Effects of Different Potassium Application Rates on Maize Growth, Potassium Uptake and Utilization Under Straw Returning Conditions

In order to promote the scientific application of potassium fertilizer in maize production, four potassium fertilizer treatments were set up under the field production conditions of Daxijiang Farm under the Jiusan Management Bureau, with application rates of 0 kg·ha^-1（control, K0）, 60 kg·ha^-1（K1）, 75 kg·ha^-1（K2）, and 90 kg·ha^-1（K3）, respectively. The effects of different potassium fertilizer rates on the growth and development, yield, potassium fertilizer utilization efficiency, and economic benefits of corn soybean rotation under full straw return were studied. The results showed that the chlorophyll content of K2 was significantly higher than that of K0 through out the entire experimental period, and K1 was significantly higher than K0 from the large bell mouth stage to the filling stage; The stem thickness K2 was significantly higher than K0 from the jointing stage to the filling stage, and there is no significant difference between K1 and K0; There was no significant difference in the accumulation of dry matter between stem and leaf K1, K2, and K3, while the accumulation of dry matter in bracts and leaves K2 was significantly higher than K1. There was no significant difference in the accumulation of dry matter between K1 and K0; There was no significant difference in potassium accumulation in stems, leaves, axes, and grains among different potassium fertilizer application rates. The total potassium accumulation in K3 was significantly higher than that in K1 and K0; Different potassium application rates do not have a significant impact on maize yield, output value, and economic benefits. Increasing potassium application rates will significantly reduce the partial productivity of potassium fertilizer. In summary, the suitable amount of potassium fertilizer application under the condition of returning straw to the field in Daxijiang Farm is 60-75 kg·ha^-1.