Impact of climate change on soil erosion and sediment yield at Hilly Farms of Cameron Highlands, Malaysia
Soil erosion is one of the major environmental problems worldwide and is becoming serious limiting factor for crop production everywhere. It seriously impacts crop productivity by removing topmost soils and results into devastating almost irreversible damages. In Cameron Highlands, soil erosion h...
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/92918/1/FK%202021%2033%20-%20IR.1.pdf |
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| Summary: | Soil erosion is one of the major environmental problems worldwide and is
becoming serious limiting factor for crop production everywhere. It seriously
impacts crop productivity by removing topmost soils and results into devastating
almost irreversible damages. In Cameron Highlands, soil erosion has been a major
environmental issue causing huge loss of agricultural soil and increasing rates of
landslides. Recent studies and field surveys have reported that there is excessive soil
erosion in Cameron Highlands with increasing risk of erosion-induced landslides
and sedimentation of major water reservoirs. The purpose of this study was to
project soil erosion and sediment yields to 2050s (2040-2069) and 2080s
(2070-2099) under different climate change impact scenarios. The objective was
also, to evaluate effectiveness of erosion control best management practices (BMPs)
toward minimizing the potential soil erosion in Cameron Highlands using Global
Circulation Models (GCMs) and four Representative Concentration Pathways
(RCPs). To achieve this, precipitation datasets were obtained from World Data
Center for Climate and downscaled using 30 years observed local precipitation
data. intensity-frequency-duration (IDF) curves were constructed for current and
future 2050s and 2080s scenarios. The rainfall trend was analyzed using Mann-
Kendall and Sense’ slope tests at 5% significance level. Soil erosion was assessed using
Revised Universal Soil Loss Equation (RUSLE) model. Moreover, soil erodibility (Kfactor)
was developed through combination of field survey and existing soil series.
Furthermore, crop management (C-factor) was established for current and
future scenarios using Land Change Modeler (LCM) embedded in TerrSet software.
Landsat 7 and 8 images were analyzed using IDRISI image processing software and
simulated future land use scenarios by applying Markov Chain model.
Furthermore, field experiments on erosion control BMPs were conducted at Cameron
Highlands farm using three varieties of mustard crop (Green Apex 5502, Lucket 9116
and Little Princess 822) sown under both open and sheltered farms.
The study revealed that performance of precipitation model indicated by KGE, NSE, RMSE, SE, MAE and MBE, are 0.64, 0.27, 1.25, 0.37, 1.63 and 0.15, respectively. The simulated precipitations were found to increase relative to baseline period by 6.8%, 12.9%, 20%, and 37% for 2050s; 16.1%, 28.6%, 39.2% and 42.3% for 2080s under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenarios, respectively. Projected IDF curves
were found greater than the baseline condition under 2, 5, and 20 years return
periods. The highest erosivity (R-factor) of 6,039 MJ mm ha– 1 hr– 1 yr– 1 was found at
Tanah Rata sub-catchment by 2080s under RCP8.5 scenario, which indicated 83%
increase relative to baseline. Moreover, spatial variation of K-factor was found ranged
from 0.00113 to 0.01613. The erosion projection showed that severe to extreme forms
of soil erosion (>50 t ha-1) will occupy 12.44% of the study catchment, with highest
annual soil loss of 1.71× 10 6 ton by 2080s under RCP8.5 scenario. Similarly, the
corresponding severe sediment yields will be 243,061 t ha-1year-1 which represents
57.6% of total soil loss by 2080s under RCP8.5 scenario. Sediment Delivery Ratio
(SDR) was computed as 0.208 which signifies the fraction of soil loss deposited
outside the study watershed. The field experiments revealed highly significant effect
of three BMPs (terracing, sediment trap and waste management) on sediment yields
generation in both open and sheltered farms. It has been presented that, largest
sediment yields of 13.9 ton/ha, 14.2 ton/ha and 14.5 ton/ha are collected from open
farm control plots sown with Green Apex 5502, Lucket 9116 and Little Princess
822, respectively. However, the application of the control BMPs achieved high
sediment reductions of 53.8%, 54%, and 52.3%, under terracing, sediment trap
and waste management, respectively. In the other hand, the sheltered farm BMPs
achieved more sediment reductions of 65.4%, 59%, and 53.8% under terracing,
sediment trap and waste management, respectively. Additionally, the crop yield
performance shows a significant effect of the varieties of mustard, but not with the types
of farms, on total sediment yields. It is noted that, nutrients loss in the runoff is a crucial
factor of crop cultivation, however, this study did not evaluate it due to complexity
of the work. In general, the study simulated the impact of climate change on
erosion and sediment yields at Cameron Highlands and revealed the effects of control
BMPs under both sheltered and open farms. This information is essential toward
reducing large amount of predicted soil loss due to effect of climate change and will
support the management and policies makers to design effective soil conservation
measures. |
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