I Sustainable Primary Production for Human Well-Being

Biodiversity Agriculture Supports Human Populations

Nobuhiro Kaneko

Abstract The “Green Revolution” has increased food production to meet world population growth, therefore global food production is at present sufficient to feed all the world's people. However, the modern agricultural system is no longer sustainable due to deterioration of soil conditions. Alternative agricultural methods that aim to conserve biodiversity and soil functioning are not intensively studied, thus the productivity of alternative methods is often not compatible with conventional agricultural practice, and most people are skeptical of the feasibility of introducing alternative methods. Recent advancements in studies of biodiversity and ecological functioning are now supporting early trials by advanced farmers, who respect biodiversity in their fields. In this review, I would like to present some ecological theories to support biodiversity agriculture and its potential to support human populations.

Keywords Aboveand below-ground interaction • Conservation tillage • Ecological theory • Food security • Soil conservation

Introduction

The world produces sufficient food to feed its population, but still there remain more than one billion people who suffer from food insecurity and malnutrition (IAASTD 2009). Agricultural activities are now one of the major factors affecting global environmental change through reducing biodiversity, increasing greenhouse gas (GHG: CO2, N2O, and CH4) emissions and accelerating eutrophication and pollution of aquatic systems. Agriculture's main challenge will be to produce sufficient food and fiber for a growing global population at an acceptable environmental cost.

To meet the global demand for food without significant increases in prices, it has been estimated that we need to produce 50–110 % more food, in light of the growing impacts of agricultural activities on climate change (Godfray et al. 2010; Tilman et al. 2011). Closing 'yield gaps' on underperforming lands, increasing cropping efficiency, shifting diets, and reducing waste can double food production while greatly reducing the environmental impacts of agriculture (Foley et al. 2011). However, most of these discussions are based on the assumption that the agricultural production is sustainable using modern agricultural technology.

Biodiversity loss is obviously a major driving force of ecosystem change (Hooper et al. 2012). Even in the field of agriculture, loss of biodiversity is linked to degradation of ecosystem function. Carbon loss (decomposition), nitrogen mineralization, and leaching are influenced by both land use and soil biota (de Vries et al. 2013). Intensification of agriculture decreases soil biodiversity, thus soil degradation is inevitable under the modern agricultural system. Soil degradation includes physical factors (e.g., decline in soil structure, crusting, compaction, accelerated erosion); chemical factors (e.g., nutrient depletion, elemental imbalance, acidification, salinization); and biological factors (e.g., reduction in soil organic matter (SOM), and the activity and species diversity of soil microorganisms) (Lal 2004). Conserving soil biodiversity and utilizing its ecosystem functioning is beneficial not only for agriculture but also for consumers (Robertson and Swinton 2005). Many ecosystem services are synergistic; for example, soil carbon storage keeps CO2 from the atmosphere and also promotes soil fertility, soil invertebrate diversity, plant wateruse efficiency, and soil conservation (Lal 2004), and these ecosystem services are supported by biodiversity (Hooper et al. 2005)