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Seminar Series 2009

How does chicory affect the nitrogen cycling of pasture systems?

Time:
Date:
Venue:
Presenter: 		3.00pm
Thursday, 25 June 2009
NSW DPI Conference Room, Wagga Wagga Agricultural Institute
Matthew Gardner, PhD Student

Growers in the medium and high rainfall zones of southern Australia wanting high quality summer forages have few alternatives to lucerne, yet it is not suited to all soils. Recently, chicory (Cichorium intybus) has been identified as a new perennial forage species that is more tolerant to acidic and waterlogged soils than lucerne.

Chicory is a short term perennial herb that can produce a large quantity of high quality feed in the warm season, which is ideally suited to lamb or steer finishing systems and for 'flushing' ewes prior to joining. Animal performance on chicory is superior to that of grass-based pastures while being similar to that from legume-based pasture. Unlike legume dominant pastures, chicory does not cause animal health problems such as bloat or redgut. Its deep tap root system provides the potential to reduce deep drainage and create large biopores that can improve soil structure, hence improve soil fertility. Being a short-term perennial species (3-4 years), chicory would be suited to phased farming system as a short pasture rotation.

However due to the high N requirement of chicory it would have to be grown in combination with a legume species or have fertiliser applied. The responsiveness and recovery of applied N by chicory is extremely efficient in comparison to other pasture and crop species. Chicory also has high mineral contents, low levels of structural carbohydrates, large taproot systems and active summer growth habits. These properties are hypothesised to significantly affect the processes within the N cycle. In particular, it is expected that mineralisation, immobilisation, plant uptake of inorganic N and biological N fixation would be effected under a chicory-legume pasture mix. These key processes of the N cycle can either reduce or promote the supply of N to pastures and subsequent cropping phases.

There are two key objectives of the research. Firstly, to quantify the effect that chicory has on N turnover under a chicory-legume pasture mix. Secondly, is to determine the mechanisms that are responsible for any changes within the N cycle under this pasture mix. Based on the findings best practice N management can be determined for chicory pasture mixes to improve their productivity in mixed farming systems.

For further information about this seminar please contact:

Convenor: Dr Mark Conyers
A/V ref: BA