Hello Yvette! You are working on a very interesting problem. As other colleagues have already explained, the matter is very complex and you need to put together data from various disciplines - geology, pedology, climatology, archaeology, chemistry... I have conducted a multi-elemental analysis of soil chemistry in central Europe and in the Mediterranean and increased levels of P are often clearly related to archaeological sites even millenia after their abandonment. But P can be introduced into soil also by other paths than by the past human activities, so a careful analysis of local conditions is always needed. An evaluation of P values together with other elements is usually very helpful and a range of geoarchaeological methods can bring additional facts important for the most plausible interpretation. If your project will continue in the next year we could even offer you assistance with the field survey, detailed mapping of soil chemistry, analysis of data etc. It would be interesting for us to compare results from diverse environmental and cultural settings.

Good luck with your project!

Ladislav

It is a different type of our test as a soil scientist . Let me have try at this question, if you can please let me know, the purpose for which you need to interpret you soil yest results. Is it for purely archaeological retrospective .

I am writing my thesis about the surprisingly similar plant communities found growing today at sites in our area in very different biomes. I hypothesise that this could be something to do with the fact that they are all useful food and medicinal plants, still used today by Khoi-San descendants in the area, and may have been deposited as waste (or perhaps intentionally) and then germinated and persisted there due to higher nutrients in the soil after thousands of years of habitation by early Khoi-San peoples. So I need to find out if the high nutrients which seem to be present track the distribution of these small patches of dense thicket vegetation and change where the vegetation changes as you go away form the sites. I can send you the results if you can help interpret them?  

Excellent , you know  my friend phosphorus has inherent tendency of having undisturbed imprints for exceptionally long period of time. There could also be a possibility of wild medicinal plants growing on those sites as their natural habitat. I will surely love to add my experience .

Anoop, how can I send you the results? I know about the phosphorus persisting for a very long time, which is why I am quite excited about the results. What I cannot find out though is what the average or normal levels of that area are likely to be and how the very variable ph readings impacts on those results etc. Yes some of the plants are quite widely found in the whole area but normally very sparse, it is is sometimes classed as desert as has low rainfall and mostly small shrubby bushes. It is the very obvious densification and increased height at the sites which I would like to understand and be able to explain. 

Yes please do send a PDF Alwynne. Thanks a lot. It is really frustrating trying to find info re hunter-gatherer, non-agricultural use of land and impacts. So many people agree they did leave impacts, but almost everyone only gives details in relation to agriculture in some way! Yvette

From your question I am not sure that my answer is goint to help but here is my take on the issue. I have read a little bit about P concentration in soil and its archaeological importance. The results you see are what you would expect from my point of view. As far as P in cencerned it accumulates in soil from human and animal waste as well as organic compounds decomposing (such as food waste and the like) so the P level wil always be higher near dwellings and in animal encosures and it's normal for it to be lower the more you move away from the settlement.  You mentioned agriculture and fertilisation, to be sure it's not recently contaminated (as P fixates in the soil) you should determine the background mean value for the area and perhaps compare it to analysis of another site which has a timeline adn type of economy determined. Here are some articles I read while studying P concentration in soil. 

Thank you so much Oana. great references which I have just skimmed but will certainly study further. I have a problem in that there are no comparable sites where it is known what inhabitants did, when they were there and for how long, the time period could stretch from 200 to 20 000 or more years before present ! they are not built structures but vary from rock walls with ancient paintings on them and a few surface stone tools, to fairly deep shelters with many tools as well as pottery. they have never been agriculturally impacted as such, but could have had goats or sheep around or in them over the past 2000 yrs. Lastly they are situated in and under rocky outcrops of very varied geological materials! I took samples from a distance away and sometimes above or below the rocky ridges or cliffs and worked my way closer to he actual site (or what I imagine to be this. The point is that the actual habitation site is not always where the paintings are and can even be on level open ground depending perhaps on the warm or cold dry or wet climate at any particular time. What would be interesting is to see whether the phosphorus extends further than the typical dense vegetation or not and if it perhaps could be shown to indicate places that would repay excavation away from the core of each site which cannot be seen in any other way. I cannot extend my research this far, but perhaps others might. Only excavating at the obvious site seems to me to perhaps be missing a whole of of information which would increase our understanding of these ancient life-ways as well as the peoples who lived there! Excuse the long ramble, I am just writing out thoughts or thinking by writing! Many thanks. 

The site sounds complex and intreaguing, it must be an interesting research. As I understand it you are looking at a migrant population or at least one that used these abris as temporary shelter? How is the filedwalking analysis of artifacts? does the P concentration relate to the areas with the most artifacts collected? 

I have never worked on a site with difficult terrain so I imagine artifact collection will have to deal with a lot of other factors such as slope and slipped matterial, but still it would give some indicators. Would you mind sharing a photo and rough sketch of the collection spots and P concentration results?

What is the method used for P concetration determination? It might affect the results. Was it an on site quick method, a physics method (XRF or similar) or a chemistry lab method (using acids for extraction and then colorimetry)? In field quick methods are less reliable while XRF gives rather quick and accurate results and it's portable.

Also, you say plants are abundant, so look for the highest abundancy, as plants need P and will tend to grow more where they find it in the soil.  For example, here in Romania, nettles grow in abundance near sheepfolds, as there is P in the soil from the sheep waste, so your ideea of searching to see if vegetation and P concentration coincides is great. 

As far as ascertaing whether the paintings coincide with an actual dwelling, you might want to look at present or last 2 centuries herding and inhabitance patterns of the area. You mentioned it was in South Africa, so you might want to look at studies of the herding done by local tribes, if you haven't allready. (I hope I don't sound too silly saying all this but I couldn't ascertain where in the research process you are at, so forgive me if I'm stating the obvious at any point). I found something on Google Books (https://books.google.ro/books?id=U55eucC8XzMC&pg=PA133&lpg=PA133&dq=traditional+herding+in+south+africa&source=bl&ots=lOoKJuauMb&sig=hqElUbmtuo7PO4Oa0G_FTIU53JI&hl=ro&sa=X&ved=0CDYQ6AEwA2oVChMI0peQ753HxwIViMMUCh21gwCk#v=onepage&q=traditional%20herding%20in%20south%20africa&f=false) that relates to this.

Lastly, is there any posibility of doing geophysical surveys? you mentioned a lot of rock, so ... i'm not sure magnetometry is efficient, but a GPR might work. In conjunction with artifact collection and the P study it might yield more consistent results. 

HI Oana, Thanks for above. Inhabitants were not migrant but possibly semi-settled or nomadic, following the rains and the game or just moving when plant food resources ran low and coming back again after a time when they recovered. Yes, I have the book thanks. Khoikhoi herders only arrived in the last 1000 to 2000 years and that period ended at least 200 to 350 years ago, and no-one else (that anyone knows of anyway) lived in or used the sites since then. The paintings are mostly older, fine line San paintings, going perhaps as far back as 20 000 years (nowadays they are saying even more)! No I can't get geophysical surveys done, in fact I should just be writing up all my data and leaving it at that, but am too curious about all the possibilities and so did the soil tests! Bray1 was used for P determination. As soon as my papers are published I will upload them here and you will see more clearly what I am doing or trying to do! 

It sounds very interesting, and I am happy that I had the chance to learn a bit about the fascinating culture you are studying so I am looking forward to your paper. All the best until then!

Hi Yvette,

I'm happy you have received several very good answers so soon. I will add some of my points of view. First to all, the soil. I don't know how is the pedo-diversity on the site, but if you take samples of different places the greater the diversity the more different the test results. So, it's important that you know which soils you have there (preferably where too), in order to compare without problems the results. If you don't have soil maps you can help you with the soilgrid webpage.

Second, the climate. When the temperatures are higher the water tends to be sparse. In the archaeological site that I study (on Yucatan's penninsula, México) the water is poor because the lime geology of the place and the higher temperatures. In this case the phosphorus is very low and the plants tends to group together in soils with higher water content instead the phosphorus status. If you don't have such situation with weather you can expect the common phosphorus-related distribution on vegetation.

Third, your work. Is pretty interesting your work searching for evidence of agriculture and backyard vegetation. It remembers me the "terra preta" works on Amazonia. I leave you a paper about it. Maybe related works in terms of the evidences of domestication could give you even more lights.

http://soilgrid.com/

Article The Domestication of Amazonia Before European Conquest

Hello Yvette! You are working on a very interesting problem. As other colleagues have already explained, the matter is very complex and you need to put together data from various disciplines - geology, pedology, climatology, archaeology, chemistry... I have conducted a multi-elemental analysis of soil chemistry in central Europe and in the Mediterranean and increased levels of P are often clearly related to archaeological sites even millenia after their abandonment. But P can be introduced into soil also by other paths than by the past human activities, so a careful analysis of local conditions is always needed. An evaluation of P values together with other elements is usually very helpful and a range of geoarchaeological methods can bring additional facts important for the most plausible interpretation. If your project will continue in the next year we could even offer you assistance with the field survey, detailed mapping of soil chemistry, analysis of data etc. It would be interesting for us to compare results from diverse environmental and cultural settings.

Good luck with your project!

Ladislav

Yes, I am really into something that I cannot possibly do on my own, especially as I am not at all young anymore though still pretty active! I just can't get to all the sites and places as easily as I once could, they are mostly pretty tough going to get to, with lots of walking and climbing involved! I would just love some younger, fitter and better qualified people to come and look. As I said the P could not have been introduced through agricultural fertilizing as these sites are on steep slopes, very rocky and rough, and if grazed at all, only intermittently and not by anything other than a few goats and perhaps wild antelope (or even Rhino and Elephant in the past!) There is no question of cultivation, this simply did not happen I don't think, the Khoi-San almost certainly never had to attempt purposeful cultivation let alone agriculture, as there was enough game and wild plant food around - though I do think a lot of sowing, seeding and spreading took place inadvertedly through plant use and waste deposits. If you are serious about doing a project here regarding soils, maybe I can ask the leader of the Klasies River Project if she would like to talk to you about it? Klasies is a long term project using a very multi-disciplinary approach to re-look at the sediments and layers of the original excavations at Klasies - one aspect being to look at the archaeobotany and the vegetation around the 5 sites (this is where I come in). We usually go for a few weeks in February/March. It is an incredibly interesting area and with what seem to be highly enriched soils near the sites where it is possible there were open air living areas at some time (look at my Powerpoint presentation on Klasies). Anyway, thanks for your very interesting comments and let me know if you are keen?.  

Of course Klasies is very famous worldwide and we'd be honoured to help! Your presentation is very interesting! Please ask your team leader and let me know if our assistance would be welcome. We have recently established an interdisciplinary Human Adaptability Studies research group at the Czech University of Life Sciences, Faculty of Environmental Sciences, and we do combine ecology, archaeology, soil science, study of agroecosystems etc. in our projects. Hard terrain is no problem for us, we can work both within a larger team or on our own, whatever seems the most effective. We can bring along our own equipment and test some 100 soil samples per day by a portable XRF and pH meter without taking any soil to the lab, everything would be localized by GPS and mapped in GIS. Other types of analyses can be done in the lab if necessary. You can write me to [email protected] for further correspondence. Thanks and best wishes, Ladislav

Great! I will get in touch directly via email as soon as I have spoken to Sarah and give her your email address too. Y

Hi Yvette,

There is two french researchers I think you should see the profile here: Christophe Petit (Paris university) and Fabrice Monna (Dijon university).

There is also a doctor of Dijon university: Estelle Camizuli, her work could be helpfull for the protocol (Ph, GPS, Mapping, analyzes, etc..)

Bests wishes for this.

G