"Buffel Grass Seed (DBIRD_NT)"
Agnote 433 No. E41 March 1998 Agdex No: 133/51 ISSN No: 0157-8243 Harvesting and Storing Buffel Grass Seed A. White, Rangeland Production Officer, Alice Springs Buffel grass (Cenchrusciliaris) is widely planted in the Alice Springs and Barkly region for improving beef production. Petty, Holt and Bertram, in their 1979 “Alice Springs District Cattle Industry Survey” estimated there was 4,200 sq km of pasture with buffel grass as a significant component. Since then further planting and natural spread has expanded this area. Buffel grass is highly regarded for its quick response to rainfall and persistence under drought conditions. Buffel grows best on more fertile soil types and natural spread is favoured by loose soil surface conditions (see Agnote No. 400, E16, Establishing Buffel Grass in Central Australia). WHY HARVEST YOUR OWN BUFFEL GRASS SEED? a) There is no possibility of introducing weeds when plant local seed. b) The seed comes from a parent cultivar/ecotype that is acclimatised and has known palatability to stock. c) It is cheaper than purchased seed. d) Surplus can be sold. COMMERCIAL HARVESTERS Commercial beater-type buffel harvesters are available in a range of sizes, from 3 to 6 m wide, with corresponding prices of approximately $6,000 to $15,000 as at 1990 harvesters are mounted on the hydraulic arms of a tractor (or dozer) 2 allowing the operator to adjust height to harvest maximum seed and avoid obstructions. Yields of up to two tonnes per day can be attained with the largest harvesters on heavily seeded areas. These harvesters have a horizontal auger which delivers seed to an elevator on one (or both) side(s) of the machine. Seed from the elevators(s) falls into woolpack(s) hung from the framework of the harvester. Only the larger machines deliver seed to both sides, keeping weight evenly distributed and reducing driver stoppage time. The reel, auger and elevator(s) are driven by a 3 to 5 horsepower petrol motor. Hydraulic rams (optional on some machines) compress the seed to get more into each woolpack. Another means of compression is trampling by a second person whilst harvesting continues. Seed to be offered for sale needs cleaning after harvesting as these machines collect leaf and stem material (trash). Cleaning allows accurate weighing and improves product saleability. A recent innovation has been the development of brush-type harvesters. They use a rotating, stiff bristled brush, similar to a road sweeping brush, to remove seed from the seedhead. The spinning brush provides sufficient airflow to convey the seed backwards to where it can be collected. The harvested seed contains very little trash and sometimes needs no cleaning to be accepted by seed merchants. A further advantage is that seed of many native grass species can also be harvested. Because of the gentle treatment the seedhead receives, immature seed is left, allowing several passes over the same stand. Agnote No 434, E42 describes one method of building a homemade harvester. WHEN TO HARVEST Buffel cultivars with purple seedheads such as Gayndah and USA are best harvested when the heads begin to lighten in colour. At this stage there will still be many immature seedheads. A good test for when to harvest is to draw the head downwards between the fingers. If the seed is stripped reasonably easily it is mature. Prior to this stage the seed is immature and is not readily threshed from the seedhead. Once the head turns almost white seed detaches too easily and a high proportion is brown away by the approaching harvester. There is usually a short period of one to two weeks when good yields can be attained, however this varies with rainfall and soil moisture. A practices sometimes used is to harvest a patch in a clockwise direction initially, then, about a fortnight later, harvest in an anticlockwise direction. Buffel will set seed in any season in Central Australia provided the weather is warm enough. For best seed production the areas to be harvested should be ungrazed for 6-10 weeks after sufficient rain to promote growth. Ungrazed plants also grow taller making harvesting easier. POST HARVEST STORAGE Stored seed is favoured by ants and mice so it is best left hung in bags or woolpacks. It is important that it be kept dry and cool. Avoid storage close to shed roofs and western walls. Seed should never be stored in cupboards, boxes or shelves made of particle board because the board releases a gas which kills seed (See Technote No. 6, January 1980). Best germination results for buffel grass occur after 9 to 18 months storage. Germination percentages above 20% are considered commercially acceptable and above 30% are considered good. Seed can be stored for up to 4 years but after 5 years storage germination 3 usually falls to zero. Planted seed has been observed to germinate up to 2 years after pitting operations and subsequent dry seasons in central Australia. Harvested seed can be sent to DBIRD for germination testing by the seeds laboratory. Each sample needs a label, available from the Department. Purity testing can also be carried out if necessary, eg. before commercial sale. This service is provided free of charge. The minimum sample size required for buffel grass is 60 g. It is important to sample from throughout a bag or bags to ensure that a truly representative sample is submitted for testing. Further information on testing can be gained from the Senior Seed Analyst on (08) 8999 2236. If seeding a germination test it is very important to notify the approximate date that the seed was harvested. Recording when and where the seed was harvested and the germination percentage at the time of planting can also give important feedback for improving any future pasture improvement or land rehabilitation processes on a property. WARNING Pasture plants have the potential to become weeds in certain situations. To prevent that, ensure that pasture seeds and/or vegetative material is not inadvertently transferred to adjacent properties or road sides. Please visit us on our website at www.primaryindustry.nt.gov.au While all care has been taken to ensure that information contained in this Agnote is true and correct at the time of publication, the Northern Territory of Australia gives no warranty or assurance, and makes no representation as to the accuracy of any information or advice contained in this publication, or that it is suitable for your intended use. No serious, business or investment decisions should be made in reliance on this information without obtaining independent/or professional advice in relation to your particular situation.