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Harvesting Native Grass Seed

Harvesting Native Grass Seed

Harvesting Native Grass Seed

Seed collection methods will vary depending on the species. Grass seed is harvested by stripping or shaking it off the stem, or by clipping the stem with scissors or small scythes just below the spikelet. Shrub seed is picked or lightly beaten or shaken, using a tarp to catch the falling seed. For species that dehisce explosively, the entire inflorescence may be cut prior to maturity and allowed to dry in mesh or paper bags, or under netting. Ladders may be required for collecting seed from taller shrubs, or plants can be lightly pruned with telescoping pole pruners. For large-scale harvesting, specialty equipment and machines may be necessary. Whatever the method, collections should always be conducted in a manner that does not damage existing vegetation or other resources. Ideally, at least 50 percent of the seed crop at a given site is left intact to allow for natural recruitment and regeneration of the native population.

Grass

Some native grasses give the appearance of indeterminate flowering but are, in fact, determinate. For example, in populations of Themeda triandra (Kangaroo grass) individual plants may not all flower at the same time, some plants producing flowers early in the summer, others flowering in response to rainfall later in the season. However, each plant produces only one lot of seed heads each year. Elymus scaber (Common wheat grass) on the other hand tends to behave as a determinate flowering plant in areas where summer rainfall is less dominant producing flowers only in the spring. Where summer rainfall is more dominant the species may behave as an indeterminate flowering grass (see Section 5).

Most 'domesticated' grasses such as cereals have been selected to retain seed in the heads for a single destructive harvest. Australian native grasses have inflorescences (seed heads) and seed structures that are far better adapted for the natural processes of seed dispersal by wind, water and animals than for man-made seed harvesters. One such adaptation is the differential flowering and ripening of seed that is common in our grasses. Seed is produced progressively along the inflorescence, and inflorescences are produced progressively on the plant throughout the growing season (Picture 1). As the seed ripens it falls to the ground (for most native grasses seed retention is low) widening the interval during which fresh seed is available to germinate. This process increases the chances of seedling survival in an extremely variable climate. It also poses a problem in terms of time of harvest and harvest efficiency. Some native perennial grasses have determinate flowering, i.e. each plant has only one flowering period each year, and some are indeterminate, i.e. can flower more than once a year, often in response to rainfall. (Source: www.dpi.nsw.gov.au)

 

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