How agriculture hurts aquifers

Depletion of aquifers has increased primarily due to expanding agricultural irrigation. Groundwater can become contaminated when an excessive amount of pesticides and herbicides are sprayed on agricultural fields, septic tanks leak, or landfills are improperly lined or managed and toxic materials seep through the soil into the aquifer.

Full
Answer

What are the causes of aquifers being depleted?

Depletion of aquifers has increased primarily due to expanding agricultural irrigation. Groundwater can become contaminated when an excessive amount of pesticides and herbicides are sprayed on agricultural fields, septic tanks leak, or landfills are improperly lined or managed and toxic materials seep through the soil into the aquifer.

What are some common misconceptions about aquifers?

A common misconception about aquifers is that they are underground rivers or lakes. While groundwater can seep into or out of aquifers due to their porous nature, it cannot move fast enough to flow like a river. The rate at which groundwater moves through an aquifer varies depending on the rock’s permeability.

How can we mitigate impacts of aquifer depletion?

Strategies to mitigate impacts of aquifer depletion may include policy, technology and management options, which should take into account local/regional conditions, including hydrogeological factors, applicability to agricultural production systems and economic factors, Porter said.

How do we get water from aquifers?

In order to access this water, a well must be created by drilling a hole that reaches the aquifer. While wells are manmade points of discharge for aquifers, they also discharge naturally at springs and in wetlands. Groundwater can become depleted if we use it at a faster rate than it can replenish itself.

How does farming affect aquifers?

Agricultural contaminants can impair the quality of surface water and groundwater. Fertilizers and pesticides don’t remain stationary on the landscape where they are applied; runoff and infiltration transport these contaminants into local streams, rives, and groundwater.

Does agriculture deplete aquifers?

Within the United States, groundwater depletion has occurred in many important agricultural production regions, including the Great Plains Region, the Central Valley of California, the Mississippi Embayment Aquifer, aquifers in southern Arizona, and smaller aquifers in many western states.

How does agriculture deplete groundwater?

Many farmers rely on irrigation, which uses groundwater from aquifers—underground water sources naturally fed by rainfall, snowmelt and other water that infiltrates the soil. Depleting the aquifers of water faster than it can refill results in reduced groundwater quantities and, therefore, reduced crop yield potential.

Does agriculture pollute groundwater?

A number of agricultural practices can contribute to groundwater pollution, if not properly managed. Contamination sources on a farm may include pesticides, fertilizers, animal waste, and underground storage tanks.

What causes aquifer depletion?

Stressors that can deplete aquifers include changes in precipitation and snowmelt patterns; withdrawal of ground water for drinking, irrigation, and other human uses; and impervious paved surfaces that prevent precipitation from recharging ground water. Some deep aquifers may take thousands of years to replenish.

Does irrigation deplete groundwater aquifers?

Abstract. Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ∼50% of groundwater depletion in the United States since 1900.

How does agriculture cause water pollution?

The most prevalent source of agricultural water pollution is soil that is washed off fields. Rain water carries soil particles (sediment) and dumps them into nearby lakes or streams. Too much sediment can cloud the water, reducing the amount of sunlight that reaches aquatic plants.

How does irrigation affect groundwater?

Such effects depend on the irrigation water source: surface water-fed irrigation decreases runoff and water table depth, while groundwater-fed irrigation increases water table depth, and increases or decreases runoff depending on the pumping intensity.

How are the agricultural activities responsible for the depletion of water table?

The main natural source based on which agriculture was dependent was the monsoonal rainfall. As nowadays the monsoonal rainfall has drastically decreased, it has arisen water depletion condition. Thus to reduce this problem, farmers utilize the water available in groundwater and this, in turn, depletes the water table.

How agriculture contributes to the soil and water degradation?

The agricultural plants that often replace the trees cannot hold onto the soil and many of these plants, such as coffee, cotton, palm oil, soybean and wheat, can actually worsen soil erosion. And as land loses its fertile soil, agricultural producers move on, clear more forest and continue the cycle of soil loss.

What are the negative effects of water pollution in agriculture?

The excessive accumulation of nutrients may also increase adverse health impacts, such as blue-baby syndrome, due to high levels of nitrate in drinking-water. Insecticides, herbicides and fungicides are applied intensively in agriculture in many countries (Schreinemachers and Tipraqsa, 2012).

How do fertilizers contribute to water pollution?

The usage of organic fertilizers results in the discharge of nitrate, potassium and phosphates that pollute the water. The contamination of groundwater occurs as a result of leaching due to nitrate. The ground and surface waters are infested with heavy metals, whose concentration poses a threat to humans and animals.

What are the strategies to mitigate impacts of aquifer depletion?

Strategies to mitigate impacts of aquifer depletion may include policy, technology and management options, which should take into account local/regional conditions, including hydrogeological factors, applicability to agricultural production systems and economic factors, Porter said.

Which aquifer system has the greatest long term storage depletion?

The paper noted the U.S. aquifer system with the greatest long-term groundwater storage depletion is the Ogallala Aquifer in the Great Plains region, where groundwater levels have declined by more than 150 feet in some areas.

When did groundwater depletion begin?

According to the paper, large-scale depletion of groundwater within the U.S. began in the 1950s and tripled by the 1990s, with approximately 71 percent directed toward irrigating crops, Tracy said.

Abstract

Agriculture is a basic economic activity in the Canary Islands, a Spanish region in the Atlantic Ocean, facing the Sahara. The main crops are bananas, tomatoes, and other special ones suitable for exportation. Fertilizers are applied in high quantities on the scarce land available.

Referenced Cited

Custodio, E., 1974, Contribuciones al conocimiento geohidroquimico de la isla de Lanzarote (Islas Canarias, España), Simposio Internacional sobre Hidrología de Terrenos Volcánicos, Arrecife de Lanzarote: Madrid, Instituto de Hidrología.

Keywords

Custodio, E., 1974, Contribuciones al conocimiento geohidroquimico de la isla de Lanzarote (Islas Canarias, España), Simposio Internacional sobre Hidrología de Terrenos Volcánicos, Arrecife de Lanzarote: Madrid, Instituto de Hidrología.

How has agriculture increased?

Agricultural methods have intensified continuously ever since the Industrial Revolution, and even more so since the “green revolution” in the middle decades of the 20 th century. At each stage, innovations in farming techniques brought about huge increases in crop yields by area of arable land. This tremendous rise in food production has sustained a global population that has quadrupled in size over the span of one century. As the human population continues to grow, so too has the amount of space dedicated to feeding it. According to World Bank figures, in 2016, more than 700 million hectares (1.7 billion acres) were devoted to growing corn, wheat, rice, and other staple cereal grains—nearly half of all cultivated land on the planet.

What are the consequences of irrigation?

One of the most obvious consequences is the depletion of aquifers, river systems, and downstream ground water. However, there are a number of other negative effects related to irrigation.

Where does nitrogen come from in fertilizer?

Roughly half the nitrogen in synthetic fertilizers escapes from the fields where it is applied, finding its way into the soil, air, water, and rainfall. After soil bacteria convert fertilizer nitrogen into nitrates, rainstorms or irrigation systems carry these toxins into groundwater and river systems.

What is the effect of nitrogen on soil?

In addition, fertilizer application in soil leads to the formation and release of nitrous oxide, one of the most harmful greenhouse gases.

What is irrigation related to?

Irrigation has also been connected to the erosion of coastlines and other kinds of long-term ecological and habitat destruction. A huge amount of agricultural territory is used primarily as pasture for cattle and other livestock.

How much of the world’s freshwater is consumed by agriculture?

Worldwide, agriculture accounts for 70 percent of human freshwater consumption. A great deal of this water is redirected onto cropland through irrigation schemes of varying kinds. Experts predict that to keep a growing population fed, water extraction may increase an additional 15 percent or more by 2050. Irrigation supports the large harvest yields that such a large population demands. Many of the world’s most productive agricultural regions, from California’s Central Valley to Southern Europe’s arid Mediterranean basin, have become economically dependent on heavy irrigation.

What causes algae blooms in China?

Nutrient pollution is a causal factor in toxic algae blooms affecting lakes in China, the United States, and elsewhere. As excessive amounts of organic matter decompose in aquatic environments, they can bring about oxygen depletion and create “dead zones” within bodies of water, where nothing can survive.

What are the effects of land use changes on agriculture?

In almost every case, land use changes — say, deforestation, or paving over green space for suburban expansion — result in more surface warming.

How much carbon dioxide does organic farming remove from the air?

We’ve said it before and we’ll say it again: Organic agriculture can remove from the air and sequester 7,000 pounds of carbon dioxide per acre per year. The Rodale Institute study that found that staggering number also found that, when properly executed, organic agriculture does not compromise yield.

Does drought increase yield?

As a matter of fact, in drought years, it increases yield, since the additional carbon stored in soil helps it to hold more water. In wet years, the additional organic matter in the soil wicks water away from plant roots, limiting erosion and keeping plants in place.

Why are crops declining in agriculture?

The National Climate Assessment also notes that “many agricultural regions will experience declines in crop and livestock production from increased stress due to weeds, diseases, insect pests and other climate change-induced stresses.”

How does water temperature affect fish?

According to NOAA, fisheries are currently and will continue to be affected by changes in water temperature that trigger shifts in the abundance and types of fish and other ocean life/seafood. These same temperature changes make certain waters more hospitable to invasive species and mess with the lifecycle timing and habitat ranges of certain fish species.

Case Studies

Overview

Isotopic Studies

Aquifer Water Level Decline

• Water extraction for irrigation and domestic water supply at rates higher than the aquifer recharge causes continuous drop of the water table and depletes water resources (aquifer water level decline). One of the worst situation was reported in the Pinios basin, where aquifer water level in some areas has dropped by hundreds of meters. In areas clo…

See more on water.jrc.ec.europa.eu

Contamination by Pesticides, Herbicides and Phosphorous

Nitrate Concentration in Groundwater

Conclusions