Rubber-based Agroforestry Systems Research Articles

Response of N, P, and metal ions in deep soil layers to long-term cultivation of rubber and rubber-based agroforestry systems

Response of N, P, and metal ions in deep soil layers to long-term cultivation of rubber and rubber-based agroforestry systems

Determining Suitable Sampling Times for Soil CO2 and N2O Emissions Helps to Accurately Evaluate the Ability of Rubber-Based Agroforestry Systems to Cope with Climate Stress

Agroforestry is known to significantly improve long-term land productivity, potentially enhancing the ability to cope with climate stress. However, there is limited information regarding the accurate monitoring of greenhouse gases (GHGs) in rubber-based agroforestry systems. Before GHGs can be accurately estimated, the diurnal variations and suitable sampling times must be studied to reduce the uncertainty of the manual static chamber method. In this study, the soil GHGs emitted from conventional single-row (SR) and improved double-row (DR) rubber plantations were compared across the dry and wet seasons in Hainan, China. A total of 1728 GHG samples from a field trial were collected, analyzed, and related to environmental factors. The results demonstrated that the diurnal fluxes of CO2 in rubber plantations were likely to remain fluctuating, with the maximum typically occurring during the night-time and daytime hours of the dry and wet seasons, respectively. A clearer double-peak (around 2:00 and 14:00) during the dry season and a daytime peak (14:00) during the wet season of the N2O were recorded. In addition to the commonalities, different seasons and different types of GHGs and rubber plantations also differed in their detailed fluctuation times and ranges; therefore, the determination of suitable sampling times should not ignore these factors in certain cases. Based on this study, it was determined that the late afternoon (16:00–18:00) was the suitable sampling time of soil GHGs in rubber plantations, instead of the most common morning times (with an underestimation of 25% on average). In addition, the air humidity during the dry season and the soil temperature during the wet season were both positively correlated with GHGs (p < 0.05). This study highlights the significance of accurately monitoring soil GHGs in rubber-based agroforestry systems, providing a basic reference for the development and management of climate-smart land use practices in rubber plantations.

Rubber-based agroforestry systems modify the soil fungal composition and function in Southwest China

Rubber-based agroforestry systems modify the soil fungal composition and function in Southwest China

Acclimatization of Tropical Palm Species Associated with Leaf Morpho-Physiological Traits to the Understorey Environment of Hevea Rubber Farms

Hevea rubber farm is viable for agroforestry systems since its canopy lessens extreme weather conditions and contributes to the adaptation of shade-tolerant plants. However, some limitations in the availability of soil water and shades vary with the age of rubber trees and affect the understorey plants’ acclimatization. Tropical palms are potentially associated plants for the rubber-based agroforestry systems because they are rainforest species adaptable to understorey environments. Two rubber farms, ages 12 and 25 years, intercropped with tropical palms were selected to investigate the acclimatization of the palms to the seasonal abiotic variations in the mature rubber farms. The studied palm species were Chrysalidocarpus lutescens and Rhapis excelsa in the 12-year-old rubber farm and Livistona speciosa and Licuala spinosa in the 25-year-old rubber farm, respectively. Leaf area, stomatal conductance, photosynthesis pigments, and leaf nitrogen content were identified as the palms’ morpho-physiological traits. The 12-year-old rubber farm had a marked soil water deficit in all soil depths at the beginning of the rainy season, reaching around 200 kPa at the 80 cm soil depth, while the 25-year-old rubber farm received greater light transmissions, ranging between 37 and 46% in the late dry season. All palms adjusted leaf area to balance the photosynthetic capacity. The Rhapis palm had greater acclimatization with significant responses of stomatal conductance. Other than the Licuala palm, all palms exhibited the allocation of chlorophyll pigments and nitrogen content significantly in their leaves in response to the different intensities of abiotic stresses in the understorey of the rubber farms.

Preliminary Study on the Effect of Different Ecological Cultivation Modes on the Water Stability of Soil Aggregates in Rubber Based Agroforestry Systems

Preliminary Study on the Effect of Different Ecological Cultivation Modes on the Water Stability of Soil Aggregates in Rubber Based Agroforestry Systems

Carbon stock of tree biomass, litter and soil in rubber based agroforestry systems

Agroforestry systems (AFSs) that have rubber tree as the main tree component are important productive systems in the Brazilian Amazon. This work aimed to evaluate carbon stock (CS) of tree biomass, litter and soil in rubber based AFSs in South-Western Amazon. The analytical observational study was carried out in Rolim de Moura (RO) from June 2018 to March 2019 and it consisted of five areas: three AFSs, a forest fragment (FL), and a pasture (PA). CS of tree biomass was determined using allometric equations, while litter and soil carbon stocks were performed through material collection and chemical analysis. Total carbon stock of AFS 1, AFS 2, and AFS 3 was 181.36, 165.77, and 99.08 Mg ha-1, and soil was the compartment that most contributed to the EC of these systems, with stocks of 108.06, 88.71, and 72.68 Mg ha-1, respectively. Total stock of FL was 188.02 Mg ha-1 and PA was 88.19 Mg ha-1. The older AFSs, with greater floristic richness, greater basal area and with the presence of cupuassu tree as a secondary crop had total carbon stock similar to the forest area, evidencing the potential of these systems to sequester atmospheric CO2.

Perennial cover crop biomass contributes to regulating soil P availability more than rhizosphere P-mobilizing capacity in rubber-based agroforestry systems

Cover crops used in agroforestry systems (AFS) are generally perceived to improve soil quality, but mechanisms underlying phosphorus (P) cycling in complex rhizosphere system are less clear, because the impacts of incorporated crops are often determined by inclusion time, residue management and species. We quantified 7-year cumulative effects of perennial legume cover crop–Flemingia macrophylla on rhizosphere P cycling and availability during the dry and wet seasons in young and mature rubber-based AFS (i.e., YAFS and MAFS) in tropical China by analyzing cover crop biomass and P content, as well as net rhizosphere changes in P-mobilizing capacity (pH, organic acids and phosphatase activity) and P fractions. Compared to their monoculture counterparts, YAFS enhanced plant biomass and P stock in both seasons, whereas MAFS exhibited an opposite trend, except for increased biomass and P stock of floor litter in the dry season. Moreover, YAFS had a greater effect on net rhizosphere properties by reducing pH and increasing organic acids concentrations and acid phosphatase activity, but MAFS hardly alter them. However, these changes had little effect on net rhizosphere P fractions in both seasons, except the contribution of calcium–P to increasing P availability to a certain extent. Net rhizosphere organic P and microbial biomass P in YAFS were enhanced in both seasons by abundant residue returns from cover crop. Net rhizosphere available P surplus occurred in YAFS in the dry season and maintained balance in the wet season, but it almost reached a deficit in MAFS in both seasons. These results suggest that rhizosphere P cycling was more improved by cover crop in YAFS than MAFS, and biomass of cover crop residue contributed to regulating rhizosphere P cycling and availability more than rhizosphere P-mobilizing capacity. Our study highlights the importance of residue management of permanent cover crops on rhizosphere P cycling and availability in AFS with different ages.

Challenges of the establishment of rubber-based agroforestry systems: Decreases in the diversity and abundance of ground arthropods

The global land area devoted to rubber plantations has now reached 13 million hectares, and the further expansion of these rubber plantations at the expense of tropical forests will have significant adverse effects on the ecological environment. Rubber-based agroforestry systems are considered a preferable approach for ameliorating the ecological environment. Many researchers have focused on the positive effects of rubber-based agroforestry systems on the ecological environment, while ignoring the risks involved in the establishment of rubber-based agroforestry systems. The present study investigated the effects of different-aged rubber-based agroforestry systems on the abundance and diversity of ground arthropods. It has been observed that the abundance and taxon richness of ground arthropods generally showed no difference when comparing young and mature rubber plantations. The rubber-based agroforestry systems significantly decreased the understory vegetation species, along with the abundance and taxon richness of ground arthropods compared to the same aged-rubber monoculture plantations. In addition, the change in the abundance and taxon richness of ground arthropods was greatly affected by the understory vegetation species and soil temperature. The abundance and taxon richness of ground arthropods decreased with the decrease in number of species of understory vegetation. The study results indicate that the establishment of rubber-based agroforestry systems have adversely affected the abundance and richness of ground arthropods to an extant greater than expected. Therefore, single, large rubber-based agroforestry systems are not recommended, and the intercropping of rubber and rubber-based agroforestry systems must be designed to promote the migration of ground arthropods between different systems.

Sustainability of rubber agroforestry strategies in boosting smallholders’ resilience to cope with the realities of new global challenges

In the face of a global pandemic, the ever-present threat of climate change and the highly unstable economic and social global systems the resource poor smallholder farmer is increasingly finding it harder to meet with the daily challenges of sustaining the livelihood of the farmer and his family. This paper is a review of the challenges of smallholder’s rubber farmers, strategies adopted to build the resilience of the farmers and technological adaptations to sustain the resilience of the smallholder’s rubber farmers in Nigeria. The work looked at the manipulation of space or spacing techniques in rubber-based agroforestry systems, mixed farming in rubber production, cropping patterns, soil nutrient and weed management methods and socioeconomic benefits to the rubber smallholders. The results indicated that RBAF systems helped resource poor rural farmers increase family food supply, improved income and reduced the gestation period of rubber leading to improved livelihood. This results will help in attracting more smallholders to rubber plantation establishment, leading to increased national rubber production for local and international markets and increase industrial development in rubber and rubber related products.

Intercrops improve surface water availability in rubber-based agroforestry systems

Despite the development of rubber agroforestry systems for ecological and economic benefits in Southeast Asia, knowledge of their water uptake dynamics and interspecific water interactions remains limited. The objective of this study is to reveal the water relations (i.e., competition/complementarity) between rubber (Hevea brasiliensis) trees and different kinds of intercrops. We investigated the stable isotopes (δD and δ18O), fine root length density, and soil water content (SWC) under three agroforestry practices and one rubber monoculture across a year (2017/2018). Our results indicated that rubber trees acquired more than 40.5 ± 21.3 % of their water from shallow (0−20 cm) soil stratum, as do perennial galangal (Alpinia officinarum), tea (Camellia sinensis), and cocoa (Theobroma cacao). The complementarity hypothesis was not supported for rubber trees and the intercrops. In the dry season (November to April), there was strong interspecific competition for shallow water resources where the intercropping was practiced. However, intercropping increased the available soil water, enabling rubber trees to acquire more (9.4–24.3 %) shallow soil water. In the wet season (May to October), interspecific water competition was less pronounced based on the relative difference in soil water content (RDSW). Higher relative water content, in the order rubber-galangal > rubber-tea > rubber-cocoa, further showed that facilitative effects dominated interspecific water competition in all the agroforestry practices. This information regarding water relations between rubber trees and their intercrops will be essential to optimize land and water resource utilization in this region.

Use of dye infiltration experiments and HYDRUS-3D to interpret preferential flow in soil in a rubber-based agroforestry systems in Xishuangbanna, China

The soil hydrological process plays an important role in transporting and distributing water in soils. However, the correlation between water flow behaviors, soil physical properties, infiltration patterns of soil exhibiting different soil layers, and the variation patterns in water flow behavior in rubber-based agroforestry systems remain poorly understood. Here, we mainly used dye-tracer infiltration to classify water flow behavior and HYDRUS-3D to interpret variation patterns of water flow behaviors in a rubber-based agroforestry system in southwest China. The results showed that (1) the soil of forestry patches under Hevea brasiliensis (HB) and Citrus reticulata (CR) exhibited better soil physical properties than those with no vegetation (NV). Compared with these in the NV, the saturated soil water content and field capacity increased by 15% and 21% in CR, and by 2% and 12% in HB, respectively; while the saturated hydraulic conductivity enhanced by 584% (p < 0.001) in the CR plot and by 226% (p < 0.001) in the HB plot. Correlation analysis shows that the soil bulk density, noncapillary porosity and capillary porosity significantly affected the field capacity, saturated water-holding capacity, and saturated hydraulic conductivity. (2) the general infiltration capacity of the whole soil profile, its order of continuity and the degree of connectivity of preferential flow path networks followed the order of CR > HB > NV. Finally, (3) the infiltration flow in soil under HB and CR exhibited a faster downward wetting front and an obvious lateral flow. These infiltration patterns compensated for the insufficiency of soil water in NV and finally caused water redistribution to be more homogenized across the whole soil profile. Therefore, our findings indicated that the rubber-based agroforestry system is a successful approach for conserving water and reducing runoff in tropical regions.

Introduction of a leguminous shrub to a rubber plantation changed the soil carbon and nitrogen fractions and ameliorated soil environments

The conversion of monoculture rubber (Hevea brasiliensis) plantations into rubber-based agroforestry systems has become a common trend in forestry management in the past few decades. Rubber–Flemingia macrophylla (a leguminous shrub) systems are popular in southwestern China’s Xishuangbanna region. The biogeochemical cycles of soil carbon and nitrogen in forests are mainly affected by their fractions. This study investigated the effect of introducing Flemingia macrophylla to rubber plantations of different ages on soil carbon and nitrogen fractions. The experimental treatments included R1 (young rubber plantation), RF1 (young rubber–Flemingia macrophylla system), R2 (mature rubber plantation) and RF2 (mature rubber–Flemingia macrophylla system). The results showed that the introduction of Flemingia macrophylla to rubber plantations of different ages significantly changed soil carbon and nitrogen fractions, improved soil labile organic carbon and nitrogen contents, and ameliorated soil environments. The average soil microbial biomass organic carbon, nitrogen and nitrate-nitrogen in the 0–10 cm soil layer during the experimental period was 38.9%, 55.5%, and 214.7% higher in RF1 than R1, respectively, and 22.1%, 22.2%, and 652.2% higher in RF2 than R2, respectively. Therefore, Flemingia macrophylla can be used as an alternative interplanted tree species within rubber plantations in similar environments of southeastern Asia.

The effects of introducing Flemingia macrophylla to rubber plantations on soil water content and exchangeable cations

Rubber-based (Hevea brasiliensis) agroforestry systems are the best way to resolve the environmental problems caused by rubber monoculture. Rubber–Flemingia macrophylla (nitrogen-fixing plants) systems have become popular in Xishuangbanna, Southwest China. Soil water content and exchangeable cations (Ca2+, Mg2+, K+, and Na+) are important for sustainably managing forest ecosystems. In this study, we investigated the responses of soil water content and exchangeable cations in rubber and rubber–Flemingia macrophylla systems. Soil water content increased in the 0–90 cm soil layer as the rubber plantations aged, and the mature rubber plantations had similar soil water storage to rainforests. The rubber plantations use soil water in the 30–90 cm soil layer to avoid drought stress during the long, dry season. The introduction of Flemingia macrophylla to the young rubber plantations significantly increased soil water depletion in the 30–90 cm soil layer. The introduction of Flemingia macrophylla to the mature rubber plantations had no significant effects on soil water in the 0–90 cm soil layer. The introduction of Flemingia macrophylla to the differently aged rubber plantations mitigated soil acidification by decreasing nitrogen inputs. The total exchangeable cations in the 0–90 cm soil layer sharply decreased as the rubber plantations aged due to the acceleration of soil acidification. When soil pH was below 5.5, 7.85 cmol kg−1 of soil exchangeable cations were released when the pH decreased by one unit. However, the introduction of Flemingia macrophylla to the differently aged rubber plantations effectively reduced the release of soil exchangeable cations by mitigating soil acidification. In conclusion, rubber–Flemingia macrophylla systems can mitigate soil acidification and reduce the release of soil exchangeable cations relative to rubber monoculture.

Can intercropping with the cash crop help improve the soil physico-chemical properties of rubber plantations?

Although rubber-based (Hevea brasiliensis) agroforestry systems are regarded as the best approach to improving the sustainability of rubber agriculture and environmental conservation, soil physico-chemical properties and their related interactions have rarely been examined in such systems. The objective of this study was to examine the management and landscape effects on soil structure, soil moisture and soil nutrients in the Xishuangbanna region. The treatments were tropical rain forest (TRF), rubber monoculture (Rm), and two rubber-based agroforestry systems: H. brasiliensis–T. cacao (HTAs) and H. brasiliensis–F. macrophylla (HFAs). The results showed that after approximately three decades of the conversion from tropical rain forest to rubber monoculture, soils in the rubber plantations suffered serious degradation (poor soil physical properties, poor soil structure, limited soil moisture, unstable aggregates, depleted nutrients and serious soil erosion). However, the rubber-based agroforestry systems (both HTAs and HFAs) evidently improved the soil physical properties and enriched the soil nutrients in the rubber plantations. Compared to the corresponding values in rubber monoculture, the total soil porosity, initial soil moisture, soil mean weight diameter (MWD) and soil hydraulic conductivity (Ks) in rubber-based agroforestry systems increased, on average, by 13.3%, 54.7%, 31.5%, and 246.4%, respectively. In addition, the nutrients of C, N, P, Ca and Mg increased, on average, by 38.8%, 38.5%, 48.2%, 47.9% and 31.4%, respectively, after the transformation from rubber monoculture to agroforestry systems. Our results clearly indicated that the soil physico-chemical properties of rubber plantations were improved by interplanting, and the patterns of the intercropping system could play key roles in promoting the sustainable development of agriculture and the environment.

Income Diversification for Rubber Farmers Through Agroforestry Practices

This study was conducted in the framework of the ANR/Heveadapt project1, in Southern Thailand (Phatthalung province), to analyze how smallholder tree plantations can adapt and survive in the face of profound changes in their socio-economic context. The study focus on rubber-based agroforestry systems in mature plantations to understand the extent to which respectively, rubber, associated crops, trees, livestock, and off-farm activities, contribute to income stability and farm resilience. Socio-economic performances were evaluated at two scales: the cropping system and the farming system using farming system modelling with the software Olympe. The characterization of farm economic structure shed light on two main strategies used by farmers to maintain their income despite volatile rubber prices. The best agroforestry systems, both in terms of land and labor valorization, associate rubber trees with fruit and timber trees. Farmers also take on off-farm activities to complement their family income. Finally, prospective modeling showed that most farms were robust to rubber price volatility due to the flexibility of their agroforestry systems. Farmers with no agroforestry system were weakened by over-reliance on rubber trees.

Phosphorous fractions in soils of rubber-based agroforestry systems: Influence of season, management and stand age

Rubber-based agroforestry system is a vital management practice and its productivity is often controlled by soil phosphorus (P) nutrient, but little information is available on P fractions dynamics in such system. The aim of this study was to examine the seasonal, management and stand age effects on P fractions, acid phosphatase activity, microbial biomass P, other physical-chemical properties and litter and roots in four systems: 10-year-old rubber mono- (YM) and intercropping (YI) with N-fixing species (NFS), 22-year-old mono- (MM) and intercropping (MI) in Xishuangbanna, Southwestern China. Most P fractions varied seasonally at different depths, with highest values in the fog-cool season (i.e. labile P at 5–60cm, non-labile P and total P at 30–60cm). By contrast, moderately labile P varied little over time, except in MI that had lower values in the rainy season. Compared with their monoculture counterparts, YI doubled resin-Pi concentration but decreased NaHCO3-extractable P, HCl-Pi and residual-Po at the 0–30cm depth, whereas MI had hardly any changes in P species at the 60-cm depth. Surprisingly, residual-Po was enriched down to the deepest soil (30–60cm) in both YI and MI in the fog-cool season. All P fractions, except NaOH0.1-Pi, were greatly reduced with increasing stand age. In addition to plants uptake, these changes can be explained by seasonality in soil environments (e.g. moisture, temperature, pH and microbial activity) and decomposition of litter and roots. Moreover, YI decreased labile Po stock, but MI increased moderately labile Pi at the 60-cm depth across seasons. The results imply that a large amount of residual-Po exists in acidic Oxisol from China and that they can be reasonably exploited to reduce the application of P fertilizers, highlighting the importance of Po pool. Taken together, intercropping mature rubber plantation with NFS appears to be an effective way to enhance productivity while maintaining adequate soil P concentration over the long run.

Throughfall kinetic energy and its spatial characteristics under rubber-based agroforestry systems

Rubber is usually grown as a monoculture but there have been recent attempts to encourage rubber-based agroforestry systems to reduce adverse environmental impacts, including the reduction of soil erosion in Xishuangbanna, SW China. To estimate the influence of different types of rubber-based agroforestry systems on soil erosion processes, we measured the throughfall kinetic energy (TKE) under different vegetation types by using 640 sand-filled Tübingen splash cups. This study was conducted in Xishuangbanna Tropical Botanical Gardens under natural rainfall conditions. Our results indicated that in both rubber-based agroforestry systems and rubber monocultures, a significant linear positive correlation exists between TKE and rainfall amount. Rainfall amount is a critical factor that contributes to soil detachment in rubber plantations in this region. TKE under rubber plantation conditions was found to be notably higher than under open field conditions (ranging from 1.84 to 2.32 times greater). However, there was no significant difference under multiple canopies compared to monoculture. TKE values under the different rubber-based agroforestry systems were closely related to the canopy structure, and TKE and leaf area index were significantly negatively correlated. The spatial variability of TKE was higher in rubber-based agroforestry systems than in rubber monocultures. In addition, TKE was usually concentrated in 3–4m bands that did not have the protection of a sub-canopy. The fact that the erosion by TKE under rubber-based agroforestry was still high highlights the importance of selecting intercrops when constructing rubber-based agroforestry systems and of improving planting patterns.

Adoption of intercropping among smallholder rubber farmers in Xishuangbanna, China

ABSTRACTWhile the expansion of rubber plantations in the mountainous areas of Southern China has contributed to poverty reduction among the indigenous ethnic groups, the concerns about the associated negatives on ecosystems and sustainable development of livelihoods is rising. One of the measures suggested to reduce environmental and economic risks is rubber intercropping. This study uses cross-section data of some 600 rubber farmers in Xishuangbanna, as a basis to develop four empirical models in order to analyse adoption of intercropping at farm and at plot level. Our study shows that only a small proportion of rubber farmers have adopted intercropping, with tea being the most frequently adopted intercrop. However, we also find that intercropping is an important source of income for the household in the lower income category. Intercropping adoption is affected by ethnicity, household wealth and family labour. The choice of intercrops depends on the nature of rubber plots, the age of rubber trees and geography. This study contributes to a better understanding of the transformation path from rubber monoculture to more diversified, rubber-based agroforestry systems and thus can provide important information for agricultural extension services charged with the promotion of sustainable rubber-based livelihood systems in the Mekong area.

Effects of rubber-based agroforestry systems on soil aggregation and associated soil organic carbon: Implications for land use

Rubber-based agroforestry (Hevea brasiliensis) systems are considered the best way to improve soil properties and the overall environmental quality of rubber monoculture, but few reports have examined soil aggregate stability in such systems. The objective of this study was to examine the management and landscape effects on water stable soil aggregates, soil aggregate-associated carbon, nitrogen content and soil carbon, and nitrogen accumulation in Xishuangbanna, southwestern China. Treatments were rubber monoculture (Rm) and four rubber-based agroforestry systems: H. brasiliensis–C. arabica (CAAs), H. brasiliensis–T. cacao (TCAs), H. brasiliensis–F. macrophylla (FMAs) and H. brasiliensis–D. cochinchinensis (DCAs). The results showed that, with the exception of CAAs, the rubber-based agroforestry treatments significantly increased total soil organic carbon (SOC) and N contents and enhanced the formation of macroaggregates compared to the rubber monoculture treatment. SOC and N contents in all water-stable aggregate fractions were significantly higher in rubber-based agroforestry systems (except CAAs) compared to rubber monoculture. The macroaggregate fractions contained more organic carbon and nitrogen than the microaggregate fractions. The proportions of C and N loss from slaking and sieving were shown to have significantly negative correlations with the mean weight diameter and the SOC and N concentrations in bulk soil. The results suggest that soil surface cover with constant leaf litter fall and extensive root systems in the rubber-based agroforestry systems increased soil organic carbon and nitrogen, helped improve soil aggregation, reduced soil erosion, decreased carbon and nitrogen loss, and ultimately improved the carbon and nitrogen accumulation rates. Given that the soil physical-chemical properties improvement and the patterns of the intercropping system played key roles in managing artificial forests, we recommend that local governments and farmers should prefer T. cacao, F. macrophylla and D. cochinchinensis and not C. arabica as the alternative interplanted tree species within rubber plantations.

Are rubber-based agroforestry systems effective in controlling rain splash erosion?

In order to evaluate the influence of different types of rubber-based agroforestry systems on soil erosion processes, rainfall and throughfall erosivity (splash erosion potential) were measured in an open field environment and under different vegetation types using sand-filled Tübingen splash cups. Our results indicate that the splash erosion potential under rubber monoculture was, on average, 3.12 times greater than those in the open environment. Splash erosion potential under agroforestry systems was higher than that of an open environment (ranging from 1.22 to 2.18 times greater), except for the rubber and tea system (0.87 times the open environment). However, in all but one system (the rubber and orange system), there was a significant reduction in splash erosion beneath multiple canopies compared to monoculture, especially for the rubber and tea system (0.27 times the monoculture) where it had high sub-canopy closure and low sub-canopy height. The erosion potential under the forest is closely related to the forest structure, especially height and canopy cover. These results indicate that low canopy height with high sub-canopy coverage is the major control on the amount of splash erosion, regardless of how the splash potential is increased by the canopy above. These results highlight the importance of selecting low near-surface intercrops for constructing rubber-based agroforestry systems. This also accentuates the importance of an intact litter layer in rubber plantations to protect the soil against splash erosion. Disturbance of these forests by latex tapping activities, herbicide application and removal of the litter layer during fertilization, for example, will also lead to higher actual splash erosion rates inside the forests in comparison with the open environment.