New book emphasizes ag modeling's practical side

Even for seasoned agricultural and soil scientists, the concept of modeling can be foreign. Making models more familiar and promoting their study and practical application is the goal of Laj Ahuja. A USDA-ARS soil scientist and research leader, Ahuja proposed a book series to the Societies seven years ago called Advances in Agricultural Systems Modeling. Here’s what he recently told CSA News about the series and its latest volume (volume 5), Practical Applications of Agricultural Systems Modeling to Optimize the Use of Limited Water. The book was published by ASA, CSSA, and SSSA in December.

Cover of modeling book

CSA News: Why publish an entire series of books on modeling? Why is modeling important?

Ahuja: The first question a lot of people ask me, including my colleague scientists, is “Why models now? We did pretty well in the 20th century without them, right?” My answer is that agriculture in the 21st century is much more complex. We have to worry about environmental quality issues—soil, water, and air quality—and about our water resources becoming limited. Climate change is beginning to have an impact. So this is why we need integrated, quantitative, system-wide approaches [i.e., system models] for planning and decision making.

CSA News: How do models work, exactly?

Ahuja: Models are nothing but a quantification of data and knowledge from experiments over the years so that we can extend their results to a variety of conditions for which no data are available: climate conditions, soil conditions, management systems. We also need models to extend short-term results—three, four, or five years—to long-term conditions. My humble judgment is that 80% of our field research has been done somewhere before. So I think we should use models to exploit knowledge that already exists and then focus our limited resources on the remaining knowledge gaps. Then once we’ve used models to extend field research, we use that extended knowledge to develop decision-support tools that will help farmers, ranchers, and others.

CSA News: Tell our readers a bit about the series.

Ahuja: We have already published four volumes, and all of the subject matter was chosen based on a lot of feedback from experimental and modeling colleagues. Each volume generally started from a symposium, and from that, we picked the best contributors. Then we also put an announcement in CSA News calling for volunteer contributions so that we didn’t miss the new, bright, younger scientists. So each volume is a combination of volunteer contributions and sought-out contributions, and each also includes the top, international contributors.

CSA News: And this latest volume?

Ahuja: The highlight of this volume is that it emphasizes practical applications of models and presents case studies for using models to make the best use of limited water all over the world. And we have emphasized quality and originality for each chapter, so that each is more like a journal paper. Each was peer-reviewed by three anonymous reviewers and emphasized originality, not just a review of literature from the past.

CSA News: Why did you choose to stress the practical side of modeling in this new volume?

Ahuja: Models advance both science and technology. So, this volume presents case studies of their use to enhance field research on practical problems, as well as how they can be developed into management decision tools for producers.

CSA News: Anything else you’d like readers to know?

Ahuja: An interesting question that some people ask me is: Why did I start this series with the Societies and not a commercial publisher? I was actually invited and approved to start the series with a well-known commercial book publisher. But I decided to publish with the Societies because I see them as a broad, nonprofit, and more trusted forum to advance the science and technology of modeling. I also consider my work on this series as service and payback to the Societies that have benefitted me. So I hope the Societies keep letting me do this. It is definitely a source of joy and satisfaction, no question about it.

This Q&A originally appeared in the Jan. 2015 issue of CSA News magazine.