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Managing Agricultural Waste

http://12.000.scripts.mit.edu/mission2017/agriculture/

Background

As the global population increases, the demand for food does as well. However, current agricultural practices damage the environment through four large sources of pollution. First, fertilizer runoff, where rainwater carries with it excess fertilizers into lakes and rivers, causes eutrophication (the overgrowth of algae that deplete bodies of water of oxygen). Second, pesticides poison habitats and pose a threat to clean drinking water. Third, animal wastes that find their way into runoff carry with them pathogens that leave groundwater and fishing sites contaminated. Lastly, sedimentation, when as a result of erosion particles settle or suspend in a fluid, kills aquatic plants as sunlight cannot penetrate the cloudy water; fish also suffer as their gills are filled with sediment [3].

In order to encourage farmers to take steps to mitigate the effects of runoff, pesticide poisoning, and erosion, governments should initiate an educational campaign to spread awareness of the dangers of overusing fertilizers and pesticides, as well as giving farmers actions they can take to reduce nutrient-laden runoff, such as split application of fertilizers. The government should also subsidize practices that reduce pesticide and fertilizer runoff, such as building artificial islands.

Implementation

The first step requires creating an environmental agency if the country does not already have one. Each country must pass laws giving the country’s environmental agency the power to regulate the responsible use of pollutants, if regulations are lacking in that country, and to subsidize practices that reduce pesticide and fertilizer runoff. It will also be part of their job to educate farmers and village leaders on how to farm more efficiently and be more environmentally responsible.

An example of government-community cooperation is Sweden’s Orissa Social Forestry project in 1983. Instead of simply telling farmers that they should plant crops between trees to conserve the forest, government officials, village leaders, and farmers met in group discussions to formulate a forest conservation plan together, with villagers as the source of some of the ideas [12]. This could be extended to agriculture as well, with group meetings on the dangers of pesticides or sedimentation, and farmers volunteering to implement new practices instead of being told what to do. Information regarding on how education should be implemented can be found here.

After the environmental agency is formed, it can pass necessary regulations (see the sections below). Forming an agency could take a whole year. Another year after regulations are passed should give enough time to promote the educational campaign and to prepare the educators. In short, agencies can start training farmers as soon as they have people qualified for the job. Laws regarding the way farmers work can start to be implemented as soon as farmers have been educated.

Wherever there are farms, this can be implemented. The cost is very flexible depending on the country’s budget. The government can decide how much money they want to spend for subsidizing responsible practices and the salary of each agency’s employee would not be that much different than that of the average salary of another government official.

Practices to Implement

Fertilizers

Fertilizers allow crops to grow in soils lacking nutrients crucial to plant growth, but at the same time, excess fertilizers pollute water with nitrogen, phosphorus, and other nutrients, leading to soil acidification, eutrophication, and ground water contamination. To prevent problems, the educational campaign should raise awareness about the dangers of over fertilization.

One way to combat the negative effects of fertilizer is to build artificial floating islands that can rely on plants to absorb excess nutrients. In addition, better farming practices, including nitrogen sensors that give more feedback on a soil’s nutrient needs, and fertigation, the practice of irrigating with water that contains dissolved fertilizers, can be implemented.

More information on the problems created by fertilizers, as well as suggested solutions that the government can subsidize, can be found here.

Pesticides

Similar to fertilizers, pesticides (herbicides, insecticides, and fungicides) can be washed off by runoff into nearby bodies of water or leach into groundwater, where the poisons can cause cancer, liver and kidney damage, and reproductive problems if ingested. Farmers in both the developed and developing world can take the following steps to reduce pesticide runoff.

Crop Rotation

Crop rotation should substitute the more commonly used practice of monocropping, or planting huge swaths of ground with just one type of crop year after year on the same land without switching in other crops. Monocropping is popular because it facilitates planning and harvesting across large fields of land, however it also has negative effects on the environment and human health [13], and is not as efficient as crop rotation. Growing just one type of crop in a large area causes the plants to be vulnerable to infection by insects, weeds and other pests – as the pest spreads, it can become impossible to eradicate [14]. Crop rotation however, in addition to increasing crop yields, makes it difficult for weeds and insects to survive as they must continually adapt to new habitats and nutrients.

One case study is a sugarcane farm in Australia, where the farmer switched from conventional farming to a reduced-tillage form of farming that included a soybean rotational crop. The end result was an incredible cost-effective crop: the new farm used $309 per hectacre on fertilizers, compared to $330 per hectacre on the old farm, and $47 per hectacre on weed control, rather than $60, for an 8 percent decrease in sugarcane growing costs. In addition, the soybeans sold for $539 per acre [16].

Pesticides should be used as a last resort, only after rotating crops, using pest-resistant plants and implementing simple precautionary practices such as cleaning farm vehicles between fields to decrease the chance of introducing weed seeds. They should not be applied before precipitation is forecast to occur, or before irrigation [13].

In the case where pesticides must be used, pesticide rotation, or rotation between using different types of pesticides, should be implemented. Pesticide rotation ensures that pests will not become resistant to one type of pesticide, which would require the application of more pesticide to be effective.

There are also a couple of practices that make applying pesticide less harmful to the environment. Soil incorporation, or tilling the pesticide into the top couple of inches of soil, reduces the amount of pesticide carried away by runoff. Another way of reducing runoff is early pre-plant application, where less than the conventional amount of pesticide is used and applied directly to the soil before the crops sprout. This can reduce pesticide runoff by one half. Spot treatment can be applied as necessary to any weeds that continue to grow.

Split application, where ½ to ⅔ of the pesticide is applied before planting, and ½ to ⅓ is applied after planting, has the potential to reduce runoff by a third. And, if the weeds can be controlled with just the first application, the second may not be needed [4].

One more option to reduce pesticide runoff is to add an adjuvant, also known as a spray mix additive – a chemical that increases the pesticide’s ability to stick to the plant’s foliage. In one study conducted on cucumber and pea leaves. Adding just 0.25 mL/L of adjuvant more than doubled the retention rate on pea plants. However, the spray did not work as well on the cucumber plant because its leaves are covered in amorphous (rather than, in the case of the pea plant, crystalline wax), and because the leaves have deep veins that channel runoff easily. More research is being done in this area [17].

In addition to steps farmers can take while applying pesticides, a vegetated buffer strip can be built to trap pesticides as runoff flows over the buffer. Buffer strips range from a minimum of 9 meters to a maximum of 15 meters; size has not been found to correlate with efficiency. According to the United States Department of Agriculture, a narrow buffer is better than no buffer at all.

Education in proper usage of pesticides is also a necessity, especially for farmers who may not be able to read the instructions on the pesticide containers [7]. Proper usage include storing pesticides safely, and disposing properly of empty containers. Some precautions include wearing proper safety masks and clothing when applying pesticides [6]. Also wearing gloves and tucking pants into boots must be emphasized [7].

In the case of extremely toxic pesticides, governments should ban these pesticides from the market [6]; the banned pesticide should be treated like any other banned substance in the country. Farmers found using the pesticide will be fined. Toxic pesticides have been defined by the Food and Agriculture Organization/World Health Organization Joint Meeting on Pesticide Management.

Some government regulation is necessary and should be established in all countries, but Mission 2017 recognizes that such regulation may be difficult to enforce in developing countries. However, the environmental agencies in developed countries should add regulations if they do not yet have any. These regulations can be modeled from already existing restrictions in other countries. These include banning certain ingredients in pesticides and taxing other pesticides (or, as in the case of Indonesia, ending subsidies, which discouraged pesticide use). Another possible regulation is requiring a certification to be able to apply pesticides, which involves receiving education on pesticide issues. In the case of a developed country, another regulation can be the requiring approval of spraying equipment and the use of new, computer-controlled sprayers that give farmers more feedback on how much pesticide is actually being applied [5].

An issue found mostly in developed countries is uncertainty over the effectiveness of a pesticide, which can lead to over application. Developed countries can mitigate some of this doubt by creating and tightly managing a licensing program. Governments can license pesticides the way they do pharmaceutical drugs, with adaptive licensing. With this program, the process of licensing is split into two; obtaining the first license would be easier but the pesticide’s use would be restricted, making it more of a trial period. More information on adaptive licensing can be found here.

Sediment

During the process of erosion by water, water flowing over the ground picks up and carries away the top layer of soil. Erosion needs to be minimized so runoff contains as little sediment as possible. Organic farms tend to have lower erosion rates because the soil is tilled less often, and a crop of legumes is rotated in in the winter as a cover crop. In one study, water erosion was found to be 8.3 tons/ha (753 tonnes/sq. km) on an organically farmed field, but 32.4 tons/ha (2939 tonnes/sq. km) on a conventionally farmed field [8]. In fact, reducing tillage as much as possible is an excellent way to decrease erosion. Leaving crop residues after harvests also acts as a cover to prevent rain from hitting the soil forcefully [9]. In orchards, which have most of their soil surfaces exposed, more complicated steps need to be taken.

  • Contour farming, or farming across the slope rather than up and down it, can reduce erosion by 50 percent.
  • Growing a winter cover crop and then, in the spring, either mowing or incorporating it. Legumes and grasses are good options.
  • Incorporating soil organic matter into soil will increase soil’s water holding capacity
  • Tilling lightly to avoid crusts that form on soil, since the crusts make it harder for water to soak in [10].

Animal wastes

Several steps can be taken to prevent the contamination of water by animal manure. Farmers should take care to prevent clean water from entering the areas where livestock and livestock waste are kept, by way of terraces to cut off runoff, or waterways to divert the movement of water. Groundwater and surface water can be protected by simply keeping livestock far away: a 100-foot buffer zone of vegetated land between animals and a well, and fencing around streams to prevent animals from entering. The same should apply to animal wastes used as fertilizer. In fact, a buffer zone can be used to soak up runoff containing pesticides and fertilizers as well.

Runoff can be managed with a runoff control system: directing runoff to a holding pond for later use. A grass filter strip is another way to soak up runoff flowing across it to prevent the nutrients from reaching bodies of water.

In the case of manure, it should be stored on a concrete or clay pad or a plastic sheet (not on sandy soil), piled to form a peak so water can run off the pile. If pipes and pumps are used to transport manure then they should be checked often for leaks.

Lagoons – storage pits dug into the earth – can be used to store liquid waste until bacteria decomposes the organic matter.

Before using animal waste as fertilizer, it should be analyzed for nutrient content so farmers can ensure that they are not over fertilizing crops. This waste should be applied as fertilizer on days when there is no precipitation, there is as little wind as possible, the ground is not frozen, and there has been less than half an inch (12 mm) of precipitation within the past week. Animal wastes should be tilled into the soil if possible [11].

Funding

The funding for the education programs will come from the environmental agency’s budget. As for the changes the farmers themselves will have to implement, some will not cost anything: for example, changing the way the farmers till the soil. However, some may be too expensive for farmers – for example, pesticide rotation could require some government subsidies. If the government is unable to provide subsidies, villages may turn to microfinancing, or small loans of up to $1000 provided by private companies.

Conclusion

Decreasing pollution from agriculture mainly involves changing the practices of farmers, with some regulations as well. In developing countries, education will be carried out by government officials and local leaders working together and giving farmers a say in the final decisions, so the new practices will be more likely to be carried out. Dozens of practices are detailed above; the villagers can agree on which ones to follow. As for developed countries, regulations will be set out immediately where needed and enforced by the country’s environmental agency, preferably modeled on Europe’s existing regulations. Adaptive licensing will also ease farmers’ concerns over the effectiveness of pesticides, hopefully preventing them from over applying just to make sure that the pesticide works.

References

  1. Health through safe drinking water and basic sanitation. (n.d.). WHO. Retrieved November 23, 2013, from http://www.who.int/water_sanitation_health/mdg1/en/
  2. Water quality. (n.d.). UN water. Retrieved November 23, 2013, from http://www.unwater.org/downloads/water_quality.pdf
  3. Protecting Water Quality from Agricultural Runoff. (2013, November 30). United States Environmental Protection Agency. Retrieved from http://www.epa.gov/owow/nps/Ag_Runoff_Fact_Sheet.pdf
  4. Managing Large-Scale Application of Pesticides to Prevent Contamination of Drinking Water. (2013, November 30). United States Environmental Protection Agency. Retrieved from http://www.epa.gov/safewater/sourcewater/pubs/fs_swpp_lspesticides.pdf
  5. Natural Resources Management and Environment Department. (2013, November 30). Chapter 4: Pesticides as water pollutants. FAO Corporate Document Repository. Retrieved November 30, 2013, from http://www.fao.org/docrep/w2598e/w2598e07.htm#pesticide management and control
  6. Food and Agriculture Organization of the United Nations. (2013, November 30). FAO – News Article: Highly hazardous pesticides should be phased out in developing countries. Retrieved November 30, 2013, from http://www.fao.org/news/story/en/item/180968/
  7. Meeghan, C. (2013, August 2). Pesticide poisoning: confronting the hidden menace. the Guardian. Retrieved November 30, 2013, from http://www.theguardian.com/global-development/poverty-matters/2013/aug/02/pesticide-poisoning-hidden-menace-ghana
  8. Reganold, J. P., Elliott, L. F., & Unger, Y. L. (2013, November 30). Long-term effects of organic and conventional farming on soil erosion. Nature Publishing Group. Retrieved from http://www.nature.com/nature/journal/v330/n6146/pdf/330370a0.pdf
  9. Al-Kaisi, M. (2013, November 30). Soil erosion: An agricultural production challenge | Integrated Crop Management. Retrieved November 30, 2013, from http://www.ipm.iastate.edu/ipm/icm/2000/7-24-2000/erosion.html
  10. TOBY O’GEEN, A., PRICHARD, T. L., ELKINS, R., & PETTYGROVE, G. S. (2013, November 30). Orchard Floor Management Practices to Reduce Erosion and Protect Water Quality. UC Davis. Retrieved from http://anrcatalog.ucdavis.edu/pdf/8202.pdf
  11. Crouse, D. A., Zublena, J. P., Barker, J. C., & Young, J. (2013, November 30). Improving Storage, Handling, and Disposal of Livestock Waste. NC State University. Retrieved from http://www.soil.ncsu.edu/publications/assist/farmassist/livestockFAS.pdf
  12. Glendinning, A., Mahapatra, A., & Mitchell, C.P. (2001). Modes of communication and effectiveness of agroforestry extension in eastern India. Human Ecology, 29(3), 283-305.
  13. Bowler, I. (2002). Developing sustainable agriculture. Geography, 87, 205-212.
  14. Hanson, J.D., Hendrickson, J., & Archer, D. (2008). Challenges for maintaining sustainable agricultural systems in the United States. Renewable Agriculture and Food Systems, 23, 325–334.
  15. Pest and Pesticide Management – Home. (n.d.). Plant Production and Protection Division: Highly Hazardous Pesticides (HHPs). Retrieved December 1, 2013, from http://www.fao.org/agriculture/crops/thematic-sitemap/theme/pests/code/hhp/en/
  16. Young, R., & Poggio, M. (n.d.). Queensland Department of Agriculture, Fisheries and Forestry archive of scientific and research publications. Queensland Department of Agriculture, Fisheries and Forestry archive of scientific and research publications. Retrieved December 1, 2013, from http://era.deedi.qld.gov.au/3127/1/Legume_Crop_Rotation_In_Sugar.pdf
  17. Krishna, H., Murray, R., Gaskin, R., & Carpenter, A. (n.d.). Effect of adjuvants on the retention of insecticide spray on cucumber and pea foliage. nzpps.org. Retrieved December 1, 2013, from http://www.nzpps.org/journal/53/nzpp_533550.pdf
  18. Crop Protection Association. (n.d.). Advancing Intelligent Mitigation, Vegetative Buffer Strips . University of Florida. Retrieved December 1, 2013, from http://abe.ufl.edu/carpena/files/pdf/software/vfsmod/VFS_Flyer_07_09_09__FINAL.pdf