Soil Chemistry, Food Security and Human Health: Overview.

Provisioning is one of the key ecosystem services provided by soils for society. Threats and opportunities for the soil resource in this context are usually framed in terms of soil erosion or as integrative concepts such as soil health. However, chemical reactions in the soil are a critical component of the mechanisms responsible for our ability to provide food and feed, both in terms of the total calories produced as well as the nutritional composition, all of which influence human health. The prevalence of stunting and low birth weights globally, sometimes in excess of 40% of the children in some developing countries, are directly related to caloric deficiencies as well as the intake of critical nutritional components such as micronutrients, proteins, vitamins, amino acids, and other essential elements. Natural soil weathering reactions can produce conditions that are not conducive to plant growth including extreme acidity, plant nutrient deficiencies, and soils that strongly sorb added nutrients. Chemical reactions in the soil directly influence the phytoavailability of indigenous plant nutrients in the soil and fertilizers added to the soil. Nutrient depletion is a significant limitation for crop production in many areas of the world and the concept of peak soil has been proposed as a mechanism for declining nutritional density in edible crops. Other soil conditions and multiple nutrient deficiencies can render crops unable to positively respond to plant nutrients added to the soil system. The extent to which micronutrient deficiencies limit plant productivity on a global scale is largely unknown. The entire nutrition value chain, from nutrients in the soil to human consumption, has multiple entry points for enhancing the nutritional quality of food including soil and foliar fertilization, biofortification, fortification, and human vitamin and mineral supplementation. Sustainable intensification can play an integral role in addressing nutrition issues.