Abstract:

To investigate the optimization effect of organic fertilizer substitution for chemical fertilizers on yield and quality of potato, and to explore the optimum organic fertilizer substitution ratio for chemical fertilizer in potato production, which can provide the scientific basis for high-quality cultivation of potato in Jiangsu Province. The experiment used ‘Zhongshu 3’ as the test variety and set up five fertilization treatments under the condition of a total nitrogen application rate of 180 kg/hm², including 100% compound fertilizer (N100), 90% compound fertilizer + 10% organic fertilizer (T10), 80% compound fertilizer + 20% organic fertilizer (T20), 70% compound fertilizer + 30% organic fertilizer (T30), and 100% organic fertilizer treatment (T100). The results showed that: (1) the substitution of organic fertilizer significantly promoted the growth of potato plant height, with an increase of 6.12% to 15.82% compared to the N100 treatment, and the differences between the T30 and T100 treatments reached a significant level. Among all treatments, there were no significant differences in the emergence rate, the number of main stems and stem diameter. However, the T10 treatment exhibited the highest emergence rate, while the T30 treatment had the largest number of main stems and the thickest stem diameter. (2) Both the potato yield and weight per plant increased first and then decreased with the increasing substitution ratio of organic fertilizer. Compared to the N100 treatment, the yield increase ranged from 37.17% to 72.80%, and the increase in the weight per plant ranged from 14.00% to 28.27%. Specifically, the T30 treatment had the highest yield and weight per plant, reaching a significant difference compared to the N100 treatment. The number of tubers per plant increased linearly with the increase in the amount of organic fertilizer substitution, with an increase of 10.57% to 40.17% (P<0.05), while there was no significant difference in the rate of commodity potato. (3) The substitution of organic fertilizer significantly enhanced the crude protein content (4.09% to 18.57%) and reduced sugar content (3.75% to 14.71%), but the dry matter content decreased. There were no significant differences in starch and vitamin C content among the treatments, with the T30 treatment having the highest starch content and the T100 treatment having the highest vitamin C content. The results of this study indicated that the combined application of 70% compound fertilizer and 30% organic fertilizer can synergistically enhance the growth, yield and quality of potato, achieving a synergistic improvement of yield and quality. It can be used as an optimized fertilization strategy for green potato production in Jiangsu Province.

Key words: organic fertilizer substitution, potato, yield, quality, combined application