Pak. J. Weed Sci. Res. 10(3-4):169-174, 2004

Dominant Weed Species of Potato Crop in

Mountain-Continental Part of Montenegro

Stešević Danijela^[1] and Jovović Zoran^[2]

Abstract

In this paper we throw light on dominant weed species of potato crop agrophytocenosis in mountainous continental part of Montenegro. Although potato is one of the main food plants for local population, with long tradition of cultivation, data about its weed flora are insufficient and incomplete. In 1998 through the project of investigations of different ways of weed control of potato crop in mountainous continental part of Montenegro we started systematic investigations of its weed flora. The data revealed that 51 weed species were registered, while dominant group of consists of Convolvulus arvensis (21.6%), Anthemis arvensis (9.9%), Sinapis arvensis (6.5%), Bilderdickya convolvulus (6.0%) Galeopsis tetrahit (5.6%), Chenopodium album (5.3%) and Fumaria officinalis (5.1%). The agrophytocenosis had terophytic character (54.9%), but with significant participation of perennial forms (45.1%). Convolvulus arvensis is the most prevalent weed in the study area.  

Key words: Potato weeds Montenegro Convolvulus arvensis L. Anthemis arvensis

Introduction

Yield losses from weeds are huge and diverse and they reflect themselves the best way through decrease of quantity and very often through decrease of quality of gotten product (Kojić and Šinžar, 1985). Plasticity of genotype, high adaptability on different environmental conditions and wide ecological prevalence has made weeds as powerful competitors to planted crop. Although they are consumers of water, food and light, they make difficulties or even unable land cultivation and implementation of agricultural techniques. Further they are hot spots and hosts of pests and different diseases. In order to successfully fight the weed problem, i.e. to choose appropriate agro-techniques, it is important to understand biology and ecology of dominant weed species (Kojić and Šinžar, 1968; Šinžar et al., 1992; Mišović et al., 1992). Since in the mountainous-continental part of Montenegro, potato is one of the main crops, we directed our investigation to this culture and its weeds as following and non-separable complex.

Materials and Methods

Investigations on impact of different ways of potato crop’s weed control were undertaken in period 1998-2000, in Vrulja area (Pljevlja district, altitude cca 900m), on alluvial soil type. The field experiment was carried in randomized complete block design with 5 repetitions, with elementary plots not treated with herbicides, surface of 25 m˛. Preceding crop of potato in 1998 was natural grassland while in 1999 and 2000 potato was grown in repeated seeding. Basic land cultivation with fertilizing, in all 3 years was done in spring at the depth of 30 cm. Preceding preparation with rolling disk harrow and hoe was done one week before planting. NPK fertilizer @1000 kg ha^-1 in 15:15:15 was used. Potato top dressing was done with KAN (25%), just before hilling in ratio 259 kg ha^-1.

Estimation of weed infestation was done by qualitative-quantitative method at square plots, 3 times during vegetation season, the first one 10 days before potato flowering, the second one in the phase of full flowering and the third one at the end the flowering period of potato. Determination of weed species was done in accordance with Rohlena (1941-42), Deyl (1964), Domac (1973), Šarić (1991), and nomenclature was adjusted with Flora Europaea I-V (Tutin et al., 1964-1980; Tutin et al., 1991).  Life forms have been defined by Stevanović (1992).

Agro-Ecological Conditions

Vrulja is placed in the mountainous-continental region of Montenegro, at altitude of 900 m. The climate belongs to moderate–continental type, with the average temperature of 6.8˚C and the average annual precipitation of 827 l/ m˛. Average temperature during growing season is 12-14˚C and 53% of the total annual precipitation is received then. Such conditions are extremely good for the planted crop but also for the weed flora. During the period of three years long investigations thermal conditions have not changed significantly compared to the long-term averages. Precipitation analysis during growing season of potato indicates that the amount of precipitation in 1998 and 1999 was higher as compared to the average during the recent years, which was good for the growth and development of potato but weeds as well. During growing season 2000, precipitation was below the long-term average so the potato yield as well as weed infestation was lower.

The land belongs to alluvial-diluvia type, by the texture classification it belongs to sandy clay type. It has a good permeability but weak retention capacity. The humus content decreases with depth, from 3.5 in the surface layer to 1.7% in the layer up to 60 cm of depth. It is of acid reaction (pH 5.7-6.5). The land is insufficiently fed with elements of plant food, phosphorus in the first place (Table-1). It is of medium productive features in terms of productivity values.

Таble-1.           Chemical features of the soil of investigated locality

Results And Discussion

            Taxonomic qualitative analysis of potato agrophytocenosis in mountainous-continental part of Montenegro (Vrulja- Pljevlaj district), showed presence of 51 weed species, belonging to 46 genera and 23 families (Table-2). Comparing this number with 36 weed species registered during investigations of potato agrophytocenosis in mountainous area of Koane (Mišović et al. 1992), we notice the great floristic richness in the study area. Adding the information that phytogeographic analysis resulted with presence of 33 floral elements (Stešević and Jovović, 2004- in press) we conclude that potato agrophytocenosis at Vrulja locality, in mountainous-continental part of Montenegro is rich as well as diverse.  Higher number of grassland species is explained with the fact that in the first year of investigation, potato crop was preceded by natural grasslands (on which herbicides had never been applied before) and also with possibility of introduction from surrounding grassland ecosystems. Dominant group of weed species gotten as the sum of 3 years long systematic investigations in field, with condition that the abundance of each species was equal or more than 3 plants m^-˛ consists of: Convolvulus arvensis (21.6%), Anthemis arvensis (9.9%), Sinapis arvensis (6.5%), Bilderdickya convolvulus (6.0%) Galeopsis tetrahit (5.6%), Chenopodium album (5.3%) and Fumaria officinalis (5.1%). Its participation in agrophytocenosis is nearly 60%. A large number of species are present with low abundance and coverage. According to the Šinžar et al., 1994, these two peculiarities are typical for potato crop in mountainous regions. Opposite to this, lowland’s potato agrophytocenosis is characterized with floristic poorness and quantity richness.

            In the whole series of investigations of different ways of weed control of potato crop in mountainous part of Montenegro, Convolvulus arvensis L. was shown as “always present” in years of investigations as well as in estimations. Phonological observation it belongs to spring-winter group of weeds. It reached maximal abundance in second estimation (3 years average- 16.5 plants m^-˛ or 32.5%, while minimal abundance was marked in the first (9.1 plants m^-˛ or 18.9%). During the years of investigation, composition of weeds in agrophytocenosis was changed so its participation increased from 13.6% in 1998, to 37.1% in 2000. Convolvulus is perennial, with strong, deep and on several levels horizontally branched roots with the ability of vegetative reproduction (alongwith seeds). Because of this peculiarity, mechanical way of treatment should not be put on the first plan, because cutting the underground parts of the plant contributes to its spreading. Chemical way of treatment expressed stronger effect on biomass that on number of individuals. Between tested products Sencor, Sencor + Fusilade super were the most efficient ones (Stešević and Jovović, 2003; Jovović and Stešević 2003).

            Anthemis arvensis L. as the second dominant weed species of potato crop of investigated area was present with 6.6%. It reached maximal abundance in 3^rd estimation (8.9 plants m^-˛ or 13.4%%) and minimal in the first one (2.2 plants m^-˛ or 4.6%). By years of investigation in 1998. it was the most abundant species with 21.5 plants m^-˛ or 25.3%, while in the 2000, abundance decreased to 1.2% (Table-2). As the rest of the species from group of dominant weeds Anthemis belongs to annuals. In general biological spectrum of potato agrophytocenosis in continental part of Montenegro terophytes participate with 54.9% while perennials with 45.1%. The spectrum is in correlation with the rule that increase of altitude and change of agro ecological conditions induces increases of hemi cryptophytic and geophytic forms in general weed infestation (Šinžar et al. 1994; Jovović et al., 2000).

            Observing the dominant group of potato crop weeds in general, efficiency of mechanical way of control was shown as irrelevant. Application of herbicides Sencor + Fusilade super expressed high efficiency especially at Anthemis and Galeopsis. Anthemis left the agrophytocenosis after the first year of treatment while Galeopsis did it after the second year. Mentioned herbicide tank mixture also affected other weed species through decrease of number of individuals as well as its biomass (Stešević and Jovović, 2003). Sinapis arvensis L., the third dominant weed species was present with 6.5% density. It reached its highest abundance in the first estimation and the first year of investigation, while minimal values are noted in the third estimation and in the third year (Tables-2&3). Other species from group of dominant one are Bilderdickya convolvulus L., Galeopsis tetrahit, Chenopodium album, and Fumaria officinalis, express some peculiarities in changes in abundance and biomass during the years of investigations and estimations (Table-4). Opposite to all other weed species, abundance of Chenopodium album was increasing during the years of investigations, and reached its maximal value in 2000 (Table-4).

               Among all mentioned peculiarities of potato crop weeds on investigated locality (abundance and biological-ecological characters), we conclude that with regular choice, in time and consequent weed prevention, extraordinary results in weed control can be achieved

Table-2.     Floristic composition of potato agrophytocenosis in mountain continental part of Montenegro (Vrulja)

Table-3.  Floristic composition of dominant group of weeds of potato agrophytocenosis in mountain-continental part of Montenegro (by years of investigations)

Table-4.     Floristic composition of dominant group of weeds of potato agrophytocenosis in mountain-continental part of Montenegro (by each estimation for 3 years long period)

Conclusions

            During the 3 years long investigation of potato weed snooze in mountain continental part of Montenegro we registered 51 weed species, while dominant group of dominant ones consists of Convolvulus arvensis (21.6%), Anthemis arvensis (9.9%), Sinapis arvensis (6.5%), Bilderdickya convolvulus (6.0%) Galeopsis tetrahit (5.6%), Chenopodium album (5.3%) and Fumaria officinalis (5.1%). The agrophytocenosis had terophytic character (54.9%), but with significant participation of perennial forms (45.1%).

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