Effects of Potassium Fertilizer on the Photosynthesis and Root Morphology of Trifolium repens L.cv.Haifa in Squaring Stage

PurposeTo study the effects of different potassium fertilizer levels on the photosynthesis, biomass and root morphology of Trifolium repens L.cv.Haifa in potted squaring stage.

MethodPot experiments of six potassium levels were carried out with 0, 60, 120, 180, 240, 300 kg/hm² (calculated as K₂SO₄) using T. repens L.cv.Haifa as the test material, and the photosynthetic parameters and root morphological indexes of the plants were measured.

Result(1) Potassium fertilizer application of 60 kg/hm² significantly increased the chlorophyll content of leaves (P< 0.05), which was 11.56% higher than the control, the application of potassium fertilizer was 120 kg/hm² significantly increased the photosynthetic rate, stomatal conductance and transpiration rate of the leaves (P< 0.05), which increased by 29.04%, 45.03% and 77.17%, respectively, compared with the control, and the intercellular carbon dioxide concentration of plant leaves was effectively reduced (P< 0.05), with a decrease of 2.24% compared with the control. (2) The application of potassium fertilizer 120 kg/hm² could significantly increase the root dry weight, shoot dry weight and root shoot ratio of the plants (P< 0.05), which increased by 25.55%, 17.31% and 7.25%, respectively, compared with the control. (3) Potassium application of 60 kg/hm² significantly increased the total root length and root activity of the plants (P< 0.05), which were 13.10% and 29.82% higher than the control, respectively; potassium fertilizer application of 120 kg/hm² could significantly increase the total root surface area, total root volume and soluble sugar content of root (P<0.05), respectively increasing by 33.10%, 20.00% and 31.00% compared with the control, but the influence of potassium fertilizer application on the average root diameter of T. repens L.cv.Haifa was not significant (P>0.05).

ConclusionIn the medium-potassium acidic soil, the recommended potassium fertilizer application level of the T. repens L.cv.Haifa is 60-120 kg/hm².