Special issue  

The eddy covariance (EC) method has become increasingly popular in soil science. The basic concept of this method and its use in different types of experimental designs in the field are given, and we indicate where progress in advancing and extending the field of applications is made. The greatest strengths of EC measurements in soil science are (1) their uninterrupted continuous measurement of gas concentrations and fluxes and (2) spatial integration over small-scale heterogeneity in the soil.

The huge carbon stocks found in soils of the permafrost region are important to the global climate system because of their potential to decompose and release greenhouse gases into the atmosphere upon thawing. This review highlights permafrost characteristics, the influence of cryogenic processes on soil formation, organic carbon accumulation and distribution in permafrost soils, the vulnerability of this carbon upon permafrost thaw, and the role of permafrost soils in a changing climate.

Since seeds are the principle means by which plants move across the landscape, the final fate of seeds plays a fundamental role in the origin, maintenance, functioning and dynamics of plant communities. In arid and semiarid patchy ecosystems, where seeds are scattered into a heterogeneous environment and intense rainfalls occur, the transport of seeds by runoff to new sites represents an opportunity for seeds to reach more favourable sites for seed germination and seedling survival.

The behaviour of carbon nanomaterials (CNMs) in soils is highly complex and dynamic. As a result, assessments of the possible risks CNMs pose within soil should be conducted on a case-by-case basis. Further work to assess the long-term stability and toxicity of CNM-sorbed contaminants, as well as the toxicity of CNMs themselves, is required to determine if their sorptive abilities can be applied to remedy environmental issues such as land contamination.

We highlight observations relevant to soil organic matter (SOM) decay and retention but often emanating from disparate fields. First, we describe relevant natural and artificial aquatic environments. Second, we describe how intrinsic patterns of decay kinetics for purified soil substrates are useful for defining baseline rates. Third, we describe theoretical advances important for the discipline. Last, we describe how these advances can be used to unravel the mysteries of deep SOM persistence.

Nitrogen is necessary for life; this element is found in all DNA and protein molecules on Earth. Nitrogen also regulates the CO2 uptake capacity of land ecosystems, with important consequences for climate change. Here we provide evidence for a new source of nitrogen that is found in many of the rock materials on which natural ecosystems form. The idea that rocks are a widely distributed source of nitrogen challenges the standard paradigm of botany, soil, and ecosystem science.

The "local adaptation" component of integrated soil fertility management operates at field and farm scale. At field scale, the application of implements other than improved germplasm, fertilizer, and organic inputs can enhance the agronomic efficiency (AE) of fertilizer. Examples include the application of lime, secondary and micronutrients, water harvesting, and soil tillage practices. At farm scale, targeting fertilizer within variable farms is shown to significantly affect AE of fertilizer.

Case studies of artworks focused on painting, installation, and film are presented, with the view of encouraging further exploration of art about, in, and with soil, as a contribution to raising soil awareness.

This paper provides a brief accounting of some of the many ways that the study of soils can be interdisciplinary, therefore giving examples of the types of papers we hope to see submitted to SOIL.