Era­di­ca­ting a­liens: poi­son or pull them out?

Knysna-Plett Herald - - News | Nuus -

Vi­gorous re­gro­wth of in­va­si­ve a­lien plants, fol­lo­wing a fi­re (such as the Knys­na ex­am­ple), le­a­ves lan­do­w­ners and land ma­na­gers with the daun­ting task of de­a­ling with a ma­jor pro­blem.

Lan­do­w­ners in fa­vour of hand-pul­ling weeds ar­gue that w­hen ap­plying her­bi­ci­de, much da­ma­ge is do­ne to in­di­ge­nous re­gro­wth, which will al­so pe­rish as a re­sult of the in­dis­cri­mi­na­te use of her­bi­ci­de.

The­re is al­so a sig­ni­fi­cant num­ber of lan­do­w­ners who feel that her­bi­ci­des are de­t­ri­men­tal to a he­althy na­tu­ral en­vi­ron­ment, which ul­ti­ma­te­ly will cas­ca­de do­wn to hu­man and a­ni­mal wel­l­being in con­ta­mi­na­ted wa­ter and food. Ex­po­sing seed­bed

Ot­hers ar­gue that, by hand-pul­ling weeds, the un­der­lying seed­bed be­co­mes ex­po­sed, al­lo­wing ma­ny new seed­lings ex­po­su­re to sun­lig­ht, trig­ge­ring re­ne­wed and im­me­di­a­te re­gro­wth.

Al­so, by hand-pul­ling lar­ger plants, chan­ces are that the (un­in­ten­ded) ef­fect, by rip­ping deep and ex­ten­ded root sys­tems from the soil, may trig­ger e­ro­si­on on steep slo­pes, le­a­ding to furt­her land de­gra­da­ti­on.

Ul­ti­ma­te­ly, the sca­le and na­tu­re of the re­gro­wth pro­blem and, per­haps mo­re im­por­tant­ly, the as­so­ci­a­ted cost in de­a­ling with the mat­ter, be­co­me the de­ci­ding fac­tors. Cost a se­ri­ous fac­tor

W­hen de­a­ling with se­ver­al hec­ta­res sub­ject to in­va­si­ve a­lien re­gro­wth, cost to com­pa­ny be­co­mes a se­ri­ous fac­tor.

Hand-pul­ling of weeds on any sca­le is la­bour in­ten­si­ve and the­re­fo­re cos­t­ly, and the win­dow to ap­ply hand-pul­ling is s­mall in com­pa­ri­son to the in­va­si­ve a­lien plant ra­te of re­gro­wth.

Cos­ts as­so­ci­a­ted with de­a­ling with ma­tu­re and se­mi-ma­tu­re in­va­si­ve a­lien plants, com­pa­red to young (be­low knee heig­ht) plants, holds an ex­po­nen­ti­al cost in­cre­a­se in e­ra­di­ca­ti­on ef­forts.

W­he­re hand-pul­ling of weeds (es­pe­ci­al­ly at an e­ar­ly s­ta­ge, and on a ma­na­ge­a­ble pie­ce of land may be an op­ti­on to lan­do­w­ners, w­hen de­a­ling with lar­ge-sca­le in­va­si­on, her­bi­ci­de ap­pli­ca­ti­on be­co­mes a vi­a­ble and pre­fe­ra­ble op­ti­on.

Re­gis­te­red her­bi­ci­des, w­hen ap­p­lied re­spon­si­bly and ac­cor­ding to spe­ci­fi­ca­ti­ons, hold litt­le ne­ga­ti­ve im­pli­ca­ti­ons for the en­vi­ron­ment. Mo­re in­for­ma­ti­on

SCLI is a pu­blic plat­form for lan­do­w­ners and land ma­na­gers with an in­te­rest in the con­t­rol and e­ra­di­ca­ti­on of in­va­si­ve a­lien plants. Mo­re in­fo: www.scli.org.za

Port Jack­son sho­wing signs of de­te­ri­o­ra­ti­on af­ter i­ni­ti­al her­bi­ci­de ap­pli­ca­ti­on.

Hand-pul­ling of rooi­krans on steep slo­pes on the We­stern He­ads (Knys­na).

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