Fenoxaprop combined with urea improves photosynthesis, weed control, and yield of potato

Abstract This study aimed to evaluate the effects of combined application of fenoxaprop (fenoxaprop‐p‐ethyl) and urea on potato ( Solanum tuberosum L.) photosynthesis, weed control, and yield. The optimal sequence and dosage of the urea and fenoxaprop combination on potato production was investigated using different concentrations of urea (0, 1, 2, 4, and 8 g L −1 ) and fenoxaprop (0, 1.33, 2.66, 5.32, and 7.98 ml L −1 ) in a randomized block experiment. Potato plant photosynthesis levels, weed control efficacy, and potato yield were explored through the analysis of chlorophyll content index (CCI), photosynthetic parameters, weed‐related statistics, and polynomial regression. The results showed fenoxaprop stress not only reduced indices such as the CCI and net photosynthetic rate (Pn) but also decreased the activity, maximum photochemical efficiency, and quantum efficiency of Photosystem II, and the photochemical quenching coefficient. Urea at concentrations of 1–4 g L −1 antagonized the toxicity of fenoxaprop, whereas 8‐g L −1 urea aggravated herbicide toxicity. Compared with fenoxaprop treatment alone, the combination of 4‐g L −1 urea and 1.33‐ml L −1 fenoxaprop significantly increased the Pn of potato plants, weed control efficacy, and potato tuber yield by 36.12, 11.35, and 11%, respectively. Furthermore, treatment with urea first, followed by fenoxaprop, displayed greater efficacy in weed control than fenoxaprop followed by urea. Taken together, urea at concentrations of 1–4 g L −1 may alleviate the side effects of fenoxaprop on potato seedlings. Meanwhile, urea treatment (4 g L −1 ) followed by fenoxaprop (1.33 ml L −1 ) may be the optimal combination for potato production.