Precision agriculture in oil palm plantations: diagnostic tools for sustainable N and K nutrient supply

Abstract

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.

Oil palm (Elaeis guineensis Jacq.) genetic differences in mineral nutrition: specific leaflet mineral concentrations of high-yielding oil palm progenies and their implications for managing K and Mg nutrition

“…Leaf analysis remains the most frequently used tool for predicting oil palms' mineral requirements. It allows to tailor fertilizer applications to speci c oil palm genotypes when cultivated in a speci c environment (Dubos et al 2019).…”

“…The seemingly inverse relation between a progeny's high yield and low lea et K concentration does not mean that leaf analysis is an inaccurate tool for assessing nutrient de ciencies in oil palms, but does imply that there is room for ne-tuning (Dubos et al 2019), and implies that genotypic differences in oil palm mineral use e ciency should be explored. Under equal K availability in the soil, contrasting lea et K concentrations are linked to speci c physiological mechanisms in oil palm progenies, such as photosynthesis and biochemical metabolism (soluble sugar and starch production), where minerals are used more or less e ciently ( ).…”

“…As the central element of the chlorophyll molecule, Mg enhances photosynthesis and is also involved in enzymatic reactions related to energy transfer (Gerendás and Führs 2013). However, there are indications that oil palm's lea et mineral concentrations can vary greatly from one progeny to another, suggesting that mineral requirements depend on the vegetal material (Jacquemard et Leaf analysis is a commonly used agronomic tool for assessing oil palm mineral requirements, hence for determining the right amounts of fertilizers to be applied (Dubos et al, 2019). Factorial trials can provide useful data for developing fertilizer x yield response curves and for determining optimum mineral concentrations in oil palm lea ets that are linked to the best economic yields (Webb 2009).…”

Piloter la fertilisation du palmier à huile

“…Au cours de ce séjour plusieurs processus contribuent à des pertes en éléments qui ne bénéficieront pas aux palmiers. (Dubos et al, 2019), mais aussi à l'intérieur des parcelles car de nombreux facteurs sont impliqués (climat, pente, couverture du sol, pratiques culturales). Plutôt que de compenser les pertes par une fertilisation difficile à évaluer, ou surévaluée par prudence, il est plus judicieux de chercher à les réduire le plus possible.…”

Oil palm (Elaeis guineensis Jacq.) genetic differences in mineral nutrition: potassium and magnesium effects on morphological characteristics of four oil palm progenies in Nigeria (West Africa)

“…Substantial amounts of K are needed to ensure palm growth. Moreover, mineral (K and Mg) requirements are calculated on the basis of leaflet mineral concentrations to assess maximum growth and yield in oil palm industrial plantations (Dubos et al, 2019).…”