Soil Amendment With Different Maize Biochars Improves Chickpea Growth Under Different Moisture Levels by Improving Symbiotic Performance With Mesorhizobium ciceri and Soil Biochemical Properties to Varying Degrees.

Dilfuza Egamberdieva,Sonoko Dorothea Bellingrath-Kimura,Li Li,Stephan Wirth,Hua Ma

doi:10.3389/fmicb.2019.02423

Abstract

Chickpea (Cicer arietinum L.) is an important legume originating in the Mediterranean and the Middle East and is now cultivated in several varieties throughout the world due to its high protein and fiber content as well as its potential health benefits. However, production is drastically affected by prevalent water stress in most soybean-growing regions. This study investigates the potential of biochar to affect chickpea-Rhizobium symbiotic performance and soil biological activity in a pot experiment. Two different biochar types were produced from maize using different pyrolysis techniques, i.e., by heating at 600°C (MBC) and by batch-wise hydrothermal carbonization at 210°C (HTC), and used as soil amendments. The plant biomass, plant nutrient concentration, nodule numbers, leghemoglobin (Lb) content, soil enzyme activities, and nutrient contents of the grown chickpeas were examined. Our results indicated that plant root and shoot biomass, the acquisition of N, P, K, and Mg, soil nutrient contents, soil alkaline and acid phosphomonoesterases, and proteases were significantly increased by HTC char application in comparison to MBC char under both well-watered and drought conditions. Furthermore, the application of both biochar types caused an increase in nodule number by 52% in well-watered and drought conditions by improving the symbiotic performance of chickpea with Mesorhizobium ciceri. Rhizobial inoculation combined with HTC char showed a positive effect on soil FDA activity, proteases and alkaline phosphomonoesterases under well-watered and drought conditions compared to the control or MBC char-amended soils. This concept, whereby the type of producing biochar plays a central role in the effect of the biochar, conforms to the fact that there is a link between biochar chemical and physical properties and enhanced plant nutrient acquisition, symbiotic performance and stress tolerance.

Highlights

The long-term use of inorganic nitrogen fertilizers, or the application of such fertilizers at rates higher than the optimum, increases residual inorganic N with adverse effects such as soil degradation or the decline of soil biological health (Gong et al, 2013; Reckling et al, 2016)
The aim of the present study was (1) to evaluate the effect of two contrasting biochar types on chickpea growth, nutrient uptake (N, P, and K) and symbiotic performance with Mesorhizobium ciceri and (2) to determine the impact on soil nutrients and soil enzymes linked to carbon, nitrogen and phosphorus cycling
Our experiment showed that the shoot and root growth, nutrient acquisition and symbiotic performance of chickpea with M. ciceri under well-watered and drought conditions were improved by hydrothermal carbonization at 210◦C (HTC) char amendment of soil

Summary

Introduction

The long-term use of inorganic nitrogen fertilizers, or the application of such fertilizers at rates higher than the optimum, increases residual inorganic N with adverse effects such as soil degradation or the decline of soil biological health (Gong et al, 2013; Reckling et al, 2016). An alternative N resource to mitigate such drawbacks is biological nitrogen fixation by legumes, which plays a major role in sustaining or improving soil productivity (Santi et al, 2013; Egamberdieva et al, 2018). Legumes are grown in many countries of the world and are considered an important food source for human and animal nutrition (Lüscher et al, 2014; Egamberdieva et al, 2015). Abiotic stresses such as drought and salinity threaten the growth and yield of legumes and other crops (Bodner et al, 2015; Egamberdieva et al, 2016a, 2017b; Abd Allah et al, 2017). Inhibition of root nodule formation in legumes can be attributed to the failure of rhizobial colonization in the rhizosphere, which indicates the susceptibility of bacterial proliferation to stress factors (Rehman and Nautiyal, 2002)

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