Partial Substitution of Chemical Fertilizer with Organic Manure Enhances Yield Attributes and Tuber Quality in Potato

Purpose Excessive application of chemical fertilizer leads to the problems of low yield and poor quality of potatoes in semi-arid areas. Therefore, the present study aimed to improve potato productivity in a semi-arid region by the partial substitution of organic fertilizers for chemical fertilizers. Methods The field trial was conducted to study the effects of different fertilizer treatments (CK1, no fertilization; CK2, urea 450 kg·ha −1 , calcium superphosphate 375 kg·ha −1 , potassium sulphate 525 kg·ha −1 (100% chemical fertilization); T1, 80% chemical fertilization + 3000 kg·ha −1 organic fertilization; T2, 80% chemical fertilization + 6000 kg·ha −1 organic fertilization; T3, 70% chemical fertilization + 3000 kg·ha −1 organic fertilization; and T4, 70% chemical fertilization + 6000 kg·ha −1 organic fertilization) on agronomic traits, photosynthetic characteristics, yield, and quality of potato. Results The findings showed that T2 significantly increased the plant height, stem thickness, and soil–plant analysis development (SPAD) value of potatoes. The net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) of T2 were significantly higher than that of the other treatments at the tuber expansion stage. In addition, higher yield, larger tubers, higher number of potatoes set per plant, and higher fertilizer contribution rate were found in T2 compared to other treatments. In T2, the yield reached 36,580 kg·ha −1 and 37,915 kg·ha −1 in 2018 and 2019, respectively. T2 significantly increased the contents of starch, vitamin C, and soluble protein in tubers but reduced the range of reducing sugar and nitrate compared to CK1 and CK2. Conclusions Thus, the application of 80% chemical fertilization + 6000 kg·ha −1 organic fertilization remarkably enhanced most agronomic and photosynthetic traits, which in turn improves potato growth, yield, and tuber quality, suggesting that 80% chemical fertilization + 6000 kg·ha −1 organic fertilization can be used as a reasonable fertilizer application pattern in semi-arid areas. Graphical abstract