The weed composition in an orchard as a result of long-term foliar herbicide application

Maria Licznar-Małańczuk,Iwona Sygutowska

doi:10.5586/aa.1685

Maria Licznar-Małańczuk, Iwona Sygutowska

Open Access

https://doi.org/10.5586/aa.1685

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Abstract

The weed composition and the dominance of individual species occurring in an orchard were assessed at the Research Station of the Wrocław University of Environmental and Life Sciences, Poland, during the first 10 years after orchard establishment. ‘Ligol’ apple trees were planted in the spring of 2004 (3.5 × 1.2 m). Foliar herbicides were applied in 1 m wide tree rows twice or three times per each vegetation period. In the inter-row spaces, perennial grass was maintained.Ten years of maintenance of herbicide fallow contributed to a change in the weed composition in the orchard. It changed as a result of different responses of the most important weed species to the foliar herbicides. Total suppression of Elymus repens was observed in the first year after planting the trees. Convolvulus arvensis, Cirsium arvense, and other perennial weeds, completely disappeared in the succeeding periods. The maintenance of herbicide fallow did not affect the abundance of Taraxacum officinale. The percentage of the soil surface covered by Trifolium repens and Epilobium adenocaulon, perennial weeds with considerable tolerance to post-emergence herbicides, increased during the fruit-bearing period of the trees. The abundance of these weeds was significantly reduced only in the rows with the stronger growing trees on the semi-dwarf P 2 rootstock. Stellaria media was the dominant annual weed. Senecio vulgaris, Poa annua, Capsella bursa-pastoris, and Lamium spp. were also frequently observed. A significant increase in the abundance of annual and perennial weeds was found in the tree rows as a result of improved water availability after a period of high precipitation.

Highlights

The species richness of weeds is higher in an orchard than in a crop field that is plowed every year [1]
In the successive 10 years (2004–2013), the diversity of weed species was observed, which was correlated to precipitation, especially in May and June (Tab. 1, Tab. 2)
Stellaria media was most dominant among the annual species in the herbicide fallow

Summary

Introduction

The species richness of weeds is higher in an orchard than in a crop field that is plowed every year [1]. According to Lipecki [2,3], in the temperate climate only 20 species play an important role in orchards and berry fruit plantations. When applied for many years, foliar herbicides can be an optimal method of weed suppression in fruit tree rows [10,11], bringing an overall reduction of the weed species number [12]. Herbicide fallow favors hemicryptophytic weeds [13] and can even contribute to invasion by perennial weed species. In the periods between herbicide applications, abundant populations of annual species, therophytes, tend to appear in the orchard [8,14]

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