Spotlight on Agrogeologist Peter Van Straaten, PhD

At the II Brazilian “Rochagem” Conference, which took place in Poco de Caldas, Minas Gerais, in May 2013, Professor Peter van Straaten gave a series of talks on the use of rock dust to increase soil health for agriculture. As a pioneer in the practice of using rocks for soil remineralization, van Straaten shared his extensive knowledge with a broad spectrum of scientists and researchers who attended the conference. An expert in agrogeology, which Van Straaten defines as “geology in service of agriculture,” he has built an international network of projects that study remineralization and sustainable agriculture in Africa. His work has helped lift many small farmers out of poverty in Africa and his research has recently expanded to Indonesia, Cuba and Brazil.

Before the 2013 conference, van Straaten had made important contributions to the field of remineralization in Brazil. After publishing his book Rocks for Crops (2002), the first Rocks for Crops International Conference was held in Brazil in November, 2004.(The second conference was held in Kenya in 2007). The event helped pave the road for the I Brazilian “Rochagem” Conference in 2010 and the most recent conference in 2013. Organized in conjunction with Othon Henry Leonardos and Suzi Huff Theodoro, two pioneers in the Brazilian scientific community at the University of Brasilia, the 2004 conference brought together researchers from all over the world “for a workshop on the state of the art of rock, mineral and organic residue utilization to maintain and enhance soil fertility for sustainable tropical and subtropical environments and improve bioproductivity of food crops, forests and biofuels.”

A Revolution in Geology

Peter van Straaten is a classically trained geologist and, since scientists in this field have historically focused their research on mineral extraction practices and related industries, his work with remineralization can be seen as an important break from this tradition. When he joined the ranks of agrogeology researchers whose focus was mainly on tropical soils, van Straaten combined the fields of geology, agronomy and soil science in a new and promising way. His work drew on agrogeology forefathers, William Fyfe, former president of the IUGS (International Union of Geophysical Scientists) and professor at the University of Western Ontario and Ward Chesworth, professor from the University of Guelph who did many studies with students and researchers in tropical countries.

In the early 1980s Dr. van Straaten was working in mineral exploration in Tanzania as a geologist for the United Nations. At this time, he realized that his talents could be better used to help people living in poverty as opposed to working for people controlling the mining and extraction industry. In 1984 he began his work researching the use of rock dust fertilizers and their potential to help farmers living in poverty. Today, the promises of remineralization practices go beyond making crops healthier and more sustainable; they contribute to carbon sequestration and climate stabilization.

Doctor van Straaten with President Jakaya Kikwete of the Republic of Tanzania
Doctor van Straaten with President Jakaya Kikwete of the Republic of Tanzania

Van Straaten’s new research received support from the Canadian government, and the School of Environmental Sciences at the University of Guelph became the base for training students from around the world in agrogeology. Van Straaten’s efforts have resulted in an internationally acclaimed project called Rocks for Crops that has grown out of a partnership initiative in Kenya, Uganda, Tanzania, Zambia, and Canada. Rocks for Crops develops multimedia learning materials that provide information on agrogeology to universities, NGOs and other institutions. Through this project, knowledge gained from almost three decades of research on the agricultural use of rock dust has been made accessible to students and farmers in order to promote food security, soil fertility and sustainable agriculture. Van Straaten’s recent projects outside Africa include the opening of an Agrogeology Center, the first of its kind, in Indonesia and collaborations with geoscientists and agronomists in Brazil.

Rocks for Crops

Van Straaten’s 2002 book, Rocks for Crops: Agrominerals of Sub-Saharan Africa, is a detailed presentation of his extensive research in Africa. The book not only discusses the function, potential applications, processing, and environmental impacts of specific agrominerals, but also provides a country by country outline that includes information on agriculture, industry, mining, and geological surveys in the region. African countries are home to tropical soils that are generally nutrient deficient – low in nitrogen and phosphorus that are crucial for plant health – making agriculture exceptionally difficult. Expensive and harmful chemical fertilizers are not a viable solution for rural farmers and, according to van Straaten, the use of local resources as opposed to fostering dependence on chemical products is a sustainable approach that could help achieve national and international development goals.

The professor enthusiastically surrounded by children Peter van Straaten

Traditional farming methods that are handed down from one generation to the next help return necessary nutrients to soils that have been depleted. Practices that use locally available fertilizers such as manure and plant materials may not be enough to sustain degraded and deficient tropical soils for agriculture. The addition of locally available agromineral resources to traditional fertilizers is a viable alternative practice, but, as Van Straaten points out, for these fertilizers to be an effective supplement their use must be integrated into the existing social and cultural structures of local communities. Rocks for Crops not only discusses remineralization from a geological and agricultural perspective, but the economic benefits and perceptions of small-scale mining for agrominerals for rural communities are also addressed. Van Straaten’s second book Agrogeology: The Use of Rocks for Crops (2007) expands on agrogeology as an interdisciplinary science, emphasizing the integration of geological processes with soil fertility and soil management.

Peter van Straaten in Brazil

Van Straaten’s work with rural farmers and study of tropical soils is being used by researchers in Brazil to help broaden the technical and scientific understanding of remineralization practices. He has taken a position at the Federal Rural University of Pernambuco where he will make regular visits to do research and teach over the next three years. He also is currently participating in a joint project with Embrapa (The Brazilian Agricultural Research Corporation) and CPRM (The Brazilian Geological Service) in the south of Brazil.

Peter Van Straaten with the research team from Embrapa in the south of Brazil Peter Van Straaten

At the II Brazilian “Rochagem” Conference, he presented a series of lectures including a brief overview of material from his book, a discussion of the importance of certain minerals in Brazilian agriculture, a discussion of the mineralogical needs of crops based on plant origins, a condensed version of a course on agrogeology taught at the University of Guelph, and an interactive lecture on determining which minerals would be appropriate to use when considering certain soils in Brazil.

The presentations van Straaten gave at the 2013 conference provided detailed information about the function of geological minerals and micronutrients for plant growth. In addition to addressing specific agromineral resources in Brazil and benefits and drawbacks to their use in agriculture, he called for a particular approach to scientific research that stems from an important and broad conceptual question: “which rocks are likely successful for which crops?”

Scientists Need to “Think Like Plants”

Considering “original edaphic and climatic conditions for crop growth at sites of crop domestication” is the first step to uncovering what soils are most beneficial for which crops. Van Straaten calls on scientists to “think like plants” and consider “physiological sensitivities and soil limitations” in areas where crops will be planted. It is necessary to understand plant’s needs and to “think more ecologically on rock-soil-plant relationships when planning agricultural development in a climatically changing world.”

Van Straaten’ presentation, “Which Rocks for Which Crops? Ecophysiological and Geological Factors,” detailed the importance of understanding “plant specific nutrient requirements during critical growth conditions as well as rock composition and release rates” in order to maximize the benefits of using rock dust for agricultural practices. An approach that asks what types of native minerals are best for specific native crops is better than conducting trial and error experiments. According to van Straaten, research that is based on plant and soil specific rock and organic matter applications would “tailor the right rocks to the right crops.”

As the agriculture sector grows in Brazil, the need for soil management and for fertilizers that provide effective and sustainable results increases, thus van Straaten’s approach to studying and using agrominerals has been well received by Brazilian scientists and researchers. Van Straaten is now Professor Emeritus at the University of Guelph and in an interview with RTE’s Joanna Campe, he charmingly stated that he is “retired, not tired and not yet expired!” He strives to continue to make a difference and help small farmers around the world. Addressing the specific needs of crops through soil management will not only benefit farmers and their products, but will affect the entire global food system. Agrogeology is key for developing and expanding remineralization practices and van Straaten’s work will be essential for the continued success of young Earth scientists today as they approach the issue of sustainable development and the planet’s changing climate.


Dr. Van Straaten’s book, Rocks for Crops: Agrominerals in sub-Saharan Africa, is available online in its entirety at:

Also visit the Rocks for Crops website at
For more agrogeology research, visit the RTE publications list research database.

Special thanks to Amy Jo Arndt for research used in this article!

RTE Staff Writer Ezra Spira-Cohen has an MA in Sociology from the PUC University in Rio de Janeiro, Brazil. He studies social movements and sustainable development in Latin America and is very interested in remineralization and sustainable agriculture.

Print Friendly, PDF & Email


Support us on Patreon
Thank you for joining us today! Please become a member of RTE and support us on Patreon. Unlike many larger organizations, we work with a team of determined and passionate volunteers to get our message out. We aim to continue to increase the awareness of remineralization to initiate projects across the globe that remineralize soils, grow nutrient dense food, regenerate our forests’ and stabilize the climate – with your help! If you can, please support us on a monthly basis from just $2, rest assured that you are making a big impact every single month in support of our mission. Thank you!

3 Replies to "Spotlight on Agrogeologist Peter Van Straaten, PhD"

  • Taapo Solomon
    January 3, 2015 (11:07 pm)

    Hi, I liked your article(s) very much, and they have motivated me very much. I say unto you keep up the good work, and may you continue to succeed in all your endeavors.

    I am a graduate in BSc. Chemistry and Geology and I am very much interested in taking care of the Earth. However, in Zimbabwe employment and research opportunities are very limited to non-existent in the Environment sector. I am interested in your area of expertise, but I don’t know where to start from. I only have 14 months experience as a graduate trainee in Exploration and Economic Geology of Gold Deposits.

    If you can offer me some advice I would greatly appreciate it.

    Thank you very much.


    Taapo Solomon

  • Holleng Bwakat
    August 14, 2023 (4:55 am)

    Hello Prof. Thank you for sharing your thought and experience with those of us interested in agrogeology. This article is a masterpiece, and I will appreciate to have more of it. As a Nigerian geologist, there are areas in my country that the population have been banned from using chemical fertilizer due to the fight against insurgency. The insurgents are found to be using chemical from fertilizer to produce IEDs, hence the farmers are left with no option that to look for alternative source of minerals for their farming activities. This has become my interest to source for local rocks that will serve as alternatives.
    It will be joyful to have your support and inputs into this local discussion and research work.

    Best wishes,

Got something to say?

Some html is OK