Nitrogen and phosphorus emission-reduction method of rice water and fertilizer ecological coupling management

The invention discloses a nitrogen and phosphorus emission-reduction method of rice water and fertilizer ecological coupling management, which comprises a rice field water management and a rice field nutrient management. The water management of rice field adopts a time selective dry-wet alternate water-saving ecological irrigation mode, comprising the following steps: (1) after the rice is transplanted for 10-14 days, starting irrigation intermittently and irrigating the rice field to an original field surface water depth of 60-80mm; (2) irrigating until the water depth reaches the original field surface water depth when the field surface water declines and dries naturally to a water depth of 50-100 mm under the surface soil; (3) performing the step 2 repeatedly, stopping repeating the step 2 and maintaining the field surface water depth of 10-80 mm during the booting stage and flowering stage of rice in the repeating step 2 procedure; and (4) when the flowering stage is over, continuing to repeat the step 2