Appropriate water and fertilizer supply enhanced yield by promoting photosynthesis and growth of strawberries

The supply of water and fertilizer influences the growth and photosynthesis of strawberries, thereby affecting the yield. To determine the optimal combination of irrigation and fertilizer, an experiment was conducted over two years in 2019 and 2020. The experiment included four irrigation levels (I1: 100 % ETc, I2: 85 % ETc, I3: 70 % ETc, I4: 55 % ETc) and three fertilization levels (F1: 120 % F-0, F2: 100 % F-0, F3: 80 % F-0), forming a total of 12 treatments, where F-0 represents the exact value determined using the target yield method. Irrigation significantly affected on all growth indicators at flowering and fruit setting (F) and harvesting (H) stages in 2019, and the interaction of irrigation and fertilization was significant on photosynthetic rate (Pn) at seedling (S) stage (S-Pn) and the final fruit dry matter accumulation (FDM) in both study seasons. I1F1 achieved the highest S-Pn, while I2 showed significant promotion on FDM, with its maximum value of I2F1 in 2019 and I2F2 in 2020. F2 exhibited significant advantages on root dry weight (RDW) at H stage (H-RDW), with I3F2 and I4F2 performing the best. Moreover, I1F1 and I2F1 exhibited significantly promotion in stomatal conductance (Gs) at S stage (S-Gs). Based on correlation and path analysis, six indicators affecting yield formation were identified (S-RDW, S-Pn, F-CHll, F-Pn, H-CHll, FDM), with FDM having the greatest direct effect on yield (Y). A comprehensive evaluation system was constructed by considering the growth process and final yield, and Y obtained the highest combined weight (0.432 in 2019 and 0.476 in 2020). I2F2 and I3F1 were consistently ranked the top three in both years based on the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) evaluation model, indicating the combined irrigation and fertilizer of 70-85 % ETc with 100-120 % F-0 can achieve optimal yield by promoting photosynthesis and growth of strawberries. This study can provide a theoretical basis for scientific water and fertilizer management of strawberries in arid and semi-arid regions.