What are the functions of nitrogen fertilizer? Why can't rice be overused? How to apply nitrogen fertilizer to vegetables?

Nitrogen element is one of the three major elements of nutrients needed in the process of crop growth. Nitrogen fertilizer is a chemical fertilizer containing crop nutrient element nitrogen. The application of nitrogen fertilizer can not only improve the yield of agricultural products, but also improve the quality of agricultural products. Lack of nitrogen fertilizer will not only affect the synthesis of proteins and amino acids in crops, but also reduce crop photosynthesis, resulting in a decline in yield and quality. So, what kinds of nitrogen fertilizer are there? What are the specific functions? Why can't rice be overused? How to apply nitrogen fertilizer to vegetables? How to apply nitrogen fertilizer mixed?

1. Types of existing nitrogen fertilizers

Nitrogen fertilizer includes animal nitrogen fertilizer and plant nitrogen fertilizer:

1. Human feces and urine, horse, cow, sheep, pig manure, fish fertilizer, horseshoe and other animal nitrogen fertilizers.

2. Sesame residue, bean cake, rapeseed cake and cottonseed cake belong to plant nitrogen fertilizer.

The above two types are all organic fertilizers.

3. Mineral nitrogen fertilizer is also called inorganic fertilizer

Ammonia sulfate, ammonia nitrate, urea, ammonia and so on are all available nitrogen fertilizers, which are usually used as extra-root topdressing, such as root fertilization, which is easy to harden the soil.

Second, what are the functions of nitrogen fertilizer?

The main function of nitrogen fertilizer is to promote plant vegetative growth, increase chlorophyll, make plant branches and leaves luxuriant, leaf color dark green, flowers enlarge, seeds full, specifically have the following functions:

1. Adjust the amount of flowers

In order to overcome the big and small years of apple, 0.5% urea solution was sprayed on the leaves at 5-6 weeks after flowering (the critical period of apple flower bud differentiation, the growth of new shoots was slow or stopped, and the nitrogen content of leaves decreased). It can increase the nitrogen content of leaves, accelerate the growth of new shoots and inhibit flower bud differentiation, so that the amount of flowers in the big year is suitable.

2. Thinning flowers and fruits

The flower organ of peach tree is sensitive to urea but slow to respond to urea. Therefore, experiments on peach and nectarine flower thinning and fruit thinning were carried out abroad with urea. The results show that peach and nectarine flower thinning needs a higher concentration (7.4%) to show a good effect, and the most suitable concentration is 8% 12%. The purpose of flower thinning and fruit thinning can be achieved within 2 weeks after spraying. However, under different land conditions, the responses of different periods and varieties need to be further tested.

3. Rice seed production

In the seed production technology of hybrid rice, in order to increase the outcrossing rate of parents and increase the seed production or male sterile line production of hybrid rice, red toxin is generally used to spray the female parent to reduce the degree of neck wrapping of the female parent or to extract it completely, or to spray the parental parent to regulate their growth and make their florescence synchronized. Because gibberellin is expensive, the cost of seed production with gibberellin is high. People use urea instead of gibberellin in the experiment. 1.5% Murray 2% urea is used at the peak booting stage and the first heading stage (20% heading). The effect of seed reproduction is similar to that of gibberellin and does not increase plant height.

4. Pest control

After mixing 400 portions of urea, washing powder and water, it can prevent aphids, red spiders, cabbage insects and other pests on fruit trees, vegetables and cotton, and the insecticidal effect is more than 90%.

5. Urea iron fertilizer

Urea forms chelated iron with Fe2+ in the form of complex. This kind of organic iron fertilizer has the advantages of low cost and good effect in preventing and controlling iron deficiency and chlorosis. In addition, 0.3% urea is added when 0.3% ferrous sulfate is sprayed on the leaf, and the effect of preventing green loss is better than spraying 0.3% ferrous sulfate alone.

Third, why can't rice be overused?

Nitrogen fertilizer is one of the essential nutrient elements in the process of rice growth, which plays an important role in improving crop yield, but excessive application will have the opposite effect. The following four hazards are the harmful consequences caused by the application of too much nitrogen fertilizer in rice. I hope farmers can understand it correctly and apply it scientifically.

1. Shrunken particles

The application of too much nitrogen fertilizer at the tillering stage will lead to the growth of the aboveground part too fast, while the root growth slows down, resulting in the formation of ineffective tillers and shrunken grains due to lack of root support.

2. Diseases and insect pests

During the growing period, the application of too much nitrogen fertilizer will promote the rapid growth of rice plants, but it is very weak, and the plant shape is relatively increased, resulting in early lower shade, relative increase in lower humidity and temperature, and poor ventilation, which can easily cause diseases and insect pests. to provide favorable conditions for the reproduction of diseases and insect pests.

3. Production reduction

During the growth period, excessive application of nitrogen fertilizer will lead to the accumulation of a large amount of nitrate nitrogen in rice, which is easy to cause poisoning, the lower leaves die early, the root system is easy to aging, and the stems of ineffective tillers are weak and easy to lodge, so the reduction of yield is inevitable.

4. Affect the taste

Excessive application of nitrogen fertilizer will increase the content of protein in rice, and then affect the quality and taste of rice.

Therefore, in the process of rice production and cultivation, nitrogen fertilizer should not be applied partially, let alone more nitrogen fertilizer, but biological bacterial fertilizer, phosphorus, potassium fertilizer and organic fertilizer must be applied scientifically.

Fourth, how to apply nitrogen fertilizer to vegetables?

A large amount of element nitrogen is a component of amino acids and chlorophyll in plants, which plays an important role in the growth of crops, among which leafy vegetables are the most needed during the whole growth period. So how to apply nitrogen fertilizer to vegetables?

According to the survey, farmers are used to using nitrogen fertilizer (take urea as an example). Most of them are watering or flushing after spraying on the surface. Farmers often think that this way of application is conducive to the rapid absorption of nutrients by crops and improve the utilization rate of fertilizer.

In fact, in this way, the utilization rate of nitrogen fertilizer in the current season is only 30%, 40%, and the remaining 60%, 70% of nitrogen is wasted in the form of volatilization, wetting, etc., increasing the amount of nitrogen fertilizer all the year round, not only failed to meet the nitrogen demand of crops during the peak period of nitrogen demand, but also destroyed the soil structure and increased the cost of fertilization.

Effective ways to improve nitrogen use efficiency of vegetables:

1. Soil burying after deep application

The suitable depth is 7cm and 10cm, and the soil is covered tightly after application. The application of soil depth can effectively prolong the time of fertilizer efficiency nearly twice as long. It can effectively improve the utilization rate. Deep application of basic fertilizer, deep application of seed fertilizer, deep application of topdressing.

2. Apply less for many times and apply an appropriate amount

Because the fertilizer effect period of nitrogen fertilizer is relatively short, it is necessary to apply nitrogen fertilizer of different weight according to the growth season of different crops, and avoid applying it once, so as to avoid unnecessary loss and waste of nitrogen fertilizer and excessive growth of plants.

3. Application due to local conditions

According to the nature of the land, different farmland choose different nitrogen fertilizer, different soil quality farmland, choose different amount and times. For example, ammonium bicarbonate can be used in paddy fields, and the water loss in sandy land is serious, so it needs to be used less each time and applied several times more. Urea should be applied 3-10 days in advance. According to the different temperature of the season, the higher the temperature is, the shorter the time is. It is applied about 7 days in advance and can only be absorbed by plants after transformation. Therefore, it is not easy to water immediately after application.

In addition, urea basically has no difference, and it is not easy to fake, mainly depends on the particle uniformity of urea, do not have a lot of noodles, do not be soaked in water or wet package phenomenon, the urea use effect of each factory is basically no difference, but the freight, labor and sales policies of different manufacturers lead to different prices, so it is suggested that farmers should use cheap urea and spend less money.

4. Apply slow-release nitrogen fertilizer

Slow-release nitrogen fertilizer can effectively prolong the aging period of nitrogen fertilizer, but the price of slow-release nitrogen fertilizer is generally high, and the market of slow-release nitrogen fertilizer is mixed, under the trend of interests, many slow-release nitrogen fertilizers are conceptual fertilizers, which can not play a real slow-release role. It is recommended to use large manufacturers or practical slow-release nitrogen fertilizer, do not want to be cheap.

5. How to apply nitrogen fertilizer mixed?

1. Add ammonium bicarbonate additive. Adding the chemical additive ammonium bicarbonate additive to ammonium bicarbonate in proportion can effectively inhibit the decomposition and volatilization of nitrogen, thus increasing the fertilizer utilization efficiency of ammonium bicarbonate by 3 to 4 times.

2. Adding nitrogen fixing agent. With the deep application of proportional nitrogen-fixing agent into nitrogen fertilizer, the amount of nitrogen fixation can be increased by 1.5-2.0 times, and the nitrogen use efficiency can be increased by 10-30%.

3. Mixed application of urea and borax. The mixed application of urea and borax at the ratio of (400: 500): 1 can significantly reduce the volatilization loss of ammonia improve nitrogen use efficiency and effectively prevent the occurrence of wheat grain unsatiety rape flower and cotton bud without flower.

4. Urea and oxalic acid mixed application of cotton base fertilizer, such as nitrogen fertilizer 200kg, phosphate fertilizer 140kg, potassium fertilizer 40kg, oxalate 5kg formula application, nitrogen use efficiency increased by 17.3%, nitrogen loss rate decreased by 25%.

Mixed application of chemical fertilizer "four can not":

① superphosphate can not be mixed with plant ash, lime nitrogen, lime and other alkaline fertilizers, otherwise it will reduce the effectiveness of phosphorus; phosphate rock, bone powder and other insoluble phosphate fertilizer can not be mixed with plant ash, lime nitrogen, lime and other alkaline fertilizers, otherwise, because the organic acids in the soil are neutralized, it is more difficult to dissolve insoluble phosphate fertilizer, crops can not absorb and use.

Alkaline fertilizer such as ② calcium magnesium phosphate fertilizer can not be mixed with ammonium nitrogen fertilizer, because if alkaline fertilizer is mixed with ammonium nitrogen fertilizer, ammonia volatilization will be increased and loss will be reduced.

③ chemical fertilizer can not be mixed with bacterial fertilizer, because chemical fertilizer has strong water absorption, corrosiveness and volatility. If mixed with rhizobium and other bacterial microorganisms, it will kill or inhibit living bacteria and make bacterial fertilizer invalid.

④ immature farm manure should not be mixed with ammonium nitrate. If mixed with ammonium nitrate, the nitrogen of immature farm manure will be lost in the process of decomposition and decay, otherwise both nitrogen will be damaged and fertilizer efficiency will be reduced.