Technology of soil testing and formula fertilization for rice

I. Principles of Fertilization

1. The principles of determining yield by soil, determining fertilizer by yield, making up for deficiency, combining organic and inorganic, and balancing nitrogen, phosphorus and potassium should be mastered in rice soil testing and formula fertilization.

One is to measure the soil. Soil testing is the premise of soil testing formula fertilization, through the analysis and determination of soil nutrients, more accurately grasp the soil nutrient status and fertilizer performance, for formula fertilization to provide scientific basis; second, to prepare a good formula. Formula is the key to fertilization. On the basis of soil testing, according to soil characteristics, cultivation habits, crop fertilizer requirements, production level and climate conditions, combined with the yield level of the previous year, determine the target yield, and then according to the effect of fertilizer, put forward the most suitable amount and best proportion of nitrogen, phosphorus and potassium; third, fertilizer (fertilizer supply). According to the formula requirements, select high-quality simple fertilizer or special fertilizer, compound fertilizer, organic-inorganic compound fertilizer and other fertilizer varieties for scientific matching; fourth, fertilization mode. According to the soil type, crop growth characteristics and fertilizer demand law, formulate the corresponding fertilization model.

The fertilizer requirement of rice is 2.0~2.4 kg N, 0.9~1.4 kg P 2O 5 and 2.5~2.9 kg K 2O per 100 kg rice. Considering the factors of soil supply ability, fertilizer use efficiency and production level, the ratio of N, P and K should be about 1∶0.5∶0.9 under the condition of medium soil nutrients.

2. Apply enough base fertilizer. Base fertilizer is mainly organic fertilizer, supplemented by chemical fertilizer. Organic fertilizer belongs to complete fertilizer, containing various nutrients, in addition to nitrogen, phosphorus, potassium, sodium, magnesium, sulfur, calcium and various trace elements, application of organic fertilizer, can improve soil ventilation performance, improve fertilizer and water retention capacity, promote rice plant steady growth, thus conducive to rice to obtain high yield and good quality. Farm manure must choose decomposed farm manure.

3. Control nitrogen fertilizer. Appropriate application of nitrogen fertilizer can promote the growth of rice plants, but excessive application will not only cause more ineffective seedlings, turning green, lodging, disease and insect pests, but also lead to more empty grains, seed setting rate decreased, affecting rice yield. Therefore, attention should be paid to controlling the amount of nitrogen fertilizer during rice growth and development.

4. Pay attention to phosphorus and potassium fertilizer application. Phosphorus and potassium fertilizer is an element that should not be lacking in rice growth and development. It can enhance the activity of plants, promote nutrient synthesis and operation, strengthen photosynthesis, prolong the functional period of leaves, make grains full and plump, and improve yield. Phosphate fertilizer is suitable for basal fertilizer, potassium fertilizer is better for topdressing.

5. Appropriate supplement of trace elements.

The medium elements Si, Ca, Mg and S can strengthen the resistance of rice plant, improve the disease resistance of rice plant and promote the growth of rice. The practice shows that the application of sulfur fertilizer in sulfur deficient soil and silicon fertilizer in silicon deficient soil can significantly increase yield. Trace elements such as zinc and boron can improve the oxygen supply of rice roots, enhance the stress resistance of rice plants, improve the disease resistance of plants, promote the development of late roots, prolong the functional period of leaves and prevent premature senescence; can accelerate the development of flowers, increase the number of pollen, promote the germination of flowers and grains, which is conducive to improving the panicle rate of rice; can also promote the panicle size and grain number, improve the seed setting rate and grain fullness, thus increasing the rice yield.

II. Reference of Fertilization Model for High Yield Rice

The soil testing and formula fertilization model for rice yield of 450~550 kg/mu is as follows:

(i) Total amount of fertilizer and proportion

The ratio of N, P and K should be 1∶0.5∶0.9, and the total amount of N, P and K should be 10~13 kg, 5~7 kg and 8~12 kg respectively.

(ii) Fertilization scheme

1. Base fertilizer:

(1) Organic fertilizer: Generally, fresh green manure 1000~2000 kg or manure 500~1000 kg or commercial organic fertilizer 60~80 kg per mu shall be applied to early rice; rice straw of early rice can be returned to the field as organic fertilizer (the amount returned to the field is 1/2~2/3 of rice straw of early rice) or manure 500~1000 kg or commercial organic fertilizer 80~100 kg shall be applied per mu to late rice; manure 500~1000 kg or commercial organic fertilizer 80~100 kg shall be applied per mu to first season rice.

(2) Fertilizer: urea 7~9 kg, calcium magnesium phosphate 35~45 kg, potassium chloride 4~6 kg, zinc sulfate 1 kg.