The importance of initial application and reapplication of biochar in the context of soil structure improvement

Abstract

It was shown that the use of biochar provides many benefits to agriculture by improving the whole complex of soil properties, including soil structure. However, the diverse range of biochar effects depends on its physicochemical properties, its application rates, soil initial properties etc. The impacts of biochar, mainly its reapplication to soils and its interaction with nitrogen in relation to water-stable aggregates (WSA) did not receive much attention to date. The aims of the study were: (1) to evaluate the effect of initial application (in spring 2014) and reapplication (in spring 2018) of different biochar rates (B0, B10 and B20 t ha−1) as well as application of biochar with N-fertilizer (40 to 240 kg N ha−1 depending on the requirement of the cultivated crop) on the content of WSA as one of the most important indicators of soil structure quality, (2) to assess the interrelationships between the contents of soil organic matter (SOM) and WSA. The study was conducted in 2017–2019 as part of the field experiment with biochar on Haplic Luvisol at the experimental station of SUA in Nitra, Slovakia. Results showed that initial application as well as reapplication of biochar improved soil structure. The most favorable changes in soil structure were found in N0B20B treatment (with biochar reapplication) at which a significantly higher content of water-stable macro-aggregates (WSAma) (+15%) as well as content of WSAma size fractions of > 5 mm, 5–3 mm, 3–2 mm and 2–1 mm (+72%, +65%, +57% and +64%, respectively) was observed compared to the control. An increase in SOM content, due to both, initial biochar application and its reapplication, significantly supported the stability of soil aggregates, while organic matter including humic substances composition did not.

Effects of Slow Pyrolysis Biochar on CO2 Emissions from Two Soils under Anaerobic Conditions

“…The economic feasibility of the application of biochar in agriculture depends on two aspects. First, we must demonstrate that biochar, at low and high rates, often contributes to an improvement in many soil quality indicators, an increase in carbon sequestration from the atmosphere, and a decrease in nitrous oxide emission from soils [2,[15][16][17][18][19][20][21][22][23][24][25][26]36,37]. This is an economical benefit of using biochar in the long term.…”

“…Incorporation of biochars into soil can improve soil structure [15], increase organic carbon content [16,17], soil porosity [18,19], saturated hydraulic conductivity [20,21], available water content [22,23], and decrease soil bulk density [24,25]. These favorable biocharinduced changes in the physical properties of soil can increase nitrogen availability [8,26].…”

Effects of slow and fast pyrolysis biochar on N2O emissions and water availability of two soils with high water-filled pore space

“…Because of high chemical stability, biochar has a great potential to enhance atmospheric carbon sequestration (Laird et al, 2008;Lehmann et al, 2006). Soil amendments such as biochar, composts or their mixtures can decrease soil bulk density (Abd El-Mageed et al, 2021;Hardie et al, 2014), improve soil structure (Ajayi and Horn, 2016;Juriga et al, 2021), increase soil pH (Horák, 2015) cation exchange capacity (Igaz et al, 2018;Jien and Wang, 2013), soil N availability (Haider et al, 2017;Van Zwieten et al, 2010), organic carbon content (Ajayi and Horn, 2016;Šrank and Šimanský, 2020), soil porosity (Blanco-Canqui, 2017;Githinji, 2014), available water content (Głąb et al, 2016;Ibrahim et al, 2013) and saturated hydraulic conductivity (Jien and Wang, 2013;Toková et al, 2020). Syakila and Kroeze (2011) reported that agricultural N2O emission in 2006 reached 23-31% of the global emissions with the main source being nitrogen fertilizer and manure application to soils.…”

90 Years of Agrophysical Institute as a History of Priority Achievements in Russian and World Agrophysical Science

“…Современные исследования направлены на сопряженную оценку степени взаимосвязей циклов углерода и азота в различных климатических условиях с динамикой температуры, содержания влаги и кислорода, доступных соединений азота и углерода, микробиологической и ферментативной активности, главным образом в самой верхней части генетического профиля почв. Во-первых, инструментальные исследования в целом предусматривают анализ влияния природных и антропогенных воздействий на секвестрацию органического вещества в почвах и их илистых фракциях (52,53). Интенсивность секвестрации и степень закрепления углерода в генетических профилях почв в наибольшей степени обусловлены количеством и минералогическим составом их илистой фракции, содержанием гидроокиси железа при различных окислительно-восстановительных, гидрофизических, теплофизических, биохимических и микробиологических условиях.…”

“…Первоначальное, а также повторное применение биоугля приводило к улучшению структуры почвы. Увеличение содержания почвенного органического вещества за счет первоначального и повторного внесения биоугля значительно поддерживало стабильность почвенных агрегатов, в то время как органическое вещество на основе гуминовых веществ не обеспечивало такой стабильности (52,57).…”