Abstract: Long-term and mechanical shallow tillage in highly intensive cultivation mode causes shallower plough layer, deeper plough sole layer , soil quality deterioration and other problems. In this study, the total soil layer was designed to be 50 cm, and plough layer were 10 cm (PL10), 20 cm (PL20), 30 cm (PL30), 40 cm (PL40) and 50 cm (PL50). The photosynthetic, fluorescence, root and plant growth-related parameters were measured in 2017 and 2018 years. The results showed that the shallower plough layer (PL10 and PL20) significantly increased the transpiration rate (T_r) and initial fluorescence value (F_o) of leaf, and significantly increased activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), and malondialdehyde (MDA) content in roots. The middle plough layer (PL30) significantly increased the relative growth rate of plant height (RGH-PH) and stem volume (RGH-SV), improved the net photosynthetic rate (P_n), maximum fluorescence value (F_m), light energy conversion rate (F_v/F_m) and photochemical quenching coefficient (qP) of the leaves, and significantly enhanced the root activity (RA), and proline (Pro), soluble sugar (SS) , soluble protein (SP) contents. The fruit yields (FY) of PL10 and PL20 were higher than those of the other treatments in early harvesting period, and lower than the others in middle and late harvesting period. Moreover, the fruit yield in the deeper plough layers (PL40 and PL50) were opposite to those of the shallower plough layers, PL30 had the highest total fruit yield in two cropping years. Through principal component analysis, the middle plough layer (PL30) and the deeper plough layer (PL50) were significantly different from other treatments. Combining plant growth and root characteristics, plough layer 30 cm was beneficial to the growth and development of cucumber with shallow root system.

Key words: plough layer, Cucumis sativus L. relative growth rate, photosynthetic fluorescence parameter, root