Nutrient management and balanced fertilization in Inner Mongolia

Field experiments were conducted on irrigated potato, oil sunflower, and maize to document yield responses to applied nutrients, water management, and nutrient accumulation.

In flood-irrigated potato in Wuchuan County, application of 240-90-165 kg N-P₂O₅-K₂O/ha produced 37.5 t/ha, which was 33%, 17%, and 24% more than the N, P, and K omission plots, respectively. A similar sprinkler-irrigated trial produced 60.2 t/ha with 300-120-150 kg N-P₂O₅-K₂O/ha, which was 26%, 36%, and 27% more than the N, P, and K omission plots. Agronomic efficiency of P and K under sprinkler irrigation was almost double that for flood irrigation. Nitrogen recovery efficiency (REN) under sprinkler irrigation was also 14% higher than flood irrigation. A study on integrated management of N and water for potato at the Wuchuan Experimental Station found that drip irrigation could produce 9% more yield with 7% higher REN compared to flood irrigation. The study used a basal N recommendation of 240 kg N/ha and plants were sown on ridges. A comparison of ridge planting versus flat planting (under flood irrigation) found a 11% yield advantage for ridge planting, but only 2% higher REN.

Oil sunflower experiments in Hangjinhouqi County, Wuyuan County, and Huhehot City demonstrated highest seed yields under the optimum (OPT) treatments of 225-120-150, 225-75-135, and 225-75-150 kg N-P₂O₅-K₂O/ha, respectively. Average agronomic efficiencies for the OPT applied across the three sites were 2.3 kg seed/kg N, 6.4 kg seed/kg P₂O₅, and 2.8 kg seed/kg K₂O, and average recovery efficiencies for N, P, and K fertilizer were 31%, 15%, and 48%, respectively. About 4.8 kg N, 1.9 kg P₂O₅, and 9.0 kg K₂O was required to produce 100 kg sunflower seed.

A sprinkler-irrigated maize trial at Dalate County, Erdos, found 270-120-180 kg N-P₂O₅-K₂O/ha produced 28%, 19%, 10% more grain yield than the N, P, and K omission plots. Agronomic efficiencies were 12.4 kg seed/kg N, 19.8 kg seed/kg P₂O₅, and 7.6 kg seed/kg K₂O, while recovery efficiencies for N, P, and K fertilizer were 39%, 28%, and 59%, respectively.

Accumulation of biomass and nutrient uptake by irrigated potato, sunflower, and maize were also evaluated for future consideration regarding nutrient management in these crops. Inner Mongolia-NMBF