Effects on Soil Fertility and Root Knot Nematode Disease of the Crops Planted in Summer after Vegetables were Harvested

Abstract

To explore the effects of continuous treatment by different catch crops on the soil nutrients and Meloidogyne incognita of continuous-cropped Cucumis sativus L. in the summer fallow, in this experiment, for the same land, the first summer fallow was designed for catch cropping of corn and the second summer fallow was designed for catch cropping of rape. The first summer fallow without corn planting and the second summer fallow without rape planting on the same land were taken as the control. After the corn and rape grew for 50 d, they were not pulled out, but turned into the soil and planted with continuous-cropped Cucumis sativus L. After corn-rape catch cropping, soil samples were taken to determine the basic physical and chemical indexes of the soil, detect the nutrient indexes of the soil when continuous-cropped Cucumis sativus L. was uprooted and investigate the incidence of Meloidogyne incognita, the number of Meloidogyne incognita in 100g soil and Cucumis sativus L. roots, and the disease index, calculate the control effect. The results showed that: after corn-rape catch cropping, the soil nutrient content of the continuous-cropped Cucumis sativus L. was changed, with the content of nitrogen, phosphorus, and potassium in the Cucumis sativus L. soil significantly reduced. Where, content of ammoniacal nitrogen, available phosphorus, and rapidly available potassium were significantly reduced by 10.17%, 12.00% and 12.22% compared to the control; content of trace elements and heavy metals in continuous-cropped Cucumis sativus L. soil was reduced, of which Ca and Mg were significantly reduced by 12.50% and 9.24% respectively, Fe, Mn, Cu, Zn , Na were significantly reduced by 15.79%, 8.06%, 17.91%, 13.30% and 16.85% respectively, Cd and Pb were significantly reduced by 26.92% and 25.14% respectively compared with the control. Catch cropping of the two reduced the field incidence rate of Meloidogyne incognita in continuous-cropped Cucumis sativus L., a significant decrease of 52.46% compared to the control, with the control effect up to 40.98%. At the same time, the number of Meloidogyne incognita in 100g Cucumis sativus L. soil and roots was reduced, which was significantly different from the control (p<0.05), and the Meloidogyne incognita decline rates reached 46.09% and 51.40%, respectively. Therefore, corn-rape catch cropping in summer fallow can improve soil nutrients of continuous-cropped Cucumis sativus L. and reduce the incidence of Cucumis sativus L. Meloidogyne incognita, which means important practical guiding significance, popularization and application value for improving soil nutrients of continuous-cropped Cucumis sativus L. and lowering incidence of Meloidogyne incognita.