What are the key points of fertilization techniques for late rice?

Late rice is usually sown in mid-late June and harvested in the first and middle of October. In the same area, after planting early rice, you can then plant late rice, commonly known as double-cropping rice. The fertilization technology of late rice has changed greatly since ancient times, and there are many problems at present. Fertilization needs to follow the law of fertilizer demand of rice and grasp the main technical points in order to maximize the efficiency of fertilizer use.

1. Fertilization methods of traditional farming in China for thousands of years

In the spring of 1909, Franklin H., a professor of agricultural physics at the University of Wisconsin. Jin traveled across the ocean to three East Asian countries, China, Japan and Korea, and went deep into the vast rural land to understand why these countries cultivate crops on very little land and feed a dense population without destroying the natural environment. The reason for sustainable development, and wrote the book "four thousand years of farmers."

Through a large number of visits, he found that in China's ancient traditional farming civilization, hardworking farmers can always make full use of all the resources that can be recycled in nature. such as river (pond) silt, crop straw, plant withered branches and leaves, weed turf, fuel ashes, human dung, livestock and poultry washer dung, animal bones and so on as fertilizer input, so as to obtain agricultural products and ensure the needs of life.

two。 Current fertilization methods and consequences

After the 1980s, with the rise of national industry, chemical fertilizer gradually replaced farm organic fertilizer with the advantages of low consumption, fast fertilizer effect, clean and sanitary, convenient application and so on, and became the main fertilizer source, which made a great contribution to the agricultural production in our country.

Due to paranoia in understanding, farmers gradually abandon farm organic fertilizer and rely heavily on the use of chemical fertilizer, which leads to the gradual decrease of soil organic matter content, the destruction of soil microflora structure, the aggravation of diseases and insect pests, land acidification or salinization, nutrient imbalance, poor quality of agricultural products, poor taste and flavor, water pollution, soil pollution, heavy metal pollution and other problems.

3. Problems existing in rice fields at present

The amount of fertilizer applied by ⑴ increased year by year, but the yield increased slowly or did not increase yield. In the 1980s, 15 jin of urea per mu of land basically met the fertilizer needs of one season of rice, but now it has increased to 40 jin, but the yield per mu is still about 1200 jin. This is Mr. Cai's real experience.

⑵ soil water and fertilizer conservation capacity decreased, easy to de-fertilize early senescence, there are a lot of leaf tips yellowing phenomenon at booting stage this year. The utilization rate of fertilizer in China is 30%, while that in developed countries is 50-60%.

Various physiological diseases of ⑶ are frequent, such as element deficiency, herbicide damage and so on. The decrease of organic matter content increases the risk of herbicide damage.

The phenomenon of partial fertilization in ⑷ is common, heavy nitrogen, light phosphorus and potassium, and lack of medium and micro fertilizer.

⑸ pays attention to the use of land, but does not maintain the land, and some large households sign contracts once a year, paying no attention to the consequences of the next year, and the soil becomes more and more greedy and impoverished; the ploughing is superficial, mechanical compaction and perennial deposition, and the ploughing layer is becoming more and more shallow.

4. The law of fertilizer requirement of rice

The demand ratio of large amounts of nitrogen, phosphorus and potassium in rice is about 1: 0.5. There are two peaks of fertilizer uptake in rice life, namely, tillering stage and booting stage, and their nutrient demand ratio is different. The tillering stage was dominated by nitrogen, with both phosphorus and potassium fertilizer, and at booting stage, potassium was dominant, followed by nitrogen, and then phosphorus.

⑴ fertilization principle

From the perspective of land use and land conservation, and the sustainable development of soil, the correct principle of fertilization should be mainly organic fertilizer, accounting for about 60%, supplemented by chemical fertilizer, accounting for about 40%.

⑵ increases fertilizer source

The feasible measures to increase the source of organic fertilizer in rice production are as follows: vigorously developing green manure planting and straw crushing and returning to the field and combined application of straw ripening agent or quicklime.

⑶ soil testing formula, balanced fertilization

According to the characteristics of local soil classification, targeted soil testing and sampling, and according to the rice yield target, soil texture, the characteristics of fertilizer demand of rice at different growth stages, the ability of varieties to apply fertilizer reasonably, and appropriate supplement of medium and trace element fertilizers. In the fields with low temperature or cold soaking in mountainous areas after planting early rice in the south, zinc fertilizer can be applied properly to raise seedlings to prevent stiff seedlings, while in some magnesium deficient fields with strong leaching, magnesium sulfate should be applied about 20 jin per mu when basal fertilizer or tillering fertilizer is applied.

5. Key points of fertilization for rice

On the basis of applying organic fertilizer, sufficient base fertilizer was applied. In the short term, due to the low content of organic matter in the soil, the effect of organic fertilizer can not be effective immediately, so the base fertilizer is still mainly compound fertilizer. Take the current southern soil as an example, 45% ternary compound fertilizer (3 15 balanced type or 1820-20-10-15-15-17) is used per mu of 50 kg 60 jin, zinc fertilizer 2 kg (to prevent stiff seedlings of early rice), boron fertilizer 400 kg 500 grams (to prevent drought) as base fertilizer. The carbon-nitrogen ratio of late rice should be adjusted to 25:1 standard because of straw returning to the field, in order to meet the nitrogen demand of microorganism rotting straw and avoid competing for nitrogen with grain seedlings, so the base fertilizer should be 10 jin of urea and 2 kg of straw ripening agent containing 50 million / g bacteria per mu. In the future, with the increase of organic matter content, the amount of chemical fertilizer can be adjusted and reduced appropriately.

Early application of tiller fertilizer in ⑴

Early topdressing tiller fertilizer, the peak of tillering appeared in 15-20 days after planting in double-cropping rice area, and in 20-25 days in one-cropping rice area. After that, the panicle rate of tillers decreased, which not only wasted nutrients, but also created conditions for inducing sheath blight and planthoppers in the later stage. In production, tiller fertilizer should be applied in time 5-7 days after early rice planting (4-5 days after late rice planting), urea 20-25 jin per mu and herbicides.

For the shallow Shatin with poor water and fertility, in order to prevent the loss of fertilizer and improve the utilization rate, it is recommended to use urea 15 jin and compound fertilizer 20 jin per mu.

For the fields with insufficient basic seedlings after planting, in order to promote early growth and rapid development, the amount of fertilizer should be increased appropriately, and 15% paclobutrazol 30kg 40g and zinc fertilizer 1kg per mu should be added to promote early tillering.

Due to the large number of basic seedlings in the direct seeding field, the amount of fertilizer applied with a large number of elements should be 2030% more than that in the seedling throwing field.

⑵ reasonable drying field

Rice drying can promote soil permeability, dissipate toxic and harmful gases, enhance root activity, promote new roots, and control ineffective tillering. Its tillering control function is mainly to inhibit the absorption of fertilizer and water by rice. It is inevitable that nitrogen volatilization will occur and part of the fertilizer will be wasted, so drying the field should be reasonably grasped according to the soil texture and the growth of rice.

Shallow Shatin and other paddy fields with poor water and fertility conservation, easy to de-fertilize and early senescence, direct seeding fields should not be overweight and light, while fields with deep mud, excessive nitrogen fertilizer and prosperous growth can be exposed to the sun properly.

⑶ skillfully applies panicle fertilizer

After drying the rice field, panicle fertilizer should be applied in time to promote the development of young panicles. Panicle fertilizer should be applied before jointing, preferably at the first and second stages of young panicle differentiation, and about 20 jin of potassium chloride per mu (Shatian should be applied twice to reduce osmotic loss). Urea 8 kg 10 jin (45% compound fertilizer 20 kg 25 jin can be replaced by 45% compound fertilizer in shallow Shatin with poor water and fertilizer conservation). For easy lodging fields or varieties, 40 to 60 grams of Zheng's chemical rice can be mixed per mu to dwarf plants and enhance lodging resistance.

⑷ applies grain fertilizer depending on the situation.

In the 5-7 days before the break, the green of some leaf ears will fade, which will be too light, which is disadvantageous to the later filling and the maintenance of green leaves. At this time, it is necessary to apply urea 3 to 5 jin per mu to avoid premature senescence of leaves after heading.

⑸ foliar topdressing

During the jointing-filling stage, combined with the use of disease control and pest control drugs, rice can be mixed with foliar fertilizer for extra-root topdressing. Before breaking, 15% boron fertilizer 30-50 g and potassium dihydrogen phosphate 150 g / time can be sprayed per mu, and heading 50% 80% can be used again for a total of 2 times. After heading, 150 grams of potassium dihydrogen phosphate and 250 grams of urea were used per mu. Conditional areas can also cooperate with the promotion of brassin, cytokinins, amine fresh fat and other regulators and silicon-potassium foliar fertilizer.

Due to the difference of soil fertility level and texture in different places, the amount of fertilizer used is for reference only, and the amount of fertilizer should be adjusted reasonably according to the characteristics of local soil fertility, variety fertilizer requirement and target yield. There may be mistakes in the manuscript. You are welcome to discuss, criticize and correct them.