Biochars in soils : towards the required level of scientific understanding

Key priorities in biochar research for future guidance of sustainable policy development have been identified by expert assessment within the COST Action TD1107. The current level of scientific understanding (LOSU) regarding the consequences of biochar application to soil were explored. Five broad thematic areas of biochar research were addressed: soil biodiversity and ecotoxicology, soil organic matter and greenhouse gas (GHG) emissions, soil physical properties, nutrient cycles and crop production, and soil remediation. The highest future research priorities regarding biochar's effects in soils were: functional redundancy within soil microbial communities, bioavailability of biochar's contaminants to soil biota, soil organic matter stability, GHG emissions, soil formation, soil hydrology, nutrient cycling due to microbial priming as well as altered rhizosphere ecology, and soil pH buffering capacity. Methodological and other constraints to achieve the required LOSU are discussed and options for efficient progress of biochar research and sustainable application to soil are presented.Peer reviewe

Introduction to Precipitation Runoff Process and Soil Erosion Risk Analysis in a Specific Area of Interest to Design Control Measures

Knowledge of the spatial variability and hydrological behaviour of contributing areas to specific outlet is a fundamental input for developing appropriate water resource planning and management actions that takes part in various areas of human activities. The aim of this contribution is to present the possibilities to assess precipitation-runoff process and soil erosion risk in a specific area using the theoretical approaches with the simplest requirements for meteorological and surface runoff data. Considering the connectivity and behaviour of natural processes, the analysis of precipitation-runoff process and soil erosion risk is crucial prior the design of technical water management practices and technical erosion control measures in the landscape. Characteristics of design rain, e.g. the intensity, annual frequency and duration can be determined using practical tools or according to analysis of the cost and damages related to specific technical measure. The intensity of design rain can be estimated according to the long-term meteorological observations and developed intensity-duration-frequency curves using region specific equations (Dub’s formula, Urcikan’s formula). For the design of water management, conservation (especially erosion) or other measures for ecological stabilization and protection of the area, it is important to determine in particular the following characteristics of surface runoff: beginning of surface runoff, design discharge from the contributing area, the depth of the surface runoff, volume of surface runoff. Estimating the soil erosion risk by water erosion can be done according to slope gradient or USLE calculation and subsequent comparison of estimated value with tolerable soil loss. Regardless of the location of specific areas, we have found that design parameters of water management and technical erosion control practices, facilities and measures, including their localization can be determined by applying and modifying existing theoretical and practical hydrological knowledge. We also found that this design cannot be executed without an analysis of the precipitation-runoff process and the erosion risk of this territory. In relation to climate change and changing rainfall patterns in all regions worldwide, further studies should be conducted to specify the regional characteristics of precipitation, soil and its usage

Short-term soil carbon dioxide (CO2) emission after application of conventional and reduced tillage for red clover in Western Slovakia

Tillage systems have impact on soil properties, crop growth and through this directly and indirectly influence the cropland CO2 emission and therefore the global warming. In Slovakia, the wider adoption of conservation practices has barriers such as large acreage of compacted soils, the absence of detailed regionalization of suitable soils for such practices and the scientific evaluation of its application on sustainable soil productivity and environment protection. This study evaluated the short-termeffect of conventional tillage (CT) and reduced tillage (RT) with (N1) and without (N0) N fertilizer application on soil CO2 emission from cropland planted with a red clover (Trifoliumpratense) during 40 days in 2013 on a tillage field experiment initiated in 1994. CO2 flux, soil temperature, and soil water contentwere monitored during the studied period in western Slovakia.Results of this study showed that there wasn’t significant difference (p< 0.05) in soil CO2 between conventional tillage and reduced tillage for both, not fertilized and fertilized plots. Averaged 40 days CO2 emissions were greater in reduced tillage as compared to conventional tillage for both fertilization levels. A linear regression between CO2 emission and soil temperature in conventionally and reduced tilled plots showed that soil temperature (r = 0.88-0.94; P <0.05) and not the soil moisture was a controlling factor. The highest CO2 emission were recorded on the CT and RT plots during the first two weeks after tillage, showing that the tillage resulted in a rapid physical release of CO2

IMPACT OF DIFFERENT SOIL TILLAGE SYSTEMS AND NITROGEN FERTILIZATION ON SOIL CARBON DIOXIDE (CO2) EMISSION FOR ORTHIC LUVISOL IN WESTERN SLOVAKIA

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