Spatial Variation and Improving Measures of the Utilization Efficiency of Accumulated Temperature

Abstract

ABSTRACTTemperature, especially accumulated temperature, is very important for agricultural productivity. Fully using the heat resource is important for increasing yields of maize (Zea maysL.). To understand spatial variation and improving measures of the utilization efficiency of accumulated temperature, we conducted experiments during the period of 2007 to 2012 at 52 locations in the north spring maize (NM) and Huanghuaihai summer maize (HM) regions of China. We found that the utilization efficiency of ≥10°C accumulated temperature for the whole year (hereafter, UE10y) and residual accumulated temperature for maize were highly correlated with latitude. The UE10y increased by 1.3 and 1.4% for 1° increases in latitude moving northward for NM and HM, respectively. In NM, the variation in residual accumulated temperature was large across the experiment locations, ranging from 76 to 1655°C degree days. To make full use of the heat resource, we studied the effects of delaying harvest, optimum sowing date, and planting‐adapted cultivars on the UE10y and maize yield. We found that, compared to conventional harvest time, delaying harvest significantly increased UE10y and maize yield. For different sowing dates, maize yield increased significantly with increasing UE10y in the northern area of NM but not in the southern area of NM. Regarding the use of different planting‐adapted cultivars, yield potentials of the longest maturity cultivars and cultivars adapted to mechanical grain harvest averaged 17.12 and 14.39 Mg ha–1in NM, which were 27.9 and 7.5% higher than the yield potential of traditional cultivars, respectively.