Fully biodegradable film to boost rainfed maize (Zea mays L.) production in semiarid Kenya: An environmentally friendly perspective

Abstract Conventional polyethylene plastic film mulching has been widely used, but its subsequent plastic residue pollution received widespread concern. Fully biodegradable film mulching is viewed as a potential substitution solution, however, it is generally thought not to be efficient as conventional plastic film mulching in field productivity and economic harvest. A two-year field experiment using a newly produced fully biodegradable film was conducted in semiarid Kenya in 2016 and 2017 respectively. Five treatments were designed as: 1) ridge-furrow mulching (RFM) with transparent plastic film (RFMT), 2) RFM with fully biodegradable film (RFMD), 3) RFM with black plastic film (RFMB), 4) RFM with grass straw (RFMG) and 5) traditional flat planting without mulching (FP) as CK. We found that RFMD achieved the similar evaporation-restricted, yield-increased and water-saving effectiveness as RFMT and RFMB did across two growing seasons. The RFMD lowered evaporation by 58.1 mm, while increasing grain yield by 70.16 %, above-ground biomass by 77.7 % and water use efficiency (in reference to grain yield) (WUEG) by 131.8 % in comparison with CK respectively. Furthermore, RFMD increased net economic income by 49.8 % in 2016 and 42.0 % in 2017 respectively relative to CK, as RFMT and RFMB did. It is noted that the degradable film used in this experiment is a non-polyethylene material and still can be maintained for 60 days in a fine physical state. Also, average soil temperature was significantly elevated by 1.6 °C in 2016 and 1.8 °C in 2017 in RFMD respectively, in comparison with CK, which was beneficial to crop growth and grain filling particularly in relatively cool long rainy season. Considering residual film pollution, the biodegradable film showed reliable advantages in environmental friendliness and field productivity. Therefore, it might be a promising farming solution to boost rainfed maize production and environmental sustainability in east African Plateau.