Study and application of nutrient expert (NE) system for maize in wheat-maize rotation

Maize is one of the most important and highly efficiency C₄ crops in the world. Anhui is one of the major maize-producing provinces in China with a total planting area of 761,000 ha in 2010. But here the average maize yield is 4,100 kg/ha, which is 25% lower than the national average. Apart from climate, an important reason for low maize yields is unbalanced fertilization. The Nutrient Expert(R) (NE) system was introduced in this study to improve nutrient management in maize.

Field experiments were conducted in Bozhou and Lixin Counties of Anhui within wheat-maize fields from 2013 to 2014. Six field trials of optimum fertilization for maize and wheat were conducted, which included recommended fertilization according to the NE system (OPT_E), a treatment of optimum fertilization based on soil testing, and a farmer practice treatment.

Maize field trials in Lixin showed a remarkable response to treatments designed by the NE system. The ecological optimum fertilization treatment (OPT_E, 182-72-75 kg/ha of N-P₂O₅-K₂O) produced a maize yield of 8,347 kg/ha. Omission of N, P, K, or NPK resulted in 22%, 1.4%, 6.9%, and 24% less yield, respectively, compared to the OPT_E. Farmer practice (FP, 240-120-60 kg/ha of N-P₂O₅-K₂O) dropped yield to 7,440 kg/ha, which was 11% lower than the OPT_E. Pptimum fertilization from soil test (OPTs, 210-90-105 kg/ha of N-P₂O₅-K₂O) yielded 8,059 kg/ha or 0.6% less than the OPT_E. In wheat, the OPT_E (167-89-99 kg/ha of N-P₂O₅-K₂O) produced 7,525 kg/ha. Omission of N, P, K, or NPK lowered yield by 22%, 9.5%, 10%, and 26%, respectively. The FP (240-120-90 kg/ha of N-P₂O₅-K₂O) yielded 9.3% less than the OPT_E. Lastly, the OPTs (180-90-90 kg/ha of N-P₂O₅-K₂O) produced 4.1% more than the OPT_E.

In Bozhou, the OPT_E (143-48-94 kg/ha of N-P₂O₅-K₂O) produced 6,925 kg/ha of wheat. Omission of N, P, K, or NPK dropped yields to 5,475, 7,050, 7,075, and 5,375 kg/ha, respectively. The OPTs (165-60-90 kg/ha of N-P₂O₅-K₂O) yielded 2.1% more than the OPT_E. The FP (240-120-120 kg/ha of N-P₂O₅-K₂O) produced 7.6% less than the OPT_E. In maize, the OPT_E (182-72-75 kg/ha of N-P₂O₅-K₂O yielded 7,640 kg/ha. Omission of N, P, K, or NPK reduced yield by 18%, 2.8%, 6.5%, and 19%, respectively. Yield under the OPTs (210-90-105 kg/ha of N-P₂O₅-K₂O) was 7,696 kg/ha, or 0.7% higher than the OPT_E. The FP (240-120-60 kg/ha of N-P₂O₅-K₂O) yielded 9.5% less that the OPT_E treatment.