Effects of land-use changes on runoff and sediment yield: Implications for soil conservation and forest management in Xishuangbanna, Southwest China

Abstract. Land degradation resulting from improper land use and management is a major cause of declined productivity in the arid environment. The objectives of this study were to examine the effects of a sequence of land use changes, soil conservation measures, and the time since their implementation on the degradation of selected soil properties. The climate for the selected 105 km2 watershed varies from semi-arid sub-tropical to Mediterranean sub-humid. Land use changes were detected using aerial photographs acquired in 1953, 1978, and 2008. A total of 218 samples were collected from 40 sites in three different rainfall zones to represent different land use changes and different lengths of time since the construction of stone walls. Analyses of variance were used to test the differences between the sequences of land use changes (interchangeable sequences of forest, orchards, field crops, and range), the time since the implementation of soil conservation measures, and rainfall on the thickness of the A-horizon, soil organic carbon content, and texture. Soil organic carbon reacts actively with different combinations and sequences of land use changes. The time since stone walls were constructed showed significant impacts on soil organic carbon and the thickness of the surface horizon. The effects of changing the land use and whether the changes were associated with the construction of stone walls, varied according to the annual rainfall. The results help in understanding the effects of land use changes on land degradation processes and carbon sequestration potential and in formulating sound soil conservation plans.

Download Full-text

Effects of land use changes and soil conservation intervention on soil properties as indicators for land degradation under a Mediterranean climate

Solid Earth ◽

10.5194/se-6-857-2015 ◽

2015 ◽

Vol 6 (3) ◽

pp. 857-868 ◽

Cited By ~ 32

Author(s):

Y. Mohawesh ◽

A. Taimeh ◽

F. Ziadat

Keyword(s):

Land Use ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Soil Properties ◽

Land Degradation ◽

Soil Conservation ◽

Land Use Changes ◽

Stone Walls ◽

Effects Of Land Use ◽

Soil Conservation Measures

Abstract. Land degradation resulting from improper land use and management is a major cause of declined productivity in the arid environment. The objectives of this study were to examine the effects of a sequence of land use changes, soil conservation measures, and the time since their implementation on the degradation of selected soil properties. The climate for the selected 105 km2 watershed varies from semi-arid sub-tropical to Mediterranean sub-humid. Land use changes were detected using aerial photographs acquired in 1953, 1978, and 2008. A total of 218 samples were collected from 40 sites in three different rainfall zones to represent different land use changes and variable lengths of time since the construction of stone walls. Analyses of variance were used to test the differences between the sequences of land use changes (interchangeable sequences of forest, orchards, field crops, and range), the time since the implementation of soil conservation measures, rainfall on the thickness of the A-horizon, soil organic carbon content, and texture. Soil organic carbon reacts actively with different combinations and sequences of land use changes. The time since stone walls were constructed showed significant impacts on soil organic carbon and the thickness of the surface horizon. The effects of changing the land use and whether the changes were associated with the construction of stone walls varied according to the annual rainfall. The changes in soil properties could be used as indicators of land degradation and to assess the impact of soil conservation programs. The results help in understanding the effects of land use changes on land degradation processes and carbon sequestration potential and in formulating sound soil conservation plans.

Download Full-text

Effects of Land Use Changes on Streamflow and Sediment Yield in Atibaia River Basin—SP, Brazil

Water ◽

10.3390/w12061711 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1711 ◽

Cited By ~ 1

Author(s):

Franciane Mendonça dos Santos ◽

Rodrigo Proença de Oliveira ◽

José Augusto Di Lollo

Keyword(s):

Land Use ◽

Sensitivity Analysis ◽

River Basin ◽

Sediment Yield ◽

Assessment Tool ◽

Land Use Changes ◽

Curve Number ◽

Moisture Condition ◽

Land Use Scenario ◽

Effects Of Land Use

The Soil and Water Assessment Tool (SWAT) is often used to evaluate the impacts of different land use scenarios on streamflow and sediment yield, but there is a need for some clear recommendations on how to select the parameter set that defines a given land use scenario and on what is the most appropriate methodology to change the selected parameters when describing possible future conditions. This paper reviews the SWAT formulation to identify the parameters that depend on the land use, performs a sensitivity analysis to determine the ones with larger impacts on the model results and discusses ways to consider future land use conditions. The case study is the Atibaia river basin, with 2838 km2 (São Paulo, Brazil). The parameters identified by sensitivity analysis with the largest impacts on streamflow and sediment yield were the initial curve number for moisture condition II (CN), maximum canopy storage for each land use (CANMX) and the cover and management factor (USLE_C). The identification and appropriate parameter change can provide real estimates of the magnitudes in the land use changes, which were verified in this study. Such information can be used as an instrument for proposing improvements in the basin’s environmental quality and management.

Download Full-text

Modeling runoff response to land-use changes using the SWAT model in the Mundaú watershed, Brazil

Journal of Environmental Analysis and Progress ◽

10.24221/jeap.5.2.2020.2828.194-206 ◽

2020 ◽

Vol 5 (2) ◽

pp. 194-206

Author(s):

Carolyne Wanessa Lins de Andrade Farias ◽

Suzana Maria Gico Lima Montenegro ◽

Abelardo Antônio de Assunção Montenegro ◽

José Romualdo de Sousa Lima ◽

Raghavan Srinivasan ◽

...

Keyword(s):

Land Use ◽

Land Use Change ◽

Sediment Yield ◽

Surface Runoff ◽

Assessment Tool ◽

Swat Model ◽

Land Use Changes ◽

Water Yield ◽

Grazing Land ◽

Runoff And Sediment Yield

Land-use change has a significant influence on runoff process of any watershed, and the deepening of this theme is essential to assist decision making, within the scope of water resources management. The study was conducted for Mundaú River Basin (MRB) using the Soil and Water Assessment Tool (SWAT) model. The study aims to assess the issue of land-use change and its effect on evapotranspiration, surface runoff, and sediment yield. Input data like land use, topography, weather, and soil data features are required to undertake watershed simulation. Two scenarios of land use were analyzed over 30 years, which were: a regeneration scenario (referring to use in the year 1987) and another scene of degradation (relating to use in the year 2017). Land use maps for 1987 and 2017 were acquired from satellite images. Overall, during the last three decades, 76.4% of forest was lost in the MRB. The grazing land increased in 2017 at a few more than double the area that existed in 1987. Changes in land use, over the years, resulted in an increase of about 37% in the water yield of MRB. Changes have led to increased processes such as surface runoff and sediment yield and in the decrease of evapotranspiration. The spatial and temporal distribution of land use controls the water balance and sediment production in the MRB.

Download Full-text