Does biochar application improve soil aggregation? A meta-analysis

Islam, Mahbub Ul; Jiang, Fahui; Guo, Zichun; Peng, Xinhua

doi:10.1016/j.still.2020.104926

Cited by 99 publications

(58 citation statements)

References 52 publications

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“…And, the present study found that the direct influence of biochar application rate on AWC was not significant, which indicated that the overuse of biochar might lead to the degradation of soil hydrology (Figure 5c). Castellini et al (2015) reported that AWC decreased by 23.5% when biochar application rate raised from 10 to 30 t ha −1 , and excessive application of biochar may result in soil hyperventilation and reduction of AWC (Regelink et al, 2015; Sun & Lu, 2014; Islam et al, 2021). Therefore, this study emphasizes that reasonable biochar application based on different soil conditions is premise and critical to improve AWC.…”

Section: Discussionmentioning

confidence: 99%

Impact of biochar amendment on soil hydrological properties and crop water use efficiency: A global meta‐analysis and structural equation model

Han

et al. 2022

GCB Bioenergy

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The regulation of soil water retention by biochar amendment has been concerned especially in cropland ecosystem. However, the quantification of biochar's effects on soil hydrological properties and crop water use efficiency (WUE) is still limited, and the factors driving the biochar effect need to be investigated. Based on a database with 681 observations, meta‐analysis and structural equation model (SEM) were employed to reveal how biochar amendment affects water supply capacity and WUE. The results showed that biochar application increased available water content (AWC) and WUE by 26.8% and 4.7% on average, respectively. According to the SEM of AWC (R2 = 0.70–0.96), the increase of soil organic carbon (+36.1%) by biochar application can not only directly improve AWC but also indirectly improve AWC by affecting permanent wilting point (−1.0%) and mean weight diameter (+11.1%). The SEM of WUE (R2 = 0.74) indicated that soil moisture and porosity were increased by 10.8% and 7.0% under biochar amendment, which was the reason why biochar improved WUE. This study emphasized that biochar can improve soil hydrology and crop yield by increasing soil water supply conditions. And a rational rate of biochar is the precondition to obtaining the benefits of soil hydrology, otherwise, the excessive use of biochar may lead to the decline of WUE.

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Section: Discussionmentioning

confidence: 99%

Impact of biochar amendment on soil hydrological properties and crop water use efficiency: A global meta‐analysis and structural equation model

Han

et al. 2022

GCB Bioenergy

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“…The quantitative analysis of the effects of biochar on physical and hydraulic properties shown in Fig. 5 is based on effect ratios presented in five meta-analyses (Rabbi et al, 2021;Islam et al, 2021). Our review draws on findings presented in two additional reviews that employed different statistical methodologies (Razzaghi et al, 2020;Kroeger et al, 2020).…”

Section: Biocharmentioning

confidence: 99%

“…Two metaanalyses reported measures of aggregate stability. included only studies that reported mean weight diameter (MWD) using wet sieving, while Islam et al (2021) included studies that reported soil aggregate stability as a per-centage of water-stable aggregates (WSAs), as well as MWD or gravimetric mean diameter (GMD) using either wet sieving or dry sieving. Both studies showed that aggregate stability increased with biochar addition and that these effects increased with the time between biochar application and measurements (Islam et al, 2021).…”

Section: Biocharmentioning

confidence: 99%

Soil and crop management practices and the water regulation functions of soils: a qualitative synthesis of meta-analyses relevant to European agriculture

Blanchy¹,

Bragato

Bene³

et al. 2023

SOIL

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Abstract. Adopting soil and crop management practices that conserve or enhance soil structure is critical for supporting the sustainable adaptation of agriculture to climate change, as it should help maintain agricultural production in the face of increasing drought or water excess without impairing environmental quality. In this paper, we evaluate the evidence for this assertion by synthesizing the results of 34 published meta-analyses of the effects of such practices on soil physical and hydraulic properties relevant for climate change adaptation in European agriculture. We also review an additional 127 meta-analyses that investigated synergies and trade-offs or help to explain the effects of soil and crop management in terms of the underlying processes and mechanisms. Finally, we identify how responses to alternative soil–crop management systems vary under contrasting agro-environmental conditions across Europe. This information may help practitioners and policymakers to draw context-specific conclusions concerning the efficacy of management practices as climate adaptation tools. Our synthesis demonstrates that organic soil amendments and the adoption of practices that maintain “continuous living cover” result in significant benefits for the water regulation function of soils, mostly arising from the additional carbon inputs to soil and the stimulation of biological processes. These effects are clearly related to improved soil aggregation and enhanced bio-porosity, both of which reduce surface runoff and increase infiltration. One potentially negative consequence of these systems is a reduction in soil water storage and groundwater recharge, which may be problematic in dry climates. Some important synergies are reductions in nitrate leaching to groundwater and greenhouse gas emissions for nonleguminous cover crop systems. The benefits of reducing tillage intensity appear much less clear-cut. Increases in soil bulk density due to traffic compaction are commonly reported. However, biological activity is enhanced under reduced tillage intensity, which should improve soil structure and infiltration capacity and reduce surface runoff and the losses of agro-chemicals to surface water. However, the evidence for these beneficial effects is inconclusive, while significant trade-offs include yield penalties and increases in greenhouse gas emissions and the risks of leaching of pesticides and nitrate. Our synthesis also highlights important knowledge gaps on the effects of management practices on root growth and transpiration. Thus, conclusions related to the impacts of management on the crop water supply and other water regulation functions are necessarily based on inferences derived from proxy variables. Based on these knowledge gaps, we outlined several key avenues for future research on this topic.

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“…The ability of biochar to modify the physical and chemical properties of soils is important for amending highly weathered soils and retarding soil degradation associated with erosion [53]. Nevertheless, the ability of biochar to promote aggregation is largely influenced by biochar feedstock, biochar production condition, and soil type [55,56]. This means that while biochar can favor aggregate formation in some soils, it can inhibit its formation in others.…”

Section: The Role Of Biochar In Soil Aggregate Formationmentioning

confidence: 99%

A Critical-Systematic Review of the Interactions of Biochar with Soils and the Observable Outcomes

et al. 2021

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Biochar research has experienced a significant increase in the recent two decades. It is growing quickly, with hundreds of reviews, including meta-analyses, that have been published reporting diverse effects of biochar on soil properties and plant performance. However, an in-depth synthesis of biochar–soil interactions at the molecular level is not available. For instance, in many meta-analyses, the effects of biochar on soil properties and functions were summarized without focusing on the specificity of the biochar and soil properties. When applied to soils, biochar interacts with different soil components including minerals, organic matter, gases, liquids, and nutrients, while it also changes soil microbial community structure and their occurrence. These different interactions modify soil physicochemical properties with consequences for dynamic changes in nutrient availability and, thus, plant performance. This review systematically analyzed biochar effects on soil properties and functions: (a) soil physical properties; (b) chemical properties; (c) biological properties; and (d) functions (plant performance, nutrient cycling, etc.). Our synthesis revealed that the surface properties of biochar (specific surface area and charge) and its associated nutrient content determine its role in the soil. At the same time, the extent of changes depends on soil properties, suggesting that both biochar and soil properties need to be considered for harvesting benefits of biochar application. Altogether, we believe our synthesis will provide a guide for researchers and practitioners for future research as well as large-scale field applications.

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Does biochar application improve soil aggregation? A meta-analysis

Cited by 99 publications

References 52 publications

Impact of biochar amendment on soil hydrological properties and crop water use efficiency: A global meta‐analysis and structural equation model

Impact of biochar amendment on soil hydrological properties and crop water use efficiency: A global meta‐analysis and structural equation model

Soil and crop management practices and the water regulation functions of soils: a qualitative synthesis of meta-analyses relevant to European agriculture

A Critical-Systematic Review of the Interactions of Biochar with Soils and the Observable Outcomes

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