Irrigation A discourse byTarek and Elliot
What is…Irrigation? • Irrigation is the artificial provision of water to support agriculture.
Methods of Irrigation • Pouring water on fields • Leveling of fields • Surge flooding • Capture and reuse of runoff • Drip irrigation (the best) • Spray irrigation • Better Spray irrigation • Conventional irrigation • Center-pivot irrigation
Problems of Irrigation • Waterlogging occurs when the water table rises to the point that water bathes plant roots, depriving them of access to gases and essentially suffocating them. If it lasts long enough, waterlogging can kill plants. • Salinization is the buildup of salts in surface soil layers. In dryland areas where precipitation is minimal and evaporation is high, water evaporation drags subcutaneous salts to the surface. These salts inhibit plant growth.
Alleviating Salinization • Salinization is much easier to prevent than it is to treat • The main strategy is to increase the efficiency of irrigation • Some possible ways to mitigate salinization is to flush the salt out of farmland with large quantities of water and planting salt-tolerant crop.
What is Fertilizer? • Fertilizers are any of various substances that contain essential nutrients, often added to soils to enhance their nutritive properties. • Fertilizers are categorized as organic and inorganic. Inorganic are mixed or synthetically manufactured mineral supplements. Organic fertilizers consist of the remains and wastes of dead plants and animals.
Why do we use Fertilizers? • Fertilizers are used to increase crop yields in areas with poor soil. • Often inorganic fertilizers are harmful to the environment, but the overuse of organic fertilizers can also be harmful. • A surfeit can lead to eutrophication. We have already thoroughly discussed all facets of this issue.
The effects of grazing policies • Overgrazing can lead to soil damage, impaired productivity, and erosion. • When livestock graze, they make areas vulnerable to invasion by non-native species • Soil compaction is another consequence of overgrazing
The Effects of Forestry • Forestry is the cultivation of trees • Clear-cutting leads to severe erosion, particularly on steep slopes • Forestry practices have been modified in an attempt to minimize damage to soils
Techniques to Promote Soil Conservation • Food Security Act of 1985 – Requires farmers to adopt soil conserving policies in order to be subsidized • Conservation Reserve Program 1985 – pays farmers to stop cultivating erodible cropland • Federal Agricultural Improvement and Reform Act – • Low-Input Sustainable Agriculture Program • Various UN programs