Field validation of Nutrient Expert for early and late rice in China

Field validation of Nutrient Expert® (NE) fertilizer decision support tool in early and late rice systems in Jiangxi and Hunan Provinces continued in 2017. The objective was to test the NE-based fertilizer recommendation method (NE) against traditional soil testing (ST) and farmers' practice (FP). Field experiments were conducted on five and seven sites each in in Hunan and Jiangxi respectively in early rice and late rice.

In Hunan, the highest grain yields were observed for both early rice (6.9 t/ha, with application of 138-53-84 kg N-P₂O₅-K₂O/ha) and late rice (7.9 t/ha with 154-53-96 kg N-P₂O₅-K₂O/ha) in the NE-based treatment. These yields were significantly higher than those of ST (5.6 t/ha with 145-56-79 kg/ha for early rice, and 7.1 t/ha with 186-40-78 kg/ha for late rice) and FP (5.4 t/ha with 105-49-76 kg/ha for early rice, and 6.8 t/ha with 120-67-76 kg/ha for late rice). The net income from the NE-based recommendation increased by 24% and 26% for early rice, and 11% and 16% for late rice, as compared to FP and ST, respectively.

In Jiangxi, the NE treatment achieved higher yield, but without significant differences as compared to ST and FP treatment for both early and late rice. The NE, ST and FP treatments received 154-87-72, 144-71-120, and 190-89-180 kg N-P₂O₅-K₂O/ha for early rice, and 142-55-60, 176-64-133, and 216-100-231 kg N-P₂O₅-K₂O/ha for late rice, respectively. Net income in the NE plots increased by 9% and 11% for early rice, and 6% and 13% for late rice, over the FP and ST.

Results of both early and late rice trials indicated that NE can maintain or improve grain yields with less nitrogen (N) or less phosphorus (P) fertilizer inputs, and more balanced fertilizer application. Besides changing the rates, NE also recommends a second N application at a later stage of crop growth than FP for both early and late rice crops. The higher yield and profitability achieved by the NE-based fertilizer recommendation were due to the application of the right fertilizer source, at the right rate and time.