Jacobo, E. J.

Kessel, K.

Rodriguez, A.

Vilarino, J.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings 21st International Grassland Congress / 8th International Rangeland Congress Changes on Floristic Composition of Flooding Pampa Rangeland by the Use of Glyphosate A. Rodriguez Universidad de Buenos Aires, Argentina E. J. Jacobo Universidad de Buenos Aires, Argentina J. Vilarino Universidad de Buenos Aires, Argentina K. Kessel Universidad de Buenos Aires, Argentina 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/21/1-3/16 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 ]115　 瞯Grasslands/Rangelands Resources and Ecology ——— Ecology of Grasslands/RangelandsChanges on floristic composition of Flooding Pampa rangeland by the use of glyphosateA .Rodriguez , E . Jacobo , J . V ilarino , K . KesselDepartamento de P roducción A nimal , Facultad de A gronomí a , Universidad de Buenos A ires . A v . San Martí n 4453 , BuenosA ires 1417 , A rgentina . E‐mail :arodrigu＠ agro .uba .arKey words : temperate grasslands , basal cover , functional groupsIntroduction To increase winter forage production of native rangelands of Flooding Pampa , a technique based on sprayingglyphosate herbicide in late summer has been widespread during the last decade in this region . Glyphosate application eliminatesgreen vegetation growing in late summer , improving germination and establishment of cool season ( C３ ) annual grasses , thatenhaces winter forage and meat production . We postulate that this technique would negatively affects plants that vegetateduring summer , such as perennial grasses and legumes , decreasing floristic diversity and deteriorating the rangeland .Materials and methods In a commercial farm located in the Flooding Pampa region , we selected １３ paddocks dominated by nativerangeland (３０‐１２０ ha each) and used them for cow‐calves operation . Five paddocks have never been treated with glyphosate andother ８ paddocks have been treated with glyphosate in late summer from the last ５ years consecutively . In spring ( October‐November ２００６) and summer ( January‐February ２００７ ) , plant basal cover and species composition were estimated using thestep‐point method along five １０‐m‐long transects (２００ points per transect) randomly placed in each paddock . Plant species weregathered in functional groups ( Jacobo et al . , ２００６) . Kruskal‐Wallis test by ranks was used .Results Basal cover of C３ annual grasses in glyphosate‐treated paddocks was significantly higher than that of non‐treated ones( Figure １( a ) and １ ( b) ) , showing the effectiveness of glyphosate application to enhance winter forage offer . Nevertheless ,glyphosate‐treated paddocks achieved lower basal cover of C３ perennial grasses and warm season legumes in spring and summer( Figure １( a) and １( b) ) , which may be consequence of the deleterious effect of this systemic herbicide in late summer over thesefunctional groups , which are growing actively . Basal cover of C４ creeping grasses was higher in glyphosate‐treated paddocks insummer ( Figure １( b) ) , consistently with the higher tolerance of Cynodon dacty lon , the main species of this functional group ,to this herbicide . Species richness was significantly lower in glyphosate‐treated paddocks respect to non‐treated ones ( ６ .８ vs .１２ , p ＜ ０ .０１) , suggesting the reduction of vegetation diversity .Figure 1 Basal cover ( ％ ) o f f unctional groups grow ing in sp ring ( a) and summer ( b ) . Functional groups : C3 AG : C3annual grasses ; C3 PG : C3 perennial grasses , C4 TG : C4 tussock grasses ; C4 CG : C4 creep ing grasses ; W SLeg : w arm seasonlegumes ; CSLeg : cool season legumes and Forbs . 倡 倡 p ＜ 0 .01 倡 p ＜ 0 .05 .Conclusions The technique of spraying glyphosate in late summer in native rangelands of Flooding Pampa reduces basal cover offunctional groups of great forage value and species richness , deteriorating this resource .RefereneJacobo E . , Rodr guez A . , Bartoloni N . , Deregibus VA , (２００６) . Rotational grazing effects on rangeland vegetation at a farmscale . Rangeland Ecology and Management , ５９ , ２４９‐２５７ .(a) .... ~ 40 I 30 J 20 10 Spring (Nov. 2006) ** ** * C3AG C3PG c .TG c .cG WSLeg CSLeg Forbs c::::::::::J Non-treated rangeland (b) Summer (Jan. 2007) 30 C3AG C3PG c . TG c .cG WSLeg CS Leg Forbs c:::::::::J Gliphosate-treated rangeland 

Changes on Floristic Composition of Flooding Pampa Rangeland by the Use of Glyphosate

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=2294&amp;context=igc

Changes on Floristic Composition of Flooding Pampa Rangeland by the Use of Glyphosate

Abstract

Similar works

Full text

Available Versions

University of Kentucky