What are the symptoms of zinc deficiency in corn?

During its growth period, corn has high fertilizer requirements, especially for nitrogen, phosphorus and potassium, which are needed in the largest amounts, and small amounts of trace elements are also indispensable. So what are the symptoms of zinc deficiency in corn?

1. What are the symptoms of zinc deficiency in corn?

When corn is deficient in zinc at the seedling stage, the leaves show chlorosis. When zinc is deficient at the 3-6 leaf stage, the tissue between the veins at the base of the old leaves becomes chlorotic and turns yellow-white, and gradually spreads toward the leaf tip. When zinc is deficient after the jointing stage, the plants become stunted, with shortened internodes, bald tips and missing kernels; in severe cases, the mesophyll tissue necroses, leading to the death of the entire plant.

2. What should be done about zinc deficiency in corn?

1. Supplementing zinc fertilizer through the soil

Commonly used zinc fertilizers include zinc sulfate, zinc oxide and others, which can be applied as a base fertilizer or a top dressing. The application rate of zinc sulfate is 15.0-22.5 kg/hm2, and it can be mixed with acidic nitrogen fertilizers, organic fertilizers, compound fertilizers and so on. If used for seed dressing, zinc sulfate can first be dissolved in water, usually at a zinc sulfate solution concentration of 0.1%-0.2%, with the solution volume accounting for 7%-10% of the seed weight, and then evenly sprayed onto the seeds and sown after drying in the shade. If applied as a foliar spray, the zinc sulfate concentration is 0.01%-0.05% at the seedling stage, and the foliar spray concentration at the later stage is 0.1%-0.2%. To avoid burning the seedlings, it should be sprayed on a windless morning or evening. During application, note that zinc fertilizer had better not be mixed with phosphate fertilizers (superphosphate, monoammonium phosphate, diammonium phosphate, monopotassium phosphate, etc.). Studies show that zinc fertilizer used for seed soaking or seed dressing, as a base fertilizer or top dressing, and as a foliar spray all have a certain yield-increasing effect. For zinc fertilizer, basal application gives the best yield-increasing effect, seed soaking is next, top dressing and spraying have similar effects, and seed dressing has the worst effect.

2. Scientific fertilization to avoid antagonism

Phosphorus-zinc antagonism is an important factor affecting the availability of zinc. Only scientific fertilization can eliminate the mutual influence between the two. Because phosphate fertilizer has low solubility and poor mobility, it can be applied in a concentrated way by hole application, band application and other methods. This can reduce the contact area with the soil, both improving the utilization rate of phosphate fertilizer and effectively reducing the probability of antagonism between phosphorus and zinc, which is conducive to giving play to the fertilizer efficiency of zinc fertilizer. In addition, mixing phosphate-containing fertilizers with organic fertilizers gives better results.

3. Applying farmyard manure to effectively supplement zinc

Decomposed farmyard manure contains large amounts of organic zinc, and has good availability and a long fertilizer effect period. Increasing the application of farmyard manure can both provide the zinc needed for corn growth and improve the physical and chemical properties of the soil, effectively promoting the release of zinc in the soil. Production practice has proven that in corn fields where decomposed farmyard manure is applied to the soil at 22.5-30.0 t/hm2 every year, symptoms of zinc deficiency in corn almost never occur.