Chin J Plant Ecol ›› 2013, Vol. 37 ›› Issue (4): 365-372.DOI: 10.3724/SP.J.1258.2013.00036

• Research Articles • Previous Articles    

Optimization of root sampling sites and modeling root length density distribution for wheat and maize

WANG Yan-Zhe1,2,3,*(), SHAO Li-Wei1, LIU Xiu-Wei1,3, ZHANG Xiao-Yu1,3, ZHANG Xi-Ying1,**()   

  1. 1Key Laboratory of Agricultural Water Resources, Chinese Academy of Sciences; Hebei Key Laboratory of Water-Saving Agriculture, Institute of Genetics and Developmental Biology, Shijiazhuang 050021, China
    2College of Biology Science and Engineering, Hebei University of Economics and Business, Shijiazhuang 050061, China
    3University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2012-07-09 Accepted:2013-02-20 Online:2013-04-01 Published:2013-04-09
  • Contact: WANG Yan-Zhe,ZHANG Xi-Ying

Abstract:

Aims Our objectives were to optimize the positions for root sampling of winter wheat and maize and to simulate the distribution of root length density (RLD) throughout the root zone profile in the North China Plain.
Methods Soil cores were taken at different locations in fields of winter wheat and summer maize at the grain-fill stage, and results were compared to decide the positions for root sampling. The bulk density parameter was used to modify the Gerwitz and Page model to increase the accuracy in simulating the distribution of RLD throughout the soil profile.
Important findings There was a larger spatial difference in RLD in the 0-10 cm soil layer for winter wheat. The difference became smaller below the 10 cm soil layer. For the top 20 cm soil layer, RLD on the row was greater than that between two rows. However, below 20 cm, the situation was reversed, i.e., RLD between two rows was greater than that on the row, indicating the strong proliferation ability of the root system of winter wheat. For maize, RLD sampled at the stem was greater than that sampled 10 cm away from the stem, and much greater than that sampled 20 cm away from the stem for the 0-10 cm soil layer. Below the 10 cm soil layer, RLD was highest sampled 10 cm away from the stem. RLD sampled at the stem around the 30-50 cm soil layer was the lowest among the three positions. The results indicated that in the top soil layer, RLD immediately under the plants was the highest, and RLD decreased with increased distance away from the plant stem. However, with increased soil depth, root proliferation reduced the differences among locations. The high bulk density of soil pan around 10-30 cm significantly influenced the shape of the curve of RLD distribution along the soil profile. Introducing the bulk density parameter into the Gerwitz and Page model significantly reduced the errors of simulated and measured RLD throughout the root zone profile.

Key words: root distribution simulation, root sampling, Triticum aestivum, Zea mays