In rice seedlings, phosphorus deficiency often appears during the tillering stage, characterized by slow growth, stunted plants, thin and upright leaves, dark green foliage, neatly arranged leaf tips, significantly reduced leaf angle, and sometimes red leaf tips. The older leaves may turn brown or even die. This condition typically arises due to low available phosphorus in the soil, cold soil or water temperatures, or the presence of harmful substances like hydrogen sulfide and ferrous ions that impair root absorption. Additionally, excessive nitrogen application can disrupt nutrient balance. To address this, it's essential to determine the appropriate phosphorus levels using soil testing methods such as "measured fertilization" and apply the right amount accordingly.
Zinc-deficient rice seedlings show different symptoms depending on the severity. Mild deficiency results in brown spots at the base of the leaves, while moderate deficiency causes light green leaves, increased rust, mid-vein chlorosis, and whitening. Severe cases lead to shortened internodes, stunted growth, smaller new leaves, shorter plants, poor nutrient transport, blackened roots, delayed heading, and significant yield loss. Zinc deficiency is often caused by low available zinc in the soil, excessive phosphate or ammonia fertilizer, or an imbalance between nitrogen and zinc. Long-term flooding and insufficient organic matter can also contribute. To manage this, applying 1–1.5 kg of zinc sulfate per 667 square meters or top-dressing with a 0.1%–0.2% zinc sulfate solution after symptom onset can be effective.
Salt-alkali damage often combines with phosphorus and zinc deficiencies, commonly occurring in coastal rice-growing areas. Symptoms include yellowing and drying of leaves from the top down, rapid root necrosis, water exudation, and curled leaf tips starting from the base. As the condition progresses, the leaves may turn completely yellow and die. This is primarily caused by high salt or alkali content in the soil or irrigation water, or high pH levels. To prevent and control this, proper soil management such as leaching saline soils with fresh water is recommended. During the growing season, irrigation should be carefully managed based on the rice’s salt tolerance at each growth stage. Maintaining a water level difference of more than 40 cm between the surface and drainage helps reduce soil acidity and improve plant health.
Hydrogen Water Machine,Hydrogen Water Generator,Best Hydrogen Water Machine,Molecular Hydrogen Water Machine,Hydrogen Water Maker
Shenzhen Yibainian Investment Industrial Co., Ltd. , https://www.100hydrogenwater.com