scholarly journals Degradation Characteristics of Soil-Quality-Related Physical and Chemical Properties Affected by Collapsing Gully: The Case of Subtropical Hilly Region, China

2019 ◽  
Vol 11 (12) ◽  
pp. 3369 ◽  
Author(s):  
Shuyue Feng ◽  
Hui Wen ◽  
Shimin Ni ◽  
Junguang Wang ◽  
Chongfa Cai

In the subtropical hilly areas of China, a collapsing gully, a particular type of permanent gully, poses a great threat to the productivity and sustainability of the local ecological and agricultural systems. However, few studies have been performed regarding the effects of collapsing gully erosion on soil degradation. The aim of this study was to evaluate the effects of collapsing gully erosion on soil-quality-related physical and chemical properties. The collapsing gullies that were severely affected by erosion processes were considered at three stages (initial, active and stable stages) and corresponding soil samples were collected to analyze the spatial variation of the soil physical and chemical quality at each stage. The changes in the properties were assumed to be considerable in the regions affected by the erosion process compared with those unaffected by this process. Soil physical properties were more susceptible than soil nutrients to collapsing gully erosion in different spatial locations. The soil quality index (SQI) system consists of total nitrogen (TN), total phosphorus (TP), pH, capillary porosity (CP), sand content (SA), soil cohesion (SC) and root density (RD). Collapsing gully erosion was found to affect the soil physical and chemical properties by progressively reducing the SQI. The mean SQI value was the lowest in the active stage of the collapsing gully, with a higher soil degradation. For the different spatial positions in the collapsing gullies, the scour channel showed the lowest SQI value. The limiting indicators varied in the different stages or spatial sites in the collapsing gullies.

2021 ◽  
Author(s):  
Ke Wang ◽  
Zhigang Wang ◽  
Jiale Wang ◽  
Jianming Li ◽  
Bei Sun ◽  
...  

<p>Rocky desertification induced by severe deforestation has caused the water loss and soil erosion in karst regions in southeast China, limiting local social and economic developments. To prevent further rocky desertification, the farmland which had obtained by deforestation were abandoned for recovery. As soil quality improved by agriculture abandonment should be examined, it is necessary to investigate the dynamics of physical and chemical properties of soil in different ages after abandonment. In this study, 38 investigation sites were selected for soil sampling on the slopes in Longtan trough valley in Youyang County, Chongqing Municipality, China. The dominant plant species of the investigation sites were also noted during soil sampling. The sites were divided into seven age classes according to their abandonment time. Dynamics of water content, bulk density, pH, and concentration of available potassium, available phosphorus, available nitrogen, total nitrogen and organic matters were examined. It suggests that soil quality might be deteriorated right after abandonment and then improved from around 20 years after abandonment. Deterioration of soil quality may be induced by lack of plant coverage and exposure of rock outcrops which may accelerate water loss and swelling and shrinkage cycles of soil. After the formation of plant communities and litter layer above the ground, soil quality was then apparently improved. These findings can provide a potential guideline for recovery management in karst regions in southwest of China.</p>


2012 ◽  
Vol 36 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Carolina Tirloni ◽  
Antonio Carlos Tadeu Vitorino ◽  
Anderson Cristian Bergamin ◽  
Luiz Carlos Ferreira de Souza

Crop-livestock integration represents an interesting alternative of soil management, especially in regions where the maintenance of cover crops in no-tillage systems is difficult. The objective of this study was to evaluate soil physical and chemical properties, based on the hypothesis that a well-managed crop-livestock integration system improves the soil quality and stabilizes the system. The experiment was set up in a completely randomized design, with five replications. The treatments were arranged in a 6 x 4 factorial design, to assess five crop rotation systems in crop-livestock integration, and native forest as reference of soil undisturbed by agriculture, in four layers (0.0-0.05; 0.05-0.10; 0.10-0.15 and 0.15-0.20 m). The crop rotation systems in crop-livestock integration promoted changes in soil physical and chemical properties and the effects of the different systems were mainly detected in the surface layer. The crops in integrated crop-livestock systems allowed the maintenance of soil carbon at levels equal to those of the native forest, proving the efficiency of these systems in terms of soil conservation. The systems influenced the environmental stability positively; the soil quality indicator mineral-associated organic matter was best related to aggregate stability.


2020 ◽  
Vol 51 (5) ◽  
pp. 1290-1299
Author(s):  
Qadir & Azeez

This study was conducted to assess desertification for dry lands in some parts of Iraq. The study area located between longitudes 43025- 41" - 460 28- 01" E and latitudes 340 18- 35" - 360 20- 56" N with an area of 26500Km2which include some parts of the governorates of Sulaimani, Diyala, Kirkuk, and Erbil in Iraq.  Eighty nine surface soil samples were taken, air dried, sieved through a 2 mm sieve and then analyzed for some physical and chemical properties.   Desertification is assessed according to Mediterranean Desertification and Land Use model (MEDALUS). ArcGIS 10.2 was used to analyze and prepare the layers of soil quality maps. In turn the geometric mean of all six quality maps was used to generate a single desertification status map .In calculating the weight of the soil quality indicator SQI it seems that it was divided into two classes, firstly, class 2(moderate quality) with an area of 25147 km2, which occupied 95% of the study area and the rest is class3 (low quality) with an area of ​​1309 km 2 which equal to 5% of the total area.


2020 ◽  
Author(s):  
Mario Kirchhoff ◽  
Lars Engelmann ◽  
Lutz Leroy Zimmermann ◽  
Irene Marzolff ◽  
Manuel Seeger ◽  
...  

<p>The argan tree (Argania spinosa) populations, endemic to South Morocco, have been highly degraded. Although the argan tree is the source of the valuable argan oil and is protected by law, overbrowsing and -grazing as well as the intensification and expansion of agricultural land lead to tree and soil degradation. Young stands cannot establish themselves; undergrowth is scarce due to the semiarid/arid climate and thus, goats, sheep and dromedaries continually browse the trees. Canopy-covered areas decrease and are degraded while areas without vegetation cover between the argan trees increase.</p><p>On 30 test sites, 60 soil samples of tree and intertree areas were studied on their soil physical and chemical properties. 36 rainfall simulations and 60 single-ring infiltration measurements were conducted to measure potential differences between tree/intertree areas in their runoff/erosion and infiltration properties. Significant differences using a t-test were found for the studied parameters saturated hydraulic conductivity, pH, electric conductivity, percolation stability, total C-content, total N-content, K-content, Na-content and Mg-content. Surface runoff and soil erosion were not statistically significant, but showed similar trends due to the higher complexity of runoff formation. The soil covered by argan trees generally showed less signs of degradation than intertree areas. With ever-expanding intertree areas due to the lack of rejuvenation of argan trees a further degradation of the soil can be assumed.</p>


2012 ◽  
Vol 193-194 ◽  
pp. 274-278
Author(s):  
Yue Shu Yang ◽  
Wen Nian Xu ◽  
Zhen Yao Xia ◽  
Qi Yang

Two vegetation-growing concrete slopes completed are chosen as research objects and the Analytical Hierarchy Process method is adopted to establish the evaluation index system, aiming at quantifying the physical and chemical properties of the base material and analyzing the results contrastively. The study shows that the physical and chemical properties of vegetation-growing concrete base material keep improving with the growth of time to better adapt to the growth of vegetation. This evaluation results tally with the actual situation of the sample sites, which suggests that this base material soil quality index system has great practical value. The differences occurring in the evaluation value of two pieces of sample sites suggest that regional environment is the main factor to affect the quality of vegetation-growing concrete base material.


2018 ◽  
Vol 197 ◽  
pp. 13001 ◽  
Author(s):  
Yohanes P Situmeang

This study aims to determine the status of soil quality after biochar treatment, compost, and phonska in the cornfield. Soil samples were taken from 48 experimental plots after harvesting of maize. Assessment of soil quality is done by collecting selected indicator data including soil physical and chemical properties to observe changes in soil due to land use and agricultural cultivation practices. The soil quality status in this study was determined by calculating the value of soil quality rating (SQR) based on the weighting of 11 indicators of soil quality. The results showed that soil quality before the research was bad (SQR 30) and improved to moderate (SQR 27) until a good (SQR 20) after the research of biochar, compost and NPK phonska on the cornfield. Improved soil quality in biochar formulations 10.52 t ha-1, compost, and phonska, due to improved soil physical properties such as porosity, bulk density, and soil moisture content, which has encouraged the process of exchange and chemical reactions in the soil to release nutrients for the plant. Giving of bamboo biochar, compost, and NPK phonska on dry land cultivated maize has resulted in good soil quality (SQR 20) or approaching sustainability status is very good (highly sustainable).


2019 ◽  
pp. 68-73

The decline in soil organic matter, nutrient depletion, and loss of soil fertility due to soil degradation contribute to low agricultural productivity. Organic amend- ments (OAs) have the potentials to reverse soil degradation processes by improv- ing the soil's physical and chemical properties and consequently improve crop growth and yield performance. At Cranfield University, United Kingdom, a greenhouse study investigated the effects of Mushroom Compost, Anaerobic Di- gestate Waste, and Poultry Manure amendments applied at 10 t ha-1 and 30 t ha-1 equivalent rates on the physical and chemical properties of degraded soil. The treatments were laid out in the greenhouse in a completely randomized design replicated four times. The results showed that all the OA treatments significantly increased the soil water holding capacity, total porosity, and significantly reduced bulk density when compared with the un-amended control treatment. Further, the OA treatments showed significant increases in the soil Total-P, Olsen-P, Total-N, total oxides of N, ammonium-N, Available-K, and Available-Mg, relative to the control treatment. The results demonstrate the effectiveness of these OAs in im- proving soils’ physical and chemical properties, and so enhancing soil health and overall ecosystem functioning. The study demonstrated that these OAs improve the physicochemical properties of degraded so


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