Effects of Plough Layer Thickness on Soil Nutrients and Cucumber Root Development

Abstract

Perennial shallow tillage (PST) causes shallow plough layer thickness, deep plough sole layer thickness, and soil quality deterioration during intensive production. Cucumber is an economically important vegetable crop in the world, but it is generally sensitive to PST. Since little information is available regarding the response of soil quality and vegetable growth to PST, a greenhouse field experiment was conducted to investigate effects of plough layer (PL) thickness on soil nutrients, root characteristics, and crop productivity-related parameters in 2017 and 2018. The treatments considered were 10 (PL10), 20 (PL20), 30 (PL30), 40 (PL40), and 50 cm (PL50) PLs. Overall, soil nutrients were mainly accumulated in 0–30 cm soil layer (55.6%–93.1%), and generally exhibited lower levels under PL40 and PL50 than under other PL treatments. The shallow PL treatments (PL10 and PL20) showed lower root volume density, root diameter and root length density, while the deep PL treatments (PL40 and PL50) showed higher specific root length. The medium PL treatment (PL30) promoted root distribution in 0–30 cm soil layer as compared to other PL treatments. Moreover, the PL30 treatment generally showed the highest values in not only crop productivity-related parameters (i.e. plant biomass and fruit yield) but also soil quality index. In summary, PL thickness played an important role in determining soil nutrient level, root growth and thereby crop yields. The optimal PL thickness for cucumber production was 30-cm, which could benefit not only crop growth but also soil quality.