How to measure, report and verify soil carbon change to realize the potential of soil carbon sequestration for atmospheric greenhouse gas removal

There is growing international interest in better managing soils to increase soil organic carbon (SOC) content to contribute to climate change mitigation, to enhance resilience to climate change and to underpin food security, through initiatives such as international '4p1000' initiative and the FAO's Global assessment of SOC sequestration potential (GSOCseq) programme. Since SOC content of soils cannot be easily measured, a key barrier to implementing programmes to increase SOC at large scale, is the need for credible and reliable measurement/monitoring, reporting and verification (MRV) platforms, both for national reporting and for emissions trading. Without such platforms, investments could be considered risky. In this paper, we review methods and challenges of measuring SOC change directly in soils, before examining some recent novel developments that show promise for quantifying SOC. We describe how repeat soil surveys are used to estimate changes in SOC over time, and how long-term experiments and space-for-time substitution sites can serve as sources of knowledge and can be used to test models, and as potential benchmark sites in global frameworks to estimate SOC change. We briefly consider models that can be used to simulate and project change in SOC and examine the MRV platforms for SOC change already in use in various countries/regions. In the final section, we bring together the various components described in this review, to describe a new vision for a global framework for MRV of SOC change, to support national and international initiatives seeking to effect change in the way we manage our soils.

Learning, memory, and transfer in profoundly, severely, and moderately mentally retarded persons

Discrimination learning, memory, and transfer capacity were assessed in representative samples of institutionalized retarded persons in order to provide information on trainability. The 56 subjects were selected from moderately, severely, and two levels of profoundly retarded adults. They learned and relearned three successive two-choice discrimination problems. Generally, the higher functioning subjects, defined by IQ and adaptive behavior learned more rapidly than did the lower functioning subjects. Forgetting was related to IQ/adaptive behavior level. Interproblem transfer was negligible at all levels of retardation, but ceiling effects may have obscured positive transfer in the higher functioning groups. Backward learning curves revealed large differences between lower and higher functioning persons in the presolution trials, but once learning began even profoundly retarded subjects solved these problems as rapidly as did the moderately retarded subjects. Ten of the 56 subjects failed to learn all three problems.