Fertilization Effects and Recommended Fertilization Rates for Albic Soil-derived Paddy Fields in the Sanjiang Plain Region

Objective Rice is the largest food crop in China, but imbalanced fertilization can lead to reduced yield and quality. This study investigates the effects of different nitrogen (N), phosphorus (P), and potassium (K) application rates and their ratios on rice yield, aiming to guide rational fertilizer application in Albic soil-derived paddy fields of the Sanjiang Plain.

Methods A “3414” incomplete orthogonal regression design was implemented across three rice production farms to determine optimal fertilization effects of N, P, and K. Fertilizer efficiency models were fitted to analyze rice yield responses.

Results The N₂P₃K₂ treatment (165.00 N kg hm⁻², 202.50 P₂O₅ kg hm⁻², 150.00 K₂O kg hm⁻²) achieved the highest average stem-leaf yield, while N₂P₂K₂ (165.00 N kg hm⁻², 135.00 P₂O₅ kg hm⁻², 150.00 K₂O kg hm⁻²) produced the maximum grain yield. Single-factor effect modeling revealed economic optimal rates of 185.97/167.98 N kg hm⁻² for nitrogen, 79.43/68.46 P₂O₅ kg hm⁻² for phosphorus, and 161.17/116.18 K₂O kg hm⁻² for potassium to attain maximum economic returns and yield. Dual-factor interaction modeling identified peak yield at 247.50 N kg hm⁻² and 135.00 P₂O₅ kg hm⁻² (N-P), 165.00 N kg hm⁻² and 225.00 K₂O kg hm⁻² (N-K), and 82.50 P₂O₅ kg hm⁻² and 75.00 K₂O kg hm⁻² (P-K). Tri-factor composite modeling determined maximum yield fertilization at 164.20 N kg hm⁻², 81.90 P₂O₅ kg hm⁻² and 132.21 K₂O kg hm⁻², with economic optimal rates of 153.74 N kg hm⁻², 78.59 P₂O₅ kg hm⁻² and 130.81 K₂O kg hm⁻².

Conclusion Recommended fertilization rates for Albic soil-derived paddy fields in Sanjiang Plain are 153.74 N kg hm⁻², 78.59 P₂O₅ kg hm⁻², and 130.81 K₂O kg hm⁻², with an optimal NPK ratio of 42.34% N : 21.64% P₂O₅ : 36.02% K₂O, achieving an expected yield of 9,358 kg hm⁻².