Sustainable planting

Sustainable planting is an approach to planting design and landscaping-gardening that balances the need for resource conservation with the needs of farmers pursuing their livelihood.^[1] The demand on resources, specifically land/crops, is constantly increasing due to the long human lifespan.^[2] It is a form of sustainable agriculture and, “it considers long-term as well as short-term economics because sustainability is readily defined as forever, that is, agricultural environments that are designed to promote endless regeneration”.^[3]

The idea of sustainable planting can be dated back millennia, when the ancient Greeks and Chinese practised organic farming, the oldest method of farming.^[4] Later this practice was largely replaced by inorganic farming. In 1907 Franklin H. King in his book ``Farmers of Forty Centuries`` discussed the advantages of sustainable agriculture, and warned that sustainable practices would be vital to farming in the future.^[5]

Advantages of sustainable planting

^[6] Sustainability, external inputs needed, and labour requirements of selected plant disease management practices of traditional farmers.

Sustainable planting does not necessarily consist only of planting native species. Some ecosystems may benefit from any increase in biomass, from the introduction of certain non-native species, or any increase in biodiversity. In the case of disturbed areas, such as areas where energy pipelines have been installed or areas where military activity has taken place, some exotic/non-native plants may fare better than the displaced, native inhabitants, in the process increasing the biodiversity and biological biomass.^[7][8] Sustainable planting may also involve crop rotation provided that they are used effectively. At the very least, constant crop rotation (see: cover crops) will prevent soil erosion, by protecting topsoil from wind and draining water.^[8] Effective crop rotation allows enough time for pest pressure on crops to be significantly reduced, and for soil nutrients to be replenished. This, in turn, reduces the need for chemical fertilizers and pesticides.^[8] Specifically in terms of industrial agriculture, increasing the genetic diversity of crops by introducing new germplasm can significantly impact the heartiness of crops (cost permitting).^[9]

Methods of planting sustainably

Entomopathogenic Nematodes Application

Entomopathogenic nematode are parasites that are beneficial because they can be used to control pests in agriculture or forestry.^[10] This serves to drastically reduce the need for using pesticides to get rid of pests in planting. Furthermore EPN(Entomopathogenic Nematodes) can also serve as excellent resources for understanding biological, ecological and evolutionary processes involving other soil organisms. EPN form a stress–resistant stage known as the infective juvenile (IJ). The infective juvenile spread in the soil and infect suitable insect hosts. Upon entering the insect they move to the hemolymph where they recover from their stagnated state of development and release their bacterial symbionts. The bacterial symbionts reproduce and release toxins, which then kill the host insect.^[11] Compared to pesticides as they have very broad host range and less likely to induce insect form immunity to them. Unlike many other chemical insecticides, they do not poison non-target animals.^[12]

Generalized life cycle of entomopathogenic nematodes and their bacterial symbionts.

An example of a property using the xeriscaping method of sustainable planting. This method reduces the need for water which is often in limited supply in arid regions.

Limitations Of EPN

Entomopathogenic Nematodes have a very limited shelf life.Furthermore, they are negatively affected by high temperature and dry conditions as they are organisms mostly suited to water. When transported, they may get exposed to these unfavourable conditions, resulting in shortening their shelf life and viability.^[13] The type of soil they are applied to may also limit their effectiveness, as most of them might die before finding a suitable host. More research is being done to discover ways to overcome these limitations.

Improving water efficiency

Water efficiency can be improved by reducing the need for irrigation and using alternative methods. Such methods includes: researching on drought resistant crops, monitoring plant transpiration and reducing soil evaporation.^[14]

Soil water evaporation

It has been discovered that abstinence from soil tillage before planting and leaving the plant residue after harvesting reduces soil water evaporation; It also serves to effectively prevent soil erosion.^[15]

Crop residues reduce the evaporation of water from soil by covering the surface of the soil, this results in a lower surface soil temperature and reduction of wind effects.^[16] No tilling reduces the need for irrigation, using this method helps with the efficient use of water. Using the Xeriscaping approach is another possible way to conserve water.^[17]

Drought Resistant crops

Drought resistant crops have been researched extensively as a means to overcome the issue of water shortage. They are modified genetically so they can adapt in an environment with little water. This is beneficial as it reduces the need for irrigation and helps conserve water. Although they have been extensively researched, significant results have not been achieved as most of the successful species will have no overall impact on water conservation. However, some grains like rice, for example, have been successfully genetically modified to be drought resistant reducing the farmers need for irrigation.^[18]

Native Plants versus Exotic Plants

There is some debate among researchers and sustainability advocates whether it is more sustainable to cultivate plants that are native to a bioregion or choose plants based on the needs of the community or environment (regardless of the plants natural bioregion). Inconsistent, scientific definitions of words like native and sustainable are largely responsible for the controversy surrounding this issue. Because evolution of a plant species can be correlated with natural migration of the species to new areas, it is unclear whether or not this would classify individuals in this new area as native or exotic. With current technology and scientific understanding, the fossil record does not allow for accurate tracking of plant evolution.^[19] There is no standard length of time a species must inhabit an area before it becomes a native species to that area.^[19] Species may be considered exotic or invasive if they have been introduced by humans and are detrimental to other species in the area. Some sustainability advocates champion for the use of native plants when water shortage and soil nutrients are an issue because some exotic plants require different amounts of water and nutrients than what will occur naturally in an area. Conversely, the use of exotic plants can be argued for when the given species will add nutrients to the soil, like during crop rotation, or will serve another purpose that native plants could not. There is no blanket preference for native species or exotic plants as the benefits are very situation-specific.

Practical Examples

• When creating new roads or widening current roads, the Nevada Department of Transportation will reserve topsoil and native plants for donation.^[20] These materials can be used by home gardeners or for large-scale agricultural operations to supplement or replace imported materials.^[20] This decreases the need to import soil and plants that may disturb the ecosystem. Native plants and soil may also be better suited to local weather conditions and require less water and fewer soil additives (fertilizers).
• The National Wildlife Federation has created a network of gardens in the USA that are Certified Wildlife Habitats through the Garden for Wildlife Program that started in 1973.
• The Grain for Green Program in China that pays farmers to convert their retired farmland back into forests or other natural landscapes (usually what it was before farming).^[21]
• Over one-hundred peer-reviewed studies published during or after the year 2010 show that urban green space lowers air and ground temperatures and improves air quality.^[22] The size, quality and density of urban green spaces are positively correlated with the derived benefits.^[22] Sustainable urban green spaces dramatically reduce heat-stress related deaths and hospitalizations in urban communities and improve the overall health of individuals within those communities.^[22] Some cities trying to increase urban green space include Ottawa, Toronto, Winnipeg, Calgary, Whistler, Chequamegon, and Dauphin Island.

See also

• Sustainable landscaping
• Sustainable gardening
• Sustainable landscape architecture

References