Effects of Re-Used Plastic Film Mulching on Soil Temperature and Sunflower’s Emergence

Aiming at reducing agricultural pollution caused by plastic film, the study compared with new plastic film mulching and bare field, to investigating the effects of re-used plastic film mulching on soil temperatures, seed emergence and all seedlings period were studied in Hetao area, China. The results showed that, (1) compared with bare field, the soil temperature of re-used film mulching increased 1.3 similar to 4.0 degrees C and 0.7 similar to 1.8 degrees C separately in the highest and lowest temperature stage. The soil average temperature of upper soil layer (0 similar to 20 cm) increased 1.7 similar to 2.1 degrees C, and 1.3 similar to 2.0 degrees C lower than new film mulching. (2) Compared with bare field, Daily maximum and minimum temperatures of re-used film mulching were postponed about 1 hour, similar as new film mulching. (3) During emergence stage (7 days after sowing), accumulated temperature of re-used film mulching was 21.6 degrees C and 23.8 degrees C higher than that of bare field in depth of 5 cm and 10 cm. Compared with new film mulching, it was 12.4 degrees C and 10.0 degrees C lower in depth of 5 cm and 10 cm. (4) Mulching with re-used film could effectively shorten seed germination for 1-2 days and shorten all seedlings period for 2-3 days compared with bare field, and no difference with new film mulching.