Science is not a linear process. Some ideas may need quite a long time to mature and transform to a concept, an experiment and finally to a publication. I often incubate ideas, to be used at a later stage. This post is about one idea that took more than 5 years to materialise.
Global predicted PyC stocks as t ha−1 for the first 2 m soil depth.
I have a box I call “incubator” where I drop ideas worth to remember. Most of the time, it stays there long enough and I give up on it. Sometimes, it actually turns out to be a good idea. Recently we published a paper coming from this box:
Reisser, M., Purves, R. S., Schmidt, M. W. I., and Abiven, S. (2016). Pyrogenic Carbon in Soils: A Literature-Based Inventory and a Global Estimation of Its Content in Soil Organic Carbon and Stocks. Frontiers in Earth Science 4, 1–14. doi:10.3389/feart.2016.00080.
Full text here
In brief, this paper is an analysis of the literature about the quantities of fire-derived organic matter in soil. It consists in a collection of data extracted from the literature. We first compared these stocks to other types of organic matter, and then we analysed the drivers that couple explain these stock distribution geographically.
I found traces of the initial idea back in 2010-2011. I guess I was searching for references for the first papers we published in the topic of fire-derived organic matter (charcoal-like material) in the soil. I was searching for an idea of how much of this material was in the soil and I was surprised to find very few references, most of them pointing to a article giving a large range, actually based on 2-3 values. I had a rapid look and built up a database of 10 values or so, showing already quite a discrepancy with the referred ones.
I am fortunate enough to teach to very capable students at master level, and I often use this opportunity to test ideas as mini-projects postgraduate. In fall 2012, two Msc students selected the following topic: “how much fire derived organic matter do we find in soils?”. They found about 50-60 values, came up with several questions and issues and wrote an excellent paper. Then the idea wen dormante for a year or two.
The first reason for this pause was the “lack of time” for such topic. By lack of time I do not really mean I was so busy that I could not go further, but rather that I felt this idea needed my full attention for a couple of weeks, so that I can turn it into a meaningful piece of information. The second reason came from the students work: the issues they raised were serious: how to compare data measured with different methods, considered as not comparable ; how to deal with very geographically heterogenous origins of data, to cite a few. Also, I considered the database was too small at that time. So the idea and the students paper went back to the incubator.
It came out again a few times, for example I tried to give the data extraction task to several student helpers. It failed consistently, mainly because the students did not manage to select the proper information to be extracted from the published literature. To be more accurate, I did not manage to explain them what I wanted, for the good reason that I did not know myself, the concept explaining the stock formation was still missing.
The next decisive step took place end of 2015, at the beginning of a new PhD project. While preparing the project together with the PhD candidate, we realised that this literature analysis was still missing and was more and more needed, particularly because we wanted to compare ecosystems around the globe, so this geographical aspect matters more than ever. In parallel, we were developing some new hypothesis about soil organic matter stock formation in the frame of another research project, and we realised these hypothesis based on ecosystem properties were fitting perfectly to selected the drivers explaining the data we wanted to collect.
So the PhD candidate did the work. He collected 560 values out of about 60 publications and was able to find most of the informations we need to describe the drivers we wanted to highlight. He collected the database in a couple of weeks, we then wrote the paper in a month or so, with the help of colleagues from the department.
From an outsider perspectives, it may have looked like a extremely fast process: the data collection took place from February to March 2016, the data analysis and the manuscript writing until May. The manuscript was submitted end of May and was very well received by the reviewers. We have a couple of revisions to do and the paper was accepted early August. So 7 months for a literature/review paper. Actually, rather 5+ years…
Again from the outsider perspectives, it may have looked as all the pieces came together logically and smoothly. It was indeed not the case, it took ages to make sense out of it, mainly because most of the concepts developed over time and constructed this logical path. During this incubation time, since 2011, about 25% of the publications used in the database were published, representing something like 35% of the data.
I think this is a useful paper, giving a very new perspective to my research field. For example, it tells that there is roughly the same quantity of carbon buried as charcoal-like organic matter in the soil than in all the plants of the world. It was worth waiting for it incubation.