Specific Yield of Unconfined Aquifers in Revisiting Efficiency of Groundwater Usage in Agricultural Systems

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey’s NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and shallow carbonate aquifers provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The agricultural system of corn, soybeans, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems, although mean nitrate concentrations in counties with dairy, poultry, cattle and grains, and horticulture systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice.

Download Full-text

Nitrate in aquifers beneath agricultural systems

Water Science & Technology ◽

10.2166/wst.2007.436 ◽

2007 ◽

Vol 56 (1) ◽

pp. 59-69 ◽

Cited By ~ 18

Author(s):

M.R. Burkart ◽

J.D. Stoner

Keyword(s):

United States ◽

Groundwater Vulnerability ◽

The United States ◽

Point Sources ◽

Nitrate Contamination ◽

Agricultural Systems ◽

Fertilizer Use ◽

Unconfined Aquifers ◽

The World ◽

Production Area

Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as in Asia, may experience the greatest impact of this practice on groundwater nitrate.

Download Full-text

UNCONFINED AQUIFERS AND THE CONCEPT OF THE SPECIFIC YIELD

International Association of Scientific Hydrology Bulletin ◽

10.1080/02626666909493727 ◽

1969 ◽

Vol 14 (2) ◽

pp. 191-197 ◽

Cited By ~ 6

Author(s):

E. G. YOUNGS

Keyword(s):

Specific Yield ◽

Unconfined Aquifers

Download Full-text

Groundwater recharge estimate at Alto Rio Grande - MG watershed

Engenharia Agrícola ◽

10.1590/s0100-69162012000600011 ◽

2012 ◽

Vol 32 (6) ◽

pp. 1097-1108 ◽

Cited By ~ 2

Author(s):

Lucas A. da Silva ◽

Antônio M. da Silva ◽

Gilberto Coelho ◽

Carlos R. de Mello ◽

Donizete dos R. Pereira

Keyword(s):

Water Cycle ◽

Rio Grande ◽

Base Flow ◽

Water Levels ◽

Specific Yield ◽

Groundwater Balance ◽

Rainwater Infiltration ◽

Unconfined Aquifers ◽

Pass Through ◽

Over Exploitation

Springs are outcrops of aquifers surface, and the water cycle in this environment pass through the recharge, generally defined as the amount of water added to the aquifer, which may occur locally from rainwater infiltration. This study uses the Water Table Fluctuation (WTF) method to estimate the direct recharge and a groundwater balance to estimate the deep recharge on unconfined aquifers. The WTF method employs data of the aquifer water levels and its specific yield to estimate the direct recharge. The groundwater balance considers the direct recharge estimated by the WTF method, as the water input in the system and outputs as the base flow and deep recharge. The recharge was estimated at four areas at the watershed of Alto Rio Grande city, Minas Gerais (MG) state, in Brazil. The direct recharge estimate was 121.11; 64.62; 83.99; 152.46 (mm/year) for the L1, L2, M1 and M2 areas. The effect of the presence of forest in the recharge area can prevail over slope of relief, allowing more direct recharge, even in sources with steeper relief. The runoff from the springs in the study period exceeded the direct recharge, indicating a situation in which the saturated zone feeds the vadose zone. The annual flow was above the direct recharge pointing a situation of over exploitation of the aquifer, a non sustainable situation. The specific yield of the aquifers could also have been underestimated.

Download Full-text

Nonlinear Dynamics and Chaos in Agricultural Systems

10.1016/s0167-4137(01)x8001-3 ◽

2001 ◽

Keyword(s):

Nonlinear Dynamics ◽

Agricultural Systems ◽

Nonlinear Dynamics And Chaos

Download Full-text

Does basic education students know the importance of agroecology production systems for the conservation of biodiversity?

Research Society and Development ◽

10.33448/rsd-v9i4.2784 ◽

2020 ◽

Vol 9 (4) ◽

pp. e04942784

Author(s):

Andrea Aline Mombach ◽

Carla Grasiele Zanin Hegel ◽

Rogério Luis Cansian ◽

Sônia Beatris Balvedi Zakrzevski

Keyword(s):

Student Perceptions ◽

Rural Areas ◽

Water Conservation ◽

Social Transformation ◽

Basic Education ◽

Production Systems ◽

Agricultural Systems ◽

Education Students ◽

Chi Square ◽

Conservation Of Biodiversity

The perception of a basic education of the importance of agroecological agricultural systems for human and environmental health is fundamental for changes in consumption habits, the conservation of local biodiversity and long-term social transformation. We analyzed, by utilizing a questionnaire consisting of open and closed questions, the perceptions about agroecological and conventional agricultural production systems in 360 final students of basic education residing in nine Functional Planning Regions of southern Brazil. We used classification categories for answers within thematic axes, expressed in percentages and analyzed by means of Chi-square and Kruskal-Wallis tests. In general, students recognize agroecological systems as healthier for their families and for soil and water conservation, largely because they do not use agrochemicals. However, they demonstrated difficulties when arguing their importance for the conservation of biodiversity, ecosystems and for ensuring the food security of populations. Television was the main source of information related to agroecology, mainly for students residing in rural areas, thus pointing out shortcomings in basic education regarding the approach of the theme in schools. Our results show the need to build a complex network of knowledge and discussions on agroecological agricultural systems in basic education, involving changes in student perceptions, behaviors and sustainable choices.

Download Full-text