How tree-based family farms can adapt to global changes? – HEVEADAPT

The originality of the project relies on the multi-disciplinary approach of both the characterization of changes and their consequences on rubber plantations and the related risks for farmers. Plant and soil sciences are associated to social sciences and economics to analyze the way socio-economic factors interact with biophysical factors. We focus on two major factors, (i) the type of holdings, particularly the emergence of new investors and (ii) the share-cropping contracts that frame the management of plantations. The main biophysical risk relate to climate changes and to the extension of plantations in new and more adverse areas. We evaluate the risks at plot or farm levels, as well as potential externalities, in terms of soil sustainability (soil fertility preservation related to soil physical quality and soil functional diversity) and tree adaptation to water stress. Specific ecological constraints are considered. In the rubber extension areas, the climate is drier and the soil fertility is low, whereas in the traditional area, continuous rubber cropping occurs for more than 60 years. The specific impact of rubber installation in mountainous area on water flow and water balance is assessed. A typology of rubber farming systems and of practices is proposed from surveys, particularly regarding land management and latex harvesting systems. The impact of practices on economic performances, soil physical and bio-functioning is evaluated through specific indicators that are developed or adapted for multi-criteria evaluation of plantation systems. The information will be integrated at different scales and shared with stakeholder through a co-innovation platform. Beside the specific case of rubber plantations, a more generic output of the project is to determine, through modelling and risk framework analysis, the most significant indicators to assess the long-term adaptation and sustainability of tree-based family farms.

The project is in data acquisition phase and few results are already publishable. However, it already mobilized a large network of Franco-Thai partners around a platform centered on the rubber tree (Hevea Research Platform in Partnership) and another one dedicated to changes in land use (LMI Land Use Changes and Soil Ecosystem Services).
Surveys are underway or under analysis on new investors and their impact on the structure of the farms, on agroforestry practices, on risk perception and on sharecropping contracts.
A field trial on the genetic variability of adaptation to water stress was set up in the Northeast with a significant set of eco-physiological measurements that started last year. Two watersheds were equipped to compare the water functioning and the water balance in landscapes dominated by rubber or by a usual crop (maize) in Northern mountainous area. Numerous studies have started or have been strengthened on the biophysical functioning of soils in rubber plantations to study both the changes in land use (from annual crops to trees) and the long-term impacts of plantations. Multi-criteria analysis of agricultural practices (agroforestry, management intensity...) is also underway in the traditional area (South) or expansion areas (NE), including the development of the Biofunctool 'toolbox'.
A strong network is being built as part of the co-innovation platform, including studies on the adaptation of rubber harvesting systems (tapping).

Beside the specific case of rubber plantations, a more generic output of the project is to determine, through modelling and risk framework analysis, the most significant indicators to assess the long-term adaptation and sustainability of tree-based family farms.
Interesting paerspectives are already emerging, particularly on rubber farms typology and about the development of a toolbox for analysing soil functional quality (Biofunctool).
A medium term objective is to build up a multidisciplinary observatory of tropical plantations, on the basis of the partnership and the Tools developed within the project.

- Agroforestry practices are an attractive alternative to monoculture through diversification of income help overcoming changes in rubber prices (Penot et al 2016 European Agroforestry Conference, Montpellier, France.).
- The decomposers of litter (main source of organic matter in the plantations) are closer to the forest type in older plantations (Heepgoen et al 2015 International Conference Soil, Cha Am, Thailand.).
- Monitoring of 3 successive cycles of plantations showed that at each felling-replanting episode, several criteria are affected (biodiversity, minerals, organic matter ...). During the mature phase, restoration occurs but only partially (Panklang et al 2015 International Conference Soil, Cha Am, Thailand).

Summary
Tropical tree plantations provide indispensable renewable goods to the global market and family farms represent the majority of their surface area and production. To ensure the sustainability of plantation systems, environmental and socio-economic conditions should remain favorable during several decades. How can such conditions be ensured when the environment is changing? Even if the local consequences of global increase in temperature are difficult to assess, the farmers will probably face a more variable climate, with probable changes in rain patterns. Moreover, all natural resources have recently faced hugely variable prices related to variations in global demand. High prices attract new investors and drive the extension of plantations into new areas, inducing land-use changes and changes in farming structures.
The final aim of the project is to analyze how smallholder’s tree plantations can adapt and keep sustainable whereas they face variable climatic conditions and deep changes in their socio-economic context. Do farmers perceive these risks and do they initiate adaptive strategies? Rubber tree-based systems in Thailand will be used as a model of tropical family plantations integrated in a major global commodity channel. The project will assess both the specificities of rubber cropping and the more general features of tree plantations.
The originality of the project relies on the multi-disciplinary approach of both the characterization of changes and their consequences on rubber plantations and the related risks for farmers. Plant and soil sciences will be associated to social sciences and economics. We will analyze the way socio-economic factors interact with biophysical factors to determine farmers’ vulnerability or adaptability to changes. This will require the identification of relevant indicators to measure farmers’ adaptation, and the impacts of changes on sustainability and resilience of the systems. We will refer to the Sustainable Livelihood Framework (Ellis, 2000) to represent the household/holding , combined with the OECD risk matrix (2009) to assess households’ viability. We will focus on two major factors, (i) the type of holdings, particularly the emergence of new investors and (ii) the share-cropping contracts that frame the management of plantations. The main biophysical risk relate to climate changes and to the extension of plantations in new and more adverse areas. We will evaluate the risks at plot or farm levels, as well as potential externalities, in terms of soil sustainability (soil fertility preservation related to soil physical quality and soil functional diversity) and tree adaptation to water stress. Specific ecological constraints linked to the different cultivation area will be considered. In the North-eastern rubber extension area, the climate is drier and the soil fertility is low, whereas in the traditional area (South) continuous rubber cropping occurs for more than 50 years (third cycle). In the North, the specific issue of rubber installation in mountainous area will particularly focus on the effects of terracing, considering the impact on water flow and water balance.
A typology of rubber farming systems and of practices will be proposed from socio-economic survey, particularly regarding land management and latex harvesting systems. The impact of practices on economic performances, soil physical and bio-functioning will be evaluated through specific indicators that will be developed or adapted in the perspective of multi-criteria evaluation of plantation systems. The information will be integrated at different scales from plot to farm and watershed and shared with stakeholder through a co-innovation platform.
Beside the specific case of rubber plantations, a more generic output of the project is to determine, through modelling and risk framework analysis, the most significant indicators to be observed to assess the long-term adaptation and sustainability of tree-based family farms.