Chemical decomposing activity can be found throughout the soil, but it is most active in five special areas. They are the arenas where activity concentrates. The drilosphere is the workplace of earth worms. As can be seen from the top right drawing, worms leave a funnel-shaped business end on top of previous funnels. Earth is cast on top and to the side, covering leaf litter in a loose fashion. In the oxygen-rich moisture, other organisms find shelter or actively take part in some of the process. Rainwater dissolves nitrates, DOC (Dissolved Organic Carbon) and transports it down the worm hole.
The detritusphere works where leaf litter is moist and rich in oxygen. Here fungi can work efficiently, decomposing cellulose while taking oxygen in and respirating carbon dioxide. Inside anoxic corners of leaf structure, bacteria convert nitric oxides to nitrogen.
Where masses of young roots are found, activity is high in the porosphere of the soil. Pores are necessary to hold water and to transport oxygen and carbon dioxide. Aggregates of soil are pierced by hair roots (yellow) and covered in hyphae of fungi (purple). By the transport channels from worms and other organisms, water, nitrates, phosphorus and dissolved organic carbon compounds leach from the top down.
In the aggregatusphere, sand and clay particles form enclosed workshops for bacteria. Many chemical processes happen here, producing nitrates (NO3-), ammonia (NH4+), carbon dioxide (CO2), nitric oxides and more. Many compounds are transported by the fine hyphae to other places.
The rhizosphere is the area directly around hair roots. This is a special place because hair roots bring food and oxygen, enabling the micro organisms to work faster than anywhere else. A continuous flow of water is caused, as water is absorbed by these roots, drawing with it dissolved substances. As these hair roots grow, they intrude into other aggregatuspheres, find nutrients, get eaten, and other fine roots take their place. The soil is in a continuous state of decomposition, provided moisture and oxygen are available.
Many agricultural activities affect air quality. These include smoke from agricultural burning; dust from tillage, traffic and harvest; pesticide drift from spraying; and nitrous oxide emissions from the use of nitrogen fertilizer. Options to improve air quality include incorporating crop residue into the soil, using appropriate levels of tillage, and planting wind breaks, cover crops or strips of native perennial grasses to reduce dust.
Socioeconomic aspects of sustainability are also partly understood. Regarding less concentrated farming, the best known analysis is Netting's study on smallholder systems through history. The Oxford Sustainable Group defines sustainability in this context in a much broader form, considering effect on all stakeholders in a 360 degree approach
Given the finite supply of natural resources at any specific cost and location, agriculture that is inefficient or damaging to needed resources may eventually exhaust the available resources or the ability to afford and acquire them. It may also generate negative externality, such as pollution as well as financial and production costs.
The way that crops are sold must be accounted for in the sustainability equation. Food sold locally does not require additional energy for transportation (including consumers). Food sold at a remote location, whether at a farmers' market or the supermarket, incurs a different set of energy cost for materials, labour, and transport.
What grows where and how it is grown are a matter of choice. Two of the many possible practices of sustainable agriculture are crop rotation and soil amendment, both designed to ensure that crops being cultivated can obtain the necessary nutrients for healthy growth. Soil amendments would include using locally available compost from community recycling centers. These community recycling centers help produce the compost needed by the local organic farms.
Many scientists, farmers, and businesses have debated how to make agriculture sustainable. Using community recycling from yard and kitchen waste utilizes a local area's commonly available resources. These resources in the past were thrown away into large waste disposal sites, are now used to produce low cost organic compost for organic farming. Other practices includes growing a diverse number of perennial crops in a single field, each of which would grow in separate season so as not to compete with each other for natural resources. This system would result in increased resistance to diseases and decreased effects of erosion and loss of nutrients in soil. Nitrogen fixation from legumes, for example, used in conjunction with plants that rely on nitrate from soil for growth, helps to allow the land to be reused annually. Legumes will grow for a season and replenish the soil with ammonium and nitrate, and the next season other plants can be seeded and grown in the field in preparation for harvest.
Monoculture, a method of growing only one crop at a time in a given field, is a very widespread practice, but there are questions about its sustainability, especially if the same crop is grown every year. Today it is realized to get around this problem local cities and farms can work together to produce the needed compost for the farmers around them. This combined with growing a mixture of crops (polyculture) sometimes reduces disease or pest problems but polyculture has rarely, if ever, been compared to the more widespread practice of growing different crops in successive years (crop rotation) with the same overall crop diversity. Cropping systems that include a variety of crops (polyculture and/or rotation) may also replenish nitrogen (if legumes are included) and may also use resources such as sunlight, water, or nutrients more efficiently (Field Crops Res. 34:239).
Replacing a natural ecosystem with a few specifically chosen plant varieties reduces the genetic diversity found in wildlife and makes the organisms susceptible to widespread disease. The Great Irish Famine (1845–1849) is a well-known example of the dangers of monoculture. In practice, there is no single approach to sustainable agriculture, as the precise goals and methods must be adapted to each individual case. There may be some techniques of farming that are inherently in conflict with the concept of sustainability, but there is widespread misunderstanding on impacts of some practices. Today the growth of local farmers' markets offer small farms the ability to sell the products that they have grown back to the cities that they got the recycled compost from. By using local recycling this will help move people away from the slash-and-burn techniques that are the characteristic feature of shifting cultivators are often cited as inherently destructive, yet slash-and-burn cultivation has been practiced in the Amazon for at least 6000 years; serious deforestation did not begin until the 1970s, largely as the result of Brazilian government programs and policies. To note that it may not have been slash-and-burn so much as slash-and-char, which with the addition of organic matter produces terra preta, one of the richest soils on Earth and the only one that regenerates itself.
There are also many ways to practice sustainable animal husbandry. Some of the key tools to grazing management include fencing off the grazing area into smaller areas called paddocks, lowering stock density, and moving the stock between paddocks frequently.
Several attempts have been made to produce an artificial meat, using isolated tissues to produce it in vitro; Jason Matheny's work on this topic, which in the New Harvest project, is one of the most commented.
Perlakuan Tanah pertanian
“Pengasapan Tanah” dapat digunakan sebagai alternatif ekologis menggantikan bahan kimia untuk sterilisasi tanah. Berbagai metode tersedia untuk mendorong uap ke dalam tanah untuk membunuh hama dan memperbaiki kesehatan tanah. Pengkomposan limbah domestic, limbah pertanian, sampah halaman, dan limbah organik dapur, dapat memberikan sebagian besar kebutuhan pupuk yang diperlukan pertanian lokal. Pengomposan ini berpotensi menjadi sumber energi yang dapat diandalkan.
Apa itu Kompos?
Kompos adalah jenis pupuk humus sehat dan kaya hara, serta menjadi bahan pembenah tanah yang dihasilkan dari dekomposisi bahan organik. Sampah organik digunakan untuk menggambarkan limbah yang berasal dari biomasa hidup seperti rumput, daun, kulit sayuran, makanan yang dimasak dll. Pengomposan merupakan sarana sederhana untuk menciptakan kondisi yang tepat untuk mempercepat proses dekomposisi limbah organic ini.