Papers by Keyword: Soil Organic Matter

Abstract: Underground mining has caused drastic disturbances to regional ecosystems and soil nutrients. Understanding the 3D spatial distribution of soil organic matter in coal arable land is crucial for agricultural production and environmental management. However, little research has been done on the three-dimensional modeling of soil organic matter. In this study, 3D kriging interpolation method and 3D stochastic simulation method were used to develop the 3D model of soil organic matter , and the root-mean-square error (RMSE) and mean error (ME) were used as evaluation indexes to compare the simulation accuracy of the two methods. Results showed that the spatial distribution of soil organic matter obtained by using 3D kriging interpolation method is relatively smooth, which reduce the difference of spatial data; while the spatial distribution of soil organic matter obtained by using 3D stochastic simulation method is relatively discrete and highlights the volatility of spatial distribution of raw data, the RMSE obtained by 3D kriging interpolation method and 3D stochastic simulation method respectively is 2.7711 g/kg and 1.8369 g/kg. The prediction accuracy of organic matter interpolation obtained by 3D stochastic simulation method is higher than that by 3D kriging interpolation method; so the 3D stochastic simulation method can reflect the spatial distribution characteristics of soil organic matter more realistically, and more suitable for 3D modeling of soil organic matter. According to the 3D modeling of soil organic matter, the content of soil organic matter has obvious spatial difference in different soil depth（0-20 cm、20-40 cm、40-60 cm） and decreases with the increase of soil depth; The result also showed that the content of soil organic matter decreased rapidly from the upper slope to the middle slope, and gradually increased from the middle slope to the bottom, so the soil organic matter content was obviously lost in the middle slope. This result may provide useful data for land reclamation and ecological reconstruction in coal mining subsidence area.

Abstract: Soil organic matter (SOM) is derived from dead biomass of animals and plants, and its formation process in which the precursor materials of SOM are transformed into macro organic molecules through geo-chemical and geo-biological reactions in the subsurface environment is referred to as humification. Carbon content increases, but oxygen content decreases along with marked increased in molecular weight and degree of condensation of SOM during humification. It has been known that humus materials evolve in the order of biopolymer, fulvic acid, humic acid, and humin. Humification process takes place in a geological time scale, but it can be accelerated at extremely high temperatures, which can be achieved by microwave (MW) with hyperthermal catalysts (HTCs). Thus, MW was irradiated to the mixture of soil and HTCs to stimulate humification of SOM and to enhance its binding capacity for recalcitrant organic contaminants in this study. MW irradiation with HTCs was optimized, and the characteristic changes of SOMs before and after the irradiation were assessed to confirm humification. Soils were collected from 4 different forest regions in Seoul, Korea (Konkuk University, Yongma Mountain, Surak Mountain, and Bukhan Mountain), and they were screened by wet-sieving. Each component of SOM was isolated by acid-base extraction/selective exchange resin, which was proposed by the International Humic Substance Society. Total organic carbon (TOC) content, specific ultraviolet absorbance (SUVA), E4/E6 ratio, and Fourier transform-infrared spectroscopy (FT-IR) spectrum of SOM before and after MW irradiation were examined. Soil of Surak Mountain exhibited the highest organic carbon content, but Yongma Mountain contained the highest amount of fulvic acid. Soils of Yongma Mountain and Konkuk University were chosen due to their high fulvic acid content, which supported that these soils are relatively geologically-young soils. Powdered and granulated activated carbon (PAC and GAC), graphite, charcoal, and carbon nanotube (CNT) were selected and screened with regard to their hyperthermal activity under MW irradiation. The temperature changes by MW with HTCs were monitored at various MW irradiation intensity and time. Graphite-and CNT-soil mixtures exhibited the optimum heating capacity at 600 W, resulting in heating HTC-soil mixtures to approximately 1,000oC within 10 min. TOCs, SUVAs, E4/E6 ratios, and FT-IR spectra of SOM supported effective humification of SOM after MW irradiation with HTCs, and notable increase in binding capacity with hydrophobic organic contaminants. The results of this study are expected to provide the fundamental information for developing the performance-efficient and cost-effective treatment process for the removal of persistent organic contaminants based on MW and HTC.

Abstract: In this paper, based on geostatistics and GIS techniques, spatial variation characteristics of soil organic matter (acronym: SOM) on a small scale were analyzed and discussed in east-one-branch gully (EG1) bed with the seabuckthorn flexible dam and the contrastive gully bed (which is non-vegetated any vegetation) located in zhun-ge-er county, Erdos, inner Mongolia, which belongs to the typical Pisha Sandstone area. The results show that the seabuckthorn can significantly increase SOM in the small catchment gully bed in the Pisha sandstone area, and the mean SOM content in gully bed with the seabuckthorn flexible dam is approximate 1.75 times that in the contrastive gully. Apparent spatial variation characteristics of SOM were found in the gully with the seabuckthorn flexible dam and the contrastive gully bed, moreover, the medium spatial autocorrelation of SOM was detected in gully bed with the seabuckthorn flexible dam, and the spatial variation of SOM was together led to by the structural and random variation at 1-6.5 m range, and of which the random variation accounts for 40%. Additional, the spatial autocorrelation of SOM in the contrastive gully bed is higher, the spatial variation of SOM was dominantly brought about by the structural variation at 1-4.5 m range, and of which the random variation accounts for 37%. Furthermore, the fractal dimension values reveal that dependence of SOM of the gully bed with the seabuckthorn flexible dam on spatial is weaker than that of the contrastive gully bed. It is judged that the seabuckthorn has an obvious effect on spatial distribution patterns and heterogeneity of SOM on a small scale.

Abstract: In this paper, we take secondary forest, orchard, and woodland soils of rubber in different planting years as a research subject and analyze the influence of different land use on soil organic matter. The results show that land use has significant influence on soil organic matter components (p <0.01). We conducted a survey and sampling on 10 age classes of Hainan Dongfang Daguangba (3, 8, 13, 18,23,29,33,35,38,42 years old) rubber plantation plots soil layer (0 cm-20 cm, 20 cm-40 cm), and conducted in-house testing analysis of its organic matter content, and achieved preliminary exploration that soil organic matter content of different land use patterns in Dongfang City in Hainan: secondary forest> orchard> rubber plantation. These differences are mainly due to the litter under different tillage quantity, quality and variety of management measures. While orchards and rubber plantation have used different tillage method, as a plantation by human, it was greatly influenced by human.

Abstract: Different vegetation patterns have difference influenced on the soil nutrients and the soil nutrient contents of different soil layers in the same vegetation patterns are also different in size. In this paper, we analyze the main soil nutrients of different soil layers in different vegetation patterns in Huanghuadianzi small watershed in Ao HanQI of Chifeng in China. The result shows that in different vegetation patterns, the secondary forest of natural bush have an obvious effect on the nutrient and concentration of organic; in the artificial forest, mingled forest has a better improving effect on soil than the pure forest and natural grassland has the smallest effect; in the same vegetation patterns, organic, total nitrogen present an overall reduction trend with the deepening of soil layer accept 40-60cm soil layers. The analysis result of this paper can provide a theoretical basis for further researching the dynamic nutrient change, tree variety optimization arrangement and regional land use planning in forest grass zone.

Abstract: Soil organic matter (SOM) is the most active material component in soil, whats more, it is significant for soil fertility evaluation and agricultural sustainable development. This paper tries to establish a regional SOM prediction model of Yang Jiaqiao town, Xiangtan county in Hunan province, which based on the data obtained in the field and SPOT-5 image with the help of remote sensing retrieval technique, and then get the regional distribution of SOM. The results show that the most SOM content in experimental area is higher than 3%, which indicates SOM plays an important role in spectral reflectance characteristics, then establish corresponding estimation model and test them after transferring the reflectivity spectral data. The paper analysis and comes to a conclusion that the most appropriate model is the second-order polynomial one of red band based on SPOT-5 image by comparing the models between SOM content and single band measured reflectance.

Abstract: Carbon dioxide is major cause of the greenhouse effect which is believed to be warming the Earth’s climate, the balance between accumulation of soil organic matter (SOM) and its loss through microbial respiration has global implications. In our study we have investigated dynamics of SOM during 2003-2011. Field investigations were conducted at two fields: fallow land and land cultivated by Tamarix. The following soil chemical properties also were evaluated: pH, electrical conductivity (EC), total and available NPK. The results revealed that amount of nutrients in soils are varied within two fields.

Abstract: The dynamics of the litter and soil organic matter content of four densities (A: 2500/hm²，B:3300/hm²，C:4400/hm²，D:6600/hm²) of hybrid Larch plantations were studied in Jiangshanjiao forest farm of Heilongjiang province of China. (1) The annual litter stock under the hybrid Larch plantation was 4634.6 ~ 5453.4 kg/hm², and the decreased order of the annual litter stock was under density of 4400, 3300 2500and 6600 trees per hectare. The decrease order of the litter stock no matter undecomposition and decomposition litter was under density of 3300, 4400, 2500 and 6600 trees per hectare, and the rate of the undecomposition litter stock to total litter stock was bigger than 50 %. (2) The seasonal dynamic of the soil organic matter under different densities of plantations basically had the same principle. In 0~10 cm soil layer, the soil organic matter was higher in June and August, was lower in May and July, and was flat or increased slightly in September, but was decreased in September under the plantations with density 4400 and 3300 trees per hectare. The soil organic matter in 10~20 cm and 20~40 cm layer had the same change principle, but the change range was flat and smooth. For the same density of plantation, the difference of the organic matter in the same soil layer between the different months was significantly (P < 0.05). (3) The difference of the soil organic matter content in the same soil layer under different densities of hybrid Larch plantation was significantly, and the decreased order of the soil organic matter in average was under density 4400, 3300, 6600 and 2500 trees per hectare. The results would provide the theories basis for manage the hybrid Larch plantations.

Abstract: Land use patterns effect on soil anti-erodibility was studied by the combinative means of field investigation and laboratory analysis in low mountain-hilly region. The results showed that he five land use patterns had high proportion of aggregates at the size of >2 mm after dry sieving and had high proportion of aggregates at the size of <0.5 mm after wet sieving. Soil dispersion was mainly reflected in aggregate at the size of 0.05- 0.001 mm under different land use patterns. It was significantly different to land use patterns effect on soil anti-erodibility. Soil anti-erodibility in Chinese fir plantation and Eucalyptus plantation were stronger than those of tea plantation, loquat orchard and abandoned farmland. Water-stable aggregate stability was the highest in Chinese fir plantation, followed by eucalyptus plantations and tea plantations, and water-stable aggregate stability was the lowest in loquat orchards and abandoned farmland. Except for coarse dust, the other soil particle content of the same size had the different change under different land use patterns. The change of status of aggregate and degree of aggregation was opposite to the change of dispersive coefficient under different land use patterns. Water stability index and soil organic matter content in Chinese fir plantation, eucalyptus plantation and loquat orchard was higher than that of abandoned farmland and tea plantation. So, land use patterns of Chinese fir plantation and eucalyptus plantation was reasonable in study area.

Abstract: Long-term effects of inorganic and corn stalks organic nutrient sources on yield, soil organic carbon(SOC) and the relationship between crop yield and SOC were investigated in Dry-Land Farming Institute of Hebei Academy of Agricultural and Forestry Sciences, Hengshui, Hebei Province, China from 1981 to 2005. Hengshui is a part the North China Plain and the dominant cropping systems are Winter wheat-maize rotations. Recently the use of organic manure with grain crops has almost disappeared. This could reduce soil fertility and crop productivity in the long run. There were sixteen treatments applied to both wheat and maize seasons: Inorganic fertilizers as main plots and corn stalks as subplots and the main plot and subplot all have four levels expressed A and B respectively. So there are sixteen treatments with three replicates were set (A1,A2,A3,A4)*(B1,B2,B3,B4). After more than 20 years crop yield and SOC decreased in treatment of without fertilizers and only applicate corn stalks just sustain it. Combine application of inorganic fertilizers and corn stalks increase SOC and crop yield very strongly. For crop yield the more fertlizers the more increase. But the SOC will decrease as the more inorganiac fertlizer application and increase with the increase of corn stalks.