AGRICULTURAL WATERS: CHARACTERISTICS, MAIN POLLUTANTS - ENVIRONMENT - 2024

Agricultural waters refer to all those water resources that are used to grow products of the land and maintain livestock. There are four main areas of water use in agriculture: irrigation of crops, provision of drinking water for livestock, cleaning of buildings and agricultural implements, and provision of drinking water for those who work on producing farms.

When agricultural water is used effectively and safely, crop production and yield are positively affected. A decrease in the quality of the applied water or a variation in its quantity can cause production and yield to decrease.

Management strategies are the most important way to improve agricultural water use and maintain optimal production and yield. On the other hand, poor water quality can affect the quality of crops and cause illness in consumers.

The global shortage of water is caused, in part, by the progressive deterioration of its quality. This reduces the amount that can be used safely.

Consequently, efficient water management in agriculture is essential. This ensures that the water can be reused. It also helps maintain the environmental and social benefits of water systems.

Characteristics of agricultural water

Sources of origin

Agricultural waters come from a variety of sources. These include the waters of rivers, streams, reservoirs, lakes, and groundwater from wells.

Other sources include waters product of the thawing of glaciers, rainwater and that coming from aqueduct systems.

On the other hand, the water supply sources vary depending on the type of farm and its location. For example, farms in eastern North America generally receive enough water from rainfall. They can also be supplemented with water from melting snow.

But also, there are drier areas where rain is scarce. In these cases, the water must be supplied through reservoirs, underground sources or the aqueduct system of the region.

Availability of agricultural waters

The growing housing and industrial development creates pressure on the availability of agricultural water. The demand for water for these developments reduces the amount of water available for agricultural projects. Similarly, climate change affects the seasonal calendars of rains, thus exacerbating the shortage.

Furthermore, global food needs are increasing every year. To the same extent, the demand for water for agricultural purposes increases.

It is estimated that this demand will increase by 14% in the next thirty years. Thus, as time passes, there is less availability of water for agricultural and livestock uses.

Applications

Agricultural activities consume around 70% of the water currently used in the world. Of this percentage, most of it is used to irrigate crops.

This irrigation process consists of the artificial application of water to the land for agricultural production purposes. There are several irrigation methods: furrows, flooding or submergence, sprinkling, infiltration or channels, and others.

Each method has its advantages and disadvantages. The selection of the method depends on the type of crop, the type of terrain and economic variables.

Agricultural wastewater

The percentage of wastewater can vary depending on the particular conditions of the area, land and environment. The largest amount is generated during irrigation.

Studies done place this amount in a minimum of 21% of the applied water. This percentage represents the water that is neither absorbed nor used by the crop.

Agricultural wastewater is related to the efficiency of the irrigation method. Research ensures that the most efficient method is dripping, and the least efficient is the flood method.

Main pollutants

In general, the main agricultural contributors to water pollution are nutrients, pesticides, salts, sediments, organic carbon, pathogens, metals, and drug residues.

These are consequently the main objectives for the control of water pollution.

Crop contaminants

Agricultural operations can contribute to nutrient pollution when not properly controlled. This occurs when fertilizers are applied at a faster rate than plants can absorb them.

The excess nutrients then pass into the soil and mix with the surface particles or seep into lower layers.

Likewise, aquatic ecosystems are also affected by excess nutrients from crops. This surplus produces a phenomenon known as eutrophication.

This type of pollution causes an increase in vegetation and other organisms in rivers and coastal waters. As a consequence, the oxygen levels of the water are depleted. This has an impact on biodiversity and fisheries.

Contaminants from livestock

Fertilizers and animal manure, which are rich in nitrogen and phosphorus, are the main sources of pollution of this type. The excess of nutrients is washed from the soils with the rains and deposited in the nearby waters.

Sediments from the earth can also reach river currents or seep into underground basins with the same effect.

The livestock sector has grown faster than crop production in almost all countries in the last 20 years. The waste associated with this activity has serious implications for water quality.

This class of agricultural pollutants comes in the form of manure, antibiotics, vaccines, and growth hormones. These wastes move from farms through water to ecosystems and drinking water sources.

Sometimes these wastes can also include zoonotic pathogens from diseased animals.

Contaminants from aquaculture

Globally, aquaculture has grown dramatically. This activity takes place in marine, brackish and freshwater environments. Other water pollutants are incorporated from this activity.

The excreta of the fish and the food not consumed by them diminish the quality of the water. Increased production has led to increased use of antibiotics, fungicides, and antifouling agents. This in turn has contributed to polluting downstream ecosystems.

References

1. United States Environmental Protection Agency. (s / f). The Sources and Solutions: Agriculture. Retrieved on February 4, 2018, from epa.gov.
2. Agricultural ERP. (2017, May 15). Stress in crops due to high temperatures: Prevention and Management. Retrieved on February 4, 2018, from sistemaagricola.com.mx.
3. Arribas, D. (s / f). Anti-frost irrigation in fruit trees and vineyards. Retrieved on February 4, 2018, from lan.inea.org:8010.
4. Lazarova, V. and Asano, T. (2004). Challenges of sustainable irrigation with recycled water. In V. Lazarova and A. Bahri (editors), Water Reuse for Irrigation: Agriculture, Landscapes, and Turf Grass, pp. 1-30. Boca raton: CRC Press.
5. Mateo-Sagasta, J.; ZAdeh, SM and Turral, H. (2017). Water pollution from agriculture: a global review. Rome: Food and Agriculture Organization of the United Nations.
6. OECD. (s / f). Water use in agriculture. Retrieved on February 4, 2018, from oecd.org.