Supplementary zinc fertilization in rice paddies can effectively prevent "sitting stumps"

After rice seedlings are transplanted, they may be slow to grow, fail to turn green, or fail to tiller and even shrink after turning green, which farmers generally call "sitting stumps." Fields with "sitting stumps" mostly occur in low-lying, damp areas and in cold, waterlogged, or poor fields, but they sometimes also occur in fertile fields. There are many causes of this phenomenon, and zinc deficiency is one very important cause.

The symptoms of zinc deficiency "sitting stumps" in rice are: the leaf tips of the basal leaves of the rice plant dry up, and yellow-brown to reddish-brown irregular patches appear in the middle section of the leaves; and these gradually spread from the old leaves to the adjacent leaves above. When the condition is severe, the rust spots on the old leaves expand into patches and appear stripe-like, the rate of leaf emergence slows markedly, the newly emerged leaves become smaller, lose green color and turn white, the plant becomes stunted, and the leaf color fades.

Soils prone to zinc deficiency symptoms mainly include: relatively fertile fields, where soil organic matter content is greater than 1% or large amounts of green manure have been applied, calcareous paddy soils are prone to zinc deficiency; strongly leached acidic soils, especially sandy soils, which contain less zinc and are prone to zinc deficiency; uneven fields that previously showed no obvious zinc deficiency, where during large-scale land leveling in recent years of comprehensive agricultural development, soils that lost more topsoil and low-temperature cold-waterlogged fields are also prone to zinc deficiency; and after many years of phosphorus and potassium supplementation, soils with high available phosphorus content, where large applications of nitrogen fertilizer increase crop zinc demand and easily cause zinc deficiency.

Zinc deficiency can lead to declines in crop yield and quality, so zinc must be supplemented in time. However, excessive zinc content in the soil can also cause crop poisoning. Therefore, when supplementing zinc in zinc-deficient fields, the application rate and concentration must be strictly controlled; otherwise, excessive correction will produce the opposite effect.

The correct method of zinc application is: when seedling zinc deficiency "sitting stumps" is confirmed, use a 0.1%-0.3% zinc sulfate solution to spray the affected rice seedlings 2-3 times consecutively, with an interval of 7 days each time; alternatively, use 1-1.5 kg of zinc sulfate per mu, mix it with dry fine soil, spread it evenly on the field surface, and perform one manual weeding and soil stirring in the field.