[1]ZHANG Zeyu,LI Zhanbin,LI Peng,et al.Spatial Variability of Soil Nitrogen and the Impact Factors of Land-Use Types in Yujiehe Watershed, Han River[J].Research of Soil and Water Conservation,2017,24(04):46-52,58.
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Research of Soil and Water Conservation[ISSN 1005-3409/CN 61-1272/P] Volume:
24
Number of periods:
2017 04
Page number:
46-52,58
Column:
Public date:
2017-08-28
- Title:
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Spatial Variability of Soil Nitrogen and the Impact Factors of Land-Use Types in Yujiehe Watershed, Han River
- Author(s):
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ZHANG Zeyu1, LI Zhanbin1,2, LI Peng1, XU Guoce1, ZHANG Tiegang1
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1. Base of Eco-hydraulic Engineering in Arid Area, Xi’an University of Technology, Xi’an 710048, China;
2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
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- Keywords:
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soil nitrogen; land use; composition of nitrogen; correlation; Han River
- CLC:
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S151.9
- DOI:
-
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- Abstract:
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Nitrogen is an indispensable nutrient element in soil, and plays a vital role in the growth of plants. Grid sampling (30 m×30 m) and typical spot sampling were carried out in the study area, and soil samples were collected in three soil layers (0—20 cm, 20—40 cm, 40—60 cm). Total nitrogen (TN), ammonium nitrogen (AN) and nitrate nitrogen content (NN) were determined. With classical analyses, geostatistical analyses, kriging interpolation, Pearson correlation analysis and Spearman correlation analysis, spatial variability of TN, AN, NN of land-use types and their correlations with environmental factors were studied. In addition, the relationships between different fractions of nitrogen were investigated. The results showed that soil nitrogen contents of the study area were at the low level; the TN, AN, NN contents decreased as soil depth increased; the spatial variability coefficient of NN was greater than AN, and both of them were larger than TN; the spatial dependence of TN and NN appeared to be high level in A1 layer and medium level in A2, A3 layers, and AN appeared moderate spatial dependence, which meant that the influence of human factors such as tillage on AN was greater than TN and NN, and it was the natural factor such as intrinsic properties of the soil and topography that controlled the distribution of TN and NN in A1 layer. The TN, AN, NN storage of the study watershed in 0-60 cm layer were 17.116 t, 183.082 kg, 62.528 kg, repectively; and the contribution ratio to TN decreased in the order: grassland > forestland > cropland; the contribution ratio of cropland to AN was larger than both grassland and forestland; grassland proved to have the biggest contribution ratio to NN among the three land-use types. The mean of AN/TN decreased as soil depth increased in cropland, but rose in grassland, and decreased in the sequence: A3 > A1 > A2; and the mean of NN/TN rose as soil depth increased in all the three land-use types. Pearson correlation analysis showed that AN/TN was highly significant positive correlated with NN/TN at a depth of 0—60 cm(r=0.440,p < 0.01); the correlations between different fractions of nitrogen were diverse in different layers and land-use types; Spearman correlation analysis indicated that nitrogen contents of cropland were mainly correlated with the soil particle size distribution, but was insignificantly correlated with topographic factors, nitrogen content of forestland had correlation with terrain factors. Therefore, increasing areas of forestland and grassland within the basin and the outlet can reduce the loss of soil nitrogen from catchment.