High‐Yield Maize Production in Relation to Potassium Uptake Requirements in China

Understanding maize ( Zea mays L.) grain yield in relation to K uptake requirements is essential for devising optimized K fertilizer management practices and agricultural policies to increase grain yield for food security. A database comprising 953 measurements was created using 56 on‐farm and research station experiments during 2000 to 2012 in the North China Plain (NCP) to determine K uptake requirements and patterns of K accumulation pre‐ and post‐silking with different yield levels. The K requirement Mg −1 grain yield (K req. ) in the K = Opt. treatment was 15.0 kg, which was lower than 20.0 kg in the K > Opt. treatment. In the Optimal K treatment, average K req. values were 15.0, 14.8, 14.8, and 15.7 kg for grain yields ranging from <8.0, 8 to 10, 10 to 12, and >12.0 Mg ha −1 , respectively. The relative consistency of K req. values with increasing grain yield was mainly attributed to an offset in the increase in stover K (from 14.0 to 18.1 g kg −1 ), an increase in harvest index (HI) from 0.49 to 0.54, and the stability of grain K concentrations (about 3.2 g kg −1 ). Higher percentages for K accumulation at the post‐silking stage were observed with >12 Mg ha −1 (24%) and 10 to 12 Mg ha −1 (22%) compared to <10 Mg ha −1 (9%). In conclusion, maintaining adequate K supply and post‐silking K accumulation is essential for achieving high‐yield maize production.