Eutrophication

RIPARIAN STRIPS

Riparian Area uplands uplands floodplain floodplain wetland wetland watercourse Riparian Area is defined as the lands immediately adjacent to a watercourse up to the limits of the floodplain

A Riparian Strip is: A strip of land on either side of a water way that is fenced off and/or is usually planted.

Reasons for using Riparian Strips Sediment removal (filtration) Nutrient removal (plant uptake & soil adsorption) Absorbs storm water run off (filtration & infiltration) Increases habitats available and so wildlife diversity

- the bank collapsing, adding to stream sediment. 5. Prevents grazing by livestock that could contribute to: - the bank collapsing, adding to stream sediment. “pugging” and loss of soil structure. faeces and urine from entering the water directly and adding to the nitrate levels.

Soil compaction/pugging

Minimize heavy traffic Good drainage Back-fencing Feed-pads

Over cultivation http://www.metacafe.com/watch/1675856/benefits_of_conservation_tillage/

No-till farming http://www.youtube.com/watch?v=eIHwhJTDKSo&feature=related

Minimum tillage

Chemical sprays Spray drift: Small droplets of spray can be carried on the wind and reach non-target plants and animals. It can also blow into waterways and affect irrigation and drinking water.

Pest resistance: A spray may kill 99% of a population but not affect 1%. If the immunity is genetic, this 1% will reproduce and pass on this trait to the offspring so that the next year a lot less will die from the spray.

Biological control The use of a living organism, a natural predator or parasite, to control a pest or disease.

Ladybird eating woolly apple aphids

Earwig

Encarsia wasp Encarsia wasp on whitefly scale

Apanteles wasp

Bacillus thuringiensis (BT) Bt (Bacillus thuringiensis) is an organic insecticide that contains a naturally-occurring bacterium found in soil. Bt, when applied at recommended rates, does not harm people, plants, animals or any insects - except for caterpillars. This is because the bacteria only become active in the caterpillar’s uniquely alkaline gut. The spray has a long history of safe use. Bt has been used in many countries to protect agricultural crops, fruit trees and forests for more than 30 years. New Zealand organic growers have been using Bt spray since 1984.

Disposal of animal effluent

The Two Pond System Effluent is washed into the first pond where the solids settle. These can be taken out regularly and used as fertiliser. The water on the top is exposed to sunlight. UV rays kill pathogens. It runs off into a lower, second pond. As it stands, ammonia gas is lost. Nutrients are used up by micro-organisms. Final water is cleaner and can be released into waterways where it is not likely to cause eutrophication and disease.

Burning off Crop Stubble The stubble left in a field after harvesting is burnt off to make way for the next crop and to get rid of weeds.

Crop Rotation This involves planting the same piece of land with a different crop each year over several years before repeating the cycle.