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Panax notoginseng cultivation planting conditions are harsh and require high soil moisture and slope of cultivated land, plus it takes 3–7 years from planting to harvesting. At present, the continuous crop barrier of Panax notoginseng has not been solved, which makes the arable land suitable for planting significantly reduced. And yet, there is almost no report on the impact of coupling water and slope on the growth of Panax notoginseng. Therefore, this study aims to explore the effects of different irrigation levels and slopes on soil water content (SWC) in the root zone, soil nutrient content, root characteristics, yield, water use efficiency (WUE), partial fertilizer productivity (PFP) and economic benefits of Panax notoginseng. During 2018–2020, a field experiment was conducted in the Panax notoginseng growing seasons with three irrigation levels (I 1 : 70–75% θ FC , I 2 : 75–80% θ FC , I 3 : 80–85% θ FC) and three slopes (S 1 : 2.43°, S 2 : 6.38°, S 3 : 16.38°). The results evidenced that soil water and nutrient content increased with increasing irrigation and decreased with increasing slope. The yield of Panax notoginseng , root morphological characteristics, WUE, PFP, and economic benefits showed a trend of increasing first and then decreasing with the increase of irrigation amount and slope, which increased with the increase of planting years. These parameters reached their maximum at the irrigation I 2 (75–80% θ FC) and slope S 2 (6.38°) treatments. Thus, based on the results of this study, medium irrigation I 2 (75–80% θ FC) and slope S 2 (6.38°) should be considered as the best slope and water management strategy to obtain both high Panax notoginseng yield and economic benefits. Through establishing a multi-objective optimization model with binary quadratic regression analysis. It was indicated that Panax notoginseng yield, WUE, PFP, and economic benefits simultaneously reached ≥ 98% of their maximum values when irrigation interval was 152–193 mm and slope interval was 5.4–9°. In summary, the results obtained in this study have important practical significance for the water management of Panax notoginseng cultivation in slope farmland in Yunnan Province, China. [Display omitted] • Water regulation technology for Panax notoginseng cultivation on sloping land was proposed. • Soil nutrient content and Soil water content gradually decreases with increasing slope. • I 2 S 2 treatment obtain maximum yield and economic efficiency. • Irrigation interval of 152-193 mm and slope interval of 5.4-9° determined to make yield, economic benefits, PFP and WUE reach ≥ 98% maximum. [ABSTRACT FROM AUTHOR]

Panax notoginseng (Burk) F. H. Chen, called Sanqi, is a valuable herbal plant and is widely used in Chinese medicine. However, the yield and saponin content cannot be guaranteed due to irrational irrigation and fertilizer management in low-latitude regions in southwestern China. To obtain suitable irrigation and organic fertilizer modes for improving the yield and saponin content of the plant, a shelter experiment was conducted using a randomized complete block design with a factorial arrangement of treatments with three replications. Three irrigation regimes, D L , D M and D S (irrigation upper/lower limit: 65–50% θ f , 50–35% θ f , and 35–20% θ f , respectively, where θ f is the field capacity), three organic fertilizer levels, F L , F M and F H (33, 48 and 63 t ha−1, respectively), and a control group, CK (65–50% θ f and 3 t ha−1), were applied in the two-year and eight-month growth cycles. With the paired comparison design, the results indicated that the flower dry yield, root dry yield and Panax notoginseng saponins (PNS) were significantly affected by different water deficit irrigation and organic fertilizer treatments, and they first increased and then decreased with increased water deficit or organic fertilizer. Compared with D L F H , D M F M reduced water use by 42.39% and fertilizer use by 23.81%, and the flower dry yield, root dry yield, PNS , water use efficiency and partial factor productivity of fertilizer increased by 19.67%, 22.52%, 54.33%, 149.72% and 91.83%, respectively. Under the D M F M treatment, the dry root yield and saponin content for 3-year-old P. notoginseng were 3039.19 kg ha−1 and 10.85%, respectively, which were higher than those resulting from other treatments. Additionally, the PNS resulting from D M F M exhibited the highest comprehensive score and comprehensive index based on principal component analysis and the TOPSIS model. This combination could create a higher yield of flowers and roots, provide a scientific management for planting, and improve the economic benefits for planters and the local government. • Study highlights role of deficit irrigation and organic fertilizer on Panax notoginseng growth. • Fertigation with highest irrigation and fertilizer amount increase root disease incidence and decrease root dry yield. • Severe drought stress significantly increased the water use efficiency for P. notoginseng. • Organic fertilizer schedule with water irrigation amount of 50~35% θf is proposed. [ABSTRACT FROM AUTHOR]

At present, the state has introduced the policy of forest Chinese herbal medicine planting planning, strictly prohibiting the planting of Chinese herbal medicine in basic farmland, coupled with the fact that the continuous cropping obstacles of Panax notoginseng have not yet been solved, which makes the area of arable land suitable for planting become less and less. However, the effect of soil moisture regulation on the growth of Panax notoginseng cultivated on sloping arable land has not been reported. Thus, the aim of this study was to investigate the impact of various irrigation levels and slopes on Panax notoginseng agronomic traits, physiological characteristics, disease attributes, biomass, and quality characteristics. During 2018–2020, a field experiment was conducted in the Panax notoginseng growing seasons with three irrigation levels (I1: 70–75% θ FC , I2: 75–80% θ FC , I3: 80–85% θ FC) and three slopes (S1: 2.43°, S2: 6.38°, S3: 16.38°). The results evidenced that the photosynthetic characteristics, root hydraulic conductivity characteristics, biomass and PNS of Panax notoginseng reached the maximum value in the I2S2 treatment, and at the same time, the incidence rate of Panax notoginseng root rot was the lowest. Therefore, based on the results of this study, irrigation volume I2S2 should be regarded as the optimal slope and irrigation management strategies for reducing Panax notoginseng diseases and realizing stable yield and quality improvement of Panax notoginseng. A multi-objective optimization model was established through binary quadratic regression analysis. The findings evidenced that when the irrigation interval was 187–203 mm and the slope interval was 5–10.7°, Panax notoginseng had the lowest incidengce rate, and the root biomass and saponin content reached > 95% of the maximum values at the same time. [Display omitted] • Moisture and slope coupling reduces root rot in Panax notoginseng • Panax notoginseng had the worst hydraulic conductivity under I1S3 treatment • The most suitable slope for planting Panax notoginseng is 5–10.7° • Irrigation 152–193 mm balanced the relationship between morbidity, yield, and PNS [ABSTRACT FROM AUTHOR]

It is still a long-term challenge to decrease root rot and improve saponin content of Panax notoginseng , thus economic benefits in Guangxi and Yunnan provinces, China. The objective of this study was therefore to propose a promising abiotic stresses strategy: deficit irrigation combined with sodium chloride (DISC) to cope with the challenge. A two-year field experiment was conducted to explore the effects of deficit irrigation combined with sodium chloride on physiological traits, yield, quality attributes, water use efficiency, and economic benefit of Panax notoginseng in 2018 and 2019. Experiment treatments consisted of two deficit irrigation levels [ D L , light deficit level: irrigation upper∼lower limit (80–65 %) θ FC ; D M , moderate deficit level: irrigation upper∼lower limit: (70–55 %) θ FC , where θ FC represents field capacity] and five NaCl application rates [0 (C 0), 15 (C 1), 30 (C 2), 45 (C 3), and 60 (C 4) mmol L−1], respectively. All treatments were designed using a randomized complete block with three replications. The results indicated that DISC could significantly promote the physiology and growth of Panax notoginseng and improve yield, quality and economic benefits under micro-sprinkler irrigation and shaded conditions in 2018 and 2019. Compared with the D M C 0 and D L C 0 treatments, D L C 1 treatment significantly improved net photosynthetic rate (Pn), stomatal conductance (Gs), root (k r), shoot (k sh), and canopy (k c) hydraulic conductance of Panax notoginseng. The D L C 1 treatment significantly increased root length, surface area, average diameter, and volume of root of Panax notoginseng compared with the D M C 0 and D L C 0 treatments. The D L C 1 treatment significantly improved rood dry matter, yield, saponin content of Panax notoginseng , water use efficiency, and economic benefits by decreasing the incidence of root rot, but reverse results were observed in the D L C 2 , D L C 3 , and D L C 4 treatments. Therefore, this study suggested that deficit irrigation amount [ D L , (80–65 %) θ FC ] combined with NaCl concentration (C 1 , 15 mmol L−1) should be recommended as an appropriate agronomic management strategy to alleviate root rot and improve water use efficiency, saponin content, economic benefits of Panax notoginseng in the seasonally arid region of Southwest China. [Display omitted] • Deficit irrigation combined with sodium chloride (DISC): a strategy to improve Panax notoginseng production. • The DISC decreased root rot and improved physiological features of plant. • The DISC improved yield, quality, and economic benefits of Panax notoginseng. • The DISC [ D L , (80–65 %) θ FC and C 1 , (15 mmol L−1)] should be recommended to promote production of Panax notoginseng. [ABSTRACT FROM AUTHOR]

Improper irrigation by Panax notoginseng growers can lead to soil consolidation, low fertilizer utilization, and decreased yield quality. In an attempt to provide a scientific and theoretical basis for Panax notoginseng cultivation to improve soil microhabitat and yield quality, field experiment were conducted on three-year-old Panax notoginseng in 2019, 2020, and 2021. The experimental design consisted of two control factors, the amount of irrigation (W) and the amount of fertilizer (F) applied. The irrigation was set to three levels, as W1, W2, and W3, with exact irrigation volumes of 5 mm, 10 mm, and 15 mm. The amount of fertilizer applied was different in all four growth stages. The amount of fertilizer applied according to the four growth stages (rooting stage: seedling stage: flowering stage: fruiting stage), where F1 (360–360–360–360 kg∙hm−2), F2 (288–360–432–360 kg∙hm−2), F3 (216–432–432–360 kg∙hm−2) and F4 (144–576–288–432 kg∙hm−2). The W and F were randomly combined to form a total of 12 treatments. And a control treatment (CK), was added, and CK was neither irrigated nor fertilization. For obtaining the best treatment results, the TOPSIS method was used to comprehensively evaluate the soil microbial biomass carbon and nitrogen, enzyme activity, physiological growth and saponin content of Panax notoginseng in 13 different water and fertilizer treatments. The results indicated that microbial biomass carbon and nitrogen, urease, sucrase, acid phosphatase and catalase activities of Panax notoginseng soil were significantly different (P < 0.05) and varied with the growth stage. The comprehensive evaluation by the TOPSIS method ranked W3F4 first and was the optimal treatment. The W3F4 treatment was more beneficial to the quality of Panax notoginseng than the other 12 treatments. W3F4 had the largest soil microbial biomass carbon and nitrogen content. W3F4 had the highest urease, sucrase, acid phosphatase, and catalase activities, which were 1.95, 1.69, 2.32, and 1.47 times higher than the CK treatment, respectively. W3F4 significantly improved R 1 , Rg 1 , Re, Rb 1 , and Rd saponin content. This study provided a theoretical basis for the water and fertilizer regulation of Panax notoginseng with its green, healthy and efficient quality cultivation. • W3F4 treatment was most beneficial for the increase of ginsenoside content. • Soil microbial biomass C and N were negatively associated with Re, and were positively associated with R 1. • Soil water content, sucrase, acid phosphatase, catalase, and urease were negatively correlated with Rb 1. [ABSTRACT FROM AUTHOR]