Effects of Wheat Cover Crop and Phosphorus Fertilizer Reduction on Growth and Soil Enzyme Activity in Continuously Cropped Cucumber（Cucumis sativus L.）
（College of Horticulture and Landscape Architecture，Northeast Agricultural University，Harbin 150030，Heilongjiang，China）
Abstract：Abstract：This study evaluates the impact of varying phosphorus fertilizer levels on the growth，yield，fruit quality of cucumbers，and soil enzyme activity following a wheat cover crop. A pot trial was conducted using cucumber（Cucumis sativus L.）with fi ve phosphorus application levels：P100（conventional application），P75（75% of conventional application），P50（50% of conventional application），P25（25% of conventional application），and P0（no application）. Results demonstrated that compared with no cover crop treatments，the wheat cover crop positively infl uenced stem diameter，total fresh biomass，total dry biomass，yield，sugar-acid ratio，soluble protein，and VC content while reducing nitrate levels and enhancing soil enzyme activity. Notably，in the wheat cover crop treatments，the P50 treatment yielded the highest production of 1.78 kg per plant，with peak values in stem diameter，total fresh biomass，and total dry biomass observed at 20、35 days post-transplanting. Soluble protein content was the highest in P25 treatment，while P50 treatment exhibited a hi gher VC content and sugar-acid ratio along with a lower nitrate level. Additionally，at 20、35 days after transplanting，urease，acid phosphatase，and alkaline phosphatase activities were significantly higher in P50 than P100. By 50 days after transplanting，sucrase activity in P25 and P50，and catalase activity in P0 and P50 were relatively high and signifi cantly exceeded those in P100. Thus，under wheat cover crop conditions，reducing phosphorus ferti lizer to 8.71 g per plant can effectively enhance cucumber growth，yield，fruit quality，and soil e nzyme activity，making it the optimal phosphorus application level for continuous cucumber cropping.
