Effects of potassium fertilizer and straw on maize yield, potassium utilization efficiency and soil potassium balance

A three-year field experiment was conducted to evaluate the effects of straw combined with potassium fertilizer on maize yield, potassium utilization efficiency and soil potassium balance. The study consisted of two straw treatments (S1: straw returning; S0: no straw returning) and five K levels (0,30,60,90,120 kg K ha(-1)). The results showed that compared to S0, the maize yield and available K content in S1 increased by 2.9%similar to 6.2% and 19.3%similar to 37.4%. The average of agronomy efficiency and surplus rate in S1 were 7.3%similar to 35.4% and 24.8%similar to 84.7% higher than S0 respectively, but the recovery efficiency, partial factor productivity under S0 and S1 were statistically identical. When the surplus rate is 0, the amount of potassium fertilizer required and the corresponding yield to maintain the soil K balance in S1 were 87.9 kg ha(-1) and 12,424.6 kg ha(-1). Compared to S0, S1 can decrease potassium fertilizer application rate by 10.2% while increasing maize yield by 3.5%. Overall, straw return combined with potassium fertilizer can improve maize yield and soil available potassium content, it can also reduce chemical fertilizer input while increasing fertilizer utilization efficiency, and play a positive role in keeping soil K balance simultaneously.