Isotopic Composition of Carbon in Humus Acids of Albic Retisols and Luvic Chernozems

Eurasian Soil Science - Carbon isotope ratios in soil organic matter are often used in paleoecological research for reconstructing climate and plant communities (type of photosynthesis). The...     

Microbial Biomass,Carbon Stocks,and CO2 Emission in Soils of Franz Josef Land: High-Arctic Tundra or Polar Deserts?

Eurasian Soil Science - The biomass of prokaryotes and fungi, organic carbon stocks, and CO2 emission were studied in the Cryosols and Leptosols of Franz Josef Land. The highest carbon stocks were...     

Relationships between the Size of Aggregates,Particulate Organic Matter Content,and Decomposition of Plant Residues in Soil

Eurasian Soil Science - The distribution of total organic matter (Corg), particulate organic matter (CPOM), and potentially mineralizable organic matter (C0) in mega- (10–5 and 5–2 mm),...     

Mechanisms behind soil N dynamics following cover restoration in degraded land in subtropical China

Purpose

Nitrogen (N) is an important nutrient for re-vegetation during ecosystem restoration, but the effects of cover restoration on soil N transformations are not fully understood. This study was conducted to investigate N transformations in soils with different cover restoration ages in Eastern China.

Materials and methods

Soil samples were collected from four degraded and subsequently restored lands with restoration ages of 7, 17, 23, and 35 years along with an adjacent control of degraded land. A ¹⁵N tracing technique was used to quantify gross N transformation rates.

Results and discussion

Compared with degraded land, soil organic carbon (SOC) and total N (TN) increased by 1.60–3.97 and 2.49–5.36 times in restoration land. Cover restoration increased ammonium and nitrate immobilization, and dissimilatory nitrate reduction to ammonium (DNRA) by 0.56–0.96, 0.34–2.10, and 0.79–3.45 times, respectively, indicating that restoration was beneficial for N retention. There were positive correlations between SOC content and ammonium and nitrate immobilization and DNRA, indicating that the increase in soil N retention capacity may be ascribed to increasing SOC concentrations. The stimulating effect of SOC on ammonium immobilization was greater than its effect on organic N mineralization, so while SOC and TN increased, inorganic N supply did not increase. Autotrophic and heterotrophic nitrification increased with increasing SOC and TN concentrations. Notably, heterotrophic nitrification was an important source of NO₃^??N production, accounting for 47–67% of NO₃^??N production among all restoration ages.

Conclusions

The capacity of N retention was improved by cover restoration, leading to an increase in soil organic carbon and total N over time, but inorganic N supply capacity did not change with cover restoration age.

     

Proteomic profiles during adventitious rooting of Eucalyptus species relevant to the cellulose industry

New Forests - Adventitious rooting (AR) is an obligatory step for vegetative propagation of commercial woody species. Paper industries have interest in Eucalyptus globulus Labill and its hybrids...     

Towards the sustainable intensification of agriculture—a systems approach to policy formulation

The sustainable intensification of agriculture involves providing sufficient food and other ecosystem services without going beyond the limits of the earth’s system. Here a project management approach is suggested to help guide agricultural policy to deliver these objectives. The first step is to agree measurable outcomes, integrating formal policy goals with the often much less formal and much more diverse goals of individual farmers. The second step is to assess current performance. Ideally, this will involve the use of farm-scale metrics that can feed into process models that address social and environmental domains as well as production issues that can be benchmarked and upscaled to landscape and country. Some policy goals can be delivered by supporting ad hoc interventions, while others require the redesign of the farming system. A pipeline of research, knowledge and capacity building is needed to ensure the continuous increase in farm performance. System models can help prioritise policy interventions. Formal optimization of land use is only appropriate if the policy goals are clear, and the constraints understood. In practice, the best approach may depend on the scale of action that is required, and on the amount of resource and infrastructure available to generate, implement and manage policy.     

Mitigating nitrous oxide emissions from agricultural soils by precision management

Nitrous oxide (N₂O) emissions make up a significant part of agricultural greenhouse gas emissions. There is an urgent need to identify new approaches to the mitigation of these emissions with emerging technology. In this short review four approaches to precision managements of agricultural systems are described based on examples of work being undertaken in the UK and New Zealand. They offer the opportunity for N₂O mitigation without any reduction in productivity. These approaches depend upon new sensor technology, modeling and spatial information with which to make management decisions and interventions that can both improve agricultural productivity and environmental protection.