Field validation of Nutrient Expert for single season rice in China

Nutrient Expert^® (NE) field validation continued for single-season rice in 2016 through 10 on-farm experiments in Jilin and Heilongjiang Provinces of China. The objective was to compare the NE-based fertilizer recommendation method with the traditional soil test-based fertilizer recommendation and farmer’s practice (FP) in terms of rice grain yield and nutrient use efficiency.

Each individual field site had a site-specific fertilizer rate based on the NE tool and soil test results. The average nutrient application rates in the NE-based plots was 143-55-84 kg N-P₂O₅-K₂O/ha, the soil test-based plots received an average of 148-52-88 kg/ha, while the FP plots had average application rates of 177-58-71 kg/ha in Heilongjiang Province. Average rice grain yield in the NE treatment (7.7 t/ha) was significantly higher than the soil test (7.3 t/ha) and FP treatments (6.9 t/ha). The average agronomic efficiency (AE) and partial factor productivity (PFP) values of N were 27.3 kg/kg and 54.2 kg/kg in the NE treatment, 24.7 kg/kg and 50.5 kg/kg in the soil test-based treatment, and 17.7 kg/kg and 39.2 kg/kg in the FP treatment.

For Jilin Province, the average N-P₂O₅-K₂O application rates were 162-64-107 kg/ha in the NE-based plots, 178-69-88 kg/ha in the soil test-based plots, and 185-74-91 kg/ha in the FP plots. There was no significant difference in rice grain yield between NE, soil test and FP treatments (9.9 t/ha, 9.9 t/ha and 9.7 t/ha). This was also reflected in the lack of difference in the AE and PFP values among the treatments. The NE tool provided fertilizer recommendation that improved yield and nutrient use efficiency in single season rice and could be very useful when soil testing is not available or timely.