A preliminary study of the effects of plastic film-mulched raised beds on soil temperature and crop performance of early-sown short-season spring maize (Zea mays L.) in the North China Plain

To identify a strategy for earlier sowing and harvesting of spring maize (Zea mays L.) in an alternative maize-maize double cropping system, a 2-year field experiment was performed at Quzhou experimental station of China Agricultural University in 2014 and 2015. A short-season cultivar, Demeiya number 1 (KX7349), was used in the experiment. Soil temperature to 5 cm depth in the early crop growth stage, crop growth, crop yield, and water use of different treatments (plastic film-mulched raised bed (RF) and flat field without plastic film mulching (CK) in 2014; RF, plastic film-mulched flat field (FF), and CK in 2015) were measured or calculated and compared. Soil temperature in the film-mulched treatments was consistently higher than that in CK (1.6-3.5 degrees C in average) during the early growth stage. Crops in plastic film-mulched treatments used 214 fewer growing-degree days (GDDs) in 2014 and 262 fewer GDDs in 2015. In 2014, the RF treatment yielded 32.7% higher biomass than CK, although its 9.4% higher grain yield was not statistically significant. Also, RF used 17.9% less water and showed 33.1% higher water use efficiency (WUE) than CK. In 2015, RF and FF showed 56.2% and 49.5% higher yield, 15.0% and 4.5% lower water use (ET), and 63.4% and 75.7% higher WUE, respectively, than CK. RF markedly increased soil temperature in the early crop season, accelerated crop growth, reduced ET, and greatly increased crop yield and WUE. Compared with FF, RF had no obvious effect on crop growth rate, although soil temperature during the period between sowing and stem elongation was slightly increased. However, RF resulted in lower ET and higher WUE than FF. Effects of RF on soil water dynamics as well as its cost-effectiveness remain topics for further study.