Book Review – Rocks for Crops

In the book Rocks for Crops, agrogeology is defined as the “study of geological processes that influence the distribution and formation of soils and the application of geological materials in farming and forestry systems as means of maintaining and enhancing soil productivity for increased social, economic and environmental benefits,” or as Professor Peter Van Straaten aptly puts it: geology in the service of agriculture.

Professor van Straaten has been one of the leading figures in agrogeology for more than 30 years. He has carried out numerous geological studies investigating rocks in Africa, a body of work that he describes in his book Rocks for Crops (2002). A detailed profile of Professor van Straaten can be read in RTE’s feature Spotlight on Agrogeologist Peter Van Straaten, PhD.

For the novice in agrogeology, Rocks for Crops provides an easy-to-understand, concise summary of the field. The first half of the book lays down the basic foundations, introduces terminology and concepts, and lists specific rocks and minerals used to enhance the productivity and health of soils. The second half of the book goes further in-depth with an overview of the geology of the 48 countries in Sub-Saharan Africa and the minerals found there that could benefit agriculture.

Author Peter van Straaten

The chapters of the book build on each other, getting progressively further in-depth with the topic. It starts off introducing the state of Africa’s agriculture, the need for productive and sustainable agriculture, and the limitations that farmers face: high costs, low-nutrient soils, and lack of support, working upwards in scale to encompass other developing countries and the tropical region as a whole. Agrogeology is introduced as a potential solution.

Then, the text switches gears to introduce some of the most common agrominerals encountered in the field. Finally, the first part finishes off with practical examples of how agrominerals have been used, such as in greenhouses and nurseries or in large-scale plantations. The chapter also discusses some of the concerns in using agrominerals. These concerns serve as a reminder of the need to use agrominerals carefully to maximize their benefits and to avoid the problems associated with conventional chemical fertilizers.

Throughout the book, Professor van Straaten focuses on Africa, which at the time was his main area of study. The second half of the book contains a short section on each of the countries in Sub-Saharan Africa. Each section presents facts about the demographics of the countries and a map, followed by discussions of the geological outline and a list of the agrominerals in the country.

To conclude, the author presents a positive vision of the application of agrogeology and the potential of agrominerals for the future of sustainable agriculture in Africa.

Since the publication of Rocks for Crops 14 years ago, Professor van Straaten has become one of the mentors of the next generation of researchers. He is currently working with an interdisciplinary group of scientists to further agrogeology in Brazil and the tropics, and he was a speaker at the recent The III Brazilian Rochagem Conference in Pelotas, Brazil. He is continuing to advance our understanding of remineralization and showing us new directions for the cutting-edge research that is most needed now.

Zu Dienle Tan recently graduated from the University of Michigan with a Master’s degree in natural resources and environment. She specializes in conservation ecology and is passionate about biodiversity conservation, agroecosystems and sustainable development.