Alchin, B. M.

Bosch, O.

Page, M.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Ecosystem Response to Cell Grazing in Australian Rangelands B. M. Alchin The University of Queensland, Australia M. Page The University of Queensland, Australia O. Bosch The University of Queensland, Australia Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/9-1/13 The 21st International Grassland Congress / 8th International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]29　 瞯Grasslands/Rangelands Production Systems——— Livestock Production SystemsEcosystem response to cell grazing in Australian rangelandsB .M .A lchin ,M .Page and O .Bosch .School o f Natural & Rural Systems Management ,University o f Queensland ,Gatton Qld A ustralia . E‐mail : b .alchin＠ uq .edu .auKey words : cell grazing ,grazing systems ,grazing ecosystemIntroduction �Cell grazing�was introduced to Australian pastoralists in the early １９９０s . Initially it received strong criticism bymany rangeland scientists .However ,the pastoral industry has largely accepted cell grazing as having a valid role in the optionsfor management ; this is based largely on the observed improvements in rangeland condition and profitability in some locations .There is still a dearth of scientific data on ecosystem responses and changes under cell grazing . This study relates to researchconducted since １９９６ .Aim The aim of this research was to develop an understanding of the ecosystem response to cell grazing ; it included acomparison with conventional ( continuous) grazing systems .Method Study sites on commercial scale �cells�adjacent to conventional grazing locations have been established across an arrayof rangeland types and climatic regimes . All sites are in the summer‐dominant rainfall zone in northern Australia and run cattle .Results /Discussion Table １ summarises important data ,with other results presented in the following paragraphs .Table 1 L andscape Function A nalysis ( L FA ) ,soil ,p lant and microbial data f or conventional and cell graz ing sites .Site Rainfall( mm)GreatSoilGroupGrazingsystemStock .Rate( ha/LSU /year)LFA indices ( ％ )Stability Infiltration NutrientcyclingBulkDensity( g / cm３ )Grass Cover( ％ )Plant Density( no ./ m２ )MicrobeActivity( g of celluloseconsumed)１  ６７０ KBlackearthConventional １２ ".０ ５３ 煙３３ �２３ \１ 乔.７ ０ 殮.８ ３ n.０ ０ 墘.０４Cell １２ ".８ ５８ 煙３３ �２６ \１ 乔.６ １１ *.８ ２ n.０ ０ 墘.０２２  ６７０ GreyearthConventional １  .６ ５１ 煙２７ �２１ \１ 乔.５ ２ 殮.９ ２ n.６ ０ 墘.０１Cell １２ ".８ ５１ 煙３０ �２６ \１ 乔.５ ５ 殮.９ ３ n.３ ０ 墘.２１３  ４９０ BlackearthConventional ４  .３ ３５ 煙３７ �３１ \‐ ９ 殮.７ １２ }.１ １２ 噰.１４１Cell １ .７ ５９ 煙５７ �５４ \‐ ２６ *.５ ２１ }.６ ９ w.２９１４  ５９０ GreyclayConventional ４  .０ ‐ ‐ ‐ ‐ ７９ *.０ ‐ ‐Cell ０  .１ ‐ ‐ ‐ ‐ ６６ *.０ ‐ ‐１ These data refer to tensile strength of cotton stripSites 1 and 2 These sites are on the same property .On Site １ ,cell grazing exhibited a ５０％ increase in the frequency of anaturalised legume ( Rhynchosiaminima) compared to the conventional . There were substantial differences in the cyanobacteriaspecies between cell and conventional grazing . Nitrogen‐fixing cyanobacteria were present on both sites .Site 3 Biological soil crusts were present under cell grazing but not under conventional grazing .Site 4 There were no significant changes in bulk density over the graze‐rest period under cell grazing .However ,soil porosity ( P＜ ０ .０１) and infiltration rate ( P ＜ ０ .１ ) were both significantly higher at the end of the rest period compared to the end of theprevious graze period . Bulk density was significantly higher and soil moisture holding capacity lower at １０‐３０ cm ,and porositylower in the １‐５ and ６‐７ cm depths under conventional compared to cell grazing .Selective grazing occurred in both grazingsystems .Rainfall amounts and timing in the rest period appeared to be the critical factors affecting both pasture recovery andchanges in the soil physical properties in cell grazing .Conclusions The results indicate that ,under a well‐managed grazing enterprise in a range of environments ,many ecosystemparameters perform at a higher level under cell grazing than conventional grazing . Current work includes a wider range ofenvironments and includes a focus on whether the rest‐graze periods under cell grazing can enhance the activity of biological soilcrusts ,particularly the N‐fixing cyanobacteria . It is anticipated that further results may provide clearer guidelines for grazingmanagement to enhance ecosystem functioning and consequent sustainable livestock productivity .

Ecosystem Response to Cell Grazing in Australian Rangelands

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Ecosystem Response to Cell Grazing in Australian Rangelands

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