Effects of tillage methods on photosynthetic performance of different functional leaf groups of summer maize in coastal saline-alkali farmland

This study aims to determine the changes in the photosynthetic performance of leaves at different leaf positions and their correlation and to screen out the basic tillage methods suitable for improving the yield. The decrease in soil salt content significantly improved the PSII performance index and quantum yield for electron transport of the bottom leaf group, synergistically enhanced the photosynthetic performance of summer maize leaves (especially the bottom leaf group), and enhanced the correlation between the bottom, middle (including the ear leaf), and upper leaf groups. Under subsoiling tillage conditions, the bottom leaves could produce more carbohydrates to meet the normal growth of the root system, promote the photosynthesis of the middle leaf group at the ear position, and increase the nutrient output of the upper leaf group to the female ear in the middle and later stages of maize aging.