The Role of Beneficial Elements in Crops

Here are three examples:
1. Sodium fertilizers are primarily used on sodium-loving crops such as sugar beets; spinach also has a relatively high sodium requirement. The main physiological functions of sodium are: (1) Sodium promotes photosynthesis when crops fix carbon dioxide (CO₂) through photosynthesis. ② When the available potassium content in the soil is insufficient, sodium can partially substitute for potassium’s functions. ③ Sodium can promote crop respiration, stimulate the activity of certain enzymes, influence nitrogen and sugar metabolism, and increase sugar accumulation. ④ Sodium can cause leaf stomata to close, reducing transpiration, lowering water consumption, and improving crop drought resistance. ⑤ Sodium can increase the fiber content of flax and enhance the strength of cotton fibers; the application of sodium-containing fertilizers to fiber crops such as flax and cotton yields significant yield increases. Major sodium-containing fertilizers include agricultural table salt (NaCl), sodium nitrate (NaNO₃), and sodium-containing potassium fertilizers. 　　2. Silicon fertilizers are highly effective when applied to rice, as silicon is an essential nutrient for rice growth. The primary physiological functions of silicon are: ① It is a component of cell walls, enhancing the mechanical strength of crop tissues and improving the crop’s resistance to lodging. ② Applying silicon fertilizers on saline-alkali soils can reduce crop transpiration and improve salt tolerance. ③ Silicon promotes photosynthesis and facilitates sugar synthesis. ④ It mitigates the toxic effects of manganese, aluminum, and iron in the soil. ⑤ Silicon regulates the crop’s absorption and utilization of phosphorus. Common silicon-containing fertilizers include calcium silicate (CaSiO₃), sodium silicate (Na₂SiO₃), and silicon-containing industrial by-products. 　　3. The effects of titanium on crops are primarily manifested as follows: ① It increases chlorophyll content and enhances photosynthesis. ② It promotes the activity of nitrogenase, significantly enhancing nitrogen fixation in leguminous crops, as evidenced by an increase in root nodules and higher nitrogen fixation rates. ③ Promoting the absorption of soil nutrients by crops. Titanium-containing formulations cannot be applied directly to the soil because titanium is easily immobilized by the soil and cannot be absorbed by crops. Titanium formulations are generally prepared as titanium-vitamin C chelates and are applied via foliar spraying.