Irrigation Systems

Purpose of irrigation To supplement natural rainfall. To increase the amount of water available for plants to absorb for photosynthesis and the absorption of nutrients for growth.

Reasons why period of soil moisture shortage occur when the total rainfall is low. when the total rainfall is unevenly distributed. the soils are shallow and or sandy with a low water holding capacity.

Benefits of irrigation Brings unproductive land into use. Lengthens the period of growth generally raising the production and stocking rates. Prevents the establishment of weeds, which occur in drought stricken pastures. Improves stock health. Reduces the necessity to feed supplements Changing a farming system :- –sheep to dairy or to orcharding and viticulture

Methods of irrigation For each of the following methods –describe advantages and disadvantages in terms of water use, even water coverage. –match each type of irrigation to a growing system and explain why it is a suitable.

Rotorrainer

Travelling Irrigator

Big Gun

Centre Pivot

K Line

Border Dyke

Sprinkler

Big Gun

Drip Irrigation: fertigation

Trickle Irrigation

Overhead Sprinkler

Environmental Issues Surface water removal becomes significant when it has a negative effect on stream health due to: –Lower water levels/decreased dilution of existing contaminants –Higher stream temperatures –Changes the fresh water ecosystem

Methods to reduce the environmental impact of irrigation Change production system Efficient irrigation scheduling Efficient irrigation systems Water consents Water meters Select plants that tolerate dry conditions Water storage systems