Horticulture

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Horticulture

Introduction

Horticulture concerns the growing and raising of plants. In particular, horticulture is concerned with plants that are economically important. These include plants that produce fruits, nuts, and berries, as well as vegetables, flowers, and shrubs. As well, the raising of turf—the large expanse of grass that is cut into strips for use in the creation of or patching of lawns—is also considered to be a horticultural activity.

Horticulture is not concerned with the raising of commercial agricultural crops such as corn, rice, and wheat; this is known as agronomy. As well, horticulture is different from the growth and harvesting of trees (forestry).

The traditional use of plant breeding techniques such as grafting—where portions of two plants are bound together to encourage their union and the subsequent development of progeny that are a blend of both parental plants—has largely been supplemented by genetic engineering, where genes coding for proteins that have a desirable attribute (a pleasing flower color, for example) can be added to the genetic material of the target plant. In another example, the nutritional content of rice has been enhanced through genetic engineering.

Other scientific goals of horticulture include improving the yield of a particular crop from a given area of land, improving plant resistance to pests, pesticides, and diseases. Increasingly, these goals are achieved by the genetic manipulation of the plants.

Historical Background and Scientific Foundations

Horticulture is centuries old. Indeed, the word has been traced back to seventeenth-century England, and is derived from the Latin words for garden and culture. Horticulture probably arose as humans shifted from a nomadic lifestyle where they moved constantly to track food to settle in a given location. In these more permanent communities, foods naturally available locally would be exploited and exhausted fairly soon, making the raising of food necessary for the continued existence of the settlement.

Archeological evidence from aboriginal North American populations and the Maya of Central America that dates back over 1,500 years has shown that the planting of field crops was augmented by the planting and care of a variety of fruit-bearing trees.

Even though this form of horticulture involved the raising of crops for food, it differed from modern-day agriculture in that the size of the plots was small and typically involved the planting of several types of plants, rather than large acreages planted with a single species.

With the stability of a more constant food supply, people became concerned with the ornamental aspects of horticulture. Gardening is an important activity for many homeowners. In the United States alone, gardening-related sales in 2006 were $34 billion, according to the National Gardening Association.

Horticulture involves a number of different aspects. One is known as arboriculture. This is the planting and cutting down of perennials (plants that bloom every year) such as trees, shrubs, and vines. Arboriculture can be as part of the maintenance of a woodlot, or for purely decorative purposes.

The second type of horticulture is called floriculture. This involves the raising and collection of ornamental flowering plants. Similar activities involving plants used to visually enhance a yard or garden are known as landscape horticulture. The growth and harvesting of vegetables is known as olericulture.

Finally, raising and harvest of fruits comes under the heading of pomology.

In addition to the commercial (industrial) and private aspects of horticulture, plant cultivation is an important part of government programs and educational study.

As with other science disciplines, horticulture no longer represents one activity, but has become fragmented into sub-specialties. These include the design and engineering of facilities for the large-scale cultivation of plants, use of tissue culture techniques to raise plants, breeding, genetics involved in the cross-breeding of plants (Mendelian genetics), molecular genetics involving the manipulation of DNA, plant diseases, and commerce.

Impacts and Issues

The commercialization of horticulture has increased the scale of the activity. Although many horticulturists are concerned with backyard garden plots or their household lawn, commercial horticulture operations such as garden centers are concerned with the raising and sale of thousands of plants. For the latter, control over the health of the plants and maintaining a steady supply of the product are very important.

Horticulture will be affected by the global climate changes that have been predicted to continue and become more prominent in the twenty-first century. For example, the 2007 Intergovernmental Panel on Climate Change (IPCC) report noted the high likelihood that

WORDS TO KNOW

AGRICULTURE: Replacement of a natural ecosystem with animals and plants chosen by people.

GRAFTING: Uniting a shoot or bud with a growing plant.

HEAT ISLAND: An urban area with significantly higher air and surface temperatures than surrounding areas. Occurs because pavement and buildings absorb solar energy while being little cooled by evaporation compared to vegetation-covered ground.

some regions of the world will continue to experience temperatures that are higher than what has been the norm for centuries, and that water shortages will create drought conditions in the same or different regions. Both of these changes impede the growth of plants.

In response, some plant species such as wheat are being bred or genetically engineered to be capable of growth in the presence of reduced moisture. More temperature-tolerant plants are also being developed.

Horticulture could also play an important role in lessening the effect of atmospheric warming on cities and could help reduce urban heat islands. Planting trees for shade and to increase retention of carbon dioxide is a

strategy being advocated by agencies including the U.S. Centers for Disease Control and Prevention (CDC) in order to promote healthier urban environments.