Biochars improve aggregate stability, water retention, and pore‐space properties of clayey soil

Abstract

The influence of biochar amendments on the physical quality of a clayey soil (Vertisol) was evaluated by aggregate‐size distribution and stability, water retention, and pore‐space structure of biochar‐amended soils. Clayey soil was treated with three kinds of biochars (straw biochar, woodchips biochar, and wastewater‐sludge biochar) at the rate of 0, 20, 40, and 60 g biochar (kg soil)–1 and incubated for 180 d in glasshouse. The application of straw biochar (SB) and wastewater‐sludge biochar (WSB) significantly enhanced the formation of 5–2 and 0.25–0.5 mm macroaggregates in the clayey soil relative to the control treatment, while the < 0.25‐cm microaggregate decreased with biochar additions. However, woodchips biochar (WCB) had no obvious effect on the formation of macroaggregate. The application of SB and WSB increased the mean weight diameter (MWD) and geometric mean diameter (GMD) of clayey soil, implying that biochar increased the aggregate stability. They improved the aggregate stability through an enhanced resistance to slaking and increased interparticular cohesion. The SB‐amended soils exhibited significant increases in the available water contents of soils. The application of SB significantly increased pore volume in the macropore (> 75 μm) and mesopore (30–75 μm) ranges, which may be the result of the reorganization of pore‐size distribution and aggregation processes induced by the addition of biochar. Results indicated that biochar had the potential to improve the physical quality and pore‐space status of clayey soil. It is suggested that biochar may be considered as a soil amendment for improving poor physical characteristics of clayey soil.

Utilization of crops residues as compost and biochar for improving soil physical properties and upland rice productivity

“…Macroaggregate formation was an important factor in maintaining soil porosity as a result of the increase in microbial activity. Sun and Lu (2014) reported that application of straw biochar (SB) and water-sludge biochar (WSB) significantly enhanced the formation of 5-2 and 0.25-0.5 mm macroaggregates in the clayey soil relative to the control treatment, while the < 0.25-cm microaggregate decreased with biochar additions.…”

“…Biochar application to soil influences various soil physico-chemical properties, due to the high specific surface area of biochar. Significant changes in soil aggregate stability, water retention, and pore size distribution were observed after addition of biochar to a clayey soil (Sun and Lu, 2014).…”

Effects of three different biochars on aggregate stability, organic carbon mobility and micronutrient bioavailability

“…This is a significant feature that will ultimately dictate its quality and ability to improve temperate agricultural soils. There are also many potential feedstocks ranging from straw, sludge and woodchip (Sun and Lu, 2014) to those derived from waste products such as sawdust (Liu et al, 2012).…”

“…Considerable work is necessary to evaluate soil-quality indicators following biochar application, but more importantly, different feedstocks must be sufficiently investigated as they may respond differently in temperate soils (Novak and Busscher, 2012;Sun and Lu, 2014). Furthermore, there are conflicting results in the literature regarding the effect of biochar on sandy soils and there is a need to understand the effects of this product on different soil types on a char by char basis (Molnár et al, 2016).…”

Impact of Biochar Addition on Productivity and Tubers Quality of Some Potato Cultivars Under Sandy Soil Conditions

“…Using biochar as a soil conditioner increased soil fertility, reduced fertilizers need while maintaining or improving crop productivity, reduced nutrient leaching, increased microbial activity in soil, improved water retention capacity and water use efficiencies, and cation exchange capacity in both sandy and clay soils. Biochar has also a potential to significantly improve durability of soil aggregates and reduce erosion and also has the potential to mitigate climate change by sequestering carbon into soils (Lehmann et al, 2006, Jha et al, 2010, Jeffery et al, 2011, Hale, 2013, Sun and Lu, 2014. Graber et al (2010) mentioned that treating tomato plants by biochar positively enhanced plant height and leaf size.…”