Journal of Geo-information Science >
Characteristics of the Spatial Variation of Soil Nutrients in Farmland of Fuzhou City
Received date: 2016-03-15
Request revised date: 2016-06-23
Online published: 2017-02-17
Copyright
It is very important to study the characteristics of spatial pattern and variation of soil nutrients and analyze the effect of topographical factors on the spatial distribution of soil nutrients for the effective use and management of soil nutrients. In this paper, the combination of GIS and Geostatistics methods were applied to analyze the spatial distribution characteristics and variation pattern of soil nutrients (organic matter, available nitrogen, available phosphors and available potassium) in the agricultural land of southeast hilly area of Fuzhou. We further studied the correlation between soil nutrients content and topographical factors (topography degrees, elevation, topographic wetness index, deposition and transport index and gradient). The results showed that: the range of organic matter, available nitrogen, available phosphors and available potassium contents were between 1.10~89.5 g/kg, 1.00~461 mg/kg, 0.300~298 mg/kg, 4.00~399 mg/kg and the range of variation coefficients were 35.3~99.0%, which belonged to moderate variability. There was obviously different in the spatial abundance of soil nutrients in the cultivated land. In most of the area, the organic matter and available phosphors content were abundant, available nitrogen content was a little above average level and available potassium content was relatively scarce. The nugget coefficient of organic matter, available nitrogen, available phosphors and available potassium were 32.0%, 37.3%,50.0% and 50.0%, respectively. They were medium spatial autocorrelation, indicating that they were controlled by structure and randomness. Spatial autocorrelation scale of organic matter and available nitrogen were large. They change smoothly in each direction (0°, 45°, 90° and 135°) when the step length was less than 0.3 km.and are isotropic. The variation of effective phosphorus and available potassium was small. Their direction of change was complex and they are anisotropy. These results suggested that the government needed to strengthen guidance of fertilization. Nitrogen fertilizer amount should be maintained and the potash should be increased reasonably. The organic fertilizer and phosphate fertilization should be decreased.. In addition, in the subsequent investigation, the setup of sample points should consider density and direction and appropriately increase the sampling of effective phosphorus and available potassium while nitrogen and organic matter and alkali solution sampling can be reduced based on the study.
Key words: GIS; geostatistics; farmland; soil nutrient; spatial variation; topographic factor; Fuzhou City
CHEN Guixiang , GAO Dengzhou , ZENG Congsheng , WANG Weiqi . Characteristics of the Spatial Variation of Soil Nutrients in Farmland of Fuzhou City[J]. Journal of Geo-information Science, 2017 , 19(2) : 216 -224 . DOI: 10.3724/SP.J.1047.2017.00216
Fig. 1 Location map of Fuzhou (including the original Pingtan county)图1 福州市(含原平潭县)区位图 |
Tab. 1 Descriptive statistics of soil nutrients表1 土壤养分描述统计特征 |
指标 | 最大值 | 最小值 | 均值 | 标准差 | CV/% |
---|---|---|---|---|---|
有机质/(g/kg) | 89.5 | 1.1 | 29.9 | 10.7 | 35.9 |
碱解氮/(mg/kg) | 461 | 1.0 | 135 | 47.7 | 35.3 |
有效磷/(mg/kg) | 298 | 0.3 | 33.9 | 33.5 | 99.0 |
速效钾/(mg/kg) | 399 | 4.0 | 80.8 | 56.2 | 69.6 |
Tab. 2 Soil nutrient level index and distribution表2 土壤养分等级指标及分布 |
指标 | 项目 | 偏低V | 缺乏IV | 中等III | 丰富II | 偏高I |
---|---|---|---|---|---|---|
有机质/(g/kg) | 标准 | <5 | 5~10 | 10~20 | 20~30 | >30 |
比例/% | 1.84 | 3.74 | 10.8 | 33.0 | 50.6 | |
碱解氮/(mg/kg) | 标准 | <50 | 50~100 | 100~150 | 150~200 | >200 |
比例/% | 5.08 | 15.00 | 45.50 | 26.90 | 7.53 | |
有效磷/(mg/kg) | 标准 | <12 | 12-15 | 15-20 | 20-25 | >25 |
比例/% | 26.9 | 9.17 | 11.30 | 7.45 | 45.20 | |
速效钾/(mg/kg) | 标准 | <60 | 60~80 | 80~100 | 100~120 | >120 |
比例/% | 52.30 | 15.10 | 9.84 | 6.19 | 16.50 |
Fig. 2 Spatial distribution of soil nutrient of agricultural land in Fuzhou图2 福州市农业用地土壤养分空间分布特征 |
Tab. 3 Semivariogram theoretical models and parameters for soil nutrients表3 土壤养分半方差函数理论模型及相关参数 |
指标 | 模型 | C0 | C0+C | C0/(C0+C) | a/km | r2 |
---|---|---|---|---|---|---|
有机质 | 指数模型 | 61.6 | 193 | 0.32 | 1.85 | 0.92 |
碱解氮 | 指数模型 | 677 | 1841 | 0.37 | 0.71 | 0.60 |
有效磷 | 指数模型 | 462 | 924 | 0.50 | 0.45 | 0.70 |
速效钾 | 指数模型 | 1893 | 3787 | 0.50 | 0.82 | 0.97 |
Fig. 3 Anisotropic semivariogram of soil nutrients图3 土壤养分各向异性半方差函数图 |
Tab. 4 The relationship between soilnutrients and terrain factors表4 土壤养分与地形因子相关关系 |
地形 起伏度 | 高程 | 地形湿度 指数 | 沉积物 运输指数 | 坡度 | |
---|---|---|---|---|---|
有机质 | 0.177** | 0.301** | -0.146** | 0.059** | 0.150** |
碱解氮 | 0.172** | 0.212** | -0.131** | 0.057** | 0.150** |
有效磷 | -0.071** | -0.102** | 0.076** | -0.024 | -0.066** |
速效钾 | -0.070** | -0.111** | 0.064** | -0.029 | -0.062** |
注:**表示P<0.01,*表示P<0.05 |
The authors have declared that no competing interests exist.
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