Impact of different sowing dates on green water footprint of maize in western Jilin Province

Abstract

Maize is the main crop in western Jilin Province. Water is a major constraint on maize production. How to effectively utilize the limited water resources to ensure maize production needs to be solved urgently. Formerly the irrigation water was as the key indicator to measure the water consumption during crop production. However, it neglected the consumption of soil water and water pollution. Water footprint connects the physical and virtual forms of water, which covers blue water, green water and gray water. It can truly reflect water demand and its sources. Recently, the most studies regarding water footprint are to investigate the water footprints of consumer products and products trade between regions or countries. Whereas researching the water footprint in the production process is little. According to the field experiments of maize, we explore the impact of different sowing dates on the source and consumption of green water, to determine the satisfactory degree of precipitation on maize growth and achieve the optimum matching relationship between sowing date and precipitation and temperature in maize growing season under the background of global warming. Results of 3鄄years experiments showed that either in the rainy year of 2005, or in the drought year of 2006 and extreme drought year of 2007, the green water consumption was the main water requirement in the maize production, which took the ratio over 98%. The green water footprint of maize production was mainly the effective precipitation in 2005 and soil water in 2006 and 2007. Effective precipitation in the green water footprint of the first three