Advances in Earth Science ›› 2003, Vol. 18 ›› Issue (4): 584-591. doi: 10.11867/j.issn.1001-8166.2003.04.0584

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ACCUMULATION OF NO 3-N IN DEEP LAYERS OF DRY FARMLAND AND ITS AFFECTING FACTORS IN ARID AND SEMI-ARID AREAS

Guo Shengli 1,2,Zhang Wenju 1,Dang Tinghui 1,2,Wu Jinshui 1,2,Hao Mingde 1,2   

  1. 1.Institute of Soil and Water Conservation, Chinese Academy of Sciences and the Ministry of Water Resources, Yangling 712100,China;2. Northwest Science & Technology University of Agriculture & Forestry, Yangling 712100,China
  • Received:2002-02-20 Revised:2003-02-24 Online:2003-12-20 Published:2003-08-01

Guo Shengli,Zhang Wenju,Dang Tinghui,Wu Jinshui,Hao Mingde. ACCUMULATION OF NO 3-N IN DEEP LAYERS OF DRY FARMLAND AND ITS AFFECTING FACTORS IN ARID AND SEMI-ARID AREAS[J]. Advances in Earth Science, 2003, 18(4): 584-591.

Accumulation of NO3-N in deep layers is the unique of N cycle in rained farmland in the arid and semi-arid areas. Based on the long-term experiment, the effects of fertilization, crop, rainfall, tillage systems, rotation, and soil properties on the NO3-N accumulation were reviewed. The over application of nitrogen fertilizer and the precipitation of 400~800 mm mainly contributed to the NO3-N accumulation in the 100~300 cm depth. The NO3-N accumulation in the 100~300 cm depth was increased with the increase of N rates, fertilizer N incorporation with phosphate fertilizer could reduce the NO3-N accumulation. The nitrogen usage efficiency also affect NO3-N accumulation due to N uptake by crops, crop rotation and fallow crop could reduce the NO3-N accumulation. NO3-N accumulation was mainly developed in the soils with heavy texture. The clay mineral with large positive charge mainly contributes to NO3-N accumulation in the tropical soils. The further research emphases about the NO3-N accumulation in the deep depth were put forward as follows: bio-availability, transport in soil profile under rain fed or irrigation, the relation to crop root distribution and growth, and the effect of the NO3-N accumulation on soil properties and soil gas.

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