Bioscience Methods 2026, Vol.17, No.1, 43-56 http://bioscipublisher.com/index.php/bm 46 period to ensure adequate soil potassium supply in the middle and later stages (Gao et al., 2021). This design concept can simulate the actual production management conditions (appropriate nitrogen and phosphorus supply, phased potassium supply) and systematically examine the impact of potassium fertilizer application levels on sweet potato growth, physiology, and yield and quality. 3.2 Observation indicators and evaluation dimensions: yield, dry matter rate, sugar components and related physiological indicators To comprehensively assess the effect of potassium fertilizer application, this study monitored multiple indicators under each treatment (Geng et al., 2024). In terms of yield, the total fresh potato yield and the rate of commercial potatoes (the proportion of tubers meeting commercial specifications) were measured, and the yield composition (number of tubers per plant, tuber weight per plant, and distribution of tuber size) was analyzed (Singh et al., 2017). In terms of quality, the dry matter rate of tubers (dry weight of tubers / fresh weight), starch content, and sugar components (mainly including reducing sugar and sucrose content) were determined (Gao et al., 2021). Reducing sugar and sucrose respectively represent the sweet substances and total sugar reserves of potatoes, which have different meanings for flavor and processing quality. In terms of physiological indicators, the physiological parameters related to yield and quality formation of the plants were monitored, such as chlorophyll content in functional leaves (SPAD value), net photosynthetic rate, potassium content in leaves and tubers, to evaluate the effect of potassium on photosynthetic source strength and nutrient absorption (Shu et al., 2024). In addition, the activities of key enzymes such as sucrose synthase and amylase in tubers were determined to help explain the physiological mechanism of potassium regulating carbohydrate allocation (Gao et al., 2021). The above observation indicators cover two dimensions of yield and quality, providing basic data for comprehensive evaluation. 3.3 Data processing and model: response curves, significance test and multi-objective comprehensive evaluation The obtained data from the experiments were processed through statistical analysis and model construction (Geng et al., 2024). Firstly, regression analysis was used to draw response curves of yield, dry matter rate, sugar content, etc. to the amount of potassium fertilizer application, to identify the trends and turning points as the potassium fertilizer application amount changes (Lv et al., 2021). Through variance analysis (ANOVA) and multiple comparison tests, the significance level of differences among different potassium fertilizer treatments was determined (Singh et al., 2017). To achieve a comprehensive evaluation of yield and quality, a multi-objective comprehensive evaluation model was introduced: each indicator such as yield, dry matter rate, sugar content was processed without dimensionality (e.g., using membership functions to normalize each indicator value to the range of 0 to 1), and then the weights of each indicator were determined according to actual needs, and the comprehensive score or index was calculated (Geng et al., 2024). This comprehensive evaluation framework can quantify the overall performance of different potassium fertilizer application levels in terms of "yield-quality", helping to determine the optimal potassium fertilizer application scheme that balances high yield and high quality. In addition, this study also considers economic benefits and resource-environment factors, incorporating input-output ratios and soil nutrient balance into the analysis to ensure that the recommended fertilization amount is feasible and sustainable in practice (Geng et al., 2024). 4 Effects of Different Potassium Fertilizer Dosages on Sweet Potato Yield and Yield Components 4.1 Changes in total yield and commercial potato rate The experimental results show that the response of total sweet potato tuber yield to potassium fertilizer dosage follows a typical pattern of "low potassium deficiency - moderate potassium sufficiency-over-limit saturation" (Singh et al., 2017; Geng et al., 2024). When no potassium fertilizer is applied or the potassium supply is severely insufficient, due to nutrient limitation, the yield of sweet potato tubers significantly decreases; as the potassium fertilizer dosage increases, the yield gradually rises, and after reaching a certain potassium application level, the yield growth tends to be saturated and a plateau period appears (Geng et al., 2024). Appropriate potassium fertilizer application results in the highest yield, but further increasing the potassium fertilizer dosage will not
RkJQdWJsaXNoZXIy MjQ4ODYzNA==