How to measure soil fertility in wheat

Soil testing and formula fertilization is based on the difference between the crop fertilizer requirement and soil fertility, calculating the amount of fertilizer to achieve the target yield, and achieving nutrient balance between crops and soil. The formula is: the amount of fertilizer applied (kg/mu) = (the amount of nutrients (kg/mu) required for the planned yield (kg/mu)) ÷ (fertilizer nutrient content (%) × fertilizer utilization rate (%) ). Take the application of nitrogen fertilizer in winter wheat as an example: the soil was measured before the sowing of wheat, and the content of alkali nitrogen (N) in the 0-20 cm layer was 35-40 mg/kg. It is planned to produce 400 kilograms per mu. It is planned to use the "20-26-9" Meisheng wheat special fertilizer as the base fertilizer and the "32-0-8" type as the top dressing. The amount of fertilizer can be obtained as follows: for every 100 kilograms of wheat grain produced Absorption of nitrogen (N) 3 kg, after investigation, the local application of nitrogen fertilizer, normal phosphorus and potassium production of about 200 kg per mu. The local nitrogen fertilizer utilization rate is about 35%, and the reasonable distribution of wheat nitrogen fertilizer should be bottom and topdressing. 1. The required nutrient content of planned output = 3 × 400 ÷ 100 = 12 kg / mu; 2. Soil nitrogen supply (N): comprehensively consider the content of alkali nitrogen and the yield of no nitrogen fertilizer, which is 6 kg/mu; 3, need to be supplemented by fertilization of nitrogen (N) = (12-6) ÷ 35% = 17 kg / mu; 4, the bottom, topdressing half, that is, 17 ÷ 2 = 8.5 kg / acre; 5, the bottom fertilizer with "20- 26-9" type, the amount of 8.5 ÷ 20% = 42.5 kg / mu; the "32-0-8" type of topdressing, the amount of 8.5 ÷ 32% = 26.6 kg / mu, can meet the yield of 400 kg of wheat per mu Nitrogen supply and demand balance. At the same time, the phosphorus supply (P2O5) 11.05 kg, potassium (K2O) 8 kg, the application ratio of NPK is 1:0.65:0.35, in line with the Ministry of Agriculture issued the Beijing, Tianjin, winter wheat pattern cultivation three factors input ratio of 1 The requirement of 0.6 to 0.7:0.3 to 0.4 is also close to the actual production. Not only does it fully reflect the nutritional balance between nitrogen, phosphorus and potassium, but also all the phosphate fertilizers are applied at the bottom, and most of the potassium fertilizers are applied at the bottom and a few are applied. The combined application of these two formula fertilizers on wheat fully demonstrates that Meisheng compound fertilizer is the carrier of balanced fertilization.
Excerpt from: Hebei Farmers Daily

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