth environment of S. miltiorrhiza under water-limited conditions. Our findings demonstrate that this approach achieved substantial improvements across multiple parameters, including a 25.2% increase in soil nitrate nitrogen, 36.1% enhancement in root dry matter weight, and over 22% increase in key medicinal metabolites compared to conventional irrigation.
The research establishes that water terminal magnetization demonstrates superior efficacy over water source magnetization, particularly when combined with aerated irrigation. The enhanced nitrogen dynamics and improved soil aeration synergistically promoted the biosynthesis and accumulation of key medicinal metabolites. We recorded significant increases in the concentrations of both tanshinones and phenolic acids, which were the primary bioactive compounds in S. miltiorrhiza roots. Future research incorporating graduated stress treatments with comprehensive physiological assessments is essential for accurately elucidating the mechanisms by which magnetized and aerated irrigation influence stress responses in S. miltiorrhiza. Furthermore, long-term field studies examining rhizosphere microbiome dynamics, seasonal variations in treatment efficacy, and economic feasibility will be critical for translating these findings into practical cultivation recommendations for arid region agriculture.

Author Contributions

Y.F.: Writing—original draft; W.Z.: Writing—original draft, Writing—review and editing, Data curation, Methodology; Y.Z.: Writing—original draft, Methodology, Resources; X.Z.: Methodology, Writing—original draft; A.-B.A.: Data curation; T.H.: Writing—review and editing, Supervision, Funding acquisition. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Key Research and Development Projects in Xinjiang (2023B02024-1-1); Major Science and Technology Projects of Xinjiang Uygur Autonomous Region (2022A02003-6); Open Fund Project of Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention (ZDSYS-JS-2024-03); China Postdoctoral Science Foundation (2023M740980); River and Lake Chief System-Guided Pilot Project Research on Scientific Dispatching Model V1.0 for Irrigation Districts (2524HXKT1); Major Science and Technology Project of the Xinjiang Uygur Autonomous Region (2023A02002-1).

Data Availability Statement

Restrictions apply to the availability of these data. Data was obtained from Xinjiang Agricultural University and are available from Tong Heng with the permission of Xinjiang Agricultural University.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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Agriculture 15 02243 g001
Figure 1. Geographical Location of the study site in the arid region. (a) Geographic location of the field experimental site (red marker); (b) Magnetized irrigation devices; (c) Schematic diagram of the experimental area. P1, P2, P3: magnetized positions (water source magnetized, water terminal magnetized, and non-magnetized, respectively); M1: aerated irrigation; M2: non-aerated irrigation; (d) Aerated irrigation device; (e) Planting pattern of experimental plots, with asterisks indicating sampling point locations and (f) Monthly evaporation (orange bars) and precipitation (blue line) patterns during the study period (2023–2024), error bars represent the variability of climate data in 2024.
Figure 1. Geographical Location of the study site in the arid region. (a) Geographic location of the field experimental site (red marker); (b) Magnetized irrigation devices; (c) Schematic diagram of the experimental area. P1, P2, P3: magnetized positions (water source magnetized, water terminal magnetized, and non-magnetized, respectively); M1: aerated irrigation; M2: non-aerated irrigation; (d) Aerated irrigation device; (e) Planting pattern of experimental plots, with asterisks indicating sampling point locations and (f) Monthly evaporation (orange bars) and precipitation (blue line) patterns during the study period (2023–2024), error bars represent the variability of climate data in 2024.
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Figure 2. Temporal variation patterns of soil nutrient indicator under combined magnetized and aerated irrigation treatments during the 2023–2024 study period. (a) Soil nitrate nitrogen; (b) Soil ammonium nitrogen; (c) Soil total nitrogen and (d) Soil organic matter.
Figure 2. Temporal variation patterns of soil nutrient indicator under combined magnetized and aerated irrigation treatments during the 2023–2024 study period. (a) Soil nitrate nitrogen; (b) Soil ammonium nitrogen; (c) Soil total nitrogen and (d) Soil organic matter.
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Figure 3. Dry matter accumulation of Salvia miltiorrhiza under combined magnetized and aerated irrigation treatments. (a) Root dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024; (b) Stem dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024; (c) Leaf dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024 and Asterisks (*) indicates the level of significance: * p < 0.05, ** p < 0.01, *** p < 0.001.
Figure 3. Dry matter accumulation of Salvia miltiorrhiza under combined magnetized and aerated irrigation treatments. (a) Root dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024; (b) Stem dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024; (c) Leaf dry matter accumulation of Salvia miltiorrhiza under different treatments during 2023–2024 and Asterisks (*) indicates the level of significance: * p < 0.05, ** p < 0.01, *** p < 0.001.
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Figure 4. Effects of combined magnetized and aerated irrigation treatments on Leaf chlorophyll index of Salvia miltiorrhiza. (a) Leaf chlorophyll index of Salvia miltiorrhiza under different treatments in 2023 and (b) Leaf chlorophyll index of Salvia miltiorrhiza under different treatments in 2024.
Figure 4. Effects of combined magnetized and aerated irrigation treatments on Leaf chlorophyll index of Salvia miltiorrhiza. (a) Leaf chlorophyll index of Salvia miltiorrhiza under different treatments in 2023 and (b) Leaf chlorophyll index of Salvia miltiorrhiza under different treatments in 2024.
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Figure 5. Interrelationships among metabolites of Salvia miltiorrhiza under combined magnetized and aerated irrigation treatments. (a) Variations in tanshinone content under different treatments in 2023; (b) Variations in tanshinone content under different treatments in 2024; (c) Variations in Sal. B content under different treatments during 2023–2024; (d) Correlation trends between Sal. B and Cry., and between Sal. B and T. IIA; (e) Correlation trend between Sal. B and T. I; (f) Correlation matrix heatmap among metabolites of Salvia miltiorrhiza. The metabolites of Salvia miltiorrhiza include cryptotanshinone (Cry.), tanshinone I (T. I), tanshinone IIA (T. IIA), and salvianolic acid B (Sal. B). Pearson correlation coefficients (r) are shown with regression lines and 95% confidence intervals. Asterisks (*) and different lowercase letters indicate significant differences among treatments (p < 0.05).
Figure 5. Interrelationships among metabolites of Salvia miltiorrhiza under combined magnetized and aerated irrigation treatments. (a) Variations in tanshinone content under different treatments in 2023; (b) Variations in tanshinone content under different treatments in 2024; (c) Variations in Sal. B content under different treatments during 2023–2024; (d) Correlation trends between Sal. B and Cry., and between Sal. B and T. IIA; (e) Correlation trend between Sal. B and T. I; (f) Correlation matrix heatmap among metabolites of Salvia miltiorrhiza. The metabolites of Salvia miltiorrhiza include cryptotanshinone (Cry.), tanshinone I (T. I), tanshinone IIA (T. IIA), and salvianolic acid B (Sal. B). Pearson correlation coefficients (r) are shown with regression lines and 95% confidence intervals. Asterisks (*) and different lowercase letters indicate significant differences among treatments (p < 0.05).
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Figure 6. Principal component analysis of Salvia miltiorrhiza parameters and soil nutrient under combined magnetized and aerated irrigation treatments and see Figure 5 for detail information, abbreviations.
Figure 6. Principal component analysis of Salvia miltiorrhiza parameters and soil nutrient under combined magnetized and aerated irrigation treatments and see Figure 5 for detail information, abbreviations.
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Table 1. Irrigation system for the growing season of S. miltiorrhiza (2023–2024).
Table 1. Irrigation system for the growing season of S. miltiorrhiza (2023–2024).
Growth PeriodIrrigation DateIrrigation Amount (m3 ha−1)Fertilizer a (kg ha−1)
Seedling15 April32015
25 April32016
5 May40020
15 May40015
Stem elongation25 May54030
5 June50039
15 June50030
Peak flowering25 June60025
5 July60025
20 July55025
Root thickening15 August55030
30 August50030
15 September45020
30 September40028
Total quota6630348
Note: a Fertilizer is applied with water during the growing season of S. miltiorrhiza.
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MDPI and ACS Style

Fan, Y.; Zhao, W.; Zhang, Y.; Zhu, X.; Aerdake, A.-B.; Heng, T. Magnetized and Aerated Irrigation Promotes Nitrogen Dynamics and Metabolite Accumulation in Salvia miltiorrhiza. Agriculture 2025, 15, 2243. https://doi.org/10.3390/agriculture15212243

AMA Style

Fan Y, Zhao W, Zhang Y, Zhu X, Aerdake A-B, Heng T. Magnetized and Aerated Irrigation Promotes Nitrogen Dynamics and Metabolite Accumulation in Salvia miltiorrhiza. Agriculture. 2025; 15(21):2243. https://doi.org/10.3390/agriculture15212243

Chicago/Turabian Style

Fan, Yaofang, Weixin Zhao, Yixin Zhang, Xiangnian Zhu, Ai-Bosheng Aerdake, and Tong Heng. 2025. "Magnetized and Aerated Irrigation Promotes Nitrogen Dynamics and Metabolite Accumulation in Salvia miltiorrhiza" Agriculture 15, no. 21: 2243. https://doi.org/10.3390/agriculture15212243

APA Style

Fan, Y., Zhao, W., Zhang, Y., Zhu, X., Aerdake, A.-B., & Heng, T. (2025). Magnetized and Aerated Irrigation Promotes Nitrogen Dynamics and Metabolite Accumulation in Salvia miltiorrhiza. Agriculture, 15(21), 2243. https://doi.org/10.3390/agriculture15212243

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