Application of Zinc Fertilizer to Rice to prevent "sitting"

Rice seedlings do not grow long after transplanting, or even do not turn green, or do not tiller or even shrink after turning green, which is generally called "sitting". Most of the "sitting" fields appear in low-lying shady and humid areas and cold rotten and thin fields, but sometimes fertile fields also occur. There are many reasons for this phenomenon, and zinc deficiency is one of the most important reasons.

The symptoms of zinc deficiency in rice were as follows: the leaf tip of the basal leaf of rice plant was dry, and irregular patches of yellowish brown or even reddish brown appeared in the middle of the leaf, and gradually developed from the old leaf to the upper adjacent leaf. When the disease is serious, the spot on the old leaf expands into a strip, the speed of leaf emergence slows down significantly, the new leaf becomes smaller, the green is white, the plant is dwarfed, and the leaf color fades.

The main soils prone to zinc deficiency are: relatively fertile fields, calcareous paddy soils with soil organic matter content more than 1% or large amounts of green manure are prone to zinc deficiency; acidic soils with strong leaching, especially sandy soil, are prone to zinc deficiency. In the uneven land that did not show zinc deficiency in the past, when a large area of land leveling was carried out in the comprehensive agricultural development in recent years, the soil that lost more topsoil and the cold-soaked field with lower temperature were also prone to zinc deficiency; after years of increasing phosphorus and supplying potassium, in the soil with high available phosphorus content, a large amount of nitrogen fertilizer will increase the zinc requirement of crops, which is easy to cause zinc deficiency.

Zinc deficiency can lead to the decline of crop yield and quality, so zinc must be replenished in time. But too much zinc in the soil can also lead to crop poisoning. Therefore, the amount and concentration of zinc in zinc deficiency fields must be strictly controlled, otherwise, it will be overcorrected and counterproductive.

The correct method of zinc application is: when the seedling is diagnosed as zinc deficiency, the diseased rice seedlings are sprayed continuously for 2 times with 0.1% zinc sulfate solution of 0.3% zinc sulfate, each time at an interval of 7 days; zinc sulfate 1: 1.5 kg per mu can also be used and sprinkled evenly on the field after mixing dry fine soil, and artificial cultivation of the field once.