Soil serves us many goods and services while soil erosion affects these economic and ecological services. I am interested to know how these impacts can be quantified in terms of PES, if conservation measures is used to check soil erosion?
Naturally soil conservation is carried out applying labour and capital, therefore, this expenditure in cost-benefit analysis will require that output (PES) should be quantified in monetary terms which is in a sense an elusive concepts as life support system cannot be measured in monetary terms. If capital and labour could do it, moon by now has been an inhabited planet.
With this acknowledgement, there may be develop some rough monetary measures of PES in the case of soil erosion. First may be to estimate the increase of production from degraded land after checking soil erosion. Or, loss of nutrients from soil due to erosion can be worked out and converted in their respective market prices and money saved annually can be calculated after stopping soil erosion. Sediments accumulation on bed results either in avulsion of river or floods and both cause damage to land and property, it can be evaluated and considered payment of ecosystem services, if soil erosion is stopped and sediments accumulated on channel bed are removed. Removing sediments incur cost but as a result saving property as well as crop and working days saved in different sectors are profit earned.
Similarly, sediment from soil erosion also result in casualties of water-bodies like ponds and lakes which purify water. Purification cost through technological means can be considered as benefit. Reduced turbidity of river water due to checking soil erosion may result in less effort and less cost of treatment of water for water supply. These savings of money and time may be taken as benefit of PES.
If degradation of land soil erosion in a forest area is carried out (since soil erosion minimisation is carried out at watershed level which may also have forests or jungles) primary productivity of them, biodiversity, forest products, improvement of local water cycle, and increase in minimisation of soil erosion, and enhanced oxygen production and reduction air pollution are benefit which may be converted into monetary terms in way or the other.
As per my knowledge, impact of ecosystem function or services may be measured with Emergy indicators like emergy money ratio, environment loading ratio etc. Emergy to money ratio will be more appropriate for the same.
Perhaps you are right to some extent. Emergy as the sum of all energy in production or carrying out a job is no doubt good measure of ecological services. I carried out this exercise when working on energy efficiency of food production systems converting all inputs and output into energy units. However, when it is hard to calculate even ecological foot print in energy terms, how so varying ecological services from protecting soil from erosion can be converted in eMergy terms.
There is a paper about this subject that stimulates some interesting thoughts. Essentially, the economic value of soil is estimated by the cost of buying or moving the topsoil as one might for construction or engineering purposes. There remains how to value the soil based on it's other values such as carbon sequestration, water storage and filtration and nitrogen cycling.
When we calculate emergy yield of any soil conservation measure, we have to calculate energy loss (or energy input) through soil loss, which is a function of rain chemical and geopotential, runoff, slope, organic matter content etc. If we are able to do the same, emergy money ratio which is calculated from GDP of any country, then we may assess the payment to ecosystem service function.
It is a good question and I appreciate it. Loss of soil from the place of its origin and other land surfaces is a global issue essentially involving two factors i.e., Climate and Biosphere on Earth. Soil loss is triggered by human interference and dabbling with nature. Soil conservation and restoration back to its past glory, can be measured in terms of soil depth, soil moisture, soil bulk density, soil organic matter content, microbial load and diversity, extent of natural vegetation, extent of animal population in a given area become the parameters to evaluate the benefits of soil conservation.
I agree with the view of Dr. Firoz Khan on relating emergy concept with PES. It is not always possible to convert ecosystem service into emergy; then what is the option? I also appreciate the view expressed by Wendy Peterman. In fact he had attached a paper which is really dealing the topic. Thank you guys for the response.
Costs of soil erosion can be estimated by considering the costs of a new soil artificial creation. See for instance Fantappiè M., Priori S. & Costantini E.A.C. (2014): Soil erosion risk, Sicilian Region (1:250,000 scale), Journal of Maps, DOI: 10.1080/17445647.2014.956349
The most important thing is the estimation of the Carbon sequestration which can be quantified by t/ ha. The second factor is the quantity of soil particles intercepted and the soil moisture improved.