Response of corn growth to climate warming in Tianshui City, Gansu Province

Global climate warming is having a significant impact on crop growth and development. Using information on air temperature and days of high temperature for 1968—2009 in Tianshui City, Gansu Province, the trends and characteristics of temperature in recent decades were analyzed for the region. This dataset was combined with that on corn growth for 1980—2005 (provided by Tianshui Institute of Agricultural Sciences) to perform statistical analysis and correlation analysis by the DPS system. Regression model equations were then constructed (by analyzing the relationships and trends between corn growth and temperature) to determine the response of corn to climate warming, followed by discussing the periods and appropriate belts for sowing the crop. This provided a theoretical basis for adjustments of planting structures and food security. The results indicated that annual average temperature in Tianshui City steadily increased at a rate of 0.469 °C·10a^-1. Positive trends were also noted in both the annual and seasonal average temperatures. Winter and spring temperatures obviously increased and days with annual temperatures above 30 °C and 35 °C gradually increased. While corn sowing and seedling operations delayed, sprouting, silking and maturity phenologies occurred early with warming temperatures. Sowing delayed by 2.7 d·a^-1, seedling extend by 0.1 d·10a^-1, and sprouting, silking and maturity occurred early by 3.3 d·10a-1, 4.4 d·10a-1 and 8.7 d·10a-1, respectively. At various stages of corn growth, the days from sowing to seedling delayed by 0.1 d·10a^-1, and seedling to sprouting, sprouting to silking and silking to maturity periods shortened by 3.4 d·10a^-1, 1.0 d·10a^-1 and 4.4 d·10a^-1, respectively. Corn growth accelerated, development occurred early and growth period shortened with increasing temperature. The average 1000-kernel weight of corn from 1980 to 2005 declined. Extreme high temperatures greatly impacted the growth period and 1000-kernel weight of corn in the region.