Maastiku mõju mesilaselaadsete arvukusele talirapsi põllul ja rapsi võit tolmeldamisest
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Kuupäev
2016
Kättesaadav alates
alates 30.05.2021
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Abstrakt
Talirapsi kasvatatakse Eestis võrdlemisi suurtel aladel ning ta pakub head korjeala
putuktolmeldajatele, kelle arvukus on nii maailmas kui ka Eestis vähenenud. Seetõttu on
vajalik täpsemalt teada saada, kas ja kuidas mõjutavad erinevad põllumajandusmaastikul
esinevad maastikuelemenditüübid putuktolmeldajate arvukust talirapsi põllul ja kas raps
võidab putuktolmeldamisest.
Esimese katse käigus selgus, et rohtse põlluserva ja puiskoridoriga piirnevatel põldudel oli
arvukamalt putuktolmeldajaid, kuid nende arvukus vähenes looduslike ja poollooduslike
koosluste osatähtsuse suurenemisel.
Teise katse käigus selgus, et putuktolmlemise välistamisel oleks rapsi saak väiksem, millest
järeldub, et putuktolmlemisel on arvestatav positiivne mõju rapsi saagile. Kuigi 2014. aastal
teostatud katses ei leitud olulist seost putuktolmeldajate arvukuse ja rapsisaagi vahel, oli
tõenäoliselt põhjuseks putuktolmeldajate väga madal arvukus põllul.
Käesoleva töö käigus välja tulnud tulemuste põhjal võib järeldada, et erinevatel
maastikuelemenditüüpidel, eriti rohtsel põlluserval ja puiskoridoril on soodustav mõju
putuktolmeldajate arvukusele ja seetõttu on oluline säilitada põllumajandusmaastikus
looduslikke ja poollooduslikke kooslusi. Samas tuleb pöörata endisest rohkem tähelepanu
tolmeldajate arvukuse soodustamisele, sest liiga madal arvukus tootmispõldudel ei taga
piisavat tolmeldamist kindlustamaks positiivset mõju talirapsi saagikusele.
Oilseed rape (Brassica napusL.) is grown in fairly large areas in Estonia and offers a good gathering area for pollinators whose abundance has declined in the whole world, including Estonia. Hence, knowing more about if and how different commonly occurring landscape elements influence the abundance of insect pollinators in winter oilseed rape fields and how does oilseed rape benefit from it is a necessity. The results of the first experiment show that pollinators were more abundant on fields bordered with herbaceous linear and woody linear elements, but their abundance decreased with higher abundance of natural and semi-natural habitats. During the second experiment it appeared that the exclusion of pollinators led to a lower pod yield suggesting that insect pollination has a positive impact on oilseed rape yield. On the contrary, the study conducted in 2014 showed no relationships between the abundance of pollinators in the field and oilseed rape yield, however, this could be explained by the overall low abundance of pollinators that year. It can be concluded from the results of the current study, that different landscape element types, especially herbaceous linear and woody linear elements, have a positive effect on the abundance of pollinators. Therefore, it is important to preserve natural and semi-natural habitats in the agricultural landscape. Meanwhile, there should be an increased focus on supporting the abundance of pollinators, as a low pollinator abundance does not ensure a positive impact on winter oilseed rape yield.
Oilseed rape (Brassica napusL.) is grown in fairly large areas in Estonia and offers a good gathering area for pollinators whose abundance has declined in the whole world, including Estonia. Hence, knowing more about if and how different commonly occurring landscape elements influence the abundance of insect pollinators in winter oilseed rape fields and how does oilseed rape benefit from it is a necessity. The results of the first experiment show that pollinators were more abundant on fields bordered with herbaceous linear and woody linear elements, but their abundance decreased with higher abundance of natural and semi-natural habitats. During the second experiment it appeared that the exclusion of pollinators led to a lower pod yield suggesting that insect pollination has a positive impact on oilseed rape yield. On the contrary, the study conducted in 2014 showed no relationships between the abundance of pollinators in the field and oilseed rape yield, however, this could be explained by the overall low abundance of pollinators that year. It can be concluded from the results of the current study, that different landscape element types, especially herbaceous linear and woody linear elements, have a positive effect on the abundance of pollinators. Therefore, it is important to preserve natural and semi-natural habitats in the agricultural landscape. Meanwhile, there should be an increased focus on supporting the abundance of pollinators, as a low pollinator abundance does not ensure a positive impact on winter oilseed rape yield.
Kirjeldus
Märksõnad
magistritööd, tolmeldajad, raps