Temporal variation and spatial distribution of the root system of corn in a soil profile

The development of the root system of corn in soil profile is an indispensable parameter for the estimation of corn growth.The distribution of the root system can be used to evaluate the influence of climate on vegetative growth.This constitutes a creative scientific management and development system of water-saving agriculture.In the Gucheng Agro-meteorological Field Experimental Station of Chinese Academy of Meteorological Sciences,root length,root areal reach,root depth and root dry-weight of Tunyu 46 corn were observed using clod sampling method and installed underground surface glazing.Observation data on the spatial and tem-poral distribution characters of the root system in the soil profile were then analyzed.The results show that root dry-weight and root length decrease with increasing soil depth.In spin silk period,root length in the 40 cm,80 cm,and 120 cm soil layer is respectively 51.5%,76.2% and 90.5% of total root length.Root length to total root length ratio in various soil layers is similar for both spin silk and late milk maturity periods.Root thickness decreases in upper soil layer and increases in lower soil layer with increasing soil depth.In the late milk maturity period,root depth may reach 230 cm,and total combined root length can reach 8.288 km·m?2.Clearly thus,root depth and the total root length of Tunyu 46 are larger than those of other corn varieties.Root distribution charac-teristics show that the root system of Tunyu 46 is a lot more developed and robust for defending drought.Based on data obtained from the installed glazing,root depth is much deeper than that observed far from the glazing.