Enhancing Rice Production by Potassium Management: Recommended Reasonable Fertilization Strategies in Different Inherent Soil Productivity Levels for a Sustainable Rice Production System

Enhancing agricultural productivity with the minimum possible cost to the environment is crucial for sustainable agriculture development. The effective management of K fertilizer would reduce the pollution risk of fertilizer residue. The data from the 29 experimental sites for rice in Liaoning province were used to determine the effect of different K fertilizer management in increasing yield, K uptake, and potassium fertilizer contribution rates (FCR K ) for rice. The relationship among rice yield, biomass accumulation and plant K uptake, and recommended reasonable K fertilizer application rates in different inherent soil productivity levels were evaluated. The four treatments comprised no K fertilizer (K0), K fertilizer application of 60 kg ha −1 (K60), 120 kg ha −1 (K120), and 180 kg ha −1 (K180). The K120 treatment showed a significant yield increase (16.59%) compared to the K0 treatment in this study. The average K uptake of grain in the K60, K120 and K180 treatments was 23.1, 24.8 and 24.9 kg ha −1 , which was significantly higher by 12.67%, 20.77%, and 21.48% compared to the K0 treatment. The average K uptake of grain, straw and plant was highest in K180 (134.8 kg ha −1 ), followed by the K120 and K60. Additionally, the correlation between grain yield, biomass accumulation (y) and plant K uptake (x) showed a significant positive polynomial function. The equation was y = −0.406x 2 + 110.43x + 639.3 and y = −0.237x 2 + 135.3x + 3796.2, respectively. The FCR K followed the sequence as K180 < K60 < K120. Furthermore, the recommended K application rates in the 29 experimental sites were ranged from 92.8 to 134.5 kg ha −1 , and the corresponding theoretical yield of recommended K rate were ranged from 7371.5 to 11144.5, and with an average of 9297.5 kg ha −1 . Remarkably, the average recommended K rate in the four inherent soil productivity levels was 116.1, 111.2, 112.2 and 111.7 kg ha −1 and the corresponding average theoretical yield was 9966.1 kg ha −1 , 10158.8 kg ha −1 , 8373.2 kg ha −1 and 8881.9 kg ha −1 . The results of this study suggest that different inherent soil productivity levels have different K application rates and yield performance. This result somewhat strengthens the finding of this study that moderate K application is conducive to effectively improving the yield and to the enhancement of agricultural productivity, which is conducive to the sustainable environment.