The Nexus of Soils, Plants, Animals and Human Health

Singh, B.R., McLaughlin, M.J., Brevik, E.C. (eds) 2017 The Nexus of Soils, Plants, Animals and Human Health Catena-Schweizerbart, Stuttgart

This book demands your attention! It starts off with the statement “soil and human health are interconnected” because “healthy soils produce healthy crops that in turn nourish humans and animals allowing for their health and productivity”. It goes on to point out “nearly 800,000,000 people are undernourished and nearly 40% of the world’s population are suffering from micronutrient deficiencies”.

Initiated by the International Union of Soil Science the book provides an overview of the linkages between soil and plant and animal and human health. It is the third in a series of publications produced each year for the Decade of the Soil 2015-2024. It consists of chapters contributed by specialists throughout the world dealing with individual aspects of soil health. With a strong research and science orientated approach, the editors set it clearly in the principles established by the founders of the organic movement in the UK; “the health of soil, plant, animal and human is one and indivisible”. It is very comprehensively referenced.

The first three chapters take a holistic perspective of the role of soil in terms of plant and animal and human health and consider the historical perspective of the principle. It faces head-on the challenge set by our far-sighted forebears in the organic movement; Balfour, Howard and McCarrison who in turn follow millennia of commentators concerned with farming and human health, stretching back to Hippocrates and Moses.

It identifies the role of soil in terms of nutrient supply, food production and nutrient content, the importance of soil biodiversity and the wider environmental relationships. It acknowledges the decline in food quality with the increase in yields resulting from conventional inputs and the effect on soil organic matter. As well as the need to ensure adequate trace elements it highlights the problems of soil pathogens and excess heavy metals.

Subsequent chapters are contributions from scientists who take a narrower or more reductionist view of the links, including the impact of soil structure and microbial processes on macro and micro-nutrients, the role of genetic engineering and the relationship of soil organic matter to crop production and climate change.

This book focuses on nutrients and minerals, ensuring that there is neither excess nor deficiency of the plant or animal’s needs. It deals specifically with issues of protein supply. It considers nutrient supply from the soil and recycling through organic matter, the action of soil organisms making nutrients more available and the need to avoid excesses, which may inhibit uptake or utilisation by the plant or animal.

The book does not address some of the more subtle aspects of food quality and health, sometimes described as “life force” or “vitality”. It doesn’t deal with some essential soil-related qualities of food such as taste or “terroir”, which undoubtedly have some impact on human health, nor the biological qualities i.e. antioxidants, which affect the immune system, or the impact on the maintenance of a healthy gut flora. It does not consider the benefits to human health of working with the soil.

It puts considerable emphasis on some negative impacts of the soil on human health, such as soil pathogens and soil borne diseases.

It leads on to the concept of soil health and the need to ensure that this recognises the impact of soil on the health of plants and the animals and people that eat them. Soil health is now widely advocated in farm, research and policy circles but in my experience this newfound thinking does not generally go beyond the functioning of the soil and rarely does it recognise the interconnections with human health.

The book shows how many of the problems of human health can be addressed by the way we manage the soil; we might not always agree with some of the means advocated and it does not provide any radical new insight into the concept of health, but it does set out the science in the context of a comprehensive awareness of the issues and the inter-connections between soils, plants, animals and humans.

It sets out the principles, which of course are all too familiar to those of us involved with organic farming. It provides an invaluable research perspective on aspects of soil nutrient management. You may therefore wonder why I haven’t mentioned organic farming in this review; that’s because this book only makes a cursory mention of organic farming, and that in an historical context. Is this another example of a deliberate attempt to avoid the “O” word for fear of frightening the horses? Or are the editors really unaware of the worldwide organic movement that has been putting the all-important principle of the link between soils, plants and humans into practice for nearly a century? Non-the-less it is a good attempt at drawing together the science focused on the central role of the soil in a healthy society and environment.