Short-Term Effect of Feedstock and Pyrolysis Temperature on Biochar Characteristics, Soil and Crop Response in Temperate Soils

At present, there is limited understanding of how biochar application to soil could be beneficial to crop growth in temperate regions and which biochar types are most suitable. Biochar’s (two feedstocks: willow, pine; three pyrolysis temperatures: 450 °C, 550 °C, 650 °C) effect on nitrogen (N) availability, N use efficiency and crop yield was studied in northwestern European soils using a combined approach of process-based and agronomic experiments. Biochar labile carbon (C) fractions were determined and a phytotoxicity test, sorption experiment, N incubation experiment and two pot trials were conducted. Generally, biochar caused decreased soil NO3− availability and N use efficiency, and reduced biomass yields compared to a control soil. Soil NO3− concentrations were more reduced in the willow compared to the pine biochar treatments and the reduction increased with increasing pyrolysis temperatures, which was also reflected in the biomass yields. Woody biochar types can cause short-term reductions in biomass production due to reduced N availability. This effect is biochar feedstock and pyrolysis temperature dependent. Reduced mineral N availability was not caused by labile biochar C nor electrostatic NH4+/NO3− sorption. Hence, the addition of fresh biochar might in some cases require increased fertilizer N application to avoid short-term crop growth retardation

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

Climate Change and Human Development in Viet Nam: A case study for how change happens

The case study presents Viet Nam's institutional arrangements and policies in disaster management, practical examples of climate change adaptation and provides conclusions on reducing climate change vulnerabilities

Interannual variation of soil losses due to sugar beet harvesting in West Europe

Soil erosion studies on cropland usually only consider water, wind and tillage erosion. However, significant amounts of soil may also be lost from the field during the harvest of crops such as sugar beet, potato, carrot and chicory root. During the harvest, soil adhering to the crop, loose soil or soil clods and stones are exported from the field together with these crops. This process of soil erosion is called soil losses due to crop harvesting or SLCH. In this study, interannual variability of SLCH for sugar beet in four west European countries, i.e., France, Belgium, the Netherlands and Germany, was investigated for the last decades. Longterm (1978-2000) average SLCH values ranged between 5.2 Mg ha(-1) harvest(-1) (Germany) and 13.8 Mg ha(-1) harvest(-1) (France), while the minimum and maximum observed annual average SLCH values were 2.0 and 20.5 Mg ha(-1) harvest, respectively. A large part of the temporal variability of annual average SLCH for sugar beet within a given country could be explained by the rainfall depth recorded during the harvesting season. However, due to efforts made by farmers and the processing industry SLCH appeared also to decrease over time during the last decade. Furthermore, significant differences in SLCH were found between the countries studied, which could only be partly explained by rainfall depth during the harvesting season. Other determining factors may be differences in soil types, harvesting technique, agronomic practices and crop yield. As SLCH values were derived from soil tare data measured in sugar factories, differences could also be attributed to differences in post-harvesting cleaning, that lowers soil tare but that does not have an effect on the true soil loss at the field plot where sugar beet was harvested. Given that SLCH contributes significantly to overall soil loss on cropland, more research is needed to fully understand the temporal and spatial variability of SLCH. © 2005 Elsevier B.V. All rights reserved.status: publishe

Soil loss due to harvesting of various crop types in contrasting agro-ecological environments

Soil erosion studies on cropland usually only consider water, wind and tillage erosion. However, significant amounts of soil are also lost from the field during the harvest of crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.), chicory roots (Cichorium intybus L.), cassava (Manihot spp.) and sweet potato (Ipomoea batatas (L.) Lam). During the harvest soil adhering to the crop, loose soil or soil clods and rock fragments are exported from the field together with these crops.status: publishe

Soil losses due to mechanized potato harvesting

Soil loss due to crop harvesting (SLCH) is a soil erosion process that occurs during the harvest of crops such as sugar beet, potato, chicory root, carrot and black salsify. Soil adhering to these crops and loose soil are harvested and exported from the field together with these crops, which consequently leads to lowering of the soil profile. Some studies report on the intensities and determining factors of SLCH for sugar beet and chicory roots. Only few studies, however, tried to estimate SLCH values for potato and no studies were found that investigated the determining factors of SLCH for this crop, although potato is, from an a real point of view, the most important crop in Europe and the Russian Federation and the second most important crop in the world leading to SLCH. This study tried to fill this knowledge gap by conducting field measurements (n = 51) on potato harvesting machines on 29 field plots located in central and northern Belgium, with soil textures ranging from loamy sand to silt loam. The main objectives of the study were to assess SLCH for potato and to get more insight into the factors determining the spatial and temporal variability in SLCH. As soil clods are sometimes selectively removed by people at the sorting table of the harvesting machine and as the processes leading to soil adhering to potatoes and to soil clods were expected to differ, total soil losses were divided into soil adhering to potatoes (adhering SLCH) and soil clods (loose SLCH). Total soil loss during potato harvest was on average 3.2 Mg ha(-1) harvest(-1) and ranged from 0.2 to 21.4 Mg ha(-1) harvest(-1). The presence of soil clods induces the largest variability in total SLCH as adhering SLCH varied only between 0.2 and 3.6 Mg ha(-1) harvest(-1). About half of the variability in adhering SLCH could be explained by soil moisture content at harvesting time, while loose and total SLCH appeared to increase by increasing content of clay or particles < 16 mu m (R-2 = 0.27 for loose and +/- 0.40 for total SLCH). Loose and total SLCH intensities are thus more difficult to predict than adhering SLCH, which is attributed to complex clod formation and destruction processes. No good multiple regression equations could be found due to strong interaction amongst the independent variables. SLCH for potatoes appeared to be lower than for sugar beet and chicory root, which can be attributed to crop morphology and planting of potatoes in ridges. (c) 2005 Elsevier B.V. All rights reserved.status: publishe