The invention discloses a method for preventing and controlling
nitrogen and
phosphorus non-
point source pollution in farmland. The method comprises the steps of control over a source of the farmlandnon-
point source pollution, wherein the use amount of chemical
fertilizer and chemical
pesticide is reduced; 2, adoption of a farmland
ditch interception
system, wherein multiple longitudinal ditchesare excavated at equal intervals in the width direction of the farmland, multiple transverse ditches are excavated at equal intervals between every two adjacent longitudinal ditches, and bio-carbon
layers, soil
layers, bio-carbon
layers and soil layers are sequentially laid in the longitudinal ditches and the transverse ditches respectively from top to bottom; 3, adoption of a farmland
tail waterpurification interception
system, wherein a
water collection ditch communicated with the longitudinal ditches is formed in the
ridge of the farmland, and a water purification device is arranged belowthe lower end of the
water collection ditch and comprises a water collecting and sand setting tank, a
hydrolysis acidification tank, an anaerobic
sedimentation tank, an ecological purification tank and a clear
water pool which are communicated with one another in sequence. According to the method, not only can
residual nitrogen and
phosphorus elements in the farmland be efficiently and quickly removed, but also
discharge of
nitrogen and
phosphorus can be effectively controlled, and recycling of farmland drainage is achieved.