Indica rice: Appropriate amount control when phosphorus deficiency fertilizer is not available at seedling stage

Indica rice: Appropriate amount control when phosphorus deficiency fertilizer is not available at seedling stage

Compared with the southern rice varieties, the northeast rice (japonica rice) has the habit of being cold-resistant and weak-resistant, has a high product potential, and has good quality and resistance. There are two periods of peak fertility in rice growth, one is the tillering period, and the other is the formation of young spikes to the booting stage. If the previous fertilizer supply is insufficient, there will be a decrease in tillering rate, thin leaves, yellow leaves, and a small number of effective panicles. When the supply of fertilizer is insufficient in the later period, there will be a reduction in the number of grains per panicle and a decrease in the weight of 1000 grains, which will seriously affect rice yield and quality. . Rice is the crop that absorbs most silicon, which is a feature of rice's absorption of nutrients.

The content of nitrogen in rice is 1% to 4% of dry weight. When nitrogen supply is sufficient, it not only promotes the growth of leaves at the tillering stage, but also promotes the growth of leaf sheaths, which has a good effect on the differentiation of spikelets and the increase of spikelet number. After spike differentiation, nitrogen still promoted leaf growth, but had adverse effects on the growth of leaf sheaths and stems. This is one of the important reasons why rice strains are under high nitrogen conditions and have poor lodging resistance and poor fruiting.

The effect of phosphorus on tillering is very obvious. Phosphorus deficiency at the seedling stage reduces the number of tillers by about 40%. Compared with nitrogen, phosphorus is more conducive to the increase of root weight and root length, and the combined application of phosphorus and nitrogen has better effects. Phosphorus in the rice body during the maturation process is mainly concentrated in the ear of rice and plays an important role in grain filling. Potassium can increase the absorption and utilization efficiency of nitrogen fertilizer and is very effective in reducing the number of black roots in each growth period. Plants with high potassium content have full grain, well-developed stalk mechanical structure, and strong anti-breaking force. Potassium also has a certain role in improving disease resistance. Soils with general pH > 6.5 are prone to zinc deficiency.

About two-thirds of the nutrients that rice has absorbed during its lifetime come from the soil, and about one-third come from fertilizers applied in the season.

The degree of rice dependence on soil is closely related to the level of soil fertility, and the higher fertility soil provides more nutrients. It can be seen that adding organic fertilizer to fertilize the soil and the importance of the combined application of nitrogen, phosphorus, and potassium fertilizers. The total amount of fertilization for medium yield rice fields in northeast China should be controlled at 10–17 kg/mu of nitrogen, 4–8 kg/mu of phosphorus pentoxide, and 3–8 kg/mu of potassium oxide, which is adjusted based on soil fertility and yield. General Mushi zinc sulfate 1 ~ 2kg. Phosphorus fertilizer can all be used as a basal fertilizer, 1/3 nitrogen and 2/3 potassium are applied as base fertilizer, and 2/3 nitrogen and 1/3 potassium are effective as top-dressing fertilizer. Fertilization methods are as follows:

Basal fertilizer: Organic fertilizers are mainly used, and phosphorus and some nitrogen and potassium in inorganic fertilizers are applied. Full-layer fertilization can be used (before or after the bubble field) and surface fertilizer method.

Top dressing: including tiller, panicle and pellet fertilizer. The tiller fertilizer is fertilizer applied 3 to 15 days after transplanting. The purpose is to promote the early growth of the tiller and achieve the ear number as soon as possible, which is particularly important for the northern cold rice region. The application of tillering fertilizer should be timely and appropriate, and it is also necessary to control ineffective delivery and prevent panicle differentiation or excess nitrogen before jointing. When the seedlings return to green, they should be used immediately after delivery.

Panicle fertilizer: It is further divided into flower-promoting fertilizer (six days before ear differentiation and four days after panicle differentiation, and three days before and after panicle differentiation are the most effective) and flower-fixing fertilizer (application from seven to fourteen days after ear differentiation).

Granular fertilizer: The main role is to maintain the appropriate level of nitrogen and higher photosynthetic rate of leaves, prevent root and leaf premature aging, so that the grain is full and full. If the plant does not have a significant lack of fertilizer, do not apply it blindly. Otherwise it will cause high nitrogen concentration and increase the consumption of carbohydrates.

(Jilin Academy of Agricultural Sciences)

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