Light and Heat Utilization Efficiency of Winter Wheat and Summer Maize in Northern Region of Henan Province

Based on the meteorological data and observed growth stage data of winter wheat and summer maize from 1983 to 2007 in northern region of Henan province,the conditions and variation trends of the crop primary phonological periods,light and heat resources during the whole growing periods and their utilization efficiency were statistically analyzed.The results showed that from 1983 to 2007 winter wheat got mature in advance significantly and the whole growing period decreased,with 4.9 days shortened every 10 years.For summer maize,the sowing date was in advance significantly and the whole growing period increased during the same period,with 4.0 days extended every 10 years.The temperature in this region increased remarkably,the effective accumulated temperature of winter wheat and summer maize during growth seasons increased significantly,at the rate of 7.8(℃·d)/a and 10.0(℃·d)/a,respectively.The global solar radiation during the growing period of winter wheat decreased significantly at the rate of 9.5 MJ/(m2·a),however,the trend was not statistically significant for summer maize.On average,the utilization efficiency of light and heat by winter wheat were 0.40% and 3.5 kg/(℃·d·ha),respectively,while for summer maize,the utilization efficiency of light and heat were 0.70% and 4.0 kg/(℃·d·ha) respectively,which were a little greater than those of winter wheat.From 1983 to 2007,the utilization efficiency of heat and light by winter wheat and summer maize both significantly increased.The increasing rates of heat utilization efficiency of wheat and maize were 0.7 kg/(℃·d·ha) and 0.6 kg/(℃·d·ha) every 10 years,and the increasing rates of light utilization efficiency of the two crops were 0.10% every 10 years.