Importance of soil amendments with biochar and/or Arbuscular Mycorrhizal fungi to mitigate aluminum toxicity in tamarind (Tamarindus indica L.) on an acidic soil: A greenhouse study

Ndiaye Ibra Ndiate,Cai Li Qun,Jackson Nkoh Nkoh

doi:10.1016/j.heliyon.2022.e09009

Abstract

Tamarindus indica L. is a forest plant species widely used in semi-arid regions and has an important socio-economic role. A 90 d greenhouse pot experiment was conducted to evaluate the efficiency of soil amendments with biochar and/or three Arbuscular Mycorrhizal Fungi (AMF) strains; Rhizophagus fasciculatus (Rf), Rhizophagus aggregatus (Ra), and Rhizophagus irregularis (Ri) on T. indica grown under aluminum stress. The amendments consisted of 5% biochar and 20 g kg−1 AMF as (i) control; (ii) biochar; (iii) biochar + Rf; (iv) biochar + Ra; (v) biochar + Ri; (vi) Rf; (vii) Ra; (viii) Ri. The treatments with biochar significantly (P < 0.05) increased soil pH and reduced the content of soil exchangeable Al3+ relative to the control and exclusive AMF treatments. All the treatments improved total nitrogen and phosphorus uptake by roots and shoot of T. indica and resulted in improved plant growth and root/shoot dry weight. The ability of biochar to enhance the soil's water-holding capacity played a key role in improving the intensity of mycorrhization. Overall, biochar amendments significantly improved the photosynthetic potential of T. indica and the activities of antioxidant enzymes compared to other treatments. Thus, the combined effects of enhanced (a) soil physicochemical parameters, (b) mycorrhization, (c) nutrient uptake, (d) photosynthetic potential, and (e) antioxidant activities played an important role in mitigating Al-related stress to improve the growth of T. indica. Therefore, the application of biochar in combination with AMFs can serve as a strategy for ensuring plant biodiversity in acid and Al-toxic soils in arid and semi-arid regions in Africa.

Highlights

World biodiversity is currently subject to drastic changes that have resulted in a reduction of the terrestrial biological wealth; of which, developing countries are on the negative end [1, 2]
The contents of NH4–N and NO3–N were significantly increased by the biochar treatments but not for treatments containing Arbuscular Mycorrhizal Fungi (AMF) alone compared to the control
For Rhizophagus fasciculatus (Rf) þ B0, Rhizophagus aggregatus (Ra) þ B0, and Rhizophagus irregularis (Ri) þ B0 treatments, the increase in Total nitrogen (TN) and TP was 67.8 and 57.14%, 78.2 and 28.6%, 55.2 and 42.9%, respectively (Figures 3A and 3B). These results show that the application of biochar alone or in combination with AMF does alleviate soil acidity and Al toxicity and improves nutrient uptake by T. indica

Summary

Introduction

World biodiversity is currently subject to drastic changes that have resulted in a reduction of the terrestrial biological wealth; of which, developing countries are on the negative end [1, 2]. Among the components of the biosphere, plants are sensitive to these changes [3, 4]. Forest trees play an important role in ensuring the well-being of the populations; those living in rural areas of semi-arid regions [5]. In most parts of West Africa, the fruits and leaves of some forest tree species provide trace elements, vitamins, and proteins. These nutrients are rare in cereals but essential to maintain a dietary balance and are a source of income and traditional medicines [6, 7, 8]. Abiotic stresses have caused a significant dysfunction in the bio-functioning of the ecosystems and in the long term, would no longer allow plant cover to ensure its sustainability and development [9]

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Discussion

Conclusion