Abstract:
Conventional polyethylene plasticfilm mulching has been widely used, but its subsequent plastic residue pol-lution received widespread concern. Fully biodegradablefilm mulching is viewed as a potential substitutionsolution, however, it is generally thought not to be efficient as conventional plasticfilm mulching infieldproductivity and economic harvest. A two-yearfield experiment using a newly produced fully biodegradablefilmwas conducted in semiarid Kenya in 2016 and 2017 respectively. Five treatments were designed as: 1) ridge-furrow mulching (RFM) with transparent plasticfilm (RFMT), 2) RFM with fully biodegradablefilm (RFMD), 3)RFM with black plasticfilm (RFMB), 4) RFM with grass straw (RFMG) and 5) traditionalflat planting withoutmulching (FP) as CK. We found that RFMD achieved the similar evaporation-restricted, yield-increased andwater-saving effectiveness as RFMT and RFMB did across two growing seasons. The RFMD lowered evaporationby 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 in-creased net economic income by 49.8 % in 2016 and 42.0 % in 2017 respectively relative to CK, as RFMT andRFMB did. It is noted that the degradablefilm used in this experiment is a non-polyethylene material and stillcan be maintained for 60 days in afine physical state. Also, average soil temperature was significantly elevatedby 1.6 °C in 2016 and 1.8 °C in 2017 in RFMD respectively, in comparison with CK, which was beneficial to cropgrowth and grainfilling particularly in relatively cool long rainy season. Considering residualfilm pollution, thebiodegradablefilm showed reliable advantages in environmental friendliness andfield productivity. Therefore,it might be a promising farming solution to boost rainfed maize production and environmental sustainability ineast African Plateau.
