Uncertainty assessment for mapping changes in soil organic matter using sparse legacy soil data and dense new-measured data in a typical black soil region of China

2014 ◽  
Vol 73 (1) ◽  
pp. 197-207 ◽  
Author(s):  
Yongcun Zhao ◽  
Xianghua Xu ◽  
Nan Hai ◽  
Biao Huang ◽  
Hailong Zheng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Uncertainty Assessment ◽  
Black Soil ◽  
Measured Data ◽  
Black Soil Region

scholarly journals Exploring Appropriate Preprocessing Techniques for Hyperspectral Soil Organic Matter Content Estimation in Black Soil Area

2020 ◽  
Vol 12 (22) ◽  
pp. 3765
Author(s):  
Xitong Xu ◽  
Shengbo Chen ◽  
Zhengyuan Xu ◽  
Yan Yu ◽  
Sen Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Dimensionality Reduction ◽  
Near Infrared ◽  
Organic Matter Content ◽  
Nir Spectroscopy ◽  
Data Transformation ◽  
Black Soil ◽  
Locally Linear Embedding ◽  
Soil Area

Black soil in northeast China is gradually degraded and soil organic matter (SOM) content decreases at a rate of 0.5% per year because of the long-term cultivation. SOM content can be obtained rapidly by visible and near-infrared (Vis–NIR) spectroscopy. It is critical to select appropriate preprocessing techniques for SOM content estimation through Vis–NIR spectroscopy. This study explored three categories of preprocessing techniques to improve the accuracy of SOM content estimation in black soil area, and a total of 496 ground samples were collected from the typical black soil area at 0–15 cm in Hai Lun City, Heilongjiang Province, northeast of China. Three categories of preprocessing include denoising, data transformation and dimensionality reduction. For denoising, Svitzky-Golay filter (SGF), wavelet packet transform (WPT), multiplicative scatter correction (MSC), and none (N) were applied to spectrum of ground samples. For data transformation, fractional derivatives were allowed to vary from 0 to 2 with an increment of 0.2 at each step. For dimensionality reduction, multidimensional scaling (MDS) and locally linear embedding (LLE) were introduced and compared with principal component analysis (PCA), which was commonly used for dimensionality reduction of soil spectrum. After spectral pretreatments, a total of 132 partial least squares regression (PLSR) models were constructed for SOM content estimation. Results showed that SGF performed better than the other three denoising methods. Low-order derivatives can accentuate spectral features of soil for SOM content estimation; as the order increases from 0.8, the spectrum were more susceptible to spectral noise interferences. In most cases, 0.2–0.8 order derivatives exhibited the best estimation performance. Furthermore, PCA yielded the optimal predictability, the mean residual predictive deviation (RPD) and maximum RPD of the models using PCA were 1.79 and 2.60, respectively. The application of appropriate preprocessing techniques could improve the efficiency and accuracy of SOM content estimation, which is important for the protection of ecological and agricultural environment in black soil area.

scholarly journals Is resistant soil organic matter more sensitive to temperature than the labile organic matter?

2006 ◽  
Vol 3 (1) ◽  
pp. 65-68 ◽  
Author(s):  
C. Fang ◽  
P. Smith ◽  
J. U. Smith
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Decay Rate ◽  
Soil Carbon ◽  
Measured Data ◽  
Temperature Sensitive ◽  
Labile Organic Matter ◽  
Soil C ◽  
Published Evidence ◽  
Labile Pool

Abstract. A recent paper by Knorr et al. (2005a) suggested that the decomposition of resistant soil organic matter is more temperature sensitive than labile organic matter. In Knorr et al.'s (2005a) model, the reference decay rate was presumed to be same for all pools of soil carbon. We refit Knorr et al.'s (2005a) model but allow both the activation energy and the reference decay rate to vary among soil C pools. Under these conditions, a similar fit to measured data can be obtained without invoking the assumption that the resistant C pool is more temperature sensitive than the labile pool. Other published evidence does not unequivocally support Knorr et al.'s (2005a) hypothesis of increased temperature sensitivity of resistant pools of soil carbon. Because of the lack of experimental data, Knorr et al.'s (2005a) conclusion that the decomposition of the resistant SOM is more temperature sensitive than the labile pool is premature.

Effect of Soil Organic Matter on Adsorption of Nitrification Inhibitor Nitrapyrin in Black Soil

2020 ◽  
Vol 51 (7) ◽  
pp. 883-895
Author(s):  
Zhongqing Zhang ◽  
Qiang Gao ◽  
Jingmin Yang ◽  
Lujun Li ◽  
Yue Li ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Nitrification Inhibitor ◽  
Black Soil

scholarly journals The adsorption and mechanism of the nitrification inhibitor nitrapyrin in different types of soils

2020 ◽  
Vol 7 (9) ◽  
pp. 200259 ◽  
Author(s):  
Zhongqing Zhang ◽  
Qiang Gao ◽  
Jingmin Yang ◽  
Yue Li ◽  
Jinhua Liu ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Adsorption Kinetics ◽  
Physical Adsorption ◽  
Nitrification Inhibitor ◽  
Black Soil ◽  
Order Kinetic ◽  
Different Types ◽  
Isotherm Adsorption ◽  
Adsorption Kinetics And Isotherm

The nitrapyrin was easily adsorbed by soil, but most current studies have focused on comparing the effects of nitrapyrin application at different soil organic matter levels and in different soil types. The adsorption kinetics and isotherm adsorption of the nitrification inhibitor nitrapyrin in black soil, chernozem and planosol were studied in this paper. The adsorption kinetics were fitted by quasi-second-order kinetic equation ( R 2 ≥ 0.8907, p < 0.05) with a lower acting energy of adsorption ( E a < 8.0 kJ mol −1 ). The isotherm was fitted by the Langmuir equation ( R 2 ≥ 0.9400 * , p < 0.05). The adsorption mechanism was determined to involve a spontaneous endothermic reaction accompanied mainly by physical adsorption to the surface that belonged to the ‘ L ’ isotherm curve ( n > 1). Temperature promoted the adsorption of nitrapyrin in these three soils, and the maximum adsorption occurring at different temperatures following the order of black soil > planosol > chernozem. The adsorption capacity and rate decreased with decreasing soil organic matter. For the black soil, the nitrapyrin EC adsorption rate was more than seven times higher than that of nitrapyrin CS. The result would determine the dose of nitrapyrin required for availability in different types of soils and to provide a theoretical basis for elucidating the adsorption of nitrapyrin in the soil environment.

scholarly journals Assessment of the degree of sloped cropland degradation in typical black soil region

2021 ◽  
Author(s):  
Shouhao Zhang ◽  
lei sun ◽  
Abdul Hakim Jamshidi ◽  
Yong Niu ◽  
Zhaofei Fan ◽  
...  
Keyword(s):  
Organic Matter ◽  
Small Angle ◽  
Soil Degradation ◽  
Black Soil ◽  
Indicator System ◽  
Slope Gradient ◽  
Index Set ◽  
Degraded Soil ◽  
Black Soil Region ◽  
Study Results

A comprehensive evaluation indicator system is needed to provide a integrated assessment of the degree of sloped cropland degradation. We employed bibliometrics to perform statistical analysis on research studies involving cropland degradation. Frequency analysis was then used to identify high-frequency indicators with which to construct a total index set (TIS) for evaluation of the degree of sloped cropland degradation in black soil region. In addition, soil measurement data from sloped cropland in Baiquan and Keshan Counties, Heilongjiang province, China, were used as a basis to construct a minimum index set (MIS). The TIS included A-horizon thickness, clay content, organic matter content, pH, slope gradient, ridge-slope angle, gully density, bulk density, large water-stable aggregate content, soil cation exchange capacity, and crop yield. The first six of these were included in the MIS. In the studied area, undegraded soil, mildly degraded soil, and moderately degraded soil and above accounted for 7%, 48% and 45% of investigated sloped croplands, respectively. Slope gradient is one of the main factors affecting soil degradation. Soil degradation mainly presented as worsening of soil physicochemical characteristics. In addition, downslope and small-angle ridge cultivation are benefit for soil organic matter maintenance and the soil structure and nutrient retention capacity is better than soil with contour or large-angle ridge cultivation. The reason might be that downslope and small-angle ridge cultivation are usually employed on soil with small slope. The study results provide a scientific basis for improving the quality and productivity of sloped cropland in black soil region.

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