18 research outputs found
Modelling environmental impacts of agriculture, focusing on oil palm
Cultivation of crops affects the environment via flows of energy and materials. Impacts are felt in the atmosphere, hydrosphere, surrounding terrestrial ecosystems and the field itself. Models are useful tools for improving our understanding of the processes and predicting how they might be affected by changes in management. Current models range from simple indicators of risk or impact, based on empirical relationships, to dynamic process-based models. Increasingly complex and comprehensive models with increasing spatial and temporal resolution and extent are being developed, mostly by coupling diverse sub-models. This chapter reviews the range of models developed for oil palm systems, and discusses how other existing models might be adapted for oil palm
Precision agriculture in oil palm plantations: diagnostic tools for sustainable N and K nutrient supply
Predicting the fertilizer requirements of an oil palm plantation has long been a difficult task. Two main methods have emerged. Leaf analyses (LA) were used for fertilization management as early as the 1950s. Leaf contents are compared to optimum references, making it possible to adjust the fertilizer rates applied in each block. Another approach, based on the nutrient balance (NB), is to evaluate and replace nutrients that are exported from the field, or immobilized by the plant. Plantations must adopt environmentally friendly practices; in particular, fertilizer inputs must be estimated with sufficient precision to achieve the highest possible yields, without applying excessive amounts of nutrients in relation to plant demand and the storage capacity of soils. We questioned the relevance of each method for achieving these objectives. We did so using some long-term fertilization trials to compare the optimum N and K rates recommended by each method in the adult phase. It appeared that LA led to moderate rates compared to NB. It also appeared that calculating a precise nutrient balance on a field scale was hampered by a lack of precise information (i) about the biomasses produced and their composition and (ii) about the highly variable outputs of the environmental losses. On the other hand, LA provided a simple indicator of the ability for each block to achieve its potential yield. We believe that this perfectible method is more protective of the environment, without the risk of a significant decrease in yields or a decrease in soil mineral reserves
Identifying cost-competitive greenhouse gas mitigation potential of French agriculture
The agriculture, forestry and other land use sector are responsible for 24% (10â12 Pg CO2e per year) of anthropogenic greenhouse gas (GHG) emissions worldwide, with concomitant opportunities for mitigation. A scientific panel used deliberative methods to identify ten technical measures comprising 26 sub-measures to reduce GHG emissions from agriculture in France. Their abatement potential and cost are compared. The proposed measures concern nitrogen (N) management, management practices that increase carbon stocks in soils and biomass, livestock diets, and energy production and consumption on farms. Results show that the total abatement potential can be divided into three parts. One third of the cumulated abatement potential corresponds to sub-measures that can be implemented at a negative technical cost. These sub-measures focus on increased efficiency in input use including N fertilisers, animal feed and energy. The second third are sub-measures with moderate cost (âŹ25 per metric Mg of avoided CO2e). These require investment with no direct financial return, the purchase of particular inputs, dedicated labour time or involve production losses. Assuming additivity, the cumulated abatement is 32.3 Tg CO2e per year in 2030, but only 10 Tg (i.e. 10% of current agricultural emissions) when calculated under current inventory rules. This study confirms that a significant abatement potential exists in the agricultural sector, with two thirds of this potential at low or even negative cost. This is likely to be an underestimated as it is based on a status quo of the current agricultural system. Results also emphasise the need to upgrade inventory rules so that efforts to reduce emissions can be accounted for
Modelling of the nitrogen budget of oil palm plantations to help reduce losses to the environment. Case study in Sumatra, Indonesia
Humanity faces the challenges of urgently decreasing the environmental impact of agriculture, shifting diets and increasing food production. Oil palm is a tropical perennial crop emblematic of these challenges. While its cultivation can be associated with environmental impacts, oil palm can produce 3 to 7 t of edible oil haâ»Âč in optimal conditions, which is 7 to 10 fold higher than in annual oil crops. In this context, improving palm oil production sustainability is crucial for both reducing negative environmental impacts and ensuring food security.
Application of synthetic nitrogen (N) fertilisers was identified as a major source of environmental impacts associated with the cultivation of oil palm. Life cycle assessments of palm oil have already been performed to help quantify impacts and identify potential improvements of management practices. However, the only available emission models to estimate N losses to environment are generally valid for annual crops and temperate climate conditions. The use of such general models in life cycle assessment may lead to very uncertain results or to low sensitivity of assessments to management practices.
The overall objective of this research work was to help identify management practices to reduce N losses in the environment. The core of the work was hence to develop a model that estimates all N losses in oil palm plantations, while being sensitive to management practices. The study focused on N fluxes in industrial oil palm plantations on mineral soils.
We performed four steps in order to complete the objectives of this research work. First, we conducted a literature review of all the existing knowledge about N fluxes and losses in plantations. Second, we compared 11 existing models that may be used to predict N losses in plantations. Third, we performed an in-depth Morris's sensitivity analysis of one of the models, the APSIM-Oil palm process-based model. Fourth, we used all the information identified in the previous chapters, together with expert knowledge, to build IN-Palm, an agri-environmental indicator for N losses in oil palm plantations. We used the INDIGOÂź method and the fuzzy decision tree modelling approach to develop IN-Palm, and we validated this indicator using a field dataset of N leaching from a plantation in Sumatra, Indonesia.
Our literature review and model comparison showed that oil palm peculiarities may impact significantly N dynamics and losses. We identified research gaps and uncertainties about N losses, their drivers and the modelling of oil palm peculiarities. We identified the main drivers of N losses and yield in the APSIM-Oil palm process-based model. We built IN-Palm, which uses 21 readily available input variables to estimate each N loss pathway. IN-Palm predictions of N leaching were acceptable, and IN-Palm has shown efficient to help testing management changes.
This research constitutes a comprehensive synthesis of the available knowledge and models for N fluxes and losses in oil palm plantations. One of the main results is a novel agri-environmental indicator, IN-Palm, operationally-oriented, sensitive to local practices and environmental conditions, as well as potentially useable as an emission model for holistic approaches such as life cycle assessment. The INDIGOÂź method and fuzzy decision tree modelling approach were shown to be very well adapted for building agri-environmental indicators in contexts of knowledge scarcity. This indicator can be a useful base for further research about using agri-environmental indicators to reduce uncertainty in life cycle assessment, and for future adaptations for other tropical perennial crops
ModĂ©lisation du bilan azotĂ© des plantations de palmiers Ă huile pour aider Ă la rĂ©duction des pertes dans lâenvironnement. Etude de cas Ă Sumatra, IndonĂ©sie.
Humanity faces the challenges of urgently decreasing the environmental impact of agriculture, shifting diets and increasing food production. Oil palm is a tropical perennial crop emblematic of these challenges. While its cultivation can be associated with environmental impacts, oil palm can produce 3 to 7 t of edible oil ha-1 in optimal conditions, which is 7 to 10 fold higher than in annual oil crops. In this context, improving palm oil production sustainability is crucial for both reducing negative environmental impacts and ensuring food security. Application of synthetic nitrogen (N) fertilisers was identified as a major source of environmental impacts associated with the cultivation of oil palm. Life cycle assessments of palm oil have already been performed to help quantify impacts and identify potential improvements of management practices. However, the only available emission models to estimate N losses to environment are generally valid for annual crops and temperate climate conditions. The use of such general models in life cycle assessment may lead to very uncertain results or to low sensitivity of assessments to management practices. The overall objective of this research work was to help identify management practices to reduce N losses in the environment. The core of the work was hence to develop a model that estimates all N losses in oil palm plantations, while being sensitive to management practices. The study focused on N fluxes in industrial oil palm plantations on mineral soils. We performed four steps in order to complete the objectives of this research work. First, we conducted a literature review of all the existing knowledge about N fluxes and losses in plantations. Second, we compared 11 existing models that may be used to predict N losses in plantations. Third, we performed an in-depth Morrisâs sensitivity analysis of one of the models, the APSIM-Oil palm process-based model. Fourth, we used all the information identified in the previous chapters, together with expert knowledge, to build IN-Palm, an agri-environmental indicator for N losses in oil palm plantations. We used the INDIGOÂź method and the fuzzy decision tree modelling approach to develop IN-Palm, and we validated this indicator using a field dataset of N leaching from a plantation in Sumatra, Indonesia. Our literature review and model comparison showed that oil palm peculiarities may impact significantly N dynamics and losses. We identified research gaps and uncertainties about N losses, their drivers and the modelling of oil palm peculiarities. We identified the main drivers of N losses and yield in the APSIM-Oil palm processbased model. We built IN-Palm, which uses 21 readily available input variables to estimate each N loss pathway. IN-Palm predictions of N leaching were acceptable, and IN-Palm has shown efficient to help testing management changes. This research constitutes a comprehensive synthesis of the available knowledge and models for N fluxes and losses in oil palm plantations. One of the main results is a novel agri-environmental indicator, IN-Palm, operationally-oriented, sensitive to local practices and environmental conditions, as well as potentially useable as an emission model for holistic approaches such as life cycle assessment. The INDIGOÂź method and fuzzy decision tree modelling approach were shown to be very well adapted for building agri-environmental indicators in contexts of knowledge scarcity. This indicator can be a useful base for further research about using agrienvironmental indicators to reduce uncertainty in life cycle assessment, and for future adaptations for other tropical perennial crops.LâhumanitĂ© fait face aux dĂ©fis urgents de rĂ©duire lâimpact environnemental de lâagriculture, de changer les rĂ©gimes alimentaires et dâaccroĂźtre la production alimentaire. Le palmier Ă huile est une plante pĂ©renne tropicale emblĂ©matique de ces dĂ©fis. Alors que sa culture peut ĂȘtre Ă lâorigine dâimpacts environnementaux, le palmier Ă huile peut produire, en conditions optimales, 7 Ă 10 fois plus dâhuile alimentaire que les cultures olĂ©agineuses annuelles. Dans ce contexte, amĂ©liorer la durabilitĂ© de la production dâhuile de palme est crucial, tant pour rĂ©duire les impacts environnementaux nĂ©gatifs que pour garantir la sĂ©curitĂ© alimentaire. Lâapplication de fertilisants azotĂ©s (N) a Ă©tĂ© identifiĂ©e comme une source majeure dâimpacts environnementaux dus Ă la culture du palmier. Des analyses de cycle de vie de lâhuile de palme ont Ă©tĂ© rĂ©alisĂ©es pour quantifier les impacts et identifier des amĂ©liorations de pratiques agricoles. Cependant, les seuls modĂšles dâĂ©missions disponibles pour estimer les pertes de N dans lâenvironnement sont gĂ©nĂ©ralement valides pour les cultures annuelles et en climat tempĂ©rĂ©. Lâutilisation de tels modĂšles dans lâanalyse de cycle de vie peut mener Ă des rĂ©sultats trĂšs incertains ou Ă une faible sensibilitĂ© aux pratiques. Lâobjectif global de ce travail de recherche Ă©tait dâaider Ă lâidentification de pratiques pour rĂ©duire les pertes de N dans lâenvironnement. Le cĆur du travail Ă©tait le dĂ©veloppement dâun modĂšle estimant toutes les pertes de N dans les plantations, tout en Ă©tant sensible aux pratiques. LâĂ©tude sâest concentrĂ©e sur les flux de N dans les plantations de palmiers sur sols minĂ©raux. Nous avons rĂ©alisĂ© quatre Ă©tapes pour mener Ă bien cette recherche. PremiĂšrement, nous avons menĂ© une revue de littĂ©rature de tout le savoir existant concernant les flux et pertes de N dans les plantations. DeuxiĂšmement, nous avons comparĂ© 11 modĂšles existants, pouvant ĂȘtre utilisĂ©s pour prĂ©dire les pertes de N dans les plantations. TroisiĂšmement, nous avons rĂ©alisĂ© une analyse de sensibilitĂ© de Morris approfondie du modĂšle mĂ©caniste APSIM-Oil palm. QuatriĂšmement, nous avons construit IN-Palm, un indicateur agri-environnemental pour les pertes de N dans les plantations. Nous avons utilisĂ© la mĂ©thode INDIGOÂź et lâapproche de modĂ©lisation par arbres de dĂ©cisions flous pour dĂ©velopper IN-Palm, et nous avons validĂ© cet indicateur en utilisant des mesures de lixiviation de N dâune plantation Ă Sumatra, IndonĂ©sie. Notre revue de littĂ©rature et notre comparaison de modĂšles ont montrĂ© que les particularitĂ©s du palmier Ă huile peuvent affecter significativement les dynamiques et pertes de N. Nous avons identifiĂ© des manques de recherche et des incertitudes sur les pertes de N, leurs dĂ©terminants et la modĂ©lisation des particularitĂ©s du palmier. Nous avons identifiĂ© les dĂ©terminants des pertes de N et du rendement dans le modĂšle mĂ©caniste APSIM-Oil palm. Nous avons dĂ©veloppĂ© IN-Palm, qui utilise 21 variables dâentrĂ© facilement accessibles pour estimer chaque voie de perte de N. Les prĂ©dictions de lixiviation de N par IN-Palm Ă©taient acceptables, et IN-Palm sâest montrĂ© efficace pour tester des changements de pratiques agricoles. Cette recherche constitue une synthĂšse exhaustive des connaissances et modĂšles disponibles pour les flux et pertes de N dans les plantations. Lâun des principaux rĂ©sultats est un nouvel indicateur agri-environnemental, IN-Palm, sensible aux pratiques et conditions locales, de mĂȘme quâutilisable en tant que modĂšle dâĂ©mission dans des approches holistiques. Cet indicateur peut ĂȘtre une base utile pour de futures recherches sur lâutilisation dâindicateurs agri-environnementaux pour rĂ©duire lâincertitude des analyses cycle de vie, et pour de futures adaptations Ă dâautres plantes pĂ©rennes tropicales