Amending a tropical Arenosol: increasing shares of biochar and clay improve the nutrient sorption capacity

Christine Beusch,Martin Kaupenjohann,Dennis Melzer,Arne Cierjacks

doi:10.1007/s42773-022-00135-4

Christine Beusch, Martin Kaupenjohann + Show 2 more

Open Access

https://doi.org/10.1007/s42773-022-00135-4

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Abstract

Tropical Arenosols may be challenging for agricultural use, particularly in semi-arid regions. The aim of this study was to evaluate the impact of the addition of increasing shares of biochar and clay on the nutrient sorption capacity of a tropical Arenosol. In batch equilibrium experiments, the sorption of ammonium-N (hbox {NH}_{4}^{+}{text{-N}}), nitrate-N (text {NO}_{3}^{-}{text{-N}}), potassium (text {K}^{+}), and phosphate-P (text {PO}_{4}^{3-}{text{-P}}) was quantified for mixtures of an Arenosol with increasing shares of biochar and clay (1%, 2.5%, 5%, 10%, 100%) and the unmixed Arenosol, biochar, and clay. The mid-temperature biochar was produced from Prosopis juliflora feedstock; the clayey material was taken from the sedimentary parent material of a temporarily dry lake. Only the Arenosol–biochar mixture with 10% biochar addition and the biochar increased the text {NH}_{4}^{+}{text{-N}} maximum sorption capacity (q_{max}) of the Arenosol, by 34% and 130%, respectively. The q_{max} of text {PO}_{4}^{3-}{text{-P}} slightly increased with ascending biochar shares (1–10%) by 14%, 30%, 26%, and 42%, whereas the undiluted biochar released text {PO}_{4}^{3-}{text{-P}}. Biochar addition slightly reduced text {NO}_{3}^{-}{text{-N}} release from the Arenosol but strongly induced text {K}^{+} release. On the other hand, clay addition of 10% and clay itself augmented q_{max} of text {NH}_{4}^{+}{text{-N}} by 30% and 162%; ascending clay rates (1–100%) increased q_{max} for text {PO}_{4}^{3-}{text{-P}} by 78%, 130%, 180%, 268%, and 712%. Clay rates above 5% improved text {K}^{+} sorption; however, no q_{max} values could be derived. Sorption of text {NO}_{3}^{-}{text{-N}} remained unaffected by clay amendment. Overall, clay addition proved to enhance the nutrient sorption capacity of the Arenosol more effectively than biochar; nonetheless, both materials may be promising amendments to meliorate sandy soils for agricultural use in the semi-arid tropics.

Highlights

Arenosols are among the most abundant soil types worldwide
This study shows that the sorption of K+ and other nutrients is largely dependent on the mineral composition of clays
All batch equilibrium experiments relating to PO34− sorption reviewed for our study report PO34− sorption for numerous types of clays, e.g., Vertisols (Nunes et al 2012; Nychas and Kosmas 1984; Solis and Torrent 1989), terra rossa (Durn et al 2016), clayey sediments (Wang et al 2009), clayey Cerrado soil (Barros et al 2005), clay from crushed recycled building bricks (White et al 2011), and clays originating from primary and secondary types of deposits (Binner et al 2015)

Summary

Introduction

Arenosols are among the most abundant soil types worldwide. They cover an area of about 1300 million ha, corresponding to roughly 10% of the land surface. Even though Arenosols can be found globally, they predominate in vast areas of arid and semi-arid regions (IUSS Working Group WRB 2014; Yost et al 2019). This includes the Itaparica region, located in the state of Pernambuco in the north-east of Brazil (Araújo Filho et al 2013). These coarse-textured soils have low contents of organic carbon (C) and clay, resulting in limited capacity to retain water and nutrients (Huang and Hartemink 2020). By increasing soil C and clay content, the nutrient retention of the Arenosol may be enhanced, leading to more efficient fertiliser use and contributing to food security in the region

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