The effects of conversion of tropical rainforest to rubber plantation on splash erosion in Xishuangbanna, SW China

Abstract

The Xishuangbanna (SW China) landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations. This study characterized the influence of conversion of tropical rainforest to rubber plantation on potential splash erosion rate and actual splash erosion rate. The average potential splash erosion rate was 2.1 times higher in the rubber plantation than in the open, while for the rainforest it was only 1.2 times higher than in the open, suggesting that the rubber plantation canopy greatly increased the rainsplash erosion. The average actual splash erosion rate was 2.0 times higher in the rubber plantation than in the rainforest, demonstrating that the rainforest was more effective in controlling splash erosion. The actual splash erosion rate was considerably lower in the terrace bench than in the riser bank in the rubber plantation, indicating that the riser bank was more sensitive to raindrop splash. Hence, protection of terrace risers with productive vegetation or litter/mulch layer is of vital importance in this bench-terraced rubber plantation. These results clearly show that conversion of tropical rainforest to rubber plantation had a negative effect on controlling splash erosion.

Land Degradation Controlled and Mitigated by Rubber‐based Agroforestry Systems through Optimizing Soil Physical Conditions and Water Supply Mechanisms: A Case Study in Xishuangbanna, China

“…However, the occurrence of runoff on the surface soil presupposes that the rainfall intensity exceeds the rate of water infiltration, and clearly, the rainfall intensity is greater than the rate of water infiltration in rainforests. Thus, ground cover (litter layer and moss layer), which covers the forest floor, would be more effective in runoff and erosion control, surface runoff reduction, and soil and water conservation (Liu et al ., ). In the present study, the agroforestry systems presented more litter and lower sand loss.…”

“…The expansion of rubber monoculture plantation took responsibility for the land degradation in Xishuangbanna during the past three decades (Zomer et al ., ), although the expansion has nearly ceased at present (Zhang et al ., ). Compared with primary tropical forests, areas of rubber ( Hevea brasiliensis ) monoculture are characterized by low biodiversity, low total biomass carbon stocks, excessive water loss and soil erosion (Ziegler et al ., ); soil hardening and crusting (Liu et al ., ); losses in soil organic matter (Li et al ., ); and rapidly fluctuating microclimate temperatures and negative hydrological effects (Ziegler et al ., ; Liu et al ., ). Additionally, owing to their low genetic diversity, rubber monoculture plantations are also vulnerable to plant diseases, pests and environmental conditions (Mann, ).…”

“…Such crops or combinations of crops are grown under rubber trees to maximize the available space at different heights and consequently improve the use of the land resources. The multilayered structures of rubber‐based agroforestry systems can also reduce wind speed, maintain the stability of internal microclimates, control water runoff and erosion (Liu et al ., ), weaken rain splash erosion (Liu et al ., ), redistribute rainfall, fix carbon (Li et al ., ), improve resistance and resilience (Verchot et al ., ), restore degraded lands and promote ecosystem stability (Parham, ). Moreover, these systems can facilitate the diversification of agroforestry and accelerate returns on investment (Snoeck et al ., ).…”

Urban Expansion and Its Impact on the Land Use Pattern in Xishuangbanna since the Reform and Opening up of China

“…As a result of these laws, the rate of forest loss declined, and instead, more shrub land was converted to rubber after 2000. Compared to rubber, natural forest functions better in controlling splash erosion [59] and soil erosion (e.g., pH and soil nitrogen) [60]. Soil erosion in monoculture rubber plantations is 40-times more than that in natural rainforest [55].…”

The transition from arable lands to rubber tree plantations in northern Thailand impacts weed assemblages and soil physical properties

“…However, these plantations also have severe effects on soil conservation: while in young plantations the soil is often protected by intercrop or understorey, mature plantations are usually clean‐weeded. Most studies investigating the impact of RT plantations on soil and biodiversity compared monocultures with lightly disturbed environments such as secondary forests (Liu et al ., ), or with other tree crops such as teak or palm tree (Guillaume et al ., ). They found that in flat areas, RT monocultures decrease insect, bird and plant species richness and soil quality compared to forests (Beukema et al ., ), but are similar to or have slightly higher biodiversity and soil conditions than other tree plantations (Gnanavelrajah & Shrestha, ; Guillaume et al ., ).…”