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Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (7): 11-21.DOI: 10.11686/cyxb2020253

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Analysis of spatial variability of soil available nitrogen in Xilingol grassland

Shuai CHANG(), Hong-bo YU(), Qiao-feng ZHANG, Zi-ce MA, Yue-xuan LIU, Xiang LI   

  1. College of Geography Science,Inner Mongolia Normal University,Hohhot 010022,China
  • Received:2020-05-27 Revised:2020-07-06 Online:2021-07-20 Published:2021-06-03
  • Contact: Hong-bo YU

Abstract:

The content of soil available nitrogen (AN) is an important index of soil nutrient levels, and AN plays an important role in the stability of the grassland ecosystem and in plant community development. This research used field sampling, laboratory analyses and data processing, using a Geographic Information System platform combined with geostatistical methods, to determine AN spatial variation characteristic in Xilingol grassland and factors affecting it. There were 30 sampling sites across six administrative regions, with sampling to 50 cm depth in six soil depth bands: 0-5 cm, 5-10 cm, and thereafter in 10 cm increments. It was found that: 1) The soil AN level displayed significant spatial different law in Xilingol grassland. In the horizontal direction, the content of AN in each depth of soil layer was banded and tends to gradually decrease from east to west. Vertically through the soil horizons, the soil AN content decreased with depth and gradually stabilizes. The soil AN content was at the lower middle level. There was a strong spatial correlation between the AN content of each layer of soil, and its spatial variation was mainly affected by structural factors, and all moderate variability. 2) The soil AN content in different grassland types displayed a similar decreasing trend with soil depth. In the 0-30 cm soil horizon, the AN level ranked: meadow grassland>typical grassland>desert grassland. In the 20-50 cm soil horizon, the AN level ranked: typical grassland>meadow grassland>desert grassland. 3) There was a very significant correlation between AN content in all soil layers (P<0.01). There was no obvious correlation between soil AN and available potassium, but soil AN had a very significant positive correlation with soil organic matter and available phosphorus (P<0.01), and a very negative correlation with soil pH (P<0.01).

Key words: soil AN, spatial variability, vertical change, Xilingol grassland