Studies of spring wheat yield response to fertilizers in a model field experiment with four different levels of mobile phosphorus content (P₂O₅ 70–117–200–393 mg kg^–1) of Luvisol loamy sand soil contaminated with ¹³⁷Cs and ⁹⁰Sr radionuclides had been conducted in 2005–2007 in the Gomel region of Belarus. The increase of phosphorus content in the studied diapason was accompanied by the grain yield enhancement in the best fertilized treatment from 3.8 to 6.9 t ha^–1. The efficiency of N_{60–90–110} nitrogen fertilizer and K₂O_{90–120–180} potassium fertilizer positively correlated with all studied levels of phosphorus content in soil. The grain yield response per 1 kg of P₂O₅ applied was highest (10.5 kg) at the 3rd level of soil P supply and was reduced by 57% at the 4th level of phosphorus content in soil.

The protein and gluten contents of wheat grain significantly increased with the rise of N-fertilizer rates on all studied levels of soil P content. The highest protein and gluten contents in grain have been observed at the 3rd level of phosphorus supply, while the protein output per hectare continued increasing up to P content in soil ≈ P₂O₅ 400 mg kg^–1.

The combined effect of increasing the content of mobile P in soil with balanced fertilization (N_90–110P₆₀K_120–180) provided the wheat grain yield increment up to 3 times simultaneously with a reduction by a factor of 2 of the radionuclides ¹³⁷Cs and ⁹⁰Sr transfer from soil to grain. The efficiency of the test fertilizers increased depending on soil supply with mobile phosphorus, resulting in a net return for food-grade grain of 89 and 227 € ha^–1 at the 1st and the 4th levels of soil P content, respectively.

Keywords: soil, phosphorus, spring wheat, yield, protein, radionuclides 137Cs and 90Sr