7.1 Agriculture – an introduction

Providing food for more than 8 billion people cannot be done without environmental impacts, any more than the mere existence of 8 billion people can occur without environmental impacts (Fig 1). Rather, sustainability in agriculture typically seeks to feed the world while maintaining or improving the productivity of soil and minimizing impacts on air and water quality, water availability, and biodiversity. Issues of safe storage and equitable distribution of food are separate from agriculture and will be addressed at the end of this chapter.

This chapter relates most closely to UN Sustainable Goal 2 on zero hunger and Goal 12 on Responsible Consumption and Production, but because our focus is on environmental impacts, goals for clean water, life on land, and life on water are also relevant. As we will see, agriculture affects the status of most of the 9 planetary boundaries of Earth, including those for biogeochemical flows (nitrogen and phosphorus), biosphere integrity (especially functional integrity of soil and water), land system change (deforestation), freshwater change (irrigation), and novel entities (synthetic fertilizers and pesticides.

Figure 1. Environmental impacts of food and agriculture. H. Ritchie, OurWorldinData. CC BY 

Some definitions relevant to agriculture

The international Food and Agriculture Organization includes within its definition of agriculture the raising of crops in soil for food and fiber, husbandry of livestock for food and other products, aquaculture of aquatic species, fisheries management, and silviculture of forests and plantations. In the US, most of these are under the purview of the US Department of Agriculture, including

• the Natural Resource Conservation Service, which has a primary focus on soil conservation on private lands under a variety of land uses including farming, grazing, and forestry and
• the US Forest Service, which manages the federal public lands of the national forests and grasslands for multiple uses include timber harvest, watershed management, grazing of privately owned livestock, hunting, fishing, biodiversity conservation, recreation, and extraction of fossil fuel and mineral resources.

Farming may seem like a narrower term, and it is. But, technically, farming encompasses growing of crops as well as animal husbandry, including aquaculture. Agronomy is the area of science related to soil management and crop production. Horticulturalists study and grow plants in managed areas, but these can include turf grasses, ornamental plants, and many food plants such as fruits, nuts, herbs, and spices, usually grown at smaller scales. Horticulture does not extend to so-called row crops, which are planted mechanically or by hand, in rows. Most major staple crops are row crops – corn, soybeans, wheat, rice – but vegetables can also be grown as row crops.

In less formal use of the term, “farming” is often limited to growing of non-woody food and fiber crops. This chapter deals primarily with this aspect of farming, and briefly with issues related to livestock production and aquaculture. Wildlife, fisheries, and forest management are addressed in later chapters.

The following terms describe agricultural and related systems, and may be used later in the chapter. Note that terms such as conventional farming, organic farming, and regenerative agriculture are stereotypical descriptions that can become rather like caricatures rather than serving a useful purpose in understanding agricultural practices. It may be easier to think of terms like these as positions along gradients of farming practices – some fields and some farmers (or producers) may use some, none, or all of the practices described here.

Conventional farming or industrial farming or intensive farming describes farming at the far end of the technical gradient that involves mechanization in soil preparation, planting, harvesting of crops, and treatment of crop residues. Most fields contain a single crop – a monoculture. Typically, high levels of inputs are used, including synthetic fertilizers and pesticides in order to maximize outputs (yields and/or profits). Genetically modified crops may also be used to maximize yields and profits. Fields managed with conventional farming can be quite large, and row crops are the most common crops. In drier areas, some form of irrigation may be used.

Organic farming occupies a different position from conventional farming with respect to synthetic fertilizers, pesticides and genetically modified crops, which are avoided. However, it may resemble conventional farming with respect to mechanization – particularly in organic farming of row crops – and in levels of soil disturbance. In many countries “organic produce” is a term defined by law, which therefore controls some of aspects of organic farming.

Regenerative agriculture is an approach to sustainable agriculture that seeks to improve resilience of agricultural systems,  maintain or improve soil health and productivity, support biodiversity, and contribute to the health and integrity of surrounding ecosystems. It incorporates a holistic view of the agricultural environment and acknowledges that the natural world can both benefit and benefit from agriculture. Conventional farms and organic may both use practices considered regenerative (for example, cover crops) without using only practices considered regenerative. Like permaculture (see below) and sustainable agriculture, generally, regenerative agriculture is defined more by the intent or aspirations of the farmers, rather than by specific practices or laws.

Precision agriculture involves the use of spatial technology, linking agricultural equipment to geolocating information to allow variable delivery of water, fertilizers and pesticides according to the precise needs of the crop, at the scale of feet or meters. Typically, precision agriculture leads to lower use of inputs and thus can reduce environmental impacts.

Climate-smart agriculture seeks to maintain or increase production under climate-change stresses while also decreasing contributions to climate change by decreasing GHG emissions from agricultural systems.

Agroforestry intentionally integrates useful trees and shrubs with crops and livestock pastures to diversify production, increase outputs, and improve environmental outcomes.

Subsistence agriculture is any kind of farming that is undertaken to feed a family or community, rather than for profit.

Shifting cultivation or swidden agriculture or slash-and-burn is a traditional farming system practiced in forested areas, especially in the tropics where soil fertility is low. Farmers clear an area of forest and burn the forest vegetation, producing mineral-rich ash that fertilizes the resulting fields for a short period. After one to a few years, a new field is cleared and the previous field is left to regrow for a longer period. Sustainable under low population densities, shifting cultivation can become unsustainable at higher population densities where forested areas are not large enough to allow forest to continue to exist under the constant pressure to clear land.

Permaculture is presently a movement, as much as, or more than, a form of farming. Because it sounds like a form of agriculture, it is included here. The World Permaculture Association defines permaculture this way.

Permaculture is an ecological design philosophy that emphasizes sustainable and harmonious integration between human systems and natural ecosystems. It goes beyond traditional gardening or farming; it’s a holistic approach that involves observing and mimicking the patterns found in nature. By understanding and working with these patterns, permaculture aims to create resilient and self-sustaining ecosystems that benefit both people and the environment.^[1]

Knowledge Check

Take a moment to complete the short quiz below to assess your understanding of this section. Read each question carefully and refer to the section content as needed. This quiz is not graded – it’s simply an opportunity for you to reflect on what you’ve learned and reinforce key concepts.