Kangaroo Island Read online

  December - Lambs that have not achieved minimum weights are sold to feedlot for production feeding. These are known as store lambs

  Grass weeds also have an impact of the meat quality if grazed by lambs late in phase 3. Shearing and lamb sales occur in this phase of the pasture production. Any excess feed that is present at this time of year is cut for hay and stored for the summer months when low protein and low energy feed exists. Feed in the latter part of stage 3 can become poor in quality in regards to protein and energy, so for the fodder conservation process, it is important to cut the pasture or crop whilst the protein and digestibility are at their maximum. The early cutting of hay also prevents the problem grass weeds from setting seed such as brome and barley grass.

  Stock management involves a number of parameters. The understanding of the climate, which includes rainfall and temperature allows for timing of stock management events.

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  The term DSE refers to Dry Sheep Equivalent. A dry sheep is a wether, which is a castrated male. Wethers are used as a measure for stocking rate equivalents. For example, 1 wether will consume a certain amount of feed per day. A ewe heavily in lamb with twins will eat more per day simply because it must support itself plus the unborn twin lambs from a nutritional point of view.

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  A crossbred ewe in July will consume 2.4 times more than a wether at that time of year. When these figures are calculated over the whole property in regards to the type of sheep run this allows for management decisions so that feed supply is maintained at the most critical times.

  The knowledge of the DSE provides an understanding of the feed required. The DSE pressure must coincide with feed demand for the season. After lambing (L) has occurred we can see how the DSE rating rises. This is because the lambs require feeding as well as the ewe. For example, as the 3000 crossbred ewes lamb in July the DSE total is 10,800. This is our greatest feed requirement for the year so knowing the seasons is important to be able to match the demand. This is why lambing time is so critical to the whole process of lamb production; to ensure the lamb achieves the target weight within the specified time frame.

  Wheat production in Australia in 2011 was 29 million tonnes and is a very important contributor to the economy. Seasonal conditions impact on the volume of grain produced. In 2012, the forecasted grain production is 20 million tonnes, primarily a decrease on 2011 due to poor seasonal conditions in some areas of Australia, in particular Western Australia.

  Crop Production has been an integral part of Stranraer over the generations. Grain has been grown for livestock use on the property and also for sales through various grain boards. In the early days the grain was exported off the island via the Karrata and then the Troubridge, which both delivered agricultural products to Port Adelaide.

  The average wheat yields over the years have ranged from 1.5 tonne to 3.0 tonne per hectare. The changes in seeding and harvesting technology, has seen increases in yields over the generations. Seeding equipment has resulted in efficiencies with fertiliser placement and seed to soil contact. The seeding rates required for barley, wheat and oats is 80kg per ha. So, seeding 80kg per hectare of seed can yield up to 3.5 tonnes of grain per hectare.

  Wheat

  Similar yields have been achieved for barley. Barley production has had 2 purposes. Barley is used in the production of beer, thus requiring a certain level of protein to achieve malting grade. Certain varieties are grown specifically for this purpose. The seasonal conditions and variety have a major impact on the protein levels in grain. The protein requirement of barley for maltsters is 12.5% or less, any barley that is higher than this can only be used for livestock feed.

  The timing of seeding is very important in regards to achieving these types of yields. Growing season rainfall and having a good understanding of the climate and rainfall patterns enables more accurate decisions to be made.

  The rainfall trend, suggest that every 40-50 years there is a flood event. 1910 was a major flood year for Kangaroo Island and in the early days of road and bridge construction there was extensive damage as minuted in the council meetings. New farming land that was been developed suffered severe erosion of the cultivated and cleared paddocks. 1956 had an impact on the wetland system at Stranraer and changed the land management in the area.

  Stranraer crop planting time is in the April – May period. It is usually by this time that the property has received its opening rain and seeding can commence.

  Crops such as wheat are required to be planted by a certain time of the year to ensure that the crop can mature and set grain. Most cereal crops such as wheat, barley and oats are planted in the April to June period. Understanding the rainfall patterns, regarded as the growing season rainfall, and temperature is very important for maximising yields. In aiming to grow wheat and achieve high protein planting, time is critical; this timing also assists is managing frost risk. Frosts can occur in the September to October period, if this occurs during the flowering time of the crop, this can result in severe yield reduction. Kangaroo Island’s climate with ocean currents prevents frost from being a major issue, however it is important that the risk is understood in regards to planting.

  Barley and oats are not as critical as wheat with regards to planting time, however enough time must be allowed for the crop to germinate, flower, set grain and then be harvested.

  Managing a cereal crop requires planning and specific observation throughout the year. As a cereal crops grows it goes through specific stages. These stages are known as the zadok score. The zadok plant scoring system begins at GS 00, (GS stands for growth stage) which is dry seed that has been planted in the ground to GS 99 which is grain ripening. The scale represents 100 days of plant growth. The early management of the cereal crop involves weeds and insects. It is important to manage weeds like annual ryegrass and broadleaf weeds such as capeweed early to reduce competition. Paddock selection is also important and how the particular paddock was managed in the previous year.

  Fertiliser is applied at seeding time these days however, fertiliser application in the early to mid-1900s was aerial application and ground broadcasting. The machinery that is available today allows the fertiliser to be placed right next to the seed in one operation. The machinery has bins that have the seed and fertiliser stored as planting occurs. Soil testing is required to ensure adequate nutrition is applied to the growing crop. Soil testing is also important at this point, to determine the deficiencies within the soil profile. Soil testing is carried out in January/February in any given year prior to the production season.

  Nitrogen and phosphorous are the main nutrients applied at seeding, this assists with germination. Fertiliser technology today also allows trace elements to be applied to the granulated fertiliser. Trace elements are placed into a solution such as copper and zinc and then into a rolling drum and coated onto the granulated nitrogen and phosphorus. Most of the fertiliser arrives either in bulk, 1 tonne bags or 50kg bags. The following chart shows the nutrient removal in some of the agricultural products. For example 1 tonne of wheat will remove 23kg of nitrogen from the soil. Therefore the need to understand soil nutrition is important to maximising crop and pasture performance.

  Prior to seeding, glyphosate is used to eliminate growing plants and competition to the pending crop. This is timed in a way that 3-7 days later the crop can be seeded.

  In the early till mid 1900’s, cultivation was the primary method of managing weeds and also eucalyptus regrowth prior to the planting of crops. This method required a lot of labour, time and money. This practice of cultivation has various impacts on the soil including compaction and waterlogging. Over time the chemical evolution came to farming with the use of herbicides to manage these weeds not only prior to sowing crops but also whilst the crop was growing. Glyphosate revolutionised the cropping industry and reduced the reliance on cultivation. The reliance on chemicals over time has created its own problems with the onset of herbicide resistant plants.

  Pre-eme
rgent herbicides may be used in front of the seeding operations as opposed to soil cultivation. These herbicides are placed close to the soil surface and as weeds germinate will eliminate the competition. The grain is seeded below this chemical so the crop is unaffected.

  As the cereal crop germinates and begins to grow, the plant goes through various stages such as leaf development, tillering and then flowering and seed set. In crop herbicides and insecticides may be applied at the leaf and early tillering stages to manage weeds that have survived the pre-emergent chemical application. Insects such as red legged earth mite can attack young cereal seedlings and cause extensive damage.

  Tillering occurs at GS 20 - GS 30. This is an important stage as the more tillers that can be produced the more grain will result. Tillers will eventually form grain heads. Leaf production continues and at approximately GS 39 (day 39) the cereal crop will send out its last leaf, this is known as the flag leaf. The flag leaf is the last leaf prior to the grain head emerging from the cereal plant. Disease management of the crop is important at this stage prior to the grain head emerging. Fungicides to manage stripe, leaf and stem rust are applied at this stage. 45% of wheat production is reliant on the flag leaf, so it is important that disease is not present at this point. Plant breeding is important in managing crop disease and the breeding of varieties which are tolerant or have a level of natural resistance to particular crop diseases.

  Seasonal rainfall impacts on this protein level. If, for example, the season finishes early in terms of rainfall, then the plant responds by filling the grain quicker tending to result in poor quality grain in regards to grain size and protein levels can be too high if trying to achieve a malting grade of barley. The use of nitrogen will also impact on protein levels, thus highlighting the importance of understanding the nitrogen content of the plant throughout the growing period. Soil testing plays a vital role in crop production in knowing the limitations to crop requirements.

  Cereal crops are sown in April-May or June depending on the season, with the main rainfall period for the property been from May to September. Wheat will be sown first to achieve high protein status, barley or oats are sown after this. If growing canola for oil production then seeding early is important to achieve high oil content. Cereal crops will be harvested in December or January, once again weather and season dependant. In some situations at Stranraer cereal crops are cut for hay so some of the specific management is not required, e.g. planting timing is not as critical, as the crop will be cut down prior to seed set. Hay crops using cereals, for example oats, may be planted with vetch which is a high protein legume plant, that when put though to hay production provides a high protein source for sheep and cattle.

  Barley

  Due to the protein requirements of malting barley, a later seeding time will allow the grain to develop below 12.5% protein at harvesting. The price difference between malting and feed grade barley can be substantial and impact on profitability. Any barley above the malting grade protein parameters is regarded as feed grade barley.

  Wheat production is similar in that grain is classified into groups based on protein levels. These groups determine how the wheat can be used. In the main, growing wheat is trying to achieve the highest possible protein as the market pays a premium. High protein wheat has many uses in food production. At Stranraer, crops have been grown in rotation over the generations. By saying this, no same crop is grown in the same paddock in consecutive years. For example, we would not grow wheat in a paddock and the next year, grow wheat again. There are disease and nutritional issues with these practices.

  Crop rotations allow production to be maintained across all crop types. Wheat production is about achieving high protein and to achieve high protein the soil nitrogen status must be high. Thus we tend to follow a legume crop, which fixes nitrogen into the soil for the wheat crop. The diagram below shows the rotation process.

  Faba Beans–Wheat–-Barley–-Pasture

  To achieve malting barley which is 12.5% protein or below, the soil needs to be devoid of nitrogen, so following the wheat crop achieves this.

  Summary - Crops are grown for the following purposes:

  Oats - Milling or feed oats. Milling oats are used for food production.

  Barley - Malting barley used for beer production, feed barley used as stock feed (sheep, cattle).

  Wheat - Various classifications. High protein wheat is used for food production and low protein wheat is used for livestock industries such as poultry, sheep and pork production.

  Canola - Oilseed crop grown for oil production, some used in livestock feed rations.

  Faba Beans

  Faba beans - High protein grain legume crop, used in livestock finishing diets for meat production and have the ability to place nitrogen back in the soil through nitrogen fixation processes.

  Peas are a high protein legume crop, grain is used in feed rations for meat production.

  Weed resistance has become a major issue in Australian agriculture over the past 20 years. The move away from cultivation towards no till farming has increased the reliance on chemicals to control competitive weeds within crops. Annual ryegrass is the major competitive weed in Australian cropping systems and has become the most challenging to control chemically. Over 380 weeds in the world have known resistance to herbicides.

  Chemicals used in broadacre farming have become dominant due to the change in tillage machinery. The use of ploughs previously provided weed control with full soil disturbance however, now with the no tillage machinery and the lack of soil disturbance, chemical use has increased to control both brassica and grass weeds in Australian agriculture.

  There are many types of chemicals used in Australian agriculture. All the chemicals are broken into ‘modes of action.’ By knowing the mode of action of a particular chemical, farmers are able to rotate groups to reduce the onset of resistance.

  This is not only a process required for cropping, chemicals used in the livestock industry to control worms and lice need to be managed correctly to reduce the possibility of resistance.

  Canola crops

  Prior to the harvesting of canola, the crop is windrowed. To explain the windrowing of canola, canola is cut at the base when 60% of the seeds within the pod have turned brown, therefore 40% remain green. By cutting the plant at base level the maturation of the remaining seed occurs more quickly allowing for harvesting to begin sooner. This is an important process on larger properties with extensive cropping operations. The canola can be harvested first before the wheat, barley and oats have naturally matured. Wheat tends to be the last crop type to be harvested to ensure maximum protein can be achieved. Windrowing of barley also occurs for similar reasons. This windrowing process also allows for grain producers to manage the climate risk and have crops harvested more efficiently prior to rain events. If canola stands and matures naturally it may result in grain shattering from the pods due to wind and rain, as a result of the height of the crop. Canola has a relatively small black seed, so managing the shattering of the pods is very important in achieving high yields. I have seen canola crops stand over 6 feet high. Canola, which is grown for oil production, yields between 1.5 and 3 tonnes with 40-44 % oil depending on the type of season.

  CHAPTER 7 - Natural Resources of Stranraer

  The soils are neutral to alkaline in pH, thus allowing for productive pasture and crop growth. With an alkaline soil pH, which is the result of limestone bedrock, many plant species are able to grow. The limestone is evident on the surface of some paddocks at Stranraer. The building of the homestead and the shearing shed involved digging up limestone in a soft state out of the ground and then the builders would shape the rock with sharp axes while it was still soft to form bricks. Once this limestone is aerated it becomes very hard. This limestone bedrock has implications for agricultural production.

  Nutrient status of the soils is important in understanding the limitations to production. Plants have a requirement for key nutrients and for minor nutrients
, which are regarded as trace elements. Phosphorus, nitrogen, potassium and sulphur are the key nutrients to assist in plant production. Phosphorus is regarded as deficient in most Australian soil types and is limited in the Stranraer soil. These nutrients need to be monitored through soil testing every 2-3 years. Soil tests involve coring the soil to 10-15 cm depth as this is where plant growth mainly occurs; the soil is sent to a lab for analysis on all the nutrient components including soil texture and pH. This report allows for planning and crop and pasture selection.

  The management of soil pH is critical to plant production. The limestone bedrock at Stranraer means that pH is not an issue however, in acidic soils of pH 7 or less lime must be applied to raise the soil pH and enable effective plant growth. Most soil nutrients are more available at a pH of 7 or above.

  Sodic soils have been an issue over the years. A soil that is sodic has a high percentage of exchangeable sodium. Sodium has a large impact on soil structure, thus the more sodium that is exchanged in the soil the more the soil will break down and crumble, thus allowing for waterlogging and lack of plant growth. Sodic soils can be managed by the use of gypsum. There were gypsum deposits on the island years ago but these deposits are now exhausted. Gypsum, which is calcium sulphate, when applied to the soil allows the calcium to chemically exchange with the sodium in the soil. The sodium then does not bind to the soil, the calcium does, which prevents soil structural damage, leading to waterlogging and loss of crop and pasture production. Calcium provides stronger bonding for the soil allowing for better water infiltration and nutrient uptake. Gypsum effectively reduces soil dispersion and thus soil structural breakdown.