Long-Term Soil Ecosystem Studies

My opinion that many preferences of LTEs can be assessed in a network study and we are lucky to use such network principles from the very beginning of LTEs foundation in the former USSR since mid 30s last century in agronomic research. This approach was realized in a series of publications which define the unified system of indicators, sampling protocols and analytical methods. As a result, already in the mid of 60s last century zonal features of average fertilizers rates efficiency were specified, in which role of soil factor was estimated at the level of the Reference Soil Groups in modern World Reference Base for Soil Resources. Geographical principles in generalization of experimental data were used in construction of statistical models for the specific agro-ecological zones (AEZ) or soil types. These models provided possibility for numerical experiments 20-30 years ago, when we had no possibility to use dynamic modeling. One example can be linking LT field experimental results with weather data series in agrometeorological publications in 70s last century for long-term forecasts of fertilizers efficiency. Updating these results based on modern climate tendencies allows to estimates effects of climate dynamics on fertilizers efficiency change. This demonstrates how modern science provides insights relevant to tomorrow’s questions, as Henry Janzen put it in one of his publications: “The insights from one generation of scientists can often be applied to the questions of the next… Though our data may be aimed at today’s queries, the understanding that emerges, if it is deep enough, can offer clues to tomorrow’s questions still unseen”.

It seems that LTEs provide an excellent example of such continuity in Earth’s studies when an importance of really long experiment becomes more substantial with time. It becomes more substantial than the views of a researcher who initiated the experiment or even an institution which supervises LTE continuation as it can be interested only in one field of interest.

A shift in approaches from plot to landscape was very important in 1990s with an attempt to use more than 150 LTEs in the former USSR for agroecosystem research with widening system of indicators, mainly physical, microbiological and physiological ones; assessment of climate factor; application of dynamic models for forecast purposes in integrated assessment of sustainability. Alas, this attempt was not fully realized, but allowed to reveal limitations for agronomic LTEs use in agroecosystem study, one of them connected with necessity of multi-disciplinary research through cooperation with other scientists in a wide range of other disciplines. Perhaps, here a “snowball” effect works – the more data are available for the specific site as a result of interest of such multi-disciplinary team, the more interest of other scientists to use the it for their own research. My own experience of Ph.D. work at one of LT experimental site with growing forest belts in semi desert was demonstrated such preference of initiation research in a place where joint information was available for crop, native plants and tree growth, trends of soil moisture and groundwater dynamics, biodiversity study and weather data for long-term … Seems to me an ideal for which we need to approach but it’s impossible without joint interest, so promotion of existing LT sites is a very important question. Plots of land with a known and well documented historical data require not less attention than nature reservations, especially taking in mind their practical importance for increasing crop yields and price we need to pay for obtain the desired yields.

The attached table contains not only answer on the question of the text title (third column) but also short description of methods necessary to achieve expected results (methodology column), limitations at the moment for that as well as detected future tasks. While the first subject, naimly networking in agronomic studies, may be more relevant for us based on existing experience of LTEs network maintenance, all others seems more general for all our participants. That’s why I suppose the table can be improved and updated by all of us.