Field validation of Nutrient Expert for middle season rice in China

The Nutrient Expert^(R) (NE) for rice decision support system was first validated in middle-season rice in Hubei and Anhui in 2014. The objective was to test the NE-based fertilizer recommendation method as compared to soil testing and farmer’s practice (FP).

There were nine field validation experiments conducted in Hubei in 2014. Higher grain yield was observed under the NE treatment (8.8 t/ha) compared to FP (8.5 t/ha). Less overall fertilizer was applied under NE (132-65-64 kg N-P₂O₅-K₂O/ha) compared to FP (150-45-78 kg N-P₂O₅-K₂O/ha). Higher agronomic efficiency (AE) and partial factor productivity (PFP) for N were calculated for NE (21.5 kg/kg and 66.9 kg/kg, respectively) than for FP (16.2 kg/kg and 55.2 kg/kg). Soil test recommendation achieved 8.0 t/ha of grain yield with 180-60-90 kg N-P₂O₅-K₂O/ha, which resulted in lower N use efficiency parameters.

Ten field validation experiments on middle-season rice were conducted in Anhui. The NE treatment produced 8.7 t/ha of grain yield with 151-64-91 kg N-P₂O₅-K₂O/ha fertilizer input, which was nearly 1.0 t higher than FP (7.8 t/ha) with 150-55-77 kg N-P₂O₅-K₂O/ha. In contrast to FP, AE and PFP values for N (9.0 kg/kg, 37.6 kg/kg, respectively), were significantly higher under NE (15.6 kg/kg, 49.9 kg/kg). Although grain yield was similar under the soil test-based treatment (8.8 t/ha), lower N efficiency was found due to its recommendation for higher fertilizer input (191-70-93 kg N-P₂O₅-K₂O/ha).

Results from 2014 field validation on middle-season rice demonstrated that NE for Rice is a useful tool to improve N use efficiency while maintaining grain yield.