scholarly journals The yield values of densimetric fractions from typical chernozems of different land use types

2020 ◽  
pp. 85-107
Author(s):  
Yulian R. Farkhodov ◽  
N. V. Yaroslavtseva ◽  
M. A. Yashin ◽  
S. F. Khokhlov ◽  
B. S. Iliyn ◽  
...  

One of the most justified and applied approaches to isolating pools of soil organic matter is fractionation in heavy liquids. The main problem with this approach is rather large losses in the separation of fractions at the stage of washing fractions from heavy liquids. The paper presents a densimetric fractionation protocol that can significantly reduce these losses. It is suggested to use 0.001 M HCl for washing. This approach, in comparison with distilled water, allows reducing losses of weight from 15 to 5% and of carbon from 7.5 to 2.5%. The paper provides a detailed protocol, used by the Laboratory of Soil Biochemistry of V.V. Dokuchaev Soil Science Institute, to isolate four densimetric fractions using sodium polytungstate solutions: free and occluded SOM with a density of <1.6 g/cm3, occluded SOM – of 1.6–2.0 g/cm3, and a mineral residue with a density >2.0 g/cm3. In the work we used samples of typical chernozems of different land use types. It was shown that the processes of soil restoration and degradation significantly affect the content of light occluded soil organic matter.

2020 ◽  
Author(s):  
Liqun Tang ◽  
Zhijie Shan ◽  
Yang Yu

&lt;p&gt;Re-vegetation has been widely carried out to prevent land degradation, reduce soil erosion, and improve soil quality. In order to investigate the characteristics of soil nutrients content in different land use types of karst gabin basin, soil organic matter, soil total nitrogen, soil total phosphorus, soil total potassium, soil pH, and soil texture in woodland, agricultural land, orchard, and grassland were surveyed in Mengzi Gabin Basin, Southwest of China. The difference of soil indicators between vegetation types was analyzed, and soil fertility quality of four land use types was comprehensively evaluated by the soil quality index (SQI). The results showed that land use significantly affected soil organic matter content. Soil organic matter content was the highest in grassland, followed by agricultural land and forest land, while orchard was lowest. There was a significant difference in soil total nitrogen content between different land uses. The total nitrogen content in farmland soil was the highest, followed by grassland and woodland, and the lowest in the orchard. Woodand had the highest total potassium content and the lowest total phosphorus content. The grassland soil had the highest total phosphorus content and the lowest total potassium content. pH value in the four land use types was acidic, ranged from 5.82 to 6.67. The soil quality index showed that woodland had the highest soil fertility quality. The results of the study could provide the basis of soil nutrients variation and status in Gabin basin, and also provides support for evaluating the soil improvements during vegetation restoration in fragile Karst ecosystems.&lt;/p&gt;


CATENA ◽  
2015 ◽  
Vol 133 ◽  
pp. 137-144 ◽  
Author(s):  
Shiliang Liu ◽  
Nannan An ◽  
Juejie Yang ◽  
Shikui Dong ◽  
Cong Wang ◽  
...  

CATENA ◽  
2018 ◽  
Vol 160 ◽  
pp. 345-353 ◽  
Author(s):  
Jingjing Chang ◽  
Jianxing Zhu ◽  
Li Xu ◽  
Hongxin Su ◽  
Yang Gao ◽  
...  

2020 ◽  
Author(s):  
Britta Greenshields ◽  
Barbara von der Lühe ◽  
Harold J. Hughes ◽  
Aiyen B. Tjoa ◽  
Daniela Sauer

&lt;p&gt;As oil-palm plantations are expanding rapidly in SE Asia, it is essential to ensure that soil functions are sustained after land-use transformation. This includes the maintenance of well-balanced soil nutrient levels to prevent soil degradation as well as understanding soil silicon (Si) dynamics to optimize oil-palm management. However, studies on the influence of oil-palm cultivation on soil Si pools have not yet been undertaken, although it is known that oil palms accumulate Si in their biomass and should thus affect Si pools and cycling. We hypothesized that under oil-palm monocultures, Si losses may exceed Si input into soils, due to (1) erosion of phytolith-enriched topsoils, (2) increased Si uptake by oil palms, (3) harvest and palm-frond management. The aim of this study is to compare Si pools in Acrisols of Sumatra (Indonesia) under rainforest and oil-palm plantations to assess whether these soil Si pools are significantly depleted under oil-palm plantations. We included both well-drained and riparian sites, hypothesizing that riparian sites are less prone to net Si depletion, as they receive additional Si through regular flooding and slope water from higher areas. Soil samples (1 g) from soil profiles (&amp;#8804; 1 m, n = 4 for each land-use type and topographic position) were subjected to sequential Si extraction to determine mobile Si, adsorbed Si, Si in soil organic matter, Si occluded in pedogenic oxides and hydroxides, and biogenic Si.&lt;/p&gt;&lt;p&gt;Si in soil organic matter (SOM) and biogenic Si represent the largest Si pools in the Acrisols. Our preliminary results suggest that these pools are controlled by land use rather than by topographic position (riparian versus well-drained). Ah horizons under oil-palm plantations have lower contents of Si in SOM (0.052-1.04 mg g&lt;sup&gt;-1&lt;/sup&gt;) than those under rainforest (0.59-1.5 mg g&lt;sup&gt;-1&lt;/sup&gt;). There is no significant difference between well-drained and riparian sites, as Si input by slope water and flooding does not affect Si in SOM. Besides, the concentrations of biogenic Si are lower in soils under oil-palm plantations than under rainforest. The contents of both mobile and adsorbed Si in soils are similar to marginally higher in riparian soils (5-30 &amp;#181;g g&lt;sup&gt;-1&lt;/sup&gt;), compared to well-drained soils (5-20 &amp;#181;g g&lt;sup&gt;-1&lt;/sup&gt;), with no clear difference between land-use types. These Si fractions unlike Si in SOM are most directly influenced by Si input through slope water and flooding.&lt;/p&gt;


2021 ◽  
Author(s):  
Anna Schneider ◽  
Alexander Bonhage ◽  
Florian Hirsch ◽  
Alexandra Raab ◽  
Thomas Raab

&lt;p&gt;Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.&lt;/p&gt;&lt;p&gt;We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils.&amp;#160;The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.&lt;/p&gt;


1991 ◽  
Vol 39 (4) ◽  
pp. 237-246 ◽  
Author(s):  
J. Wolf ◽  
L.H.J.M. Janssen

The changed crop rotation on arable land, the decreasing grassland area and the increase in forest area in the Netherlands resulted in a decrease in C pool size. For the calculation of this C pool a method requiring only three input data (average amount of crop or tree residue rate, soil organic matter decomposition and the humification coefficient) has been applied. However the method can only be applied to situations in equilibrium where all three input data are equal. For a changing land use a new state of equilibrium and rate of change in C pool size can be calculated. (Abstract retrieved from CAB Abstracts by CABI’s permission)


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