-Palm oil is nowadays the first vegetable oil consumed worldwide. Given the world population growth and the increasing demand in fat for food and fuel, the increase in oil palm production is expected to continue. It is thus important to find ways of reducing the ecological impact of oil palm plantations at both the agroecosystem and the mill supply area levels, by improving agricultural practices and land uses. This is where agroecology can play a very critical role. The present article gathers short stories on agroecological practices currently taking place in oil palm plantations in South-East Asia. Such stories notably highlight the importance of the various palm co-products and how appropriate recycling strategies can allow for reducing external inputs to both the field and the mill. Besides limiting environmental impacts thanks to such savings, several coproducts used as organic amendments can even help to maintain or enhance soil quality. Other stories explored agroecological practices developed for biological controls. Although integrated pest management has been applied in palm plantations for a long time, the underlying mechanisms are still not fully deciphered and practices still need to be improved. More knowledge is needed in order to better account for the holistic role of biodiversity and arbitrate trade-offs between practices and ecosystem services, at both plantation and landscape levels.Keywords: palm oil / agroecology / biological control / recycling / composting / soil quality Résumé -Pratiques agroécologiques en plantations de palmier à huile : exemples de terrain. L'huile de palme est aujourd'hui la première huile végétale consommée au monde. Étant donné la croissance démographique mondiale et la demande accrue en corps gras pour l'alimentation et les biocarburants, l'augmentation de la production d'huile de palme devrait perdurer. Il est ainsi primordial de trouver des moyens de production permettant de réduire l'impact écologique des plantations de palmier à huile, à la fois à l'échelle de l'agroécosystème et celle du bassin d'approvisionnement de l'huilerie, en améliorant les pratiques et la gestion des usages des sols. Les principes de l'agroécologie peuvent aider à développer des solutions à ces diverses échelles. Cet article rassemble diverses histoires courtes illustrant des pratiques agroécologiques mises en place dans des plantations de palmier à huile en Asie du Sud-Est. Ces illustrations mettent en évidence l'importance des nombreux co-produits issus du palmier et leur rôle clé dans les stratégies de recyclage pour réduire le recours aux intrants externes pour la plantation comme pour l'huilerie. Au-delà de la réduction des impacts environnementaux du fait de ces économies d'intrants, certains co-produits restitués en plantation peuvent également permettre de maintenir, voire d'améliorer, la qualité des sols. D'autres histoires courtes parcourent quelques autres pratiques agroécologiques dans le domaine de la lutte intégrée. Bien que de nombreuses pratiques de contrôle bi...

This article follows on from an earlier one about the same experiment in 2014. A range of various planting distances (from 7.5 to 9.5 metres) between oil palms was tested using an equilateral triangle design. The current planting density experiment was set up in an oil palm plantation in Nigeria. The climatic conditions are quite stable, with two seasons and around 2000 mm of annual rainfall. The soil is of the desaturated ferralitic type, sandy on the surface, deep and without coarse elements. After twelve years of continual monitoring and extrapolation of the results obtained up to the end of the cycle, we concluded on an optimum planting density of between 143 and 160 oil palms per hectare in a monospecific, equilateral triangle planting design (i.e. a distance of 8.5 to 9 metres between palms). It will take another few years of yield recording to fine-tune the result. For 12-year-old palms, this density range corresponds to a Leaf Area Index of 3.5 to 4, a light interception percentage of 89 to 90 and a foliage overlap percentage of 51 to 68. A thinning treatment was included in the protocol. Thinning at eight years has not led to any advantage after four years.

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.

-A range of various different planting distances (from 7.5 to 9.5 m) between oil palms were tested using an equilateral triangle design in a plantation density experiment which was settled in an oil palm commercial plantation in Nigeria. Climatic conditions were quite stable, with two seasons and around 2000 mm of annual rainfall. The soil was of desaturated ferralitic type, sandy on the surface, deep and without coarse elements. The early impact of plantation density was analysed at eight years after planting. Some early signs of depressive effect on yields were found for high planting densities (180 and 205 p/ha). Such a negative impact was not severe enough to counteract the effects of a higher number of palms per hectare. As a consequence, a gradient could be observed as yields (in tons of bunches per hectare) increased with density. We can anticipate that the competition effect between palms will increase over time with high densities, so that the counteracting point ought to be reached in a few years. A thinning treatment has been included in the protocol. Thinning was carried out at the end of the eight-year period. Keywords:Oil palm / planting density / spacing / thinning / yield Résumé -Premiers effets de la densité de plantation sur les variables végétatives et de production du palmier à huile en Afrique de l'Ouest. Une gamme de différentes distances de plantation entre palmiers à huile (7,5 à 9,5 m) a été testée dans un dispositif en triangle équilatéral. L'expérience de densité de plantation a été établie dans une plantation de palmier à huile au Nigéria. Le climat est très régulier, à deux saisons avec environ 2000 mm de précipitations annuelles. Le sol est de type ferralitique désaturé, sableux en surface, profond, sans éléments grossiers. Un premier bilan a été établi à huit ans après plantation. Des signes d'effet dépressif des fortes densités de plantation (180 et 205 p/ha) sur le rendement ont été mis en évidence. Cet effet dépressif n'est toutefois pas assez fort pour contrebalancer l'augmentation du nombre d'arbres à l'hectare, de sorte qu'il existe un gradient de rendement (tonnes de régimes à l'hectare) croissant avec la densité. Un éclaircissage des palmiers à huit ans est inclus dans le protocole.L'effet concurrentiel entre palmiers va augmenter avec le temps dans les fortes densités, de sorte que le point de compensation devrait être atteint dans quelques années. Mots clés :Palmier à huile / densité de plantation / écartement / éclaircissage / rendement

SUMMARYPotassium chloride (KCl) is the most widely used fertilizer in oil palm (Elaeis guineensis) plantations and the rates applied are based on interpretation of leaf K contents. When no positive response on leaf K contents can be detected, no optimum content can be established whatever the yield response to KCl rates. We used data from 13 fertilization trials conducted on several continents to study the responses of leaf K, leaf Cl, leaf Ca and yield to KCl rates as a function of the soil properties of each site. We found that the abundance of exchangeable Ca in the soil expressed as a percent of the cation exchange capacity (CEC) was the best soil variable to predict if leaf K content would increase with KCl rates. In addition, we found that the leaf K contents of unfertilized controls at the end of the trials were also correlated with Ca/CEC. This ratio thus appears to be a better index of soil K reserves than soil exchangeable K content.

On a large coconut plantation planted on a deep peat soil in Sumatra, Indonesia, hybrid coconut yields are stabilizing at values well below their potential, even in plots where known production factors have been mastered since the outset: land preparation, water control, and mineral fertilization. To explain this situation, five hypotheses have been proposed. They were tested one by one in field trials. The authors have demonstrated that the main reason for stabilized yields was the Lepidoptera root pest Sufetula spp. and conclude by considering lines of research for controlling this pest in the context of rehabilitation and replanting.

We demonstrated experimentally that Sufetula, a root-mining insect, has a depressive effect on coconut yields on peat soils. The impact of the pest resulted in a shortfall in earnings that warranted taking control measures. We considered control methods suitable for rehabilitating infested mature coconut plantings and for preserving young coconut plantings. Currently, cultural control is the only effective method. It involves eliminating all identified shelters for the adult insect, i.e. fern cover and heaps of coconut waste (dry fronds and husks). The aim is to achieve totally bare soil, with moss cover that does not attract the pest, or planted with an unattractive intercrop such as pineapple.

Background and aims: In oil palm, similar fertilization treatments can result in lea et potassium and magnesium concentrations that vary signi cantly from one progeny to another. This hinders the development of standardized fertilizer recommendations for this crop, as they are usually calculated based on optimum lea et nutrient concentrations.Methods: 4-high-yielding oil palm progenies with contrasting lea et K and Mg concentrations (C1, C2, and C3 of Deli x La Mé origin and C4 of Deli x Yangambi origin) were treated with combinations of 3-levels of KCl and MgSO 4 , in a completely randomized split-plot factorial design with 6-replicates, where progenies were a sub-factor.Results: For a given level of KCl or MgSO 4 , different lea et K and Mg concentrations were found between progenies (p < 0.0001). Lea et K concentration and yield response to KCl applications revealed that the four oil palm progenies have different optimum lea et K concentrations. In our study period (5-8 YAP), progenies C1 and C3 showed their highest fresh fruit bunch (FFB) yields (13.62 and 16.54 t ha -1 year -1 , respectively) at K2, whereas progenies C2 and C4 showed their highest yields (14.62 and 12.39 t ha -1 year -1 , respectively) at K1. Conclusion:Our study highlighted speci c optimum lea et K and Mg concentrations for different oil palm progenies in a given environment. It paves the way for adopting K and Mg fertilizer application rates adapted to speci c requirements of each type of oil palm planting material.