Field validation of Nutrient Expert for middle season rice in China

The Nutrient Expert® (NE) field validation study continued for middle season rice in 2017. Field experiments were set up in the Anhui and Hubei Provinces of China to compare the NE-based fertilizer recommendation method to the recommendations based on soil testing (ST) and farmer’s practice (FP).

In Anhui, the average nitrogen, potassium, and phosphorus (N-P₂O₅-K₂O) recommendations were 154-54-105 kg/ha, 195-69-93 kg/ha, and 208-67-67 kg/ha for the NE-based, ST-based, and the FP plots, respectively. Rice grain yield in the NE treatment (8.9 t/ha) was not significantly different from the ST recommendation (8.9 t/ha) and FP treatment (8.2 t/ha). The average agronomic efficiency (AE) and partial factor productivity (PFP) values of N were 14.3 kg/kg and 57.7 kg/kg in the NE treatment. The average AE and PFP in the ST-based and FP treatments were 11.6 kg/kg and 46.0 kg/kg, and 7.5 kg/kg and 39.7 kg/kg, respectively.

In Hubei, the average N-P₂O₅-K₂O recommendation for the NE plots was 159-70-64 kg/ha, for the ST based plots was 158-62-90 kg/ha, while the FP plots received an average of 163-117-117 kg/ha. No significant grain yield difference was observed between the NE-based, ST-based and FP (7.4 t/ha, 7.6 t/ha, and 7.4 t/ha, respectively) nutrient applications. The AE and PFP values also did not show any significant difference among NE, ST, and FP treatments.

The on-farm trials suggest that the NE could be used as an effective tool for providing 4R-based site-specific fertilizer recommendations when the soil test is not available or timely.