1. Nitrogen-deficit fertilizers In the absence of nitrogen fertilizers in wheat, the two-leaf assemblage shows a yellow-green young wheat seedling with a small number of leaves and upright seedlings. The tips of the leaves are dry and the old leaves of the base are yellow. This kind of wheat field is generally thin soil, sowing date is too early, no base fertilizer or fertilizer is not applied, or organic fertilizer is not fully cooked, so that the organic fertilizer continues to decompose after the application of wheat, microbial and wheat seedlings compete for nitrogen fertilizer and cause yellow seedlings . Remedy: Spray the 2% urea solution on the leaves twice in a timely manner, every 7 days, and immediately apply 20 kg of ammonium bicarbonate or 7 kg to 8 kg of urea per acre.
2, if the potassium deficiency of wheat seedling leaves yellow, and first from the tip of the old leaf, and then extended down along the veins, the macular and healthy part of the demarcation line is obvious, under the yellow leaves, later posted to the ground, the entire leaf like burned , is the performance of potassium deficiency. Remedy: Immediately spray 1% potassium chloride solution or 0.2% potassium dihydrogen phosphate solution on the foliage, or apply 5 kg to 7 kg of potassium sulfate per mu in the rhizosphere.
3. Phosphate-deficient phosphate-deficient wheat seedlings have grayish green leaves and purple leaves. Remedy: For acidic soil, it is advisable to supplement calcium magnesium phosphate fertilizer in time. If it is alkaline soil, calcium superphosphate should be applied.
4. Symptoms of calcium depletion begin with the heart. The symptoms are plant dwarf, growth point and shoot tips withered. Sometimes the plant leaves clusters, the young leaves cannot be unfolded, and the leaves are yellow. Remedy: Timely spray 5% of the calcium chloride leaching solution or 3% to 5% of the superphosphate leaching solution, and then afterwards per mus of sorghum to give lime 50 kg to 70 kg.
5, lack of zinc deficiency zinc, wheat long-term dwarf not long. Jointing period is not jointing. The plants are dwarf, with chlorosis on both sides of the main veins of the leaves, forming yellow-greenish bands with clear edges and granular spots and mildew. The roots are underdeveloped and turn black. Remedy: Spray zinc sulfate solution at a concentration of 0.2% to 0.3% during the seedling stage. Http://
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