Five new uses of urea

Thread Content

Urea is a commonly used quick-acting nitrogen fertilizer. In addition to being used as top dressing, it has many other uses. 1. Adjust the amount of flowers. In order to overcome the problem of large and small years of apple trees, in the critical period of apple flower bud differentiation, 5-6 weeks after flowering, new shoots grow slowly or stop, and the nitrogen content of the leaves shows a downward trend. Spray 0.5% urea aqueous solution on the leaves twice. Spraying twice in a row can increase the nitrogen content of the leaves, accelerate the growth of new shoots, inhibit flower bud differentiation, and make the flower amount suitable in the big year. 2. Flowers and fruit thinning The flower organs of peach trees are more sensitive to urea but their surface reaction is slow. Therefore, urea was used abroad to conduct flower and fruit thinning tests on peaches and nectarines. The results showed that the flower and fruit thinning of peaches and nectarines requires a larger concentration of 7.4% to show good results. The most suitable concentration is 8%-12%. The purpose of flower and fruit thinning can be achieved within 1-2 weeks after spraying. However, further experiments are needed on the response of different land conditions, different periods and different varieties. 3. Rice seed production In hybrid rice seed production technology, in order to increase the outcrossing rate of the parental parents and increase the amount of hybrid rice seed production or sterile line breeding, gibberellin is generally used to spray the female parent to reduce the degree of necking of the female parent or to completely extract it. ； Or spray the parents to regulate their growth and synchronize their flowering periods. Since gibberellins are relatively expensive, the cost of using them for seed production is high. People use urea instead of gibberellin for experiments. In the peak booting stage and the initial heading stage, 1.5%-2% urea is used in 20% of heading. Its breeding effect is similar to that of gibberellin, and it will not increase the plant height. 4. To prevent and control pests, use 4 to 1 to 400 parts of urea, washing powder, and water. After stirring and mixing, it can control aphids, red spider mites, cabbage caterpillars and other pests on fruit trees, vegetables, and cotton. The insecticidal effect can reach more than 90%. 5. Urea Iron Fertilizer Urea forms chelated iron with iron ions in the form of a complex. This kind of organic iron fertilizer is low in cost and very effective in preventing iron deficiency and chlorosis. In addition, adding 0.3% urea when spraying 0.3% ferrous sulfate on the leaves has a better effect on preventing and controlling chlorosis than spraying 0.3% ferrous sulfate alone.