Film mulched furrow-ridge water harvesting planting improves agronomic productivity and water use efficiency in Rainfed Areas

Film fully-mulched ridge–furrow (FMRF) water harvesting, film mulched conventional flat planting with one-half (FMCF) and two-thirds (FTMCF) has been widely adopted in Northern China. However, it is unclear whether sustainability are. An 8-year corn yield in these three systems was investigated at Zhenyuan of East Gansu in 2008 to 2015, and a 4-year location study with FMRF and FMCF, three corn hybrids, and three densities was conducted at Pengyang of South Ningxia from 2012 to 2015. The results indicated that FMRF with rain-harvesting efficiency of 65.7%–82.7% makes rainwater infiltrate deep soil and soil moisture double increase in furrow root-zone. The 8-year average grain yield increased by 22.7% in FMRF and 14.5% in FTMCF compared with FMCF. In the 4-year field trail, rainfall and its seasonal distribution highly impacted grain yield and water-use efficiency (WUE), but order of importance for grain yield and WUE increases were density > mulching type > hybrid. Grain yield and WUE increased by 20.0% and 3.45 kg ha−1 mm−1 and 12.0% and 2.97 kg ha-1 mm−1 from low to medium density and medium to high density; ET and grain yield and WUE increased simultaneously from low to medium density, however grain yield and WUE improved but ET changed slightly from medium to high. Soil water content of the 0–200 cm layer during growing season was always higher in FMRF than in FMCF, and ET did not differ. FMRF kept more than 50–90 mm soil water in the 0–200 cm during grain filling period. Neither higher grain yield in the FMRF depleted soil water, nor resulted in soil desiccation regardless of the year of precipitation. On the contrary, the FMRF kept much more water into soil layers at corn harvest, and negative effects to soil water balance were not observed. Thus, the package of FMRF combining with close planting and density tolerance hybrids is climate-smart technique for coping with droughts and ensuring corn yield in rainfed areas.