Analyse van de inlvoed van de morfologie van de onkruiden melganzevoet en vogelmuur op het concurrentievermoge

Bastiaans, L.

Habekotte, B.

Joenje, W.

Kropff, M.J.

Oene, H., van

Werner, R.

Name not available

Competition between a sugar beet crop and populations of Chenopodium album L. and Stellaria media L.

van Oene, H.

NARCIS 

Wageningen Yield 

Netherlands Journal of Agricultural Science 35 ( 1987) 525-528 SYNOPSIS 
Competition between a sugar beet crop and populations of 
Chenopodium album L. and Stellaria media L. 
M. J. Kropff1, W. Joenje2, L. Bastiaansl.2, B. Habekottel.2, H. van Oene1.2 and R. 
Werner1.2 e Department of Theoretical Production Ecology, Agricultural Univer-
sity, P.O. Box 430, 6700 AK Wageningen, Netherlands; 2 Department of Vegeta-
tion Science, Plant Ecology and Weed Science, Agricultural University, Wagenin-
gen, Netherlands) 
Received 9 April1987; accepted 29 July 1987 
Abstract. Competition between a sugar beet crop and populations of Chenopodium 
album L. (fat hen) and Stellaria media L. (chickweed) was studied in field experi-
ments. Fat hen plants reduced crop production by 37 % at a density of 5.5 plants 
per m2, while chickweed reduced crop production by 21 % at a density of 11 clumps 
per m2• Although chickweed populations had a much higher leaf area index, fat hen 
appeared to be the stronger competitor to sugarbeets because fat hen plants grew 
much taller and were able to overgrow the sugar beets. 
Key words: competition, sugar beet, weed, Chenopodium album, Stellaria media 
Introduction. Weeds can reduce crop growth by competition for light, water and 
nutrients, especially in crops such as sugar beets which need a long growing period 
to form a closed canopy. Quantitative information about expected yield losses at 
different weed infestations is required for the development of weed control advi-
sory systems. 
The effect of weeds on crop yield may vary strongly among years (Kropff et al., 
1984). Theoretical studies on crop-weed competition with dynamic simulation mod-
els (Spitters, 1984; Kropff, 1987) have suggested that both relative time of emer-
gence and morphological characteristics, such as plant height and leaf area, may 
strongly influence competitive ability. To analyse the influence of weed morpholo-
gy on competitive ability, a field experiment was designed with sugar beets in mix-
ture with fat hen (Chenopodium album L.) and sugar beets in mixture with chick-
weed (Stellaria mediaL.). 
Materials and methods. In 1985, the growth of sugar beets (Beta vulgaris L. cv. 
Monohil), fat hen (Chenopodium album L.) and chickweed (Stellaria mediaL.) was 
analysed by frequent harvesting of monocultures and a mixture of the sugar beets 
with each of the weed species. The field experiment (a split-plot design with 4 repli-
cates) was performed in Wageningen on a sandy loam soil ( 4 % organic matter) 
with an adequate supply of nutrients and water. Sugar beet plants were grown at a 
spacing of 30 x 30 cm2 (11 plants per m2). The weeds were equally distributed be-
525 
M. J. KROPFF ET AL. 
tween the sugar beet plants. Fat hen was sown at 5.5 plants per m2 in mixture with 
sugar beets and at 11 plants per m2 in monocufture. Chickweed was grown at 11 
clumps of plants (consisting of 10-20 plants per clump) per m2 in mixture with sugar 
beets and in monoculture. The net plot size was 6 x 1.5 m2• Average dates of emer-
gence for sugar beet, fat hen and chickweed were 9 May, 21 May and 20 May, re-
spectively. 
Results and discussion. The time course of sugar beet growth in monoculture and in 
mixtures with fat hen and chickweed is presented in Fig. 1. Crop biomass reduction 
by weed competition first appeared in July and increased in August and September. 
The effect of fat hen on sugar beet production was much stronger than the effect of 
chickweed. Table 1 shows the effect of the weed species on several production char-
acteristics of the sugar beets at final harvest. Total dry matter of the sugar beets was 
reduced 37 % by fat hen and 21 % by chickweed at final harvest. The same pattern 
was found in the sugar yields of the crop (Table 1). Analysis of data on rainfall, soil 
water content and calculated evapotranspiration showed that water stress did not 
occur in the experiment. An analysis with a simulation model of crop growth under 
nitrogen shortage indicated that nitrogen did not limit crop growth in mixture or in 
monoculture. From these results it was concluded that competition for light was the 
main factor causing differences in sugar beet production. 
22 
20 
18 
16 
14 
12 
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with Stellana 
with Chenopodium 
0 ..___...::;;._5..,.0------,10-0-----,-,50 Days after 
emergence 
May June July Aug. Sept. 
Fig. l. Time courses of sugar beet biomass in monoculture and in mixture with fat hen and chickweed. 
526 Netherlands Journal of Agricultural Science 35 ( 1987) 
M. J. KROPFF ET AL. 
Table 1. Supr beet production in monocultures and mixed cultures at ·final narvest in t ha-1 and in% of 
weed-free crop (in parenthesis). Different letters indicate significant difference between treatments (P 
< O.OS, capitals P < 0.01). . · 
Total dry weight (t ha- 1) 
Shoot dry weight (t ha-1) 
Root dry weight (t ha- 1) 
Total fresh weight (t ha-1) 
Sugar content (%) 
Sugar production (t ha-1) 
LAI 
7 
e 
~ 
4 
3 
0 Sugar b~~t 
!IID Ch~nopodium 
I[) St~llaria 
: nci:~ U 
2% y7 
39 ~3 
Height (em) 
1~0 
100 
~0 m B o/c a/s 0 0 Dun [b . 
'~e '/7 
39 ~3 
Sugar beet 
weed-free with Stallaria 
23.1 (100) a(A) 18.2 (79) b (AB) 
8.6 (100) a( A) 6.8 (79) b (AB) 
14.5 (100) a 11.3 (78) ab 
61.9 (100) A 48.9 (79) B 
15.04 a 15.43 b 
9.3 (100) A 7.5 (81) B 
,... 
22j7 2o/9 Oat• 
I""" 
74 139 Days att•r 
~m~rgence 
- --~ ~ 
2~7 2o/9 Oat~ 
74 139 Cays aft~r 
~m~rg~nc~ 
with Chenopodium 
14.6 (63) b(B) 
6.4 (74) b(B) 
8.2 (57) b 
33.1 (53) c 
15.43 b 
5.1 (55) c 
Fig. 2. Top: leaf area index of sugar beets in monoculture and mixtures and development of leaf area of 
fat hen and chickweed in mixture at various dates. 
Bottom: plant height of sugar beets in monoculture (B) and mixture and fat hen (C) and chickweed (S) in 
mixtures. 
Netherlands Journal of Agricultural Science 35 ( 1987) 527 
M. J. KROPFF ET AL. 
Chickweed had a much higher LAI than fat hen (Fig. 2). However, fat hen plant~ 
had a stronger effect than chickweed on sugar beet growth, probably because the 
fat hen plants were taller and able to shade the sugar beets (Fig. 2). This effect illus-
trates the importance of the factor plant height in crop weed competition. 
In the 1985 experiment fat hen plants reduced crop production by 37 %, whereas 
in a similar field experiment carried out in 1984 fat hen plants reduced crop produc-
tion by 78 %. Analysis of these two experiments with a simulation model of crop 
weed competition showed that the difference between years was mainly attribut-
able to differences in relative times of emergence of the crop and the weeds: in 1984 
the weeds emerged simultaneously with the crop, whereas in 1985 the fat hen plants 
emerged 12 days after the crop (Kropff, 1987). These results suggest that quantifi-
cation of damage relationships should not be based upon weed density alone but on 
a combination of weed density and relative time of emergence. 
References 
Kropff. M. J .• F. J. H. Vossen, C. J. T. Spitters & W. de Groot, 1984. Competition between a maize 
crop and a natural population of Echinochloa crus-galli (C.). Netherlands Journal of Agricultural 
Science 32: 324-327. 
Kropff. M. J .. 1987. Simulation of crop weed competition. In: Proceedings of the CEC meeting on weed 
control in vegetable crops (in press). 
Spitters. C. J. T .. 1984. A simple simulation model for crop weed competition. In: 7th Symposium on 
weed biology. ecology and taxonomy. (COLUMA-EWRS, Paris), p. 355-366 .. 
This synopsis is based on an undergraduate thesis 1 Konkurrentie tussen het gewas sui-
kerbiet en de onkruiden melganzevoet en muur; veldexperiment en simulatie van 
monocultures' by L. Bastiaans, B. Habekotte, H. van Oene and R. Werner, Depart-
ment of Theoretical Production Ecology, Wageningen Agricultural University, 
1986.126 pp., 44 figs., 27 tables, 105 refs., appendices. 
Available as paper copy (order R075P, f 30 including postage) or microfiches (or-
der R075M, f 17.50 including postage) at: NARD, c/o Pudoc, P.O. Box 4, 6700 AA 
Wageningen, Netherlands (telex 45015 blhwg). 
528 Netherlands Journal of Agricultural Science 35 ( 1987) 


Competition between a sugar beet crop and populations of Chenopodium album L. and Stellaria media L.

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