Fertilization control

[Adjustment of flower amount] In order to overcome the large and small year of the apple field, spraying 0.5% urea aqueous solution on the leaf surface at 5-6 weeks after flowering (the critical period of apple flower bud differentiation, the growth of new shoots is slow or stops, and the nitrogen content of leaves shows a downward trend), spraying twice in succession, can increase the nitrogen content of leaves, accelerate the growth of new shoots, inhibit flower bud differentiation, and make the flower amount of big year appropriate.

[Flower and fruit thinning] Peach flower organs are more sensitive to urea, but the reaction is slow, so foreign peach with urea test, the results show that peach and nectarine flower and fruit thinning, need a large concentration (7.4%) to show good results, the most suitable concentration is 8%-12%, 1-2 weeks after spraying, to achieve the purpose of flower and fruit thinning.

[Rice seed production] In brid rice seed production technology, in order to improve the outcross rate of parents, in order to increase the seed production amount of brid rice or the fertility amount of sterile lines, the experiment was carried out with urea instead of gibberellin, and the use of 1.5% to 2% urea in the pregnancy peak stage and the first ear stage (20% ear selection), the fertility effect was similar to gibberellin, and it did not increase the plant height.

[Pest control] With urea, washing powder, water 4:1:400, after mixing, can prevent fruit trees, vegetables, cotton aphids, red spiders, cabbage insects and other pests, insecticidal effect of more than 90%. [Urea iron fertilizer] Urea forms chelated iron with Fe2+ in the form of complex. This kind of organic iron fertilizer has low cost and good effect on preventing iron deficiency and green loss. The control effect of chlorosis is better than that of 0.3% ferrous sulfate.