Farming yields increase through native shelterbelts

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Farming yields increase through native shelterbelts
Trees For Life’s landholder ordering season opens on May 1, offering low-cost native seedlings to help South Australian landholders with their on-farm productivity.
A wide range of provenance species are offered from 42 different zones throughout the State, with the majority suitable for all-important shelterbelt establishment.
Native shelterbelts provide a multitude of productivity and biodiversity benefits for farming industries.

According to a National Landcare Network’s ‘Economic Benefits of Native Shelter Belts’ report, the value of shelterbelts in raising agricultural productivity has been demonstrated in many countries suggesting potential improvements in crop yields (25%), pasture yields (20-30%), and dairy milk production (10-20%).

Productivity increases relate to all agricultural industry sectors, including the dairy, wool, meat, cropping, and horticultural industries.
According to the report, native shelterbelts with strategic placement and well-defined objectives have numerous potential benefits to farm productivity such as:

  • Protect crops and pastures from drying winds

  • Protect livestock from cold or hot winds

  • Provision of shade to protect stock from the effects of heat stress in summer as ‘extreme’ heat years increase

  • Provide habitat for wildlife and natural biological control agents

  • Help prevent salinity and soil erosion

  • Boundary shelter/windbreaks can reduce bio-security hazards to stock from neighbouring land3 (eg. prevent nose-to-nose contact, weed movement control)

  • Provide posts, firewood, timber, fodder, honey, bushfoods, nuts, cork and various other products

  • Protect and enhance living and working areas

  • Acts as a firebreak

  • Increase medium to long-term land values

In terms of specific primary industries, trial results have also shown shelterbelts to be extremely beneficial.
Livestock - dairy (trial results)

  • Sheltered areas have up to 17% estimated increase in dairy milk production.

  • On a 27 degree (Celsius) day, unsheltered cows have 26% less milk production than shaded stock.

  • Milk yields are depressed by cold at a rate of up to 1.34kg per day (4% fat-corrected milk).

  • Over (approx.40-60 years) the lifetime of fencing and shelterbelt; total dairy production will increase by 30% (20% improved pasture growth, 10% improved milk production), and $150/ha of sheltered pasture.

  • Heat stress can markedly reduce stock fertility, milk production and increase mortality of calves.

  • The use of trees can reduce heat load (summer) in cows by 50%19 and heat loss in winter, and is more cost-effective than using electricity-driven sprinklers and fans while absorbing carbon dioxide.

Livestock – sheep (trial results)

  • Fewer stock losses specifically lambs and shorn sheep; shelter reduces livestock losses of new-born lambs with trials in SE Australia suggesting effective shelter reduces these losses by 50%.

  • Sheltered sheep show a 31% increase in wool production and a 21% increase in live-weight (5 year trial).

  • In shorn sheep, shelter that reduces wind speed by 50% can reduce energy losses by 20%, 23increase live-weight by 30%.

  • Cold stress reduces live-weight gain by 6kg in sheep and depresses wool growth by 25%, while heat stress reduces wool growth by reducing feed intake.

  • Sheltered lambs exhibit a 50% reduction in losses (SW Victoria) and 28% increase in survival rates.

  • Winter lamb mortality (birth to 48 hrs) reduced by 10% in sheltered areas.

  • Sheltered off-shear wethers require only 1/3 the supplementary feed as unsheltered stock.

  • Heat-load reduction on ewes at joining and lambing results in 10-16% more lambs present at marking.

  • Heat stress is detrimental to ram fertility, ovulation rate and conception in ewes, and foetal development.

  • The use of hedgerows using native shrubs/grasses is an emerging trend for specifically providing shelter in lambing paddocks

Livestock – cattle (trial results)

  • Efficiency of production (live-weight gain or milk output per unit of feed) is improved by shelter; shading and protection from high-humidity alleviates stress, and improves milk production and weight gain.

  • Protected areas of farms have a 20% to 30% higher yield than unprotected areas, with annual benefits of $38-$66 per hectare.

  • Cold stress reduces live-weight gain in cattle by 31% over several weeks.

  • Heat stress reduces stock fertility, weight gain, and increased mortality of calves and sheep, and may cause abortion and under-sized calves.

  • Shorthorn cows show reductions in cud-chewing in unsheltered areas and increased rumination, reducing productivity.

Pasture Production (trial results)

  • Shelter improves plant growth and increased pasture and crop production, by reducing moisture loss from soils and transpiration in crops and pastures; shelter reduced the loss of water from soil in late spring by 10-12mm.

  • On one farm protected areas had a 20% increase in average annual growth pasture growth.

  • Major gains in decreased animal stress and greater pasture production in winter can support an extra 1-3 sheep/ha.

  • Shelter can increase agricultural production such as increased wool production, increased pasture growth (10-60%) therefore increase stocking rates.

  • There is growing evidence that soils around trees contain elevated amounts of organic material and a higher nutrient status, thereby promoting pasture growth.

  • Shelterbelts increase crop yields, even allowing for cropping land lost from paddock and near-shelter competition.

  • Shelterbelts can potentially be affective for a distance 12-15 times the height of the tallest tree, with protection of some crops observed at up to 25 times the height.

  • Increases in crop yields in Australian studies include: 22% for oats, 47% for wheat47 in areas of above 600mm annual rainfall.

  • Sand-blasting at seedling stage of cereal crops leads to reduced plant growth, due to moisture stress and physical damage.

General on-farm benefits

Long-term development of 30% of total farm contributes to a more environmentally sustainable land use, reducing salinity and erosion, with the remaining land better managed and fertilised as productivity increases.

  • Land protection benefits; control of groundwater recharge and salinity; deeply-rooted trees provide necessary recharge control.

  • Shelterbelts reduce topsoil loss via reducing wind scour and rapid drying of soils; removal of clay and silt particles by wind contain much precious nutrients; reducing paddock wind speed by half, will reduce wind erosion to one-eighth . (If 10% of the farm is dedicated to shelterbelts; the potential reductions in wind speed can amount to between 33-50%).

  • Shelterbelts placed above and as buffers along watercourses, reduce stream sedimentation and eutrophication, improve water quality, and reduce soil and nutrient run-off from paddocks. Interception of nutrients before entering water storages improves water quality for stock.

  • Stabilise soil surface; reduce waterlogging, also useful in non-arable areas such as those impacted by gully erosion.

  • Improved landscape amenity and aesthetics.

  • Potential fire protection; as localised wind speeds can be reduced.

Planting shelterbelts and species
Landholders are advised to do their research and carefully plan the establishment of native shelterbelts on their properties. The report recommends that shelterbelts incorporating trees and shrubs in 3-6 rows (12-24m wide) are effective for most situations.
Other recommendations are that smaller trees and shrubs are placed on the outside of central tall trees to prevent shading out and local provenance species are selected as they have a higher establishment and survival rate (species selection is based on the objectives of the shelterbelt and influenced by height, growth rate, and density characteristics).
Fodder, honey and timber species can be incorporated to provide periodic or long-term resources.
Species recommended by Trees For Life for native shelterbelts include Eucalyptus porosa (Mallee Box) and Eucalyptus socialis (Summer Red Mallee) which grow well in most regions. Other species offered through Trees For Life for shelterbelts include Allocasuarina verticillata (Drooping Sheoak), Dodonaea viscosa (Hop Bush) Pittosporum angustifolium (Native Apricot) and Melaleuca lanceolata (Dryland Tea Tree).
These species all have peak flowering at different times, and provide leaf, flower, seed and fruit for native animals to eat. They are also nice and dense, especially when planted together.
Trees For Life offers low-cost native seedlings for bulk revegetation at just 15 cents per seedling. This equates to $100 for 300 seedlings.

For more information or advice please phone the office on (08) 8406 0500. Species lists for the different South Australian regions can be found on our website at or by phoning the office.

(Source: The Economic Benefits of Native Shelter Belts. Produced by Basalt to Bay Landcare Network. Author: Peter Austin, Landtech Consulting)

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