RESUMEN
Residual plastic film in soil destroys the soil structure and changes the normal transportation and distribution of water and nutrient. In this work, we compared experiments on soil containing residual plastic film with a control experiment to investigate how residual film affects the transportation and distribution of water and nitrate (NO3-) in wetted soil. The experiment used Mariotte bottle, water tube, and soil tank to test six levels of residual-film concentration varying from 0 to 720â¯kg/hm2 in the soil. The wetting front, soil water content, and nitrate concentrations were all measured, and the results showed that when the concentration of residual-film was less than 360â¯kg/hm2, more water and nitrate remained in the upper part of the wetted volume due to block of residual film. Excessive residues (>360â¯kg/hm2) resulted in obvious phenomenon of preferential flow, which increased the wetting distance, wetted volume, and water content in the lower part of the wetted volume and the concentration of nitrate at the boundary of the wetted volume. These results not only help us to understand the consequences of plastic-film-residues pollution in terms of water and nitrate movement, but also provide scientific support to the development and establishment of reasonable irrigation, fertilization and management systems for polluted farmland with differential mulch residual concentrations.
Asunto(s)
Agricultura , Monitoreo del Ambiente , Nitratos/análisis , Plásticos/análisis , Contaminantes del Suelo/análisis , Suelo/química , Contaminación Ambiental , Fertilizantes/análisis , Nitrógeno/análisis , Óxidos de Nitrógeno , Agua/análisisRESUMEN
Plastic film has become an important agriculture production material in recent years. Over the past three decades, the amount and application area of plastic film have increased steadily, and in 2014, which are 1.4 million tons and more than 180 million hm² respectively. It plays a key role for ensuring the supply of agricultural goods in China. Meanwhile, plastic film residual pollution becomes more and more serious, and in some regions, the amount of plastic film residues has reached over 250 kg/hm². In part of the Northwest region, soil structure of farmland has been destroyed by plastic film residues and then crop growth and farming operations were suppressed. It is recognized as a good choice to replace plastic film with biodegradable plastic film, an effective measure to solve the plastic film residue pollution. Now, it is in a critical stage of study and assessment of biodegradable plastic film in China and fortunately some biodegradable plastic films show effects in the production of potatoes, peanuts and tobacco. Overall, a series of challenges has still been faced by the biodegradable plastic film, mainly including improving the quality of biodegradable plastic products, such as tensile strength, flexibility, improving the controllability of rupture and degradation, enhancing the ability of increasing soil temperature and preserving soil moisture, and to satisfy the demand of crops production with mulching. In addition, it is essential to reduce the cost of the biodegradable film and promote the application of biodegradable film on large-scale. With the development of biodegradable plastic technology and agricultural production environment, the application of the biodegradable film will have a good future.