Turfgrass intercropping prevents non-point source pollution in sweet pepper production

Greenhouse vegetable production is one of the major non-point source (NPS) pollution due to its high fertilizer input and low nutrient use efficiency. Excessive salt and nutrient accumulation in the topsoil is responsible for the NPS pollution in greenhouse vegetable production. This study was designed to investigate the effects of turfgrass intercropping on NPS pollution in greenhouse sweet pepper production. The results showed that the pollution discharges via both surface runoff and leaching were significantly reduced by turfgrass intercropping. The reduction of pollution was associated with the capacity of turfgrass species in the absorption and accumulation of salts and nitrate. Paspalum vaginatum with preferential accumulations of nitrate and salts performed best results in the alleviation of soil salinity and NPS pollution. Paspalum vaginatum-intercropping decreased 51.2% of nitrate and 23.9% of electrical conductivity in the soil, 71.8% of total nitrogen, 54.9% of ammonia-nitrogen, 67.0% of nitrate-nitrogen, 68.8% of total phosphorus, 68.2% of phosphates, and 73.2% of potassium in the surface runoff, and 64.1% of total nitrogen, 53.4% of ammonia-nitrogen, 67.0% of nitrate-nitrogen, 44.3% of total phosphorus, 54.8% of phosphates, and 32.9% of potassium in the leachate. These results indicated that Paspalum vaginatum-intercropping could be a clean and sustainable solution to prevent NPS pollution in greenhouse vegetable production.