Experimental validation of a new approach for rice fertiliser recommendations across smallholder farms in China

Abstract

Inappropriate fertiliser applications have caused a series of environmental problems and threaten the sustainable production of rice in China. The aim of this study was to evaluate the effects of a new approach, Nutrient Expert (NE), a nutrient decision support tool for rice (Oryza sativa L.). Experimental validation was carried out under field conditions from 2013 to 2015 at 211 sites in the main rice-growing regions of China. The results showed that, compared with current farmers’ fertiliser practices (FP) and soil testing (ST), the NE approach balanced nutrient application – decreased the nitrogen (N) and potassium (K) rates, and increased the phosphorus (P) rate – and improved grain yield, nutrient uptake, and fertiliser use efficiency. The NE treatment produced a 3.5–6.3% higher grain yield, 2.3–14.2% higher N, P, and K uptake in aboveground plant dry matter, and higher agronomic efficiency, apparent recovery efficiency (RE), and partial factor productivity of applied N and K, but not for P. In particular, the RE of the NE approach was greater by 12.2 and 8.4 percentage points for N, 3.7 and 2.9 percentage points for P, and 16.3 and 6.4 percentage points for K, compared with FP and ST respectively. The results obtained from field validation suggested that the NE approach could predict target yields; nutrient uptake of N, P, and K within specific ranges; and could be used as a tool to make fertiliser recommendation for rice in China.