Tomahawk Resilient Pasture Trial

Transcription

1 Tomahawk Resilient Pasture Trial 5th year update trying to farm on such stark contrasts in soil, slope and fertility is very challenging. fencing to soil type isn t the easy answer as cattle and fences combined make erosion in this environment. Tim Gunn The Northeast Discussion Group were interested in a pasture persistence trial in 2012, seeking to identify what pasture varieties last long enough in dryland production on sandy soils. They asked other organisations to help deliver a long-term trial, and started with a planning day in August A group effort formed with the discussion group, the Tasmanian Institute of Agriculture, NRM North and seed and fertiliser companies contributing to the establishment and ongoing management of this trial. Trial goal Demonstrate long-term persistence of new and common pasture cultivars in a challenging site. Site details Coastal dune plain near Tomahawk, north-east Tasmania Soil types: peaty flats, sandy lower slopes and sand dunes Previous use as 20+ year old pasture, generally low fertility 670mm average annual rainfall, winter dominant but with some summer rain Good weed control (capeweed, fog grass) prior to sowing in October 2012 Two very dry seasons since establishment (2015, 2017)

2 Initial soil test results AREA DEPTH AMMONIUM NITRATE COLWELL PHOSPHORUS COLWELL POTASSIUM SULPHUR PH (WATER) COPPER IRON MANGANESE cm Dune Slope Flat Low Low Ok Ok Ok Low on flat Low Ok Ok Low ZINC Land preparation - Tasmanian Institute of Agriculture Sprayed twice prior to sowing with 2 l/ha Roundup 450. The flat was worked prior to sowing to break up the Yorkshire fog grass root mat. Sowing Sown with a precision drill on the 2nd and 3rd of October The grass plots were sown in one direction, covering the dune, slope and the flat. The legumes were sown across the grass strips, in areas suited to them (i.e. lucerne on the dune only). Fertiliser of 120 kg/ha of NPK + Molybdenum and Copper was applied at sowing. Establishment Received rain immediately after sowing, but low spring rainfall caused seedling losses on the dune. The cocksfoot entries suffered the highest losses. Establishment across the rest of the site was excellent. 2 NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL 2018

3 DISCUSSION GROUP AT TRIAL SITE, th Year soil test results (March 2018) COLWELL COLWELL AREA DEPTH AMMONIUM NITRATE PHOSPHORUS POTASSIUM SULPHUR PH (WATER) COPPER IRON cm Dune Slope Flat MANGANESE ZINC one location in the flat zone was tested for ph by depth in march 2018, showing soil ph was 1 unit lower at 20cm depth compared to the top 5cm. ROTATIONALLY GRAZED DUNE LEFT OPEN GRAZING FLAT RIGHT NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL

4 Species/cultivars sown (October 2012) Sowing rates and seed supplier for grass cultivars sown SPECIES CULTIVAR/LINE SOWING RATE SEED SUPPLIER Cocksfoot Greenly 5kg/ha Seedforce Cocksfoot Megatas 5kg/ha Tasglobal Seeds Cocksfoot Porto 5kg/ha Ardent Seeds Cocksfoot Tekapo 5kg/ha PGG Wrightson s Seeds Hispanic cocksfoot Uplands 5kg/ha Tasglobal Seeds Coloured brome Exceltas 15kg/ha Tasglobal Seeds Phalaris Advanced AT 6kg/ha Heritage Seeds Perennial ryegrass Victoca/Avalon 15kg/ha Ardent Seeds Long rotation ryegrass/cocksfoot Barberia/Howlong 12+3kg/ha Heritage Seeds Tall fescue Demeter 15kg/ha Ardent Seeds Tall fescue Dovey 15kg/ha Heritage Seeds Tall fescue PGG Wrightson Seeds test line 15kg/ha PGG Wrightson s Seeds Tall fescue Quantum II 15kg/ha PGG Wrightson s Seeds Tall fescue Tasglobal Seeds test line 15kg/ha Tasglobal Seeds Tall fescue/cocksfoot Festival/Greenly 10+4kg/ha Seedforce Sowing rates and seed supplier for legume and herb cultivars sown SPECIES CULTIVAR/LINE SOWING RATE SEED SUPPLIER Alsike clover Hytas 4kg/ha Tasglobal Seeds Bladder clover Bartolo 3kg/ha PGG Wrightson s Seeds Caucasian clover Kuratas 5kg/ha Tasglobal Seeds Red clover Astred 5kg/ha PGG Wrightson s Seeds Red clover (Stoloniferous) Rubitas 5kg/ha Tasglobal Seeds Strawberry clover Palestine 5kg/ha Heritage Seeds Strawberry clover Upward 5kg/ha PGG Wrightson s Seeds Subterranean clover Denmark 5kg/ha Heritage Seeds Subterranean clover Bindoon 3kg/ha PGG Wrightson s Seeds Subterranean clover Campeda 5kg/ha Heritage Seeds Talish clover Permatas 5kg/ha Tasglobal Seeds Talish clover Duratas 5kg/ha TIA White clover Tahora 5kg/ha PGG Wrightson s Seeds Birds foot trefoil Lotus corniculatus 4kg/ha TIA Narrow leaf trefoil Lotus tenuis 4kg/ha TIA Lotus major Lotus pedunculatus 4kg/ha TIA Variegated lucerne KI creepa 5kg/ha Tasglobal Seeds Lucerne SARDI-Grazer 5kg/ha Heritage Seeds Yellow serradella Yellowtas 15kg/ha (pod) Tasglobal Seeds Chicory Puna II 2kg/ha PGG Wrightson s Seeds Plantain Tonic 2kg/ha PGG Wrightson s Seeds 4 NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL 2018

5 WARNING: Information contained within this report relates specifically to the Tomahawk site, its soil type and environment. What has been successful at Tomahawk may not be applicable to different soils types and environments. What has not been successful at Tomahawk may be successful at other locations. In addition: Rooted plant frequency was measured as a means of assessing persistence, not biomass, groundcover or production The flat area of the trial had a low surface ph(water) of 5.3 at sowing Major grazing differences exist between zones with the flat and lower slope mostly continually grazed whereas the dune is fenced and subject to rigorous controlled grazing Some cultivars were sown in seed company blends so may record lower frequency than cultivars sown on their own The October sowing time was not ideal for annual legumes or the seed set they require The site has received low-moderate levels of PKS blend fertiliser over the last 5 years. 2nd and 5th year results tables show average frequency of rooted plants per square metre assessed 2014 (after 2 years) 2017 (after 5 years) grasses DUNE SLOPE FLAT DUNE SLOPE FLAT Tall Fescue Wrightson s Tall fescue Tas Global Tall Fescue Quantum II Tall Fescue Dovey Tall Fescue Demeter Tall Fescue Blend Festival Ryegrass Victoca Avalon NS Ryegrass (Barberia) in blend Phalaris Advance AT Cocksfoot Uplands Cocksfoot Tekapo Cocksfoot Porto 34 NS Cocksfoot Megatas Cocksfoot (Howlong) in blend Cocksfoot Blend Greenly Brome Exceltas NS NS: not sown NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL

6 TRIAL FLAT VIEWED FROM DUNE, JUNE (after 2 years) 2017 (after 5 years) legumes and herbs DUNE SLOPE FLAT DUNE SLOPE FLAT Red clover Astred NS NS 2 1 Bladder clover Bartolo NS NS 0 0 Sub clover Bindoon NS NS 0 0 Birdsfoot trefoil NS NS 1 0 Sub clover Campeda NS 0 NS 43 Sub clover Denmark NS NS 0 0 Talish clover Duratas NS NS 1 0 Alsike clover Hytas NS NS 2 0 Lucerne KI Creepa NS 10 9 Caucasian clover Kuratas NS NS 1 0 Lotus major NS NS 1 0 Narrow leaf trefoil NS NS 2 0 Strawberry clover Palestine NS NS 8 57 Chicory Puna II 5 12 NS 1 1 Talish clover Permatas NS NS 1 0 Red clover Rubitas NS NS 17 2 SARDI-Grazer lucerne 9 7 NS 5 2 White clover Tahora NS NS Plantain Tonic NS NS 19 0 Strawberry clover Upward NS 2 NS 0 Yellow serradella Yellowtas 1 NS NS 20 NS: not sown 6 NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL 2018

7 Interpretation Tim Gunn: I was surprised some fescues have done so well on the dune, and was really excited about KI Creepa at first, but it didn t fulfil my expectations. Serradella has done very well Peter Ball (TIA): Trials like this are excellent venues for discussion and interpretation and it s fantastic that the discussion group has been interested in this work and supported to conduct it. Pasture persistence is the focus and at five years this trial is only just starting. There are no proven winners yet, but we have some strong stories featuring selected Tall fescue cultivars and Porto cocksfoot. One important caution is that for persistence to be measured, there must first be establishment. The conditions and results of establishment are thus essential considerations. Here a range of species did not establish well, including cocksfoot on the dune. The spring sowing of annual legumes probably also limited their flowering and reseeding. Drawing conclusions on their persistence would be unfair. Another important caution is that rooted plant frequency is the measure used to compare persistence, which doesn t translate directly into biomass. A number of the fescues and Porto cocksfoot have dominated the grass frequency results, displaying persistence or improved frequency. However, the growing conditions appear to have favoured more Porto cocksfoot biomass. Summer dormant cocksfoot cultivars haven t been favoured in either biomass or frequency. This may reflect their lower capacity to utilise the site s summer rainfall. Adrian James (NRM North): The Porto cocksfoot and some fescues seem the real winners so far with good persistence on both flat and dune. The hard-seeded yellow serradella has spread and persisted well on the dune but as an annual, it won t maintain groundcover all year round and the site needs more perennial cover. On the heavily-grazed flat, the Tahora white clover and Palestine strawberry clover have dominated the legumes in the long run. Peter s comment about persistence vs. biomass was highlighted on the dune, since the data showed only 1 chicory plant per square metre after 5 years, and low numbers of lucerne. I d suggest that despite declining numbers, on the dune too. I was hoping for life after Porto, but other cocksfoots were a disappointment. As this is a persistence trial, there are lessons to be learned from species disappearing. The strong density of fescue apparent across the dune, slope and flat environments does offer potential for growth. Some ryegrass is apparently persistent and improving on the flats only. This composition may however include naturalised ryegrasses resident prior to sowing. Overall the legumes have been very disappointing both in plant frequency and biomass, with a few exceptions. On the flat, strawberry clover was a strong improver and white clover was present. Elsewhere only yellow serradella and sub clover made notable contributions. Species like lucerne and chicory have appeared showy, but have made relatively small and declining contributions. Red clover has not contributed to the flat where it was sown. Currently Porto cocksfoot plus selected varieties of tall fescue are most promising, supported by strawberry clover, yellow serradella and sub clover in suitable environments. Addressing nutritional limits may further unleash their potential. Sometimes sites challenge our thinking. Here the grass strips continue across the three environments. On the rested dune Porto is clumpy, a mix of green leaf and stem. On the flat zone green, dense, vegetative, grazed or even selectively grazed cocksfoot appears. One group member asked if we had mown it. We hadn t, but discerning cattle had. these plants were still providing nutritional benefit to stock in the warmer months when the grasses have high fibre content, so worth having a few kg of seed in the dune mix as long as the rotational grazing is maintained. Soil acidity at the site, particularly subsoil acidity on the flat, is probably limiting some species, especially legumes. An application of lime with high effective-neutralising-value is likely to assist legume nodulation (and nitrogen production), nutrient availability and in the longer term, encourage roots to seek out soil moisture deeper in the profile. NRM NORTH TOMAHAWK RESILIENT PASTURE TRIAL

8 Future of the trial the future of the trial is up to the group, but i m not going to spray or re-sow since there s more to learn over the next 5-10 years. i d like to look at more frequent grazing on the dune. Tim Gunn For more information contact: Northeast Discussion Group Coordinator kevin wagner kebjwagner@gmail.com TIA Industry Development & Extension Officer peter ball peter.ball@utas.edu.au NRM North Land Program Manager & Regional Landcare Facilitator adrian james ajames@nrmnorth.org.au This trial and publication were funded by NRM North with investment provided by the Australian Government