Soil management

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Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance (such as soil fertility or soil mechanics). It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.

Environmental Impact[edit]

According to the EPA, agricultural soil management practices can lead to production and emission of nitrous oxide (N2O), a major greenhouse gas and air pollutant. Activities that can contribute to N2O emissions include fertilizer usage, irrigation and tillage. The management of soils accounts for over half of the emissions from the Agriculture sector. Cattle livestock account for one third of emissions, through methane emissions. Manure management and rice cultivation also produce emissions.[1] Using biochar may decrease N2O emissions from soils by an average of 54%.[2]

Soils can sequester carbon dioxide (CO2) from the atmosphere, primarily by storing carbon as soil organic carbon (SOC) through the process of photosynthesis. CO2 can also be stored as inorganic carbon but this is less common. Converting natural land to agricultural land releases carbon back into the atmosphere. The amount of carbon a soil can sequester depends on the climate and current and historical land-use and management.[3] Cropland has the potential to sequester 0.5-1.2 Pg C/year and grazing and pasture land could sequester 0.3-0.7 Pg C/year.[4] Agricultural practices that sequester carbon can help mitigate climate change.[5] Intensive farming deteriorates the functionality of soils.

Methods that significantly enhance carbon sequestration in soil include no-till farming, residue mulching, cover cropping, and crop rotation, all of which are more widely used in organic farming than in conventional farming.[6][7] Because only 5% of US farmland currently uses no-till and residue mulching, there is a large potential for carbon sequestration.[8] Similar practices such as arable land conversion to grasslands, crop residues and cover crops have been proposed in Europe[9]

Practices[edit]

Conventional agriculture is driven by industrialization and aims to maximize efficiency. Practices include large-scale farming that specializes in monoculture and uses pesticides, herbicides, and fertilizers.[5][10] Alternatives include conservation, regenerative, and organic agriculture, which can be broadly grouped as sustainable agriculture. Conservation agriculture has three main practices: minimizing soil disturbance, maintaining permanent soil coverage, and diversifying crop species.[11] Similarly, regenerative agriculture practices use minimal to no tillage, cover crops, crop rotations, compost, and grazing.[12] Organic agriculture incorporates most of these practices and emphasizes biological, not synthetic, management.[13] There are three overarching practices that improve carbon sequestration in soils: increasing biomass inputs, decreasing SOC losses, and increasing the mean residence time (MRT) of SOC.[4]

Cover cropping and mulching practiced as soil manegement in Palau

Specific soil management practices that affect soil health include:[14]

  • Controlling traffic on the soil surface helps to reduce soil compaction, which can reduce aeration and water infiltration.
  • Planting cover crops that keep the soil anchored and covered in off-seasons so that the soil is not eroded by wind and rain.
  • Crop rotations[15] for row crops alternate high-residue crops with lower-residue crops to increase the amount of plant material left on the surface of the soil during the year to protect the soil from erosion.
  • Nutrient management can help to improve the fertility of the soil and the amount of organic matter content, which improves soil structure and function.
  • Tilling the soil, or tillage, is the breaking of soil, such as with a plough or harrow, to prepare the soil for new seeds. Tillage systems vary in intensity and disturbance. Conventional tillage is the most intense tillage system and disturbs the deepest level of soils. At least 30% of plant residue remains on the soil surface in conservation tillage.[16][17] Reduced-tillage or no-till operations limit the amount of soil disturbance while cultivating a new crop, and help to maintain plant residues on the surface of the soil for erosion protection and water retention.
  • Adding organic matter to the soil surface can increase carbon in the soil and the abundance and diversity of microbial organisms in the soil.[18][19]
  • Using fertilizers increases nutrients such as nitrogen, phosphorus, sulfur, and potassium in the soil. The use of fertilizers influences soil pH and often acidifies soils, with the exception of potassium fertilizer.[20] Fertilizers can be organic or synthetic.

References[edit]

  1. ^ "Agriculture: Sources of Greenhouse Gas Emissions". EPA. 2015.
  2. ^ Cayuela, M.L., van Zwieten, L., Singh, B.P., Jeffery, S., Roig, A., & Sanchez-Monedero, M.A. (June 15, 2014). "Biochar's role in mitigating soil nitrous oxide emissions: A review and meta-analysis". Agriculture, Ecosystems & Environment. 191: 5–16. doi:10.1016/j.agee.2013.10.009.CS1 maint: Multiple names: authors list (link)
  3. ^ "Soil Carbon Storage | Learn Science at Scitable". www.nature.com. Retrieved 2019-04-12.
  4. ^ a b Lal, Rattan (2018-03-25). "Digging deeper: A holistic perspective of factors affecting soil organic carbon sequestration in agroecosystems". Global Change Biology. 24 (8): 3285–3301. Bibcode:2018GCBio..24.3285L. doi:10.1111/gcb.14054. ISSN 1354-1013. PMID 29341449.
  5. ^ a b Shennan, Carol; Krupnik, Timothy J.; Baird, Graeme; Cohen, Hamutahl; Forbush, Kelsey; Lovell, Robin J.; Olimpi, Elissa M. (2017-10-17). "Organic and Conventional Agriculture: A Useful Framing?". Annual Review of Environment and Resources. 42 (1): 317–346. doi:10.1146/annurev-environ-110615-085750. ISSN 1543-5938.
  6. ^ Susan S. Lang (13 July 2005). "Organic farming produces same corn and soybean yields as conventional farms, but consumes less energy and no pesticides, study finds". Retrieved 8 July 2008.
  7. ^ Pimentel, David; Hepperly, Paul; Hanson, James; Douds, David; Seidel, Rita (2005). "Environmental, Energetic, and Economic Comparisons of Organic and Conventional Farming Systems". BioScience. 55 (7): 573–82. doi:10.1641/0006-3568(2005)055[0573:EEAECO]2.0.CO;2.
  8. ^ Lal, Rattan; Griffin, Michael; Apt, Jay; Lave, Lester; Morgan, M. Granger (2004). "Ecology: Managing Soil Carbon". Science. 304 (5669): 393. doi:10.1126/science.1093079. PMID 15087532.
  9. ^ Lugato, Emanuele; Bampa, Francesca; Panagos, Panos; Montanarella, Luca; Jones, Arwyn (2014-11-01). "Potential carbon sequestration of European arable soils estimated by modelling a comprehensive set of management practices". Global Change Biology. 20 (11): 3557–3567. Bibcode:2014GCBio..20.3557L. doi:10.1111/gcb.12551. ISSN 1365-2486. PMID 24789378.
  10. ^ Driver, Kelly; Health, JH Bloomberg School of Public. "Industrialization of Agriculture". Johns Hopkins Bloomberg School of Public Health. Retrieved 2019-04-12.
  11. ^ "Conservation Agriculture | Food and Agriculture Organization of the United Nations". www.fao.org. Retrieved 2019-04-12.
  12. ^ "What is Regenerative Agriculture?" (PDF). February 16, 2017.
  13. ^ "What is Organic Farming?". www.sare.org. Retrieved 2019-04-12.
  14. ^ "Soil Quality: Management: Soil Management Practices". soilquality.org. Retrieved 2019-04-12.
  15. ^ "Forage and Food Crops". Penn State Extension. Retrieved 2019-04-12.
  16. ^ "Tillage Systems". www.sare.org. Retrieved 2019-04-12.
  17. ^ "USDA ERS - Soil Tillage and Crop Rotation". www.ers.usda.gov. Retrieved 2019-04-12.
  18. ^ Brennan, Eric B.; Acosta-Martinez, Veronica (June 2017). "Cover cropping frequency is the main driver of soil microbial changes during six years of organic vegetable production". Soil Biology and Biochemistry. 109: 188–204. doi:10.1016/j.soilbio.2017.01.014. ISSN 0038-0717.
  19. ^ Baldantoni, Daniela; Bellino, Alessandro; Morra, Luigi; Alfani, Anna (2015-05-17). "Compost Amendment Enhances Natural Revegetation of a Mediterranean Degraded Agricultural Soil". Environmental Management. 56 (4): 946–956. Bibcode:2015EnMan..56..946B. doi:10.1007/s00267-015-0539-4. ISSN 0364-152X. PMID 25982619.
  20. ^ "Fertilizers And Soil Acidity | Mosaic Crop Nutrition | Mosaic Crop Nutrition". www.cropnutrition.com. Retrieved 2019-04-12.

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