Effects of Amazonian Dark Earths on growth and leaf nutrient balance of tropical tree seedlings

Estela Quintero-Vallejo,Frans Bongers,Marielos Peña-Claros,Marisol Toledo,Lourens Poorter

doi:10.1007/s11104-015-2558-6

Abstract

Amazonian Dark Earths (ADE) are ancient anthropogenic soils distributed in the Amazon basin. They are characterized by high nutrients such as phosphorus, calcium, potassium and nitrogen. We studied the effect of ADE on growth, morphology and physiology of 17 tree species from a Bolivian tropical moist forest. We conducted a greenhouse experiment where seedlings were grown for 2–4 months on ADE and non-ADE. We evaluated soil nutrient concentrations, seedling growth, leaf and root functional traits, and leaf nutrient concentrations. Soil type affected 10 out of 24 evaluated seedling traits. Seedlings did not invest more in roots in non-ADE, but they invested in leaves and leaf area in ADE, although this did not lead to faster growth rate. Species responded differently to soil Ca increment; some species seemed to suffer from Ca toxicity as indicated by low survival, others from nutrient imbalance, whereas other species increased their leaf calcium, phosphorus and nitrogen concentration in ADE. Only for this latter group of nutrient accumulators, there was a positive interspecific relationship between leaf Ca and seedling growth rates. ADE did not lead to increased seedling growth. The ability of plants to colonize patches of ADE might depend on plant responses to increased soil Ca and their capacity to regulate internal tissue calcium to balance nutrition.

Highlights

Nutrient availability in tropical soils is the result of complex biogeochemical processes that generate high spatial heterogeneity (Townsend et al 2008)
Soils and shade-house experiment The soil used for testing germination and plant growth was collected at La Chonta, where we previously identified a site with dark earth and the presence of pottery shards, hereafter Amazonian Dark Earths (ADE), and a site at least 500 m away with more clear soils, hereafter non-ADE
We expected soil fertility from ADE to have a positive effect on plant growth, but most of the species had a similar growth rate on both soils

Summary

Introduction

Nutrient availability in tropical soils is the result of complex biogeochemical processes that generate high spatial heterogeneity (Townsend et al 2008) This heterogeneity is important, since it can determine tree species distribution at different spatial scales (John et al 2007). The exact mechanisms that drive the underlying patterns of plant distribution are still far from being fully understood This lack of explanation is partly because plants respond differently to a multitude of soilrelated factors, such as water availability (Brenes‐ Arguedas et al 2013) and nutrients (Ordoñez et al 2009). Earths (ADE) are ancient anthropogenic soils distributed in the Amazon basin They are characterized by high nutrients such as phosphorus, calcium, potassium and nitrogen. We studied the effect of ADE on growth, morphology and physiology of 17 tree species from a Bolivian tropical moist forest

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Conclusion