Water Consumption Patterns and Crop Coefficient Models for Drip-Irrigated Maize (Zea mays L.) with Plastic Mulching in Northeastern China

摘要

Our investigations into the water consumption patterns of maize (Zea mays L.) grown using surface drip irrigation with and without plastic mulching were based on three consecutive years (2014-2016) of field experiments in a typical area of northeastern China. We evaluated seasonal crop evapotranspiration (ETC) and how it was partitioned into soil evaporation (Es) and plant transpiration (Tp) during the season. Development of crop coefficient (Kc) prediction models was based on the growth day (GD) andleaf area index (LAI) of the crop, as well as the growing degree-days of air (GDDair) and soil (GDDS0u). Results showed that plastic mulching significantly reduced Es by 41.6 to 53.5 mm (p < 0.05) compared to not mulching, while it increased Tp by 23.2to 40.4 mm (p > 0.05) for spring-planted maize. While plastic mulching normally reduced ETC during the crop growth period, the change was not significant (p> 0.05). The three-year mean Kcfor the maize growth period declined by 3.0% under plastic mulching. The mean Kc was lowerfor the plastic mulching treatment than for the non-mulching treatment in both the early and late season, while it was slightly higher at mid-season. The three-year means of mid-season Kc (Kc.md) under plastic mulching and non-mulching were 1.06 and 1.05 lower, respectively, than the FAO-56 recommended value. In addition, the Kc estimation model based on GDDson achieved the best fitting accuracy. We recommend applying this GDDsou model to mulched drip irrigation of maize in northeastern China to obtain more accurate Kc estimation for optimizing and developing mulched drip irrigation in this region.