Method for near-natural long-term breeding of economic crops in wetland by using returned farmland

A method for breeding of economic crops in a wetland by using a returned farmland, comprising:

• selecting a site of the returned farmland and restoring a landform (S1);
• selecting a returned farmland paddy field adjacent to a natural wetland as a restoration plot, excavating a soil layer of the restoration plot, and piling a ridge on a peripheral edge of the restoration plot (S11);
• loosening a soil in a middle part of the restoration plot, and adding reed crushed matrix into the restoration plot and fully mixing with a loosened soil layer (S12);
• excavating a V-shaped water delivery ditch with a ditch depth of 50-70 centimeters in the restoration plot, and reserving water delivery outlets of 1-2 meters in a staggered way on the ridge adjacent to the water delivery ditch (S13);
• and
• planting reed rhizomes at a slope of the water delivery ditch (S14);
• performing germplasm improvement treatment of Euryale ferox by obtaining mature Euryale ferox seeds, and sequentially performing disinfection, low-temperature sand storage and seed soaking priming treatment on the mature Euryale ferox seeds (S2);
• controlling sowing of the Euryale ferox seeds by soaking the Euryale ferox seeds after the germplasm improvement treatment in a water body at 31-35° C. in a continuous illumination environment for 5-10 days;
• evenly sowing the Euryale ferox seeds that have undergone germplasm improvement treatment in the restoration plot, and keeping a seed coat break for downward cultivation;
• wherein a soil moisture content is kept at 90-100% at an initial stage of cultivation, and a depth of surface water accumulation is kept at 10-15 centimeters during a seedling development stage, and a depth of the surface water accumulation is kept at 70-80 centimeters during an adult plant development stage (S3);
• and
• performing the germplasm improvement and ecological conservation by collecting a portion of each of the Euryale ferox seeds, wherein 5% of the Euryale ferox seeds developed in a current year are reserved for near-natural sexual breeding in the restoration plot, and 10% of collected Euryale ferox seeds are subjected to the germplasm improvement treatment;
• pumping out a water body in the restoration plot to a surface water depth of 10-20 centimeters, and mixing Euryale ferox stems with a soil with a depth of 30-40 centimeters (S4).