Key Technical Points of Soil Testing and Formula Fertilization for Rice

Based on the technical principles of soil testing and formula fertilization, and combined with the actual work of soil testing and formula fertilization in Pulandian City, 10 technical steps in the experimental process of soil testing and formula fertilization for rice were summarized.

1. Site selection: Select locally representative plots, and arrange experimental plots according to the areas of high-, medium-, and low-fertility farmland. The fertility status of the experimental site should be uniform and consistent, and the fertilization status of the previous crop should be as similar as possible.

2. Soil sampling and testing: Collect soil samples before plowing, using a "plum blossom shape" or "snake shape" to take 15-20 points, with a vertical depth of 0-15 cm. After the soil from the sampled points is fully mixed, use the "quartering method" to reduce it to 0.5-1.0 kg. After natural air-drying, test the soil samples. The main test indicators are available nitrogen, phosphorus, and potassium.

3. Variety selection: Select varieties with strong local resistance, high yield, and large application area. The varieties at each experimental point should be the same.

4. Seedling raising and transplanting: The seedling raising time should be the same. Raise seedlings in dry fields, sow sparsely to cultivate strong seedlings, and keep the types and amounts of base fertilizer and topdressing the same. The transplanting time should be the same, with a row spacing of 30 cm, a plant spacing of 13 cm, 3 plants per hill, and 17,000 hills per mu. The number of hills for each treatment should be the same.

5. Treatments and ridge blocking: Separate irrigation and separate drainage (with a central main channel) should be implemented between treatment plots. The ridges should be 0.5 m wide and 0.3 m high, compacted while being built along the edges. They must not be built low and narrow, so as to prevent water seepage, irrigation water, or excessive rainfall from flooding and flowing between plots and affecting the fertilizer effects among treatments. At the same time, set up a protective row of more than 4 m around the perimeter.

6. Application of farmyard manure and chemical fertilizer: The type and amount of farmyard manure should be consistent. After first building the plot ridges well, spread the farmyard manure into the plots and then plow, or apply it mixed with chemical fertilizer (with 2/3 of the nitrogen fertilizer reserved for topdressing).

7. Selection of irrigation conditions: Choose plots at the upper water head or where water lifting is convenient, mainly to prevent water from flowing between plots after farmers apply fertilizer.

8. Selection of chemical fertilizers: It is more convenient to use single-element chemical fertilizers in the experiment. The nitrogen, phosphorus, and potassium fertilizers used must be produced by the same manufacturer and have accurate nutrient contents.

9. Chemical fertilizer application: 1/3 of the total nitrogen fertilizer is mixed with the total phosphorus and potassium fertilizers and applied as a one-time base application, and the remaining 2/3 of the nitrogen fertilizer is topdressed separately at the tillering, jointing, and grain-filling stages of rice.

10. Separate harvesting and separate threshing: Conduct growth surveys during the growth period. At harvest, harvest and thresh each plot separately. When drying, pay attention to damage from chickens, birds, rats, and others to ensure the accuracy of plot yields.