User:RatCactus/Sustainable Agricultural Practices

Sustainable agricultural practices are methods and actions that can be employed to reduce the impact of agriculture and farming on the environment and ultimately create a system of agricultural production that leaves little to no impact on the environment. The need for sustainable agricultural practices is spurred by the use of unsustainable fuel sources, biodiversity loss, water scarcity, waste production (livestock waste, fertilizer runoff, etc.), and human health impacts that can result from or cause modern farming methods to be less efficient. Along with ecological concern, sustainable agricultural practices look to address the economic impacts of many modern farms due to the high level of industrialization and resultant diminishing returns for the farmers on these farms. Creation and continuation of sustainable agricultural practices is difficult as they must meet or come close to industrial models in terms of production, however, cannot rely on the same methods that allow industrial methods to output at the scale that they do. There are many possibilities for the creation of sustainable agriculture, such as rooftop greenhouses and gardens, indoor agriculture, and hydroponics, though it is worth noting that large scale farms would still need to exist, at least in the beginning phases of transition away from more industrial methods. The use of strategies such as these have the potential to aid people in having secure food sources, aiding in bioremediation (particularly of wastewaters), and providing food to those who typically would not be able to afford it.

Excess Nutrient Input
One of the largest issues within current agricultural practices stems from the over use of fertilizers. Fertilizer use has been rising due to falling soil fertility, a result of increased demand for agricultural products and conditions that negatively impact soil fertility such as drought, which is worsened by climate change and, in a positive feedback loop, the further application of fertilizers. Fertilizers are filled with micronutrients, such as nitrogen, phosphorus, and in some cases, iron, which are essential for effective plant growth, rendering fertilizers necessary to continue to meet the growing food demand.

Phosphorus
Phosphorus is a common element that is in fertilizers and is particularly prominent in manure fertilizers. Phosphorus is important as a nutrient for plant health, however, when applied in excessive amounts, it can runoff of the land where it was spread into nearby water sources, causing eutrophication and transport downstream. Phosphorus is frequently transported in colloids, which are small pieces (1-1000nm) of rock and minerals that have a high surface area and are generally rich in the elements aluminum, calcium, or iron. These elements bind to the phosphorus, trapping it and increasing its ability to be transported to and within aquatic systems. Consistent manure application can dramatically increase the amount of both phosphorus and colloids present in aquatic settings near to the source of application. In addition to increasing phosphorus transport, colloids and continuous manure application can increase the levels of phosphorus that leach into groundwater. Excess consumption of phosphates has been linked to multiple human health issues, such as abnormal bone calcium and bone metabolisms, an increase in parathyroid hormone, and abnormalities in endothelial cell function.

Phosphorus availability is another concern when discussing phosphorus use in agricultural settings, as currently very few countries have large phosphorus reserves, foremost among them being Morocco and Algeria. Due to the necessity of phosphorus, particularly in agricultural settings, and due to the increased demand, the cost of phosphate rocks has increased some 800%. As a result of these limited reserves, phosphorus reserves are often modeled under the peak resource theory, which states that there exists a point where demand effectively depletes reserves and the resource is no longer readily available, this theoretical point is termed peak phosphorus when discussing phosphorus. This makes phosphorus and its effective use a large economic issue as well as an environmental one.

Nitrogen
Nitrogen, in the form of nitrogen fertilizers, is the most widely used soil amendment to stimulate plant growth, increase productivity, and increase crop yield. Its use is essential in countries were the soil is not conducive crop growth, however, when used in such excess quantities, it can cause environmental damage and even harm to humans by leaching into groundwater. Nitrogen fertilizer is effective at increasing crop yield in the short term, however, multiple studies have produced data that suggests that increasing and sustained use of nitrogen based fertilizers can acidify soils and lead to lower crop yields in later years as a result. Additionally, sustained nitrogen fertilizer use, specifically ammoniacal nitrogen fertilizers, has been correlated with a decrease in exchangeable base cations, which are necessary for plant health. Of particular note, the available Ca2+ and Mg2+ cations decreased by 31% and 36%, respectively, in soils amended with nitrogen fertilizers over a sustained period.

Nitrogen fertilizers are often over used, both over immediate periods (single growing seasons) and over long periods of time (several years to decades), leading to many of the negative effects associated with excess nitrogen in an environment. One of the primary reasons that nitrogen fertilizers are used at the levels they are is because nitrogen will readily move through soils and ecosystems via transport in water (runoff). This transient nature of nitrogen in causes the need for reapplication and year after year use. The importance and necessity of nitrogen fertilizers cannot be understated as their use supports 40-60% of the world's population, which is why alternative methods, such as controlled release nitrogen fertilizers are being investigated. Controlled release nitrogen fertilizers have been shown to reduce the amount of nitrogen that is released into the environment as a result of fertilizers and decrease the effort needed to sustain sufficient nitrogen levels to amended soils. Effective use of methods such as controlled release nitrogen fertilizers, crop cycling, two crop harvest systems, and remediation methods have the potential to decrease need for nitrogen fertilizers, while still gaining the benefits of their use.

Iron
Iron is an important micronutrient for life. A deficiency in iron can cause anemia and a reduction in cognitive function in humans and in plants can lead to growth reductions and decreased yields. Soils than struggle the most with iron uptake are typically rooted in calcareous soils. As a result, iron fertilizers are used in such cases to supplement iron deficient systems. The main issue with iron fertilizers is that they have a low use efficiency. As a result, much of the iron that is put onto fields is transported away from the fields, primarily by water, where they can act as a driver in algal blooms, thus driving eutrophication. While this is an issue from agriculture, acid mine drainage (AMD) is a larger contributor to the issue of excess iron in ecosystems The use of special types of iron fertilizers, such as Fe3O4 and Fe2O3 nanoparticles, which increase uptake rates due to higher efficacy, and thus need to be used in smaller amounts, reducing the amount of iron that is lost from a fertilizer.

Livestock
Livestock both produce and consume large amounts of micronutrients through the food that is farmed to feed them and their manure production, causing them to be a point of interest in for excess nutrient management. Additionally, livestock emit methane (CH4) at high levels, the gas accounting for 44% of their emissions. Livestock emissions account for a large percentage of anthropogenic CO2 emissions globally, totaling 7.1 gigatons CO2 e y-1 or approximate 14.5% of total CO2 emissions. One of method of mitigating the effect of livestock on the environment is more controlled management and social incentives for the production and maintenance of livestock in a more sustainable manner, a method which would be beneficial as the demand for livestock products is projected to further increase over the next decade.

Land Use
Agricultural expansion has seen the destruction of vast amounts of forests and other ecosystems in order to create new land for agriculture. Approximately as much as three quarters of the forests on earth have been removed to create space for agriculture. In addition, agricultural lands are often abandoned. While abandonment allows for some regrowth, it leaves behind land that has been damaged and thus regrowth of natural landscapes is diminished, an effect which is seen more strongly in areas with larger farms and more abandonment. Efforts are currently being made to increase the efficiency at which humans use land, at the heart of which lies altering current management processes, which brings up ethical and economic concerns.

Hydroponics
Hydroponics is a useful method of agriculture that does not require soil, where the plants are instead grown in a nutrient-rich solution. In hydroponics, the water source is rich with essential minerals, and is circulated around the roots of the plants, providing them with the necessary nutrients, water, and oxygen for growth.

In hydroponic systems, plants are typically grown in containers or trays filled with a non-soil medium, such as perlite, coconut coir, or gravel. The roots of the plants are suspended in the solution or in the non-soil medium, and the nutrient solution is regularly replenished to ensure that the plants receive the necessary nutrients for optimal growth.

Hydroponic systems can range from simple, homemade setups to more complex and automated systems used in commercial agriculture. Hydroponics is often used to grow vegetables, herbs, and other crops in urban or indoor environments, where space is limited or where soil is not available or not suitable for plant growth.

In hydroponic systems, the lighting requirements can vary depending on the type of plants being grown and the specific stage of growth. However, in general, plants grown using hydroponics require high-intensity lighting that mimics the natural light spectrum. Most hydroponic growers use artificial light sources, such as high-intensity discharge (HID) lamps, fluorescent lights, or light-emitting diodes (LEDs) to provide the necessary light for plant growth. HID lamps are popular in hydroponic systems due to their high light output and efficiency, but they can generate a lot of heat and require adequate ventilation to prevent heat buildup.

Passive aeration (the Kratky method)
In a passive deep water system, the aeration of the plant is provided by air gaps above the water. This is why it’s important to only partially submerge the net pot, a slotted or webbed containers with holes of varying sizes along the sides, as the seedlings grow, and why it’s important to keep the roots only 1/3 to 1/2 submerged once they start to develop beyond the net pot.

Active aeration
In active aeration an airstone, a porous stone that is paired with an air diffuser that is essential to the hydroponic system, is the most common type of aeration device in hydroponics. An airstone is a synthetic “stone” full of pores. It is connected through tubing to an external pump. The pump pushes oxygen through the stone, which, due to its porous structure, releases the air as tiny bubbles. They are commonly used in aquariums and come in a wide variety of sizes and shapes.

In hydroponics, there are two types of harvesting that present themselves depending on the species that is grown. Continuous harvesting involves harvesting mature plants as they reach maturity, while leaving other plants in the system to continue growing. This approach can provide a steady supply of fresh produce over an extended period, making it suitable for commercial growers and those who want a continuous supply of fresh vegetables and herbs. Continuous harvesting is typically used for crops that produce multiple harvests, such as lettuce, herbs, and strawberries. In a hydroponic system, new plants can be added to the system as older plants are harvested, allowing for a continuous cycle of growth and harvest.

On the other hand, there is the single harvest, which is similar to the typical means of harvesting in modern agriculture. Single harvest involves harvesting all plants in the system at once when they reach full maturity. This approach is suitable for crops that have a single harvest cycle, such as tomatoes or cucumbers.

Community Based Agriculture
Community supported agriculture (CSA) is an approach to farming that emphasizes the involvement and empowerment of local communities in the food system. This approach prioritizes the needs and interests of the community and aims to create a more equitable and sustainable food system.

CSA is important to agricultural sustainability for several reasons. It helps to build strong, resilient communities by creating opportunities for people to connect with each other and with the land. By involving community members in the farming process, it can also help to increase awareness and appreciation for local agriculture.

Additionally, CSA can help to support local economies by providing jobs and keeping money circulating within the community. By reducing the reliance on large-scale, industrial agriculture, it can also help to promote local food sovereignty and reduce the negative environmental impacts associated with industrial agriculture.

CSA can help to promote sustainable farming practices by prioritizing soil health, biodiversity, and ecological sustainability. By working in partnership with nature, farmers can create more resilient and sustainable farming systems that benefit both the environment and the community.

Indoor Agriculture
Indoor agriculture, also known as vertical farming or controlled environment agriculture, is a method of growing crops in a controlled environment using technologies such as hydroponics, aeroponics, and aquaponics. This form of agriculture allows for the cultivation of crops year-round, regardless of weather conditions or seasonal changes. Indoor agriculture has been practiced in various forms throughout human history. The ancient civilizations of Babylon and the Aztecs are two examples of cultures that practiced forms of indoor agriculture.

In Babylon, which was located in present-day Iraq, the Hanging Gardens were a famous example of indoor agriculture. These were a series of terraced gardens that were built on the roofs of buildings, possibly as early as 600 BCE. The gardens were irrigated with water that was lifted to the top of the structure using a system of pumps and aqueducts. The Hanging Gardens were believed to have been created by King Nebuchadnezzar II as a gift for his wife, who missed the green hills of her homeland.

The Aztecs, who lived in what is now Mexico from the 14th to the 16th centuries, practiced a form of indoor agriculture known as chinampas. These were artificial islands that were created by piling mud and vegetation on top of a woven reed mat, which was placed on the shallow lake beds that surrounded their capital city of Tenochtitlan. The chinampas were used to grow crops such as maize, beans, and squash, and were irrigated using the nutrient-rich water from the lake.

Indoor agriculture is important to agricultural sustainability for several reasons. First, it allows for the efficient use of resources such as water, energy, and space. Because the growing environment is controlled, there is less waste and loss of these resources compared to traditional farming methods.

Also, indoor agriculture can help to reduce the negative environmental impacts of agriculture, such as soil erosion, water pollution, and greenhouse gas emissions. By using efficient growing methods and reducing the need for transportation, indoor agriculture can help to minimize these impacts.

Finally, indoor agriculture can increase food security by providing a reliable source of fresh produce, regardless of location or climate. This is particularly important in urban areas where access to fresh produce may be limited.

Wetlands
Wetlands can absorb excess nutrients that are the result of agricultural runoff. They accomplish this by way of converting nutrients into biomass, typically in the form of plant biomass. The plants in the system uptake nutrients, often times the targets are nitrogen and phosphorus, which the plants use to enhance their growth. Such systems have been effectively used to treat waste water from urban areas and in agricultural settings. The efficacy of these systems can be further increased by adding layers of chemical nitrogen and phosphorus sequestrants, such as biochar (a solid carbonaceous residue produced at high heat), increased nitrogen and phosphorus removal in treated wetlands by 58% and 65%, respectively. In addition to remediating excess nutrients, wetlands, when created with native species in mind, can help offset the land that is used for agriculture and promote biodiversity of native species, thus providing a solution for two issues that current agricultural practices pose.

Hydroponics
Several studies have found evidence that the use of wastewaters can be used to effectively fuel hydroponic systems. Hydroponic systems can be used not only to remediate, but to produce food as well, creating a cyclic system of recycling biomass and nutrients. While hydroponic remediation systems are still a relatively new area of active research, they have shown to be promising in the removal of phosphorus, nitrogen, and even heavy metals. . It must be noted that the creation of a functional hydroponic system is not as easy as just growing plants in wastewater. Evidence points to criteria, such as salinity and life stage of the plant, that can dramatically alter the rates of remediation and plant growth, thus making wastewater parameters important considerations in hydroponic creation. Despite this, hydroponics remain an attractive option for the remediation of wastewaters and the production of some farmed products.

Manure Treatment
As manure constitutes a large portion of the fertilizers used, reducing its impact is an important step in maintaining sustainable environmental conditions. There are many ways in which manure can be processed or treated in order to reduce its impacts, such as phytoremediation, soil and manure amendments, addition of soil aggregation inducers, and even biochar. Phytoremediation, or remediation preformed by plants, is very similar to wetland remediation where plants uptake excess nutrients that escape from the manure, incorporating them into biomass. Phytoremediation in the context of manure treatment is not limited to wetlands, however, as buffer strips of deep rooted plants can act to absorb the excess nutrients before they spread further into the environment. Amendments to manure and soils, most commonly clay, can reduce the amount of nutrients and greenhouse gases, such as CH4, from being released from manure by up to 45%. Clay soil amendments in particular make an enticing choice for remediation of manures due to their low cost, high availability, and high efficacy. Turning manure into biochar has been proposed as a potential method to dispose of and recycle manure and other biological agricultural waste as it can be used to treat wetlands and improve their efficiency.