The successful use of winter active tall fescue in a mixed cropping program
Charlie Roberts – farmer and consultant
Dunbogan Merino stud consists of 1835 hectares 75 km east of Dubbo in the central western slopes and plains of New South Wales. The property is 80% arable with a mix of both red clay (4.8-5.5 pH CaCl2) and sandy loam (4.2-4.7 pH CaCl2) soil types. Average annual rainfall is 650mm split evenly between autumn-winter and spring–summer.
The livestock operation includes stud and commercial merino sheep (6.5kg/head of 19.5 micron wool), cows and progeny plus the opportunity backgrounding of cattle for the feedlot market.
A typical cropping program on the red clay loam soil type consists of wheat > canola > wheat following by a traditional pasture mix of lucerne, phalaris and sub-clover. In contrast a cropping program on the sandy loam soil type includes oats > oats followed by premier digit, rhodes grass and sub-clover pasture mixes sown in the late Spring.
- The challenge has been to find new pasture species that would:
- Provide strong Autumn and Winter pasture growth,
- Be free from the risk of red gut and phalaris staggers during Autumn,
- Tolerant of long dry periods and recover sufficiently to make use of unseasonal rainfall events,
- Reduce the variable costs required to re-sow oats every year.
A range of pasture species were researched and trialled with winter active tall fescue selected as the species of choice.
The first tall fescue paddocks were sown in autumn 2009 following the traditional cropping program of wheat, canola and wheat. During the cropping phase lime was applied and incorporated at 2.5 t/ha. Lime was applied to increase the soil pH (reduce acidity) from the typical level of 4.8pH (CaCl2) up to 5.5pH (CaCl2). Raising the soil pH helped provide the pasture with optimum growing conditions, increasing production and persistence. Applying lime also assisted in stimulating microbial activity, enhancing the availability of soil nitrogen (N) and phosphorus (P).
The paddock of choice was 44 hectares of red clay loam with a long history of cropping and a heavy infestation of horehound where previous control methods (chemical, biological and pasture competition) had failed. The pasture mix consisting of Flechca tall fescue 7kg/ha, Urana sub-clover 1.5kg/ha, Seaton Park sub-clover 1.5kg/ha, Puna chicory 0.5kg/ha-- and Tonic plantain 0.75kg/ha. In early May the pasture mix was direct drilled (post stubble burning) from the small seeds box of a John Shearer trash cultivator with 85kg/ha of diammonium phosphate (DAP).
After a dry start the paddock received its first grazing in early September, with rotational grazing continuing until February 2010. The 2010 calendar year saw 1007mm of rain fall with stem elongation and seed head difficult to control during Spring. The large size of the paddock made stem control particularly difficult with the fescue closest to the water grazed short and hard with other areas of the paddock left tall and rank. As a result the paddock was slashed in the early summer to a height of 10cm to remove dead indigestible stem and seed head.
Total pasture establishment costs were $195/ha including, seed, fertiliser, labour and herbicides. Breakeven for the paddock occurred 15 months post sowing with an average stocking rate over this period of 15DSE/ha. Traditional pasture species including lucerne carried 6-8 DSE/ha over the same time period. During this time the paddock was grazed with cross bred lambs, merino wethers and feeder steers with an average gross margin of $25/DSE. The paddock is now approaching 5 years old with fescue populations still strong.
What has been learnt?
Paddock size is essential to ensuring optimum pasture utilisation and livestock performance when grazing tall fescue. The original paddock was 40 hectares in size which proved difficult to manage. After 12 months the paddock was divided into two twenty hectare blocks with a tank and trough system set up. Decreasing the paddock size enhanced the ease of management, enabled an even grazing of the tall fescue, increasing pasture utilisation (reducing wastage), pasture recovery and livestock performance.
The tall fescue paddock established ended up being very fescue dominant with few companion species. The dry autumn conditions made clover establishment and recruitment difficult. Future paddocks will be sown at lower rates of tall fescue (4-5kg/ha) which will encourage clover growth and assist in achieving an optimum 30% clover mix. Where the optimum clover percentage cannot be achieved and where nitrogen cycling is not occurring, the economics of nitrogen fertiliser in autumn or early winter will be considered. If rampant stem and seed head elongation occurs in the future the fescue will be slashed, opening the pasture up, increasing sunlight infiltration encouraging clover recruitment.
Fescue, relative to other pasture species is expensive to establish, with the paddocks on Dunbogan showing that returns are possible where livestock classes are carefully selected for finishing rather than maintenance. It is also clear from the experience at Dunbogan that where summer seasonal conditions allowed (rainfall and temperature) the fescue continued to grow actively. It was only once a combination of both increasing temperature and drying soil conditions that the fescue became dormant.
(Source: Article from NSW Grasslands 2014)