Responses of Garlic Quality and Yields to Various Types and Rates of Potassium Fertilizer Applications

Abstract

Potassium (K) is a critical plant nutrient that determines quality in a myriad of crops and increases production yields. However, excessive application of various types of K fertilizers can decrease both the food quality and yields, which translates as economic losses and food safety issues. The objectives of this study were to 1) elucidate the impacts of different application rates of various K fertilizers on garlic, with the aim to identify the optimal and most economical K fertilizer dosage and 2) compare the effects of applying two common K fertilizers (KCl and K2SO4) on garlic, to determine the optimal combination. From 2018 to 2020, we utilized two distinct K-fertilized fields to conduct our experiments. The results revealed optimal KCl fertilization increased the biomass and vegetation index in garlic, and promoted the transfer of nitrogen, phosphorus, and potassium nutrients from the stem and leaf to bulb, thereby increasing bulb production. The application of KCl fertilizer increased the number of cloves, the diameters of the cloves and bulbs, and reduced variations in bulb size. In addition, the application of KCl fertilizer improved the nutritional quality (Vitamin C, soluble sugar, soluble protein, and allicin) of the garlic and reduced the accumulation of nitrate. However, excessive KCl fertilizer cause decreased yields, appearance traits, and nutritional quality. Applying the same rate of K fertilizer in the form of K2SO4 in isolation increased the garlic yield by only 0.1% to 22.5% when compared with KCl fertilizer. However, the results were not always significant. In this study, the highest yields, appearance traits, and nutritional quality were achieved with the ratio of K2SO4: KCl = 3:1. Consequently, to ensure the highest economic value (considering the market prices of K fertilizer, garlic sprouts, and bulbs), the authors recommend a K fertilizer rate of 252.5 kg·ha−1 K2O, with K2SO4 accounting for 61.6% for garlic production in field.

Effects of Potassium Application on Lilium davidii var. unicolor Growth, Polysaccharide Accumulation, and Metabolism

“…The results showed that potassium could promote the development of underground bulbs and leaf growth, increase the plant height and stem diameter, increase the chlorophyll content, and make full use of light energy to enhance the photosynthetic efficiency, thus promoting the plant's growth and development. We also found that the bulb weight and bulb circumference decreased significantly with an excessive K fertilizer application, as also found in other crops [27,28], possibly because the application of an excessive amount of K hinders the absorption of other nutrients such as N and P, thereby negating the positive effects of K fertilization [29]. Potassium is involved in the synthesis, transportation, and transformation of sugars, where it can inhibit acid invertase and promote the activity of sucrose phosphate synthase to decrease the hydrolysis of sucrose and promote the accumulation of polysaccharides [30].…”

Garlic-specific Fertilizer Improves Economic and Environmental Outcomes in China

“…Effect of special fertilizer on garlic bulb quality. adjusted the S:Cl ratio (3:1; Wang et al 2022). In addition, considering the long growth period of garlic ($210 d), 60% polyurethane controlled-release nitrogen fertilizer was used to instead of available nitrogen fertilizer.…”

“…On a global scale, the leading producers are China, India, Bangladesh, Korea, Egypt, and Spain. Garlic is predominantly grown in Asia (87%), where China and India collectively account for 78% of global production (Wang et al 2022). According to the Food and Agricultural Organization (FAO) database, the global production of garlic reached 30.7 million tons with a land area of 1.6 million hectares in 2019.…”

“…Meanwhile, soil nutrient imbalance reduces soil quality and therefore garlic yield and quality while even risking disease (Norris and Congreves 2018). In recent years, the research on garlic fertilization has mainly focused on how to optimize the fertilization strategy to improve the yield and quality of garlic, and the application of organic fertilizer has gradually attracted attention, and further attention may be paid to more efficient and environmentally friendly fertilization strategies in the future (Li et al 2018;Wang et al 2022;Wei et al 2023).…”

Optimizing Nitrogen, Phosphorus, and Potassium Fertilization Levels for Container Plants of Lagerstroemia Indica ‘Whit III’ Based on the Comprehensive Quality Evaluation

“…After the leaves turned white, the absorbances (at 645 nm and 663 nm wavelengths) of the extracts were determined using an ultraviolet spectrophotometer. The leaf soluble sugar concentration was determined based on the anthrone colorimetry method (Wang et al 2022), with the modification that we incubated the sample solution for 10 min in a water bath at 95 C. The soluble protein concentration was determined according to the bicinchoninic acid method (Song et al 2015), with the modification that the sample solution was incubated for 30 min in water at 60 C.…”