Soil analysis and selection of fertilizers for winter wheat: data decoding
Mineral food is the most expensive item in winter wheat growing technology. In the context of the constant increase in fertilizer prices, the introduction of “on the eye” or “as a neighbor” becomes an unacceptable luxury. The only reliable tool for cost optimization is agrochemical soil analysis. However, obtaining the protocol from the laboratory often puts the farmer at a standstill: the incomprehensible figures of milligrams per kilogram (mg / kg), the presence of chlorides and hidden deficiencies of trace elements require professional decoding. How to translate the results of the analysis into a specific purchase plan for ammonophos and selitra? This issue is heatedly discussed by agronomists before the start of the sowing campaign. If you visit
Content of the article:
For winter wheat, it is critical to provide a full phosphorus-potassium nutrition from autumn, as these elements are responsible for the development of the root system and the accumulation of sugars in the digestive node – the key to a successful wintering.
Phosphorus and potassium deficiency: replenishment strategy
If the analysis showed a low phosphorus content (less than 15-20 mg / kg by the Chirikov method), the wheat from autumn will “sit” in place, without forming side runs. In such a situation, it is necessary to introduce high doses of phosphorus-containing fertilizers (ammonophos, diamophos) for basic soil treatment.
Dose calculation: At low phosphorus levels, it is recommended to introduce at least 60-80 kg of the active substance P2O5 per hectare. Important: 80% of this norm should be placed under spawning or deep disking (to a depth of 15-20 cm), and the remaining 20% — locally when sowing with a seeder.
Potassium factor: If the soil is deficient in potassium, its introduction is mandatory. But remember that potassium fertilizers often contain chlorine. The increased content of chlorine in the soil (especially in saline areas) suppresses wheat yields. In this case, it is better to use chlorine-free forms – potassium sulfate.
Trace elements: zinc and magnesium
A slight zinc and magnesium deficiency detected by the analysis can become a “bottleneck” for your crop. Zinc is responsible for the synthesis of oxyns – growth hormones of the root system. Without zinc, even with an abundance of phosphorus, the roots will be weak.
Solution: Add zinc chelate to the backing mixture during seed digestion or the first spring herbicidal treatment. Magnesium is the central atom of the chlorophyll molecule. In its absence (especially on acidic soils), wheat will have a pale appearance. The intake of magnesium sulfate (5-10 kg / ha) along with nitrogen feeding in the spring will give an immediate visual effect and increase the efficiency of photosynthesis.
Seletra or carbamide: what to choose in spring?
The question of spring nitrogen feeding in the absence of phosphorus and potassium requires caution. If you give a shock dose of nitrogen in the spring against the background of phosphorus starvation, the plants will overgrow, form a fragile stem and are guaranteed to lie down in the first storm.
For the first spring feeding on frozen soil, ammonium selitra is ideal (nitrogen nitrate will immediately grow). If the spring is fast and dry, it is better to use carbamide (urea), but only in liquid form (CAS) or with sediment in the soil. Liquid nitrogen in conditions of moisture deficiency works 30-40% more effectively than granules.
Remember that the soil analysis sheet is your financial document. Proper calculation of doses on the basis of real figures allows to save up to 20% of the budget for agrochemistry, redistributing funds from unnecessary potassium to deficient phosphorus and zinc, which will eventually ensure an increase in yield of 5-7 cents per hectare.
