High Soil Calcium Saturation Limits Use of Leaf Potassium Diagnosis When KCL Is Applied in Oil Palm Plantations

Abstract

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.

Responses to K deficiency and waterlogging interact via respiratory and nitrogen metabolism

“…Variations in K were mirrored by Mg and Na suggesting that they could substitute K for electrochemical potential homeostatis and play the role of counter‐cation. These variations in Mg and Na differed in leaves where Ca was quantitatively more important, K and Ca contents being antagonistic in leaves under varying KCl fertilization (Dubos, Baron, Bonneau, Flori, & Ollivier, ). In contrast to roots, waterlogging caused a decrease in leaf phosphorus (Figure a) as previously found (Milroy, Bange, & Thongbai, ).…”

On yield gaps and better management practices in Indonesian smallholder oil palm plantations

“…The K concentrations changed more slowly, and average concentrations never reached the critical threshold ( Figure 6.3). The limited increase in leaflet K concentrations in Jambi may be explained by the observations of Dubos et al (2017), who noted that in some soils with high Ca 2+ concentrations the application of KCl can actually reduce the leaflet K concentration while increasing yield. The leaflet K concentration in relation to Total Leaf Cations (K + , Mg 2+ and Ca 2+ ; Foster, 2003) is considered a better indicator of sufficiency than individual critical values.…”

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

“…The planting material and the main soil class are generally homogeneous within each block, which makes it possible to refine the biomass production data for NB. The correct interpretation of the leaf K content must also take into account the chemical properties of soils (Dubos et al, 2017a) and the origin of the planting material, since nutrient uptake may vary by up to 30-40% from one type of material to another, for the same level of production (Ollivier et al, 2017). As previously mentioned, environmental losses vary widely depending on the situation, but the parameters that determine them are known as characteristics of the blocks.…”