Effect of potassium application rate on potassium absorption, distribution and yield of spring maize under different soil fertilities

Field experiments were conducted to study the effects of different potassium dosages on potassium absorption, distribution and yield of maize in high (Yushu City) and low (Gongzhuling City) fertility soils in Jilin Province. The results showed that potassium dosages of 83.3 kg(K2O)·hm^-2 and 113.9 kg(K₂O)·hm^-2 produced the highest maize yields while potassium dosages of 75.1 kg(K₂O)·hm^-2 and 103.1 kg(K₂O)·hm^-2 were most economic for Gongzhuling and Yushu, respectively. The highest and optimum economic yields for Gongzhuling respectively increased by 3.70% and 3.68% compared with Yushu. Potassium fertilizer application effectively improved maximum potassium absorption and dry matter accumulation rates of maize. It also caused maximum dry matter accumulation and potassium absorption rate to occur early during the growth season. When potassium dose exceeded 60 kg(K₂O)·hm^-2, maximum dry matter accumulation and potassium uptake rates in Gongzhuling were higher than those in Yushu. Appropriate dosage favored high translocation (rate and amount) of potassium from vegetative organs to grain and also increased grain nutrient efficiency ratio. Grain nutrient ratio in Yushu was less than that in Gongzhuling by 0.5% 1.7%. Except potassium fertilizer treatment of 60 kg(K₂O)·hm^-2, the agronomic efficiency of potassium, partial factor productivity of potassium and recovery efficiency of potassium in Gongzhuling were higher than those in Yushu by 7.3 8.8 kg·kg^-1, 4.4 8.3 kg·kg^-1, 1.6% 6.2%, respectively. To improve maize yield along with the benefits and use efficiency of potassium, the recommended optimum potassium dosages for Yushu (high soil fertility) and Gongzhuling (low soil fertility) areas were 75 kg(K₂O)·hm^-2 and 103 kg(K₂O)·hm^-2, respectively.