Molecular Soil Biology 2025, Vol.16, No.3, 126-136 http://bioscipublisher.com/index.php/msb 128 3 Sorghum Physiology and Nutrient Requirements 3.1 Overview of growth stages (germination to grain filling) Sorghum is a relatively drought-tolerant and barren-tolerant grain crop. Its entire growth process roughly includes several stages: germination, emergence, jointing, heading, flowering and grain filling. Adverse weather such as drought will affect seed germination and embryonic development. As a result, photosynthesis becomes weaker and nutrient transport is unbalanced, which may eventually affect grain filling, resulting in reduced yield and poor quality (Abreha et al., 2022). Sorghum has different nutritional requirements at different growth stages. Sometimes the absorption capacity is strong, and sometimes it is weak. Therefore, scientific fertilization is critical throughout the growth period, which can help sorghum grow smoothly throughout the entire cycle. 3.2 Macronutrient and micronutrient needs during development Sorghum is rich in nutrients. It contains a lot of protein and dietary fiber, as well as B vitamins (such as thiamine, riboflavin, and niacin), vitamin E, and some minerals, such as phosphorus, magnesium, iron, and zinc (Stefoska-Needham et al., 2015; de Morais et al., 2017; Xiong et al., 2019; Tanwar et al., 2023). In the process of sorghum growth, nitrogen, phosphorus, and potassium are particularly important nutrients, especially during the period from jointing to filling, when their demand is the highest (Li et al., 2023). Although trace elements such as iron, zinc, manganese, and copper are used less, they are also very useful for improving the quality of sorghum. However, in some areas, the content of potassium, calcium, manganese, and copper in sorghum grains is low, which needs to be solved by supplementing fertilizers or breeding new varieties (Jean-Baptiste et al., 2021; Palé et al., 2022). Soil type, climate conditions and planting methods also affect the absorption and accumulation of these nutrients (Li et al., 2023; Osman et al., 2022). 3.3 Nutrient uptake efficiency characteristics unique to sorghum One characteristic of sorghum is that it is very good at "saving" nutrients. Even in saline-alkali or arid areas, it can still maintain good yield and quality (Abreha et al., 2022; Li et al., 2023). When growing sorghum in saline-alkali land, the amount of nitrogen fertilizer should be determined according to the soil. For example, inland saline-alkali land is recommended to use 100 kg/hectare of nitrogen fertilizer, while coastal saline-alkali land requires 150 kg/hectare. If there is more organic matter in the soil, the effect of nitrogen fertilizer will be better (Li et al., 2023). Combining organic fertilizers with chemical fertilizers, such as using 75% of the recommended amount of fertilizer, plus some zeolite, pressed mud or biofertilizers, can also make sorghum grow better, and improve yield and quality. In addition, the protein, minerals and some active ingredients in sorghum grains that are beneficial to the human body also respond quickly to changes in fertilizers, indicating that scientific management of nutrients is really important (de Morais et al., 2017; Xiong et al., 2019; Tanwar et al., 2023). 4 Classification of Fertilization Strategies 4.1 Synthetic fertilizers: NPK blends, urea, ammonium nitrate Nowadays, many people use synthetic fertilizers when growing sorghum, such as NPK compound fertilizer, urea and ammonium nitrate. These fertilizers can make sorghum grow faster and stronger, especially in fields with irrigation conditions, the effect is more obvious (Ismaeil et al., 2024; Sebetha and Modisapudi, 2025). Nitrogen fertilizers such as urea, ammonium nitrate and ammonium sulfate can increase sorghum ear weight, biomass and grain yield. NPK compound fertilizer can not only increase production, but also improve nutrients such as protein and fat (Ivanina et al., 2019; Ismaeil et al., 2024). Chemical fertilizers should not be used indiscriminately. If used too much, nutrients in the soil will be lost and even pollute the environment. So be sure to control the amount when using (Wang et al., 2024). 4.2 Organic amendments: Farmyard manure, compost, biochar In addition to chemical fertilizers, there are many organic fertilizers that can be used, such as farmyard manure, compost and biochar. These fertilizers can increase the organic matter in the soil, improve the soil structure, and increase the activity of microorganisms, which is conducive to the growth of sorghum (Tonitto and Ricker-Gilbert, 2016; Oueda et al., 2025; Wang et al., 2025). Materials such as livestock manure, straw return to the field, and compost can effectively improve soil fertility and sorghum yield. Some organic fertilizers, such as Bokashi, can
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