Earth Stats

The Soil Food Web

The soil food web is the community of organisms living all or part of their lives in the soil. It describes a complex living system in the soil and how it interacts with the environment, plants, and animals.

The most abundant energy resource in the soil is detritus, or dead plant and animal matter. The primary consumers in soil are often microbes such as bacteria and fungi that consume detritus. There are at least 10,000 species and more than 1 billion individual bacteria in 1 gram of soil (Torsvik et al. 1990). These fast growing microbes act as a food base for many other soil organisms such as mites, collembolans, nematodes and enchytraeids. Underground herbivores can also get energy directly by grazing on or parasitizing plant roots and these herbivores have their own predators (such as entomopathogenic nematodes).  Source: http://en.wikipedia.org/wiki/Soil_food_web

In a balanced soil, plants grow in an active and vibrant environment. The mineral content of the soil and its physical structure are important for their well-being, but it is the life in the earth that powers its cycles and provides its fertility. Without the activities of soil organisms, organic materials would accumulate and litter the soil surface, and there would be no food for plants. The soil biota includes:

  • Megafauna: size range 20 mm upwards, e.g. moles, rabbits, and rodents.
  • Macrofauna: size range 2-20 mm, e.g. woodlice, earthworms, beetles, centipedes, slugs, snails, ants, and harvestmen.
  • Mesofauna: size range 100 micrometre-2 mm, e.g. tardigrades, mites and springtails.
  • Microfauna and Microflora: size range 1-100 micrometres, e.g. yeasts, bacteria, fungi, protozoa, roundworms, and rotifers.
Soil life or soil biota is a collective term for all the organisms living within the soil. Of these, bacteria and fungi play key roles in maintaining a healthy soil. They act as decomposers that break down organic materials to produce detritus and other breakdown products. Soil detritivores, like earthworms, ingest detritus and decompose it. Saprotrophs, well represented by fungi and bacteria, extract soluble nutrients from delitro. Source: http://en.wikipedia.org/wiki/Soil_life

Human Impact on the Biosphere - The Problem

The Millennium Ecosystem Assessment provides the most comprehensive current synthesis of the state of the Earth's ecosystems. Natural systems (often referred to as ecosystem services) are humanity's life-support system, providing the necessary conditions for humans to flourish. Over the last 50 years the rapidly escalating and potentially critical nature of human global impact on the biodiversity of these ecosystem services has become the source of major biological concern.
At a fundamental level human impact on the Earth is being manifest through changes in the global biogeochemical cycles of chemicals that are critical to life, most notably those of water, oxygen, carbon, nitrogen and phosphorus.

Source: http://en.wikipedia.org/wiki/Sustainability

There is now clear scientific evidence that human activity is having a significant effect on all of these cycles.

Direct global environmental impacts

Atmosphere

The most obvious human impact on the atmosphere is the air pollution in our cities. The pollutants include toxic chemicals such as nitrogen oxides, sulphur oxides, volatile organic compounds and particulate matter that produce photochemical smog and acid rain. Anthropogenic particulates such as sulphate aerosols in the atmosphere reduce the direct irradiance of the Earth's surface. Known as global dimming the decrease is estimated at about 4% between 1960 and 1990 although the trend has subsequently reversed.

Global dimming may have disturbed the global water cycle by reducing evaporation and rainfall in some areas: it also creates a cooling effect and this may have partially masked the effect of greenhouse gases on global warming.[36] [37] However, it is now human-induced climate change and the carbon cycle that have become a major focus of scientific research because of the potential for catastrophic effects on both biodiversity and human communities (see Energy below).

Cultivated land

Feeding more than six billion human bodies takes a heavy toll on the Earth's resources. This begins with the human appropriation of about 38% of the Earth's land surface and about 20% of its net primary productivity. Added to this are the resource-hungry activities of industrial agribusiness - everything from the initial cultivation need for irrigation water, synthetic fertilizers and pesticides to the resource costs of food packaging, transport (now a major part of global trade) and retail. The benefits of food production are obvious: without food we cannot survive.

But the list of costs is a long one: topsoil depletion, erosion and conversion to desert from tillage for monocultures of annual crops; overgrazing; salinization; sodification; water logging; high levels of fossil fuel use; reliance on inorganic fertilizers and synthetic organic pesticides; reductions in genetic diversity by the mass use of monocultures; water resource depletion; pollution of waterbodies by run-off and groundwater contamination; social problems including the decline of family farms and weakening of rural communities.

http://en.wikipedia.org/wiki/Sustainability

Soil Erosion

An escalating world population will certainly result in increased demand for food, fiber, water, and other natural resources. Only one billion persons are estimated to have lived throughout all history up to the year 1850. Contrast this statistic with an estimated world population of seven billion by the year 2000 and the potential problem becomes more sharply focused. World population is currently doubling about every thirty-five years. Will we realistically be able to feed and clothe this burgeoning mass by the year 2025? By 2050?

As one of earth's most vital and fragile natural resources, soils come under ever increasing pressure. Quite simply, there is less soil per person with each passing day, making increased productivity per unit of land area a requirement. At the same time there are issues of appropriate land uses, sustainability, environmental protection and water rights.

In much of the developing world, where population growth has been greatest, organized conservation efforts have been weak and pressure on arable soil resources has been great. This growth has led to a tragic loss of valuable resources partially because resources not well suited for crop production are being used as food requirements increase.

Land use planning, not popular with persons who value individual rights in use of owned property, is becoming more widespread as more demands are placed on soil and water resources. Further, concern that land retain its productivity over time is increasing. "Wearing out the soils" on a farm and moving on to a virgin territory is no longer the option that it was well into the present century.

An additional land use issue which will take on increasing global importance is urban development. Many of the world's large cities developed where they did because of the stable agricultural production from productive soils in the area. As cities expand, formerly productive agricultural land is covered by highways, housing subdivisions, shopping malls, and other commercial developments. Once appropriated for such uses, these lands cannot economically be returned to agricultural production. Responsible land use planning is expected to become increasingly important in the future.

Organic gardening and farming have attracted much attention in recent years. As emphasized, the organic component in soils has essential roles in determining the soil's physical, chemical and biological behavior.

Increasingly, decisions that impact use and management of soil resources arise from discussion of problems such as sustainable use of finite resources, water quality, sedimentation in lakes, food quality, endangered species, preservation of wildlife habitats, and cultural practices.
Every citizen, through the right to vote, can influence laws that determine how soil and water resources are used and managed. All citizens share the responsibility for ensuring that all natural resources are treated with respect and wisely used. Some citizens must devote their careers to developing still better technology for management and conservation that will ensure continued utility of these precious resources by our successors on planet earth.

http://organiclifestyles.tamu.edu/soilbasics/index.html

Freshwater

Freshwater habitat is the world's most vulnerable of the major biological systems due to the human need for potable water for food irrigation, industry and domestic use. Human freshwater withdrawals make up about 10% of global freshwater runoff and of this 15-35% is considered unsustainable - a proportion that is likely to increase as climate change worsens, populations increase, and water supplies become polluted and unsanitary.

In the industrial world demand management has slowed absolute usage rates but in the developing world water security, and therefore food security, remain among the most important issues to address. Increasing urbanization pollutes clean water supplies and much of the world still does not have access to clean, safe water.

Indirect global environmental impacts

Addressing sustainability now focuses much of its attention on managing levels of consumption and resource impact by seeking, for example, to modify individual lifestyles, and to apply ideas like ethical consumerism, dematerialization and de-carbonization, while at the same time exploring more environmentally friendly technology and methods through eco-design and industrial ecology.

Patterns of consumption must reflect the cleverer use of resources: e.g. using renewable energy rather than fossil fuels and fewer embodied resources in goods and services.

In coming to terms with human consumption sustainability science focuses on four interconnected and basic human resource needs - for: water (agriculture, industry, domestic use), energy (industry, transport, tools and appliances), materials (manufacturing, construction) and food (horticulture, agriculture and agribusiness).

In 2007, after prolonged skepticism about the human contribution to climate change, climate scientists of the IPCC concluded that there was at least a 90% probability that this atmospheric increase in CO2 was human-induced - essentially due to fossil fuel emissions and, to a lesser extent, the CO2 released from changes in land use.

Projections for the coming century indicate that a minimum of 500 ppm can be expected and possibly as much as 1000 ppm. Stabilizing the world's climate will require high income countries to reduce their emissions by 60-90% over 2006 levels by 2050.

Water

. Water covers 71% of the Earth's surface.
. The oceans contain 97.2% of the Earth's water.
. The Antarctic ice sheet (visible here at the South Pole) contains 90% of all fresh water on Earth.
. Condensed atmospheric water, as clouds, contributes to the Earth's albedo.

Awareness of the global importance of preserving water for ecosystem services has only just begun as, during the 20th century, more than half the world's wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems.
Currently towards 35% of human water use is unsustainable, drawing on diminishing aquifers and reducing flows of major rivers.

Over the period 1961 to 2001 there was a doubling of demand and over the same period agricultural use increased by 75%, industrial use by more than 200%, and domestic use more than 400%. [4] Humans currently use 40-50% of the globally available freshwater in the approximate proportion of 70% for agriculture, 22% for industry, and 8% for domestic purposes and the total amount is progressively increasing being about five times that at the beginning of the 20th century.

The path forward appears to lie in improving water use efficiency through: demand management; maximising water resource productivity of agriculture; minimising the water intensity (embodied water) of goods and services; addressing shortages in the non-industrialised world; moving production from areas of low productivity to those with high productivity; and planning for climate change.

Materials

Materials used by humans are still increasing in volume, number, diversity and toxicity. Synthetic chemical production is escalating and global transport systems accelerate distribution across the globe. Much of the sustainability effort is directed at converting the linear path of materials from one of extraction to production and disposal as waste, to a cyclical one that reuses materials indefinitely, much like the waste cycle in nature.

At the local level there are various movements working towards more sustainable use of wastelands, peripheral urban land and domestic gardens. Included here would be permaculture, urban horticulture, local food, slow food, organic gardening and the like.

Decoupling environmental degradation and economic growth

Over the second half of the 20th century, world population has doubled, food production has tripled, energy use quadrupled, and overall economic activity has quintupled.  Historically there has been a close correlation between economic growth and environmental degradation: as communities grow, so the environment declines. This trend is clearly demonstrated on graphs of human population numbers, economic growth, and environmental indicators.

Unsustainable economic growth has been compared to the malignant growth of a cancer because it eats away at the Earth's ecosystem services which are its life-support system. Mismanagement of finite natural resources by cultures such as the Maya, Anasazi and Easter Islanders eventually led to their demise by destroying their resource base and there is the concern that, unless growth is checked, planet Earth will follow a similar path.

Part of the task for sustainability is to find ways of reducing (decoupling) the amount of resource (e.g. water, energy, or materials) needed for the production, consumption and disposal of a unit of good or service. In other words the goal of sustainability is to minimise resource use per unit of product or money spent (the resource intensity) and to maximise the output per unit of resource input or money spent (the resource productivity)

The Sustainability Transition

Almost all developed nations have an Ecological Footprint (the area of land needed to support a community and its waste) significantly larger than their geographic area - they are consuming more than they are producing. The extra resources needed to maintain this level of consumption are gained in three ways: embedded in the goods and services of world trade; taken from the past (e.g. fossil fuels); or taken from the future as unsustainable resource usage.

The sustainable development goal is to raise the global standard of living without increasing the use of resources beyond globally sustainable levels; that is, to not exceed "one planet" consumption.

At present the developing world per capita consumption is sustainable (as a global average) but population numbers are increasing and individuals are aspiring to high consumption Western lifestyles. The developed world population is stable (not increasing) but consumption levels are unsustainable. The task is to curb and manage Western consumption while raising the standard of living of the developing world without increasing its resource use and environmental impact. This must be done by using strategies and technology that decouple economic growth from environmental damage and resource depletion.

http://en.wikipedia.org/wiki/Sustainability

Land degradation

Intensive farming often leads to a vicious cycle of exhaustion of soil fertility and decline of agricultural yields. Approximately 40% of the world's agricultural land is seriously degraded. In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25% of its population by 2025, according to UNU's Ghana-based Institute for Natural Resources in Africa.

http://en.wikipedia.org/wiki/Food_security#Land_degradation


Causes of Land Degradation

Land degradation is a global problem, mainly related to agricultural. The major causes include:
  • Land clearance, such as clearcutting and deforestation
  • Agricultural depletion of soil nutrients through poor farming practices
  • Livestock including overgrazing
  • Urban conversion
  • Irrigation and overdrafting
  • Land pollution including industrial waste
  • Vehicle Off-roading
  • Weeds
Effects

The main outcome of land degradation is a substantial reduction in the productivity of the land.

Severe land degradation affects a significant portion of the earth's arable lands, decreasing the wealth and economic development of nations. Land degradation cancels out gains advanced by improved crop yields and reduced population growth. As the land resource base becomes less productive, food security is compromised and competition for dwindling resources increases, the seeds of famine and potential conflict are sown.

Unless land rehabilitation measures are effective a downward eco-social spiral is created when marginal lands are nutrient depleted by unsustainable land management practices resulting in lost soil resilience leading to soil degradation and permanent damage.

We often assume that land degradation only affects soil fertility. However, the effects of land degradation often more significantly affect receiving water courses (rivers, wetlands and lakes) since soil, along with nutrients and contaminants associated with soil, are delivered in large quantities to environments that respond detrimentally to their input.

Land degradation therefore has potentially disastrous effects on lakes and reservoirs that are designed to alleviate flooding, provide irrigation, and generate hydroelectricity.
Climate change

Significant land degradation from seawater inundation, particularly in river deltas and on low-lying islands, is a potential hazard that was identified in a 2007 IPCC report. As a result of sea-level rise from climate change, salinity levels can reach levels where agriculture becomes impossible.

http://en.wikipedia.org/wiki/Land_degradation


Risks of fertilizer use

The problem of under-fertilization is primarily associated with the use of artificial fertilizers, because of the massive quantities applied and the destructive nature of chemical fertilizers on soil nutrient holding structures. The high solubilities of chemical fertilizers also exacerbate their tendency to degrade ecosystems, particularly through eutrophication.

Storage and application of some nitrogen fertilizers in some weather or soil conditions can cause emissions of the greenhouse gas nitrous oxide (N2O). Ammonia gas (NH3) may be emitted following application of inorganic fertilizers, or manure or slurry. Besides supplying nitrogen, ammonia can also increase soil acidity (lower pH, or "souring"). Excessive nitrogen fertilizer applications can also lead to pest problems by increasing the birth rate, longevity and overall fitness of certain pests.

The concentration of up to 100 mg/kg of cadmium in phosphate minerals (for example, minerals from Nauru and the Christmas islands) increases the contamination of soil with cadmium, for example in New Zealand. Uranium is another example of a contaminant often found in phosphate fertilizers, also radioactive Polonium-210 contained in phosphate fertilizers is absorbed by the roots of plants and stored in it tissues. Tobacco derived from plants fertilzed by rock phosphates contains Polonium-210 which emits alpha radiation estimated to cause about 11,700 lung cancer deaths each year worldwide.

Global issues
"    We throw away nutrients for our plants in underground sewage systems. We do this in such a way that pollutes underground water tables. Then we buy manufactured "nutrients" for our plants which aren't as good as what we threw away. This is modern day wastewater "technology".
Michael Reynolds - Earthship Vol.2: Systems and Components    "

The growth of the world's population to its current figure has only been possible through intensification of agriculture associated with the use of fertilizers. There is an impact on the sustainable consumption of other global resources as a consequence.

The use of fertilizers on a global scale emits significant quantities of greenhouse gas into the atmosphere. Emissions come about through the use of:

  • animal manures and urea, which release methane, nitrous oxide, ammonia, and carbon dioxide in varying quantities depending on their form (solid or liquid) and management (collection, storage, spreading)

  • fertilizers that use nitric acid or ammonium bicarbonate, the production and application of which results in emissions of nitrogen oxides, nitrous oxide, ammonia and carbon dioxide into the atmosphere.

By changing processes and procedures, it is possible to mitigate some, but not all, of these effects on anthropogenic climate change.

The nitrogen-rich compounds found in fertilizer run-off is the primary cause of a serious depletion of oxygen in many parts of the ocean, especially in coastal zones; the resulting lack of dissolved oxygen is greatly reducing the ability of these areas to sustain oceanic fauna.

http://en.wikipedia.org/wiki/Fertilizer

Risks to food security


Fossil fuel dependence


While agricultural output increased as a result of the Green Revolution, the energy input into the process (that is, the energy that must be expended to produce a crop) has also increased at a greater rate, so that the ratio of crops produced to energy input has decreased over time. Green Revolution techniques also heavily rely on chemical fertilizers, pesticides and herbicides, some of which must be developed from fossil fuels, making agriculture increasingly reliant on petroleum products.

Between 1950 and 1984, as the Green Revolution transformed agriculture around the globe, world grain production increased by 250%. The energy for the Green Revolution was provided by fossil fuels in the form of fertilizers (natural gas), pesticides (oil), and hydrocarbon fueled irrigation.

http://en.wikipedia.org/wiki/Food_security#Land_degradation


Human Impact on the Biosphere - The Solution (Expanded)

Protecting the Biosphere

To reduce the effects of human impact on the planet, we must begin to monitor and respond to direct human impacts on the oceans and freshwater systems, the land and atmosphere. This approach is based on information gained from environmental science and conservation biology. However, this is management at the end of a long series of causal factors (known to ecologists as drivers) that are initiated by human consumption, our demand for food, energy, materials and water.

It is the assessment of consumer demand for these basic resources that is now a major study area for sustainability science which monitors resource use through the chain of human consumption starting with the effects of lifestyle choices and individual and collective spending patterns, through to the resources used in producing specific goods and services, the demands of economic sectors - and even national economies.

This is pre-emptive demand management of causes, rather than a reactive response to the effects of this demand. Sustainability governance can be implemented at all levels of human and biological organization, from local to global.

http://en.wikipedia.org/wiki/Sustainability

Natural Environment

The terminology and concept of what comprises the natural environment includes a few key components:
  • Complete ecological units that function as natural systems without massive human intervention, including all vegetation, animals, microorganisms, rocks, atmosphere and natural phenomena that occur within their boundaries.
  • Universal natural resources and physical phenomena that lack clear-cut boundaries, such as air, water, and climate, as well as energy, radiation, electric charge, and magnetism, not originating from human activity.

http://en.wikipedia.org/wiki/Natural_environment

Sustainability

Sustainability, in a general sense, is the capacity to maintain a certain process or state indefinitely. In recent years the concept has been applied more specifically to living organisms and systems. As applied to the human community, sustainability has been expressed as meeting the needs of the present without compromising the ability of future generations to meet their own needs.

The term has its roots in ecology as the ability of an ecosystem to maintain ecological processes, functions, biodiversity and productivity into the future. To be sustainable, nature's resources must only be used at a rate at which they can be replenished naturally.

There is now clear scientific evidence, (environmental science), that humanity is living in an unsustainable way, by consuming the Earth's limited natural resources more rapidly than they are being replaced by nature. Consequently, a collective human effort to keep human use of natural resources within the sustainable development aspect of the Earth's finite resource limits is now an issue of utmost importance to the present and future of humanity.

http://en.wikipedia.org/wiki/Sustainability

Environmental Goals:


Goals commonly expressed by environmental scientists include:
  • Reduction and clean up of pollution, with future goals of zero pollution;
  • Cleanly converting non-recyclable materials into energy through direct combustion or after conversion into secondary fuels;
  • Reducing societal consumption of non-renewable fuels;
  • Development of alternative, green, low-carbon or renewable energy sources;
  • Conservation and sustainable use of scarce resources such as water, land, and air;
  • Protection of representative or unique or pristine ecosystems;
  • Preservation of threatened and endangered species extinction;
  • The establishment of nature and biosphere reserves under various types of protection; and, most generally,
  • The protection of biodiversity and ecosystems upon which all human and other life on earth depends.

http://en.wikipedia.org/wiki/Natural_environment

Sustainable Agriculture

Sustainable agriculture integrates three main goals: environmental stewardship, farm profitability, and prosperous farming communities. These goals have been defined by a variety of disciplines and may be looked at from the vantage point of the farmer or the consumer.

http://en.wikipedia.org/wiki/Sustainable_agriculture


Sustainable Landscape Architecture

Sustainable landscape architecture is a category of sustainable design concerned with the planning and design of outdoor space. This can include ecological, social and economic aspects of sustainability. For example, the design of a sustainable urban drainage system can: improve habitats for fauna and flora; improve recreational facilities, because people love to be beside water; save money, because building culverts is expensive and floods cause severe financial harm.

The design of a green roof or a roof garden can also contribute to the sustainability of a landscape architecture project. The roof will help manage surface water, provide for wildlife and provide for recreation.

http://en.wikipedia.org/wiki/Sustainable_landscape_architecture


Soil


Start from the ground up is an old saying but holds the key to successful organic practices. Soil is the foundation. It is the beginning and the end, the alpha and the omega, if not managed properly. Healthy soil is full of living things. Managing this living system and keeping it alive and well can make the difference between success and failure.

http://en.wikipedia.org/wiki/Sustainable_landscape_architecture

Soils are vital, fragile, finite natural resources that are essential for the sustained production of food and fiber. Soils, however, are subject to degradation and erosion when mismanaged. Between 1950 and 1993, grain area per person worldwide decreased from 0.58 to 0.33 acres (0.23 to 0.13 hectares). As human populations increase, soil resources are used more intensively, with increasing probability that many practices will lead to deterioration of the resource.

In ecosystems, soils, water, air, plants, animals and people have interdependent relationships. Soils are dynamic, living systems whose productivity, through management that often includes additions of nutrients, organic materials and water, can be sustained indefinitely. Soils exhibit unique physical and chemical sorptive qualities and dynamics reflective of their inorganic and organic composition. Cycling of carbon, nitrogen and other nutrient elements in nature involves transformations in soils.

Great diversity occurs among soils, sometimes in very small geographical areas, such as building lots in urban areas. The rise and fall of civilizations sometimes has been related to the wise use and misuse of natural resources including soil and water.

The principal environmental variables affecting life in soils include moisture, tempera¬ture, pH, aeration (i.e. presence or absence of sufficient oxygen), organic matter, and inorganic nutrients such as nitrogen and phosphorus. The balance of these factors controls the abundance and activities of the microbes and larger animals in soils which in turn have a marked influence on the critical processes of soil aggregation and degradation of plant and animal residues and the nutrient cycling that accompanies this latter process.

Nutrient Cycling by Soil Microbes


Soil microbes exert much influence in controlling the quantities and forms of various chemical elements found in soil. Most notable are the cycles for carbon, nitrogen, sulfur and phosphorus, all of which are elements important in soil fertility, and as we know today, may be involved in global environmental phenomena. The mineralization (i.e. the conversion of organic forms of the elements to their inorganic forms) of organic materials by soil microbes liberates carbon dioxide, ammonium (which is rapidly converted to nitrate by soil microbes), sulfate, phosphate and inorganic forms of other elements. This is the basis of nutrient cycling in all major ecosystems of the world. John Burroughs once said, "Without death and decay, how could life go on?"

In the world's agricultural soils, the source of our food supply, mineralization of nitrogen by soil microbes is a most important process. In those soils not receiving external inputs of fertilizer nitrogen (e.g. most forested lands and many grasslands) the liberation of ammonium from organic debris makes possible the continued growth of new plant matter. Therefore, it is the soil microbial population which controls the productivity of these soils if other environmental factors (moisture, temperature) are suitable. In fact, fertilization of a soil represents our attempt to balance the competition between plants and soil microbes for available soil nitrogen.

Sixteen chemical elements are recognized as being essential for the growth of all plants. Five others, silicon, sodium, cobalt, vanadium, and nickel, have been recognized as necessary for the growth of some plant species. Although certain essential elements can exist in nature in a number of ionic forms, plants can use only specific ones.

Most soils cannot provide one or more plant essential nutrients in sufficient available form for modern crop production. Soil samples are frequently tested to determine the quantities of nutrients and other amendments which should be applied. Soil testing normally involves extraction or reaction of a sample with a specific chemical solution(s) which removes essential elements in amounts related to those required for plant growth. Soil testing is recommended to prevent both under and over fertilization of crops, thereby providing economic crop production in an environmentally effective manner.

Irrigation

Irrigation is a method of at least partially overcoming problems in natural precipitation patterns. These problems may result from an overall lack of precipitation or poor seasonal distribution. Irrigation is normally practiced not only to increase yield, but to provide yield stability. Yields may be increased many fold by irrigation depending on climate and the crop produced. Large scale irrigation projects may also be one facet of an overall program to provide hydroelectric power, flood control, municipal water supplies, and recreation.

Although development of irrigation capabilities almost immediately increases crop production, long-term effects must also be addressed. Irrigation water must be of reasonable quality (sufficiently low in dissolved salts and of proper ionic composition) to be used for an extended period of years. Many irrigation systems from ancient times through today have failed because of increasing soil salinity over time.

Irrigation has been extremely important throughout the world in providing a stable and abundant food supply, but proper planning and expertise are necessary to sustain economic and environmentally sound irrigated crop production.

http://organiclifestyles.tamu.edu/soilbasics/index.html


Landscape Design

Sustainable landscaping incorporates seven basic principles that save water:
  • Planning and design
  • Soil analysis
  • Practical turf areas
  • Appropriate plant selection
  • Efficient irrigation
  • Use of mulches
  • Appropriate maintenance

Wise plant selection and careful attention to improving environmental conditions through soil preparation, proper after-planting care, and efficient irrigation practices are essential.

Planning

The starting point for every successful sustainable landscape is a good plan, preferably on paper and not just in your mind. The process involved in drawing up a landscape design will 1) help you understand, organize, and develop the site for the best use and enjoyment; 2) create a visual relationship between the house/ business and the site 3) reduce the overall maintenance level and 4) preserve and protect the environment.

Soil Preparation
Nearly every soil can be improved to increase plant health and conserve water. Both sandy soils and heavier clay soils benefit from the addition of large quantities of organic matter, such as rock powders, coconut coir, and compost. This will increase the soil's ability to absorb and store both water and nutrients in a form available to the plants. A 4-inch layer of organic matter, mixed in with the soil at planting time, will aid in the establishment of shrubs and trees. Flower beds and gardens can be amended every time they are replanted. In sandy soil, strategic planting areas can be modified by incorporating top soil or loam. Make a gradual transition from sand to loam by mixing the first layer of top soil with the sand.

Plant Selection

There are a number of native plants that have been adapted for use in home and commercial landscapes, as well as a wide range of highly adapted non-native species. These plants have good drought tolerance, and exhibit resistance characteristics to insects and diseases. When used appropriately, native and adapted plants can assist in reducing landscape water consumption. Also, since these plants are a little tougher than most, they don't require the use of potentially harmful chemical fertilizers and pesticides.

http://earthkind.tamu.edu/EKDesign.pdf

Landscape Maintenance

An added benefit of sustainable landscapes is less maintenance. A well-designed landscape can decrease maintenance by as much as 50 percent through reduced mowing; once-a-year mulching; elimination of weak, un-adapted plants; and more efficient watering techniques.

Watering

Of the tremendous amounts of water applied to lawns and gardens, much of it is never absorbed by the plants and put to use. Some water is lost to runoff by being applied too rapidly, and some water evaporates from exposed, un-mulched soil; but, the greatest waste of water is applying too much too often.

In addition to over-watering the plant, excess irrigation can leach nutrients deep into the soil away from plant roots, increasing the chances of polluting groundwater. Similarly, runoff caused by excess irrigation can carry polluting fertilizers and pesticides to streams and lakes. The waste or pollution of high quality water through inefficient irrigation practices can be eliminated through proper watering techniques.

Most lawns receive twice as much water as they require for a healthy appearance. The key to watering lawns is to apply the water infrequently, yet thoroughly.

Irrigation Systems

The goal of any irrigation system is to give plants a sufficient amount of water without waste. By zoning an irrigation system, grass areas can be watered separately and more frequently than groundcovers, shrubs and trees. Both sprinkler and drip irrigation can be incorporated to achieve water conservation in the landscape.

Drip irrigation offers increased watering efficiency and plant performance when compared to sprinkler irrigation. In areas of the state with poor water quality (i.e., high salt content), drip irrigation also allows safer use of "salty water" in the landscape and garden.

Drip irrigation slowly applies water to soil. The water flows under low pressure through emitters, bubblers or spray heads placed at each plant. Water applied by drip irrigation has little chance of waste through evaporation or runoff.

Seeking professional irrigation advice and experimenting with available drip irrigation products in small sections of the landscape are the best ways to become familiar with the many benefits of this watering technique.

Mulching Conserves Moisture
Mulch is a layer of nonliving material covering the soil surface around plants. Mulches can be organic materials such as pine bark, compost and woodchips; or inorganic materials, such as lava rock, limestone or permeable plastic, not sheet plastic.

Use mulch wherever possible. Good mulch conserves water by significantly reducing moisture evaporation from the soil. Mulch also reduces weed populations, prevents soil compaction and keeps soil temperatures more moderate.

Proper Mowing and Fertilizing Conserves Water
Mowing grass at the proper height conserves water.

Fertilizers also can be a major source of pollution of streams and groundwater if excessive amounts are applied. Fertilize the lawn once in the spring and again in the fall to produce a beautiful turf without excess growth which demands frequent watering.

Organic Fertilizers
http://en.wikipedia.org/wiki/Image:Havekompostbunke.jpgNaturally occurring organic fertilizers include composted manure, , worm castings, seaweed, and guano. In fact, seaweed and sea solids may have the most balanced proportion of trace elements than any other fertilizer used in agriculture today. Green manure crops are also grown to add nutrients to the soil. Naturally occurring minerals such as mine rock phosphate, sulfate of potash and limestone are also considered Organic Fertilizers.
Manufactured organic fertilizers include compost, bloodmeal, bone meal and seaweed extracts. Other examples are natural enzyme digested proteins, fish meal, and feather meal.

Other Cultural Practices to Save Water
Other cultural practices that add to the efficient use of water by plants are periodic checks of the irrigation system, properly timed insect and disease control and elimination of water-demanding

http://earthkind.tamu.edu/EKWaterConservation.pdf

Rain gardens
A rain garden is an artificial depression in the landscape that collects and stores storm water runoff until it can infiltrate the soil. Storm water runoff increases urban flooding and erodes the banks of rivers and streams. Urban runoff also carries many pollutants into streams and rivers.
A rain garden is an approach to rainwater harvesting that can prevent flooding and erosion and turn storm water problems into water supply assets by slowing run-off and allowing it to soak into the ground. Rain gardens are not ponds. They are usually planted with native vegetation that is hardy and attractive. Plants in a rain garden can give color to the landscape at all times of the year.

Rain gardens can be designed for an individual yard or a neighborhood. They provide a habitat for many animals including birds, butterflies and other insects.

http://rainwaterharvesting.tamu.edu/raingardens.html

Water Conservation Commitment

Water must always be a vital concern. Water is a limited and fragile resource. The water used to irrigate landscapes is considered a luxury use of water by many people. Nonessential use of water implies a special responsibility to efficiently use the resource and to protect its quality.