Nutrient management and balanced fertilization on main crops in Qinghai province


20 Feb 2010

2009 Annual Interpretive Summary

Nutrient Management and Balanced Fertilization in Qinghai, 2009

In 2009, experiments in Qinghai were mainly focused on finding the yield-limiting nutrient factors for spring wheat, rapeseed, rainfed potato, and forage grass in Xi’ning City, Huzhu County, and Chengduo County.

In spring wheat grown at Xining, N was the main nutrient limitation. Application of 150 kg N/ha produced 38% more grain yield compared to the N omission plot supplied with 90 kg P2O5/ha and 135 kg K2O/ha. Omission plots in rapeseed grown at Huzhu County also found N to be a larger yield-limiting factor compared to P. However, the balanced OPT of 125-75-135 kg N-P2O5-K2O/ha only produced 4% more yield than the farmer practice (FP) of applying 140-86-90 kg N-P2O5-K2O/ha. Agronomic efficiencies (AE) under this OPT were 6.3 kg seed increase/kg N and 3.8 kg seed increase/kg P2O5. In rainfed potato grown at Huzhu County the recommended NPK treatment of 214-86-193 kg N-P2O5-K2O/ha and the corresponding set of nutrient omission plots determined N to be most limiting followed by K, then P. The recommended treatment produced a 10% higher tuber yield compared to the farmer practice (FP) of applying 343-74-0 kg N-P2O5-K2O/ha. The AE values calculated under this recommendation were 38 kg tuber increase/kg N, 20 kg tuber increase/kg P2O5 and 28 kg tuber increase/kg K2O. Balanced use of NPK (450-210-120) in natural grassland in Chengduo County resulted in 359%, 246%, 9% more dry matter yield than the N, P, and K omission plots, respectively, and also generated an additional US$644/ha compared to the FP of zero fertilization. Data of dry matter accumulation and nutrient uptake at different crops stages were also investigated in this study. Qinghai-NMBF