Search results for "Bulk density"
showing 10 items of 40 documents
Long-term annual burning of grassland increases CO2 emissions from soils.
2016
7 pages; International audience; Grasslands have potential to mitigate against climate change because of their large capacity to store soil organic carbon (SOC). However, the long-term impact of grassland management such as burning, which is still common in many areas of the world, on SOC is still a matter of debate. The objective of this study was to quantify the long-term effects of annual burning on CO2 output from soils and SOC stocks. The study was performed on a 62 years old field trial comparing annual burning (AB) to no burning associated with tree encroachment (NB), and to annual mowing (AM) with all treatments laid out in randomized block design with three replicates per treatment…
Poplar Biochar as an Alternative Substrate for Curly Endive Cultivated in a Soilless System
2020
Imminent necessity for eco-friendly and low-cost substitutes to peat is a defiance in the soilless plant cultivation systems. Wood biochar could entirely or partly substitute peat as a plant growing constituent to produce vegetables. Nevertheless, knowledge concerning potential plant performance of leafy green vegetables grown on wood biochar is restricted. The present study assessed the main physicochemical traits of various growing media constituted by decreasing the content of peat and by increasing the percentages of poplar wood biochar. Yield, nutritional and functional properties of curly endive plants cultivated in a protected environment were also tested. Biochar was pyrolyzed from …
Responses of above- and below-ground fungal symbionts to cessation of mowing in subalpine grassland
2017
Abstract The cessation of mowing in subalpine grasslands promotes the dominance of Festuca paniculata leading to the reduction in plant diversity. Moreover, it affects positively the abundance of Epichloe sp. inhabiting F. paniculata leaves and negatively the soil density of arbuscular mycorrhizal fungi (AMF). We explored how the cessation of mowing influences root AMF communities in F. paniculata and the neighboring plants, and Epichloe sp alkaloids. Thirteen AMF operational taxonomical units were found. The neighboring plants affected positively the abundances of Aalpin and GLOM_7 whereas the interaction plant/management type influenced significantly Claroide_1 , GLOM_1 and GLOM_7 . The N…
Evaluating equilibrium and non-equilibrium transport of bromide and isoproturon in disturbed and undisturbed soil columns.
2007
19 pages; International audience; In this study, displacement experiments of isoproturon were conducted in disturbed and undisturbed columns of a silty clay loam soil under similar rainfall intensities. Solute transport occurred under saturated conditions in the undisturbed soil and under unsaturated conditions in the sieved soil because of a greater bulk density of the compacted undisturbed soil compared to the sieved soil. The objective of this work was to determine transport characteristics of isoproturon relative to bromide tracer. Triplicate column experiments were performed with sieved (structure partially destroyed to simulate conventional tillage) and undisturbed (structure preserve…
Policies can help to apply successful strategies to control soil and water losses. The case of chipped pruned branches (CPB) in Mediterranean citrus …
2018
[EN] There is a need to devise management strategies that control soil and water losses in agriculture land to allow the design of proper policies to achieve sustainability. It is the responsibility of scientists to work with other actors to co-construct strategies that will lead to sustainable land-use policies. Using chipped pruned branches (CPB) as mulch can be a viable option because they represent local (in situ) organic material that can restore soil nutrient and organic matter. This research assesses: i) the perception of farmers towards different types of management strategies and CPB's costs; ii) the biomass yield of citrus branches and the impact of CPB on soil properties; iii) ho…
Segregated ice and liquefaction effects on compaction of fragipans
2004
The brittleness of fragipans is generally ascribed to the close-packing fabric arrangement acquired at the initial step of pedogenesis thanks to physical processes. However, there is an on-going debate over the agent causing soil densification. In this work, we tested the plausibility that ice segregation or liquefaction could have been the cause of the compaction of four fragipans. Two of them are located in nonseismic areas that have experienced periglacial conditions; one is from a strongly seismic area not affected by periglacial conditions, while the fourth site underwent moderate seismic activity and slight periglacial conditions. After disaggregation in the laboratory, soil specimens…
Long-term effects of contrasting tillage on soil organic carbon, nitrous oxide and ammonia emissions in a Mediterranean Vertisol under different crop…
2018
This 2-year study aimed to verify whether the continuous application of no tillage (NT) for over 20 years, in comparison with conventional tillage (CT), affects nitrous oxide (NO) and ammonia (NH) emissions from a Vertisol and, if so, whether such an effect varies with crop sequence (continuous wheat, WW and wheat after faba bean, FW). To shed light on the mechanisms involved in determining N-gas emissions, soil bulk density, water filled pore space (WFPS), some carbon (C) and nitrogen (N) pools, denitrifying enzyme activity (DEA), and nitrous oxide reductase gene abundance (nosZ gene) were also assessed at 0–15 and 15–30 cm soil depth. Tillage system had no significant effect on total NH e…
Contribution of raindrop impact to the change of soil physical properties and water erosion under semi-arid rainfalls
2017
Soil erosion by water is a three-phase process that consists of detachment of soil particles from the soil mass, transportation of detached particles either by raindrop impact or surface water flow, and sedimentation. Detachment by raindrops is a key component of the soil erosion process. However, little information is available on the role of raindrop impact on soil losses in the semi-arid regions where vegetation cover is often poor and does not protect the soil from rainfall. The objective of this study is to determine the contribution of raindrop impact to changes in soil physical properties and soil losses in a semiarid weakly-aggregated agricultural soil. Soil losses were measured und…
Determining Soil Hydraulic Properties Using Infiltrometer Techniques: An Assessment of Temporal Variability in a Long-Term Experiment under Minimum- …
2020
Conservation agriculture is increasingly accepted by farmers, but the modeling studies on agro-environmental processes that characterize these agricultural systems require accurate information on the temporal variability of the soil&rsquo
Beerkan Estimation of Soil Transfer parameters (BEST) across soils and scales
2019
Abstract Theories and models used in soil hydrological sciences rely on the knowledge of the spatially and temporally variable soil hydraulic properties, i.e. the water retention and hydraulic conductivity curves. Obtaining reliable experimental information on these curves for an area of interest is not easy and it still remains a challenge for soil scientists. In 2006, a simple and physically based methodology was proposed to completely characterize the soil using a single ring infiltration experiment in the field and determination of soil particle size distribution, initial and final soil water content and dry soil bulk density. This methodology, named BEST – Beerkan Estimation of Soil Tr…