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INSAM - The International Society for Agricultural Meteorology

Last modified January 12, 2015 09:51

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Dear colleagues and INSAM Members,

You all know Moore's “law” according to which the power of microprocessors doubles every two years. This is a completely empirical statement that was first published in 1965; it has largely remained true to date, in spite of it's lack of any “scientific” basis. Moore just captured something profound in a simple statement, and he was lucky to be right! Of course, this is a kind of “luck” that doesn't happen by chance, as it is actually based on knowledge. Here's an agrometeorological example: the number of hectares of rangeland that can sustainably support a livestock unit (LU) is equal to the number of rainless months in the year. This too is mostly correct; I have verified it on many occasions but I cannot remember who told me, or whether I read it somewhere.

Another well known empirical law is “Pareto's rule” (associated with the Pareto distribution, a power law distribution). Pareto's rule, also known as the 20-80 rule, says that, in a number of situations, 20% of causes produce 80% of effects. For instance, just 15% of wheat producers account for 80% of world production (FAOSTAT). In many countries, 20% or less of farmers own 80% of the land, which was the case in Italy when Pareto (1848-1923) put forward the rule.

The rule is ubiquitous and also applies to INSAM membership. As you can discover by logging into the members section, we currently have 2141 members in 127 countries. Five countries (India, Nigeria, Iran, US and Brazil) make up 50% of membership, and twenty-five (19.7%) account for 1716 members (80.1%). Fifty percent of countries make up 94% of members. Twenty countries have just two members, and twenty-eight have just one, including some large countries and some that do have a long and distinguished agrometeorological tradition of excellence. 

When we look at the detail of countries, it is easy to see that membership is large in countries where Prof. Stigter has been most active... which is a lesson for us: without a dedicated person actively promoting INSAM, membership will stagnate and eventually regress.

We must all be that dedicated person!

How can we promote INSAM? A simple way would be to mention INSAM in our presentations, on the final slide, where it is easy to add, next to the traditional “Thank you” a sentence saying “Join me at the International Society of Agrometeorology (”. There are certainly many other ways, which we could discuss in the “Members' corner” of the newly established INSAM forum ( Do visit the forum and contribute your ideas!

Let me conclude by coming back to rules of thumb and observe that they often have in common with standard agrometeorological techniques that their authors are unknown.  Who invented Growing Degree Days? Was it Ivanov around 1948? Who invented crop coefficients and the concept of evapotranspiration (ET)? There are so many ET equations around that it is obvious that many people have been trying and inventing  approaches valid for specific environments, until Penman eventually came up in 1948 with a formulation that appealed to many practitioners.

Who invented the soil water balance (SWB)? Trewartha has been using it in the 1950s, but there is little doubt  that the Versatile Soil Water Budget (VSWB) of Baier and Robertson (1966) was a formally explicit and trend setting method, as demonstrated by the “Baier and Robertson Symposium on Modelling and Measurement of Soil Water Content” organized in Canada in 1996. 

All crop models and all crop monitoring approaches incorporate a soil water balance that is derived from the VSWB, and this is why I would like to pay a tribute to our friend George Robertson who just turned 100 years at the end of December. The tribute is also a personal one, as I had the privilege to travel with George during his last African trip for WMO, which coincided with one of my first missions to the continent. I have remained in contact with George since then and would like to thank him for being such an inspiration for many agrometeorologists worldwide. 

(1) Baier, W. and Robertson, G. W. 1966. A new Versatile Soil Moisture Budget. Can. J. Plant Sci. 46: 299–315.

René Gommes

Current President of INSAM

Visiting Professor, Chinese academy of sciences


Percentage of INSAM members as a function of the percentage of the countries represented by at least one member.

Percentage of INSAM members as a function of the percentage of the countries represented by at least one member.


The 24 countries shown in the fan chart above make up 79.5 % of INSAM membership (only 20 countries are listed by name).

The 24 countries shown in the fan chart above make up 79.5 % of INSAM membership (only 20 countries are listed by name).

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