Journal of Ecology and Rural Environment ›› 2016, Vol. 32 ›› Issue (3): 397-403.doi: 10.11934/j.issn.1673-4831.2016.03.010

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Wheat Root Exudation and Soil Nitrogen Transformations in Farmland Reclaimed From Coal Gangue

CHENG Lin-sen, CHENG Wei, BIAN Zheng-fu, LEI Shao-gang   

  1. College of Environment and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2015-11-10 Online:2016-05-25 Published:2016-05-27

Abstract:

To investigate fundamental mechanisms of coal gangue affecting winter wheat (Triticum aestivum) root exudation and nitrogen transformations, a field experiment was conducted on a tract of farmland reclaimed from coal gangue. Exudates from wheat roots, soil N transformation rate, and activities of two extracellular enzymes at various growth stages of the crop in the farmland were analyzed and determined. Results show that: (1) The existence of coal gangue significantly decreased root length, root biomass and root activity of the crop wheat throughout its growth season; (2) The existence of coal gangue decreased root exudation rate Ⅰ by 25.47%, 23.71% and 9.95%, respectively, and root exudation rate Ⅱ by 39.83%, 25.81% and 10.84%, respectively at the jointing stage, flowering stage and maturing stage, and root exudation rate Ⅲ decreased significantly by 23.71% at the jointing stage as compared with that of the crop in a control field. Root exudation rate Ⅲ(y) was found to be positively related to root activity(x) and the correlation could be fitted with the regression equation of y=0.012x-0.43, R2=0.874(P<0.05, n=30); (3) Coal gangue inhibited significantly N transformations and soil enzyme activities at all the growth stages, and the two were positively related to root exudation rate Ⅲ (P<0.05), which suggests that coal gangue decreases N transformation rate by inhibiting crop root exudation, thus reducing the supply of available N and then restraining growth of the crop.

Key words: mining subsidence area, reclaimed farmland, root exudate, nitrogen transformation

CLC Number: