Phosphorus (P) in agricultural runoff may cause eutrophication of recipient waterbodies. As one of the key waterbodies to be protected in China, the Dianchi Lake is highly sensitive to pollution sources, so agricultural runoff of the region must be treate Phosphorus (P) in agricultural runoff may cause eutrophication of recipient waterbodies. As one of the key waterbodies to be protected in China, the Dianchi Lake is highly sensitive to pollution sources, so agricultural runoff of the region must be treate