Clarke-Hill, W. J.

Goulter, C. L.

Knight, Trevor L.

White, Todd A.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress The Impact of Different Grassland Land‐Uses on Earthworm Populations in a New Zealand Fragi‐Pallic Soil Todd A. White AgResearch, New Zealand Trevor L. Knight AgResearch, New Zealand C. L. Goulter AgResearch, New Zealand W. J. Clarke-Hill AgResearch, New Zealand 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/21/2-2/4 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 Ⅰ 　 瞯 ]349　 瞯Grasslands/Rangelands Resources and Ecology ——— Soil Quality and Plant NutritionThe impact of different grassland land‐uses on earthworm populations in a New Zealand fragi‐pallic soilT . A . W hite , T . L . K night , C . L . Goulter and W . J . Clarke‐H illA gResearch L incoln , Priv ate Bag 4749 , Christchurch 8140 , New Zealand . E‐mail : todd .white＠ agresearch .co .nzKey words : earthworms , cattle grazing , sheep grazing , mowing , fallow , irrigation , nitrogen , New ZealandIntroduction In the North Otago region of New Zealand摧s South Island , the first stage of a new irrigation scheme has recentlybeen completed allowing land use to change from dryland sheep farming ( １０ stock units/ ha) to more intensive irrigated dairyfarming ( ＞ ２０ s .u ./ ha) . The implications for the pasture and soil resources of this region ( pallic soils characterised by weakstructure and a compact fragipan subsoil horizon ) are largely unknown . Reported here are the impacts of different land‐usetreatments on earthworm populations .Methods Factorial combinations of harvest method ( cattle grazing , sheep grazing , mowing and pasture fallow ) , pasture species[ perennial ryegrass ( R) and tall fescue ( F) ] and irrigation ( with and without ) treatments were applied to ２４ paddock pairs .Enough nitrogen ( N ) was applied ( in split applications) to one paddock of each pair so that N was not limiting pasture grow th( see White & Knight ２００７ for details) . In winter ２００６ and ２００７ , four to eight １０ cm wide × ２０ cm deep cores were taken fromeach paddock and all earthworms were found and counted .　 　 　 　 Figure 1 Total earthworm number (million per ha) underdi f f erent land‐use treatments over two w inters .Results Irrigation , harvest method , pasture speciesand nitrogen all affected earthworm numbers( Figure １ ) . There were fewer worms under cattlegrazing compared to sheep grazing , mowing andfallow in ２００６ . In ２００７ , there were fewer wormsunder cattle grazing and mowing than fallow whichhad less worms than sheep grazing ( P ＜ ０ .００１ ) .Overall , there were ８０ and ７３％ more earthworms inirrigated soil compared to dryland soil in ２００６ and２００７ , respectively ( P ＜ ０ . ００１ ) . However , theincrease in worms due to irrigation in ２００６ wasgreater under sheep grazing and fallow than cattlegrazing and mowing ( P ＜ ０ .０１ ) . There were moreearthworms in ryegrass compared to fescue paddocksbut only when combined with fallow ( ２００６ and２００７) and sheep grazing ( ２００７ only ) ( P ＜ ０畅０３ ) .Adding N had no effect on worm numbers in ２００６ .In ２００７ , there were fewer worms overall in plus‐Npaddocks but this effect was only significant whencombined with irrigation and cattle grazing ormowing ( P ＜ ０ .０５) .Conclusions Irrigation increases whereas cattlegrazing generally decreases worm abundance . Thegreater number of earthworms in irrigated soilagrees with previous research and relates to their need for a moist well‐aerated environment ( Lee １９８５ ) . Pasture grazing /harvesting impacts on earthworm populations have received little research attention . Fewer earthworms under cattle grazingmay be related to greater soil bulk density , lower macroporosity and injury from trampling (Bruyn & Kingston １９９７) . Futureresearch will examine worm biomass and earthworm species abundance to help understand how land use change may affect thepotential beneficial processes performed by earthworms in soil .Acknowledgement This research was made possible by the generous support of landowners Grant and Elle Ludemann . DavidBaird performed the statistical analysis and funding was provided by FRST .ReferencesBruyn , L .A . & T .J . Kingston ( １９９７) . Effects of summer irrigation and trampling in dairy pastures on soil physical propertiesand earthworm number and species composition . A ustralian Journal o f A gricultural Research , ４８ , １０５９‐１０７９ .Lee , K .E . (１９８５) . Earthworms . Their ecology and relationships with soils and land use . Academic Press , Sydney .White , T .A . & T .L . Knight ( ２００７ ) . Pasture yield and composition under different land uses in North Otago RollingDownlands . Proceedings o f the New Zealand Grassland A ssociation , ６９ , in press .ro 12 2006 .c <ii 10 Q. C 8 ~ 6 I 4 (/) E 2 6 :s: 0 ro 12 2007 .c <ii 10 Q. C 8 ~ 6 E (/) 4 E 2 ~ 0 Dryland Irrigated Dryland lrrig ated Dry land Irrigated Dry land Irrigated Cattle Sheep Mown Fallow 

The Impact of Different Grassland Land‐Uses on Earthworm Populations in a New Zealand Fragi‐Pallic Soil

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2516&amp;context=igc

The Impact of Different Grassland Land‐Uses on Earthworm Populations in a New Zealand Fragi‐Pallic Soil

Abstract

Similar works

Full text

Available Versions

University of Kentucky