Physicochemical Changes in Loam Soils Amended with Bamboo Biochar and Their Influence in Tomato Production Yield

Karolina Villagra-Mendoza,Jaime Quesada-Kimsey,Rainer Horn,Federico Masís-Meléndez,Carlos A García-González

doi:10.3390/agronomy11102052

Abstract

Soil degradation and water stress in Costa Rica challenge the production of highly sensitive crops. This work is aimed at evaluating the physical and chemical changes in sandy loam (SL) and a silt loam (SiL) soil when amended with bamboo biochar while estimating the enhancement of tomato productivity. Biochar, obtained from Guadua Angustifolia bamboo feedstock, was mixed into sieved bulk soil substrate from the topsoil, from Andosol and Umbrisol groups, at application rates of 1, 2.5, and 5% (dry mass). Physicochemical and morphological properties of biochar such as pH, hydrophobicity, scanning electron microscopy images, helium picnometry, specific surface area by the Brunauer–Emmett–Teller (BET) method, CHNS, and ash content were determined. Soil hydrophobicity, acidity, electrical conductivity, cation exchange capacity and water retention, available water content, and air capacity were analyzed for the amended soils. Tomato yield was quantified after a harvest period of two months. The admixture of biochar did not significantly increase soil cation exchange capacity but increased water retention in the range of available water content. Class A (>200 g) tomato yield increased 350% in the SL and 151% in the SiL. Class B (100–200 g) tomato yields increased 27% in the SL but decreased about 30% in the SiL. Tomato yield response seems attributable to variation of water retention capacity, available water content, and air capacity. These results support the use of adapted water management strategies for tomato production based on soil physical changes of biochar.

Highlights

Mankind is facing the challenge of feeding an increasing population by producing more food with optimal use of natural resources
This study aims to provide insights into the physical and chemical mechanisms by which biochar amendments impact the yield of tomato fruits in degraded tropical soils
In the silt loam treatments, we found an opposite behavior between soil water retention and Available water capacity (AWC)

Summary

Introduction

Mankind is facing the challenge of feeding an increasing population by producing more food with optimal use of natural resources. The preservation of the quality of soils used for agricultural production is fundamental for this purpose, but climate change, water scarcity, and soil degradation have emerged as limiting factors for crop productivity [1]. Tomato is one of the crops with the highest greenhouse production in Costa Rica. It is cultivated throughout the year; often in soils of the group Andosols [2] of volcanic origin, with textures ranging from sandy loam to silt loam. Biochar has shown to favor tomato crop performance with an increased yield production and weight under controlled deficit irrigation [5,6,7,8]. Studies like these have associated observed changes in fruit quality, yield to plant, and nutrient dynamics responses, but without investigating deeply the underlying soil physical mechanisms [5,6,7,8]

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