How do farmers use agricultural plastic mulch film to prevent soil salinity?

Farmers use agricultural plastic mulch film to prevent soil salinity by covering the soil surface with the film. This practice reduces soil evaporation, thereby decreasing the amount of salt that is drawn to the surface through capillary action. The film also helps to retain soil moisture, which can dilute the salt concentration. Additionally, it can improve the efficiency of water and nutrient use by directing water directly to the plant roots, reducing the overall water needed and thus limiting the potential for salt buildup. By controlling the microclimate around the plant, plastic mulch film can also enhance the overall health of the crop, making it more resilient to soil salinity issues.