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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]

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]

Water and fertilizer are two important factors affecting crop growth and yield. Crop growth models are powerful tools for making irrigation and fertilization scheduling and predicting crop yield. The performance of crop models on potato under different irrigation amounts along with different N, P and K rates has been rarely evaluated, especially under drip fertigation. In this study, the accuracy of AquaCrop and DSSAT-SUBSTOR-Potato models in simulating potato growth, yield and water productivity under different drip fertigation regimes was compared. For model calibration and validation, a two-year field experiment with three irrigation levels (W 1 , 60% ET C ; W 2 , 80% ET C and W 3 , 100% ET C , where ET C was the crop evapotranspiration) and four fertigation (N-P 2 O 5 -K 2 O) rates (F 1 : 100–40–150 kg ha−1, F 2 : 150–60–225 kg ha−1, F 3 : 200–80–300 kg ha−1 and F 4 : 250–100–375 kg ha−1) was carried out in a sandy region of northwest China in 2018 and 2019. The statistical indicators showed that the AquaCrop model gave satisfactory predictions of canopy cover (R 2 ≥ 0.92, NRMSE ≤ 14.7%, d ≥ 0.96 and RMSE ≤ 10.8%), total dry matter (R 2 ≥ 0.92, NRMSE ≤ 25.0%, d ≥ 0.94 and RMSE ≤ 2.2 t ha−1), final dry tuber yield (R 2 ≥ 0.57, NRMSE ≤ 12.21%, d ≥ 0.82 and RMSE ≤ 0.83 t ha−1) and fresh tuber yield (R 2 ≥ 0.53, NRMSE ≤ 12.02%, d ≥ 0.81 and RMSE ≤ 4.91 t ha−1) in the four fertigation treatments (F 1 -F 4) under W 3 and W 2 during the two potato growing seasons. The final total dry matter and tuber yield under W 1 were over-estimated. The simulated water productivity and soil water content also agreed well with the observations (R 2 ≥ 0.91 , NRMSE ≤ 5.51%, d ≥ 0.94 and RMSE ≤ 0.48 kg m−3, and R 2 ≥ 0.40 , NRMSE ≤ 14.8%, d ≥ 0.77 and RMSE ≤ 11.5 mm). The simulation accuracy of DSSAT-SUBSTOR-Potato model was lower than that of AquaCrop model, which only showed a goodness of fit between simulated total dry matter, soil water content, tuber yield, water productivity and observations under high irrigation amount with high fertilization rate (W 3 F 4). Since the observed tuber yield increased with the increase of irrigation level (60–100% ET C) under the same fertigation rate, 120%ET C and 40%ET C were further simulated using the AquaCrop model to test the changes in tuber yield with further increased or decreased irrigation levels. The scenarios simulation showed that the tuber yield was only increased by 0.19%−1.52% under 120%ET C compared with that under 100% ET C , but 18.0% more irrigation water was consumed. Comprehensively considering water resources and tuber yield, the irrigation level of 100% ET C (W 3) along with fertigation (N-P 2 O 5 -K 2 O) rate of 200–80–300 kg ha−1 (F 3) was recommended for the sustainable potato production in the study region. The results of this study can provide guidance for the application of crop models in drip-fertigated potato. • AquaCrop and DSSAT-SUBSTOR-Potato were evaluated under various drip fertigation regimes. • AquaCrop adequately simulated the effects of irrigation and fertilization regimes on potato. • Simulation accuracy of DSSAT-SUBSTOR-potato was lower than that of AquaCrop. • 100% ET C along with N-P 2 O 5 -K 2 O rate of 200–80–300 kg ha−1 was recommenced for potato production. [ABSTRACT FROM AUTHOR]