Water and Agriculture

Terms to Know Potable: Drinkable water. Water that is free from harmful chemicals and organisms. Fresh water: water that flows from the land to oceans and contains little or no salt. Tide water: water that flows from the sea up the mouth of a river at high tide. Contains too much salt for drinking or agricultural use.

Terms to Know Water Cycle: The cycling of water among the water sources, atmosphere, and surface area. Irrigation: the addition of water to plants to supplement that water provided by rain, snow, or natural methods. Deserts: Areas with continuous, severe water shortages.

Terms to Know Precipitation: The formation of rain or snow in the atmosphere which falls to earth. Evaporation: The changing from a liquid into a gas. Watershed: A large area of land which stored water by absorbing melting snow or rainfall.

Terms to Know Water Table: The portion of the ground below the saturation point. The higher the water table the more ground water present. Hygroscopic Water: Water that is held too tightly by the soil particles and cannot be taken up by plants. Capillary Water: After gravitational water has drained from the soil, the moisture that is left behind.

Terms to Know Gravitational Water: The water that drains out of the soil after it has become wet from rain, snow, or other sources. Saturated: When water is added until all the spaces or pores in the soil is filled. Percolation: The movement of water through soil. Water Vapor: Water that is in the gas state.

Terms to Know Runoff: An amount of water or melted snow that is carried by an area of streams and rivers. Transpiration: The process by which a plant loses water vapor. Ground Water: Water that is beneath the surface of the ground.

Water Water is an essential component for healthy plant growth. Our Earth is over 70% water, yet water as a natural resource is in jeopardy. 99% of the earth’s water is salty and will not support or promote human life or plant growth.

Water (continued) Fresh water resources in developed countries are shrinking. Climate change and global warming is rapidly increasingly evaporating water resources all over the world. The highest areas of this drought is located in hot, dry climates…..in other words many of the undeveloped nations who need it the most.

Water and Agriculture Agriculture is one of the biggest users of water worldwide. Whether it is to irrigate crops or to water livestock, farming uses huge amounts of water for daily operations. In dry and hot locations like Arizona, New Mexico, and Nevada, rainwater is very rare so irrigation methods are used to put water back into the soil needed to grow crops.

How much land is irrigated? 267 million hectares worldwide are irrigated. 18% of the world’s cropland is irrigated. 60% of the world’s irrigated lands are in Asia. Irrigation usage has increased 5 times since 1900 but is on a steady decrease as time passes.

Types of Irrigation in Agriculture 1) Surface Irrigation: water is moving over the land by simple gravity flow in order to wet it and to infiltrate into the soil. 2) Localized Irrigation: water is distributed under low pressure through a piped network, in a pre-determined pattern, and applied as a small discharge to each plant or adjacent to it.

Types of Irrigation in Agriculture (cont…) 3) Drip Irrigation: Water is dripped on plants from pipelines that are suspended above the plants. 4) Lateral Movement Irrigation: Water is moved onto plants by irrigation structures at operate on wheels and move around the field. 5) Flood irrigation: When dykes or dams are broken to flood fields under a layer of water. The nutrients from the flood water nourishes the ground and plants once it evaporates. 6) Sprinkler Irrigation: water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns.

How much water is used for crops/food Crop/FieldKg of water/ Kg of food Potato500/1500 Wheat900/2000 Alfalfa900/2000 Corn1000/1800 Rice1900/5000 Soybean1100/2000 Chicken3500/5700 Beef15000/50000

Water used by Livestock AnimalLiters/Animal each day Milk Cows154 Steers and Beef Cattle51 Pigs9 Sheep3 Horses68 Chickens0.3

Water and Living Things Most living things are made up of cells that are around 90% water. Because of this, water is necessary for survival. We can last several weeks without food but only 3-4 days without potable water in our diets.

Water Conservation There are several easy steps to save our precious water supplies. They are: 1) Reduce water usage. Turn off taps when not in use. 2) Dispose of household products carefully. Never put chemicals down drains. 3) Care for lawns carefully. Don’t run sprinklers too often. 4) Practice sensible pest control. Avoid using harsh chemicals. 5) Control water runoff from fields and properties. 6) Maintain septic systems. 7)Control and contain chemical spills.

The Water Cycle Also referred to as the Hydrologic Cycle, the water cycle essentially evaporates water from the Earth’s oceans, causing it to condense into water vapour. When water condenses, it rises into the atmosphere forming clouds. Clouds will remain in the air until warm aim masses meet cold air masses. This causes water vapour to change from a gas to a liquid where it falls in the form of rain, snow, or sleet.

The Water Cycle Precipitation will fall to earth and land on the land and in the waterways. When it falls on land, fresh water will flow into lakes, rivers, and streams. This surface runoff will eventually find its way back to the earth’s oceans and will continually move throughout the water cycle.

Types of Ground Water 1) Saturated Water 2) Gravitational Water 3) Capillary Water 4) Hydroscopic Water

End of Section Questions 1) List and explain the six different types of irrigation used in Agriculture. 2) Explain the principles of the water cycle. 3) List and explain the seven ways you can conserve and maintain fresh water sources.