Nutrient Management and Optimized Fertilization on Wheat and Maize in Shanxi Province

On-farm experiments with summer maize at 11 farmer fields in Linfen, Shanxi Province, tested the hypothesis that maize yields, profit, nutrient uptake, and fertilizer efficiency can be improved through a fertilizer recommendation based on Nutrient Expert (NE). In this study, we evaluated the performance of NE management using 144-53-51 kg N-P₂O₅-K₂O/ha compared to prevailing farmer practices (FP) of applying 226-61-25 kg N-P₂O₅-K₂O/ha.

On average, NE plots obtained 8.9 t/ha grain yield and generated a net profit over fertilizer cost of USD 2,212/ha, which was similar to the 8.6 t/ha and USD 2,123/ha obtained with FP. However, NE management achieved significantly higher N use efficiency parameters such as N recovery efficiency (9.4%), partial productivity of N (62.6 kg/kg), and agronomic efficiency of N (5.9 kg/kg), than those with FP (i.e., 7.5%, 42.0 kg/kg, and 1.0 kg/kg). The NE recommendation, also used 36% less N compared to FP. Although the NE-based fertilizer recommendation increased grain yield and improved N use efficiency, the level of N use efficiency was still very low in NE plots. Further analyses with the ASI soil testing method indicated that the initial ammonium (NH₄-N) and nitrate (NO₃-N) in the topsoil before sowing was very high at 28.9 mg/L (69.4 kg NH₄-N/ha) and 22.3 mg/L (53.5 kg NO₃-N/ha), respectively.

This study demonstrated that N can be optimized with smaller rates since soil mineral N supplying capacity was very high at the site, but N use efficiency can be improved further. Shanxi-NMBF