Energy/water budgets and productivity of the typical croplands irrigated with groundwater and surface water in the North China Plain

• Published in: Agricultural and forest meteorology 2013-11, Vol.181, p.133-142
• Main Authors: Shen, Yanjun, Zhang, Yucui, R. Scanlon, Bridget, Lei, Huimin, Yang, Dawen, Yang, Fan
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; Carbon; Carbon budget; carbon sinks; China; corn; crop yield; Cropping system; Cropping systems. Cultivation. Soil tillage; Crops; double cropping; eddy covariance; energy; Energy and water balance; Evapotranspiration; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; groundwater; irrigated farming; Irrigation; Maize; North China Plain; Rivers; Seasons; Surface water; Triticum aestivum; Water balance and requirements. Evapotranspiration; water table; Water use efficiency; wet season; Wheat; winter wheat; Yellow River; Zea mays
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/j.agrformet.2013.07.013

•Water, energy and CO2 fluxes over irrigated lands were observed for 4 years in the NCP.•Water, energy, and carbon balances were analyzed at seasonal and interannual scales.•Water deficit in wheat season and surplus in maize season were quantified.•Shifting wheat–maize double cropping to maize single can lead to a more sustainable future. Although irrigation has markedly increased agricultural productivity in the North China Plain, it has reduced groundwater levels by up to 0.8myr−1 and dried up the Yellow River for extended times since the 1970s. The objective of this study was to compare water, energy, and carbon fluxes in regions irrigated with groundwater and surface water (Yellow River) using almost four years of eddy covariance data from agricultural stations in Luancheng (water table depth: ∼42m) and Weishan (near Yellow River, water table depth: 1–3m). Irrigation is mostly restricted to winter wheat as summer maize grows during the rainy season. Mean annual ET was 693mmyr−1 for Luancheng site, which is higher than Weishan site (648mm, ignore partial years). About ∼390–480mm of ET occurred during the wheat season (from early October to next early June, about 247 days), 230–300mm in the maize season (from early June to late September, about 107 days). Annual crop yields were ∼6864kg/ha in the two regions. Annual water use efficiencies ranged from 4 to 6gCO2kg−1H2O. Water use efficiencies were higher for maize than for wheat. Annual cropland carbon budget (CCB) was 230–280gCm−2yr−1 at the two sites and suggested a weak carbon sink. Irrigation compensated for seasonal and inter-annual variability in precipitation. Shifting the cropping pattern from wheat–maize double crops to a single crop of maize could significantly reduce water withdrawal and lead to a more sustainable use of water resource in this region.