Hydrologic Simulation of a Winter Wheat–Summer Maize Cropping System in an Irrigation District of the Lower Yellow River Basin, China

Lei Liu,Tiegang Liu,Chansheng He,Yi Luo,Jianqin Ma

doi:10.3390/w9010007

Abstract

Conflicts between water supply and water demand are intensifying in irrigation districts along the Lower Yellow River due to climate change and human activities. To ensure both adequate food supply and water resource sustainability in China, the Soil and Water Assessment Tool (SWAT) model was used to simulate the water balance and water use of agro-ecosystems in an irrigation district of the lower Yellow River Basin, China. Simulated average annual irrigation requirements decreased from 1969 to 2010. Irrigation requirements during the winter wheat season decreased owing to reduced reference evapotranspiration and increased precipitation. Annual evapotranspiration (ET) increased with increasing irrigation volume, and differences among irrigation scenarios were mainly due to ET of winter wheat. Water deficit typically occurred during winter wheat seasons with less precipitation. Field seepage and surface runoff tended to occur in years with high precipitation, particularly during the summer maize season under full irrigation and scheduled irrigation scenarios. Frequent and heavy irrigation did not always lead to high water use efficiency. To cope with limited water resources in this region, it is necessary to properly irrigate crops based on soil water content and take full advantage of precipitation and surface runoff during the summer maize season.

Highlights

Irrigation districts along the lower reaches of the Yellow River are primary grain production regions in China
The amount of water used for irrigation was influenced by crop water demand and precipitation
There was a negative relationship between precipitation and total irrigation (r = −0.65, p < 0.01 under Scenario 1)

Summary

Introduction

Irrigation districts along the lower reaches of the Yellow River are primary grain production regions in China. In 2000, total grain production in the lower Yellow River Basin was 3.583 × 107 t, which accounted for about 7.8% of China’s total grain production. Water from the Yellow River is a main source for irrigation in the lower Yellow River Basin. Under the influence of climate change and human activities, irrigation districts are facing serious shortages in the amount of water available from the Yellow River, further intensifying conflicts between water supply and water demand. Understanding the water cycle and water use in this important agricultural ecosystem is critical for ensuring adequate food supply and water resource sustainability in China.

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