White mulch film offers good light transmission and rapid temperature increase; black mulch film provides good heat retention and weed suppression but has poor light transmission; black and white striped mulch film balances temperature increase, light transmission, and weed suppression. Other colors include blue, yellow, red, purple, and silver-gray, each with different functions.
National standards require mulch film thickness not to be less than 0.01 mm, implemented since May 1, 2018. Thickened, high-strength mulch film often reaches a thickness of 0.015 mm or more to improve recyclability.
Mulch film should not be applied too early; it is recommended to wait until the crops have recovered from transplant shock before covering. The mulch film should not be tightly attached to the base of the stem; a gap of 5-8 cm in diameter should be left. Avoid covering the entire greenhouse floor to maintain soil aeration. The operating rows should be covered with organic matter such as straw, not mulch film.
Fully biodegradable mulch film is made primarily from biodegradable materials and can degrade into carbon dioxide and water under natural conditions. Its effective service life is categorized into several types, including less than 60 days, 60-90 days, 90-120 days, and more than 120 days. Its temperature-increasing and moisture-retaining properties are weaker than those of ordinary polyethylene mulch film.
