The best would be UK standards.
Defra and lab gives target levels but I cannot find what they are depending on crop/climate/soil type.
Where can I find ‘official’ standards for organic matter levels in arable soils and in forestry?
The best would be UK standards.
There are really no “official ” standards for soils in either forestry or agricultural soils. One must take into account the initial state (undisturbed by humans) at a site to evaluate what the organic matter content really should be. However, this is impossible because most soils are perturbed in some way. Each soil type has its own capacity for storing organic matter and is impacted by the five soil forming factors. When we impose human practices on the soil, we change the soil as the organism component of the formation factors. A survey of similar soils under similar forestry practices in a region would be helpful in evaluating if the soil in question is better, worse or similar to the soil in question. Beginning monitoring of a soil by establishing a current baseline of the soil by sampling now and then again in the future will help determining if the status of the soil is improving, declining or remaining the same.
it depends on many factors, and the “content of organic matter” itself is not very relevant. Although it is considered “more organic matter – better” actually there very good soil containing about 1% of organic matter (0,58% organic C) or less, and soils not so good due to drainage problems with 3% of organic matter. However, as the question refers to “official standards” see these papers.
The first one refers to Poland, the data are not in the table but in the text, at the bottom of page 75 according to numeration, when printed, or 77 (numeration in the file).
For Peru, you can see this information in the last page (18), as “materia organica” – it is in Spanish, “alto” – “high”, “medio” – “medium”, “bajo” – “low”.
“official standards” for organic matter would not be helpful, as the organic matter contents of soils differ widely due to their history of cultivation, particle size distribution, pH et cetera. Further, the percentage of organic matter in soils underlies seasonal variability (to a certain extent). Therefore, it is not possible to have an “official standard” target level. Rather, it is necessary to observe the momentary levels of organic matter and to observe whether or not measures you are taking to increase organic matter content are successful. I am not sure about information from the UK, but TEAGASC from Ireland has some good information on this topic.
Not only the organic matter, but I would say, the other soil parameters like pH, CaCO3, textural variation, the fertility index, they all have to be standardized for major soil types or at soil series level in response to different crops and forest species having differential agro-pedological requirements, if sound land use planning has been realised. that is why we always say SOIL SUITABILITY CRITERIA in response to specific crop and soil is urgently needed in order to exploit the potential of soil resource inventory of ant land unit.