Root Growth Ability And The Space-time Distribution Characteristics Of Different Soybean Varieties

The research was conducted in Heilongjiang Bayi Agricultural University experimental bases in 2014 and 2015, used sub-indeterminate podding habits drought-sensitive varieties heinong 48 and drought-tolerance hefeng 50, as well as used indeterminate podding habits drought-sensitive varieties hefeng 55 and drought-tolerance nenfeng 18 as materials. The two homemade cultivation device were adoped to sample with sub-layer and subsection in six fully expanded leaves period(V6), full flowering(R2), full pod stage(R4), beginning seed stage(R5), full seed stage(R6), beginning maturity(R7). The spatial and temporal distribution characteristics of root length, root surface area, root volume and root dry weight distribution were analysised. Revealling the role of spatial and temporal distribution of different soybean root to find the key point and spatial location of root growing. The main results are as follows:1. Root dry weight, root length, root surface area, root volume of different soybean varieties were incressed to culmination until R5 or R6 stage then decresed as time progresses.2. The tend of soybean nodule number increased firstly and then decreased in different varieties, emerged a maximum value at the stage of R6. In the vertical direction, the nodules were mainly distributed in 0~40 cm of soil depth, representing 86.64%~96.50% of the total., While the nodules in 0~5 cm and 20~25 cm layers higher than other levels The horizontal direction, both of which accounted for 44.33%~57.27% overall.Among them 0~5 cm layers decreased first and then rised, while were the opposite. in 20~25 cm of the soil.3. Soybean roots could break through the soil surpass 100 cm in the vertical direction. More than 100 cm of soil depth, the rates of root biomass accounted were 0.91%~5.97%. Different varieties of soybean root dry weight density, root length density, root surface area density and root volume density decreased with the increase of soil depth, but root diameter decreased then increased with increasing soil depth.4. The tend of the density of root dry weight density, root length density, root surface area density and root volume density decreased then increased along with distance from the main stem in the horizontal direction, however, the root diameter decreased with the level of the horizontal distance.5. In the horizontal and vertical cultivation device, root length are mainly concentrated in the range of root diameter from 0.15 to 0.3 mm, root surface area are mainly distributed from 0.15 to 0.3 mm and above 0.45 mm of root diameter range, and root volume are mainly distributed above 0.45 mm of root diameter range.6. The index between root and aboveground in any soybean varieties have highly significant positive correlation.In the vertical direction, the correlation coefficient betwwen root indexes and yield at R4 was higher than other growth stages. The correlation coefficient between root length density, root surface area density, root volume density and yield in 40~60 cm layer higher than other layers, and in 0~40 cm soil layers, an average diameter of root yield correlation coefficient higher than other layers, The correlation between dry weight density in 0~20 cm and yield was highest. While was related closely at R4 and R6 in the horizontal. Correlation coefficient between root length density, root surface area density, root volume density 20~25 cm and yield in 20~25 cm was highest, in 0~5 cm layers average diameter root and yield have the largest correlation coefficient.7. The sub-indeterminate podding habits drought-sensitive varieties hefeng50,which has advantage on root dry weight, root length, root surface area density and root volume, and gain the more yield in both cultivation device.