scholarly journals Growth of weeds in cereal populations

1972 ◽  
Vol 44 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Leila-Riitta Erviö

The weeds in this study consisted mainly of Chenopodium album, Stellaria media, Viola arvensis, Polygonum convolvulus, P. aviculare and P. lapathifolium. Increasing cereal seed rates reduced the numbers, individual weights and total yields of the most abundant species, Chenopodium album. The decreases in plant weight and total yield of the weeds were very steep when the cereal seed rate was raised from 25 to 200 kg/ha. Increases in the seeding rate reduced the total yields of weeds rather than their numbers. The effect of the cereal on weeds became apparent as soon as heading of the cereal was complete and was further enhanced by prolonged competition. Added nitrogen raised the weed yields at cereal seed rates of 25—100 kg/ha but reduced them at higher seed rates. Nitrogen also raised the yield and individual plant weight of C. album. Cereal seed rate did not affect the nitrogen, phosphorus, potassium, calcium and magnesium contents of the weeds grown among the crop. Due to larger total weed yields, however, the amounts of these nutrients in the weeds were higher in sparse than in dense cereal populations.

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Kamlapati Chamoli

Weed commonly called ‘khar- kabad’ in Uttarakhand or ‘kharpatvar’ in India, and is one of the major biological constraints that limits crop productivity. The present communication pertains to survey and inventory of weed flora in Agastyamuni block of district Rudraprayag, Uttarakhand. The study was based on extensive and intensive field survey made during July 2018 to October 2019. During the study period the authors have reported a total 312 species belonging to 188 genera and 54 families from dicots, monocots and pteridophyta. Asteraceae was found to be the most dominant family followed by Poaceae, Lamiaceae and Fabaceae respectively. Survey results also revealed that most of the recorded species were annuals followed by perennials and biennials. Most abundant species were Bidense pilosa, Chenopodium album, Erigeron canadensis, Cynodon dactylon, Gallinsogo parviflora, Eupatorium adenophorum, Oxalis conrniculata, Parthenium hysterophorus, Lantana camara, Soncchus arvensis, Ageratum conozoides, Plantago major, Ganaphallium lutealbum, Siegesbeckia orientalis, Youngia japonica, Amaranthus virids, Stellaria media and Phalaris minor. Many weeds are ethnobotanically important and utilized by the local community.


2013 ◽  
Vol 39 (1) ◽  
pp. 129-141 ◽  
Author(s):  
Leszek Malicki ◽  
Czesława Berbeciowa

We have determined the contents of N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn in winter wheat, spring barley, sugar beets and winter rape, as well as in the most common weed species infesting these crops. It was established that the percentage of mineral components in the dry matter of the majority of weeds is higher than in that of the cultivated plants. The most dangerous weed species competing with plants for the investigated nutrients were: <i>Chenopodium album, Cirsium arvense, Convolvulus arvensis, Polygonum convolvulus, Sonchus arvensis</i> and <i>Stellaria media</i>.


1983 ◽  
Vol 55 (5) ◽  
pp. 385-423
Author(s):  
Mikko Raatikainen ◽  
Terttu Raatikainen

Koko Suomen syysvehnäpelloista tutkittiin v. 1972-1974 otannalla 0.8 %. Tällöin todettiin, että syysvehnää viljeltiin yleensä suurilla tiloilla, vanhoilla pelloilla, savimailla, suurilla lohkoilla ja lähellä talouskeskusta. Syysvehnälohkoilla oli käytetty ennen syysvehnän viljelyä hyvin usein leikkuupuimuria ja herbisidejä. Esikasvina oli tavallisimmin syysvehnä tai muu vilja, vaikka neuvonta vastusti monokulttuuria. Peruslannoituksessa noudatettiin yleensä ohjeita, jopa ylitettiinkin suositellut käyttömäärät. Lajikesuosituksia yleensä noudatettiin ja uudet lajikkeet otettiin käyttöön muutamassa vuodessa. Kasvinsuojelu, varsinkin peittaus laiminlyötiin usein. Rikkaruohoruiskutuksissa olisi tullut käyttää useammin seosvalmisteita ja oikeata ruiskutusaikaa. Kylvösiemenmäärä oli usein ylisuuri ja kylvökausi liian pitkä, mistä aiheutui yksittäisillä tiloilla haittoja ja sadonmenetyksiä. Valistuneimpien viljelijöiden tiloilla neuvontaa seurattiin ja noudatettiinkin melko nopeasti, mutta osa viljeli perinnäisiä tapojen noudattaen. Helppotajuinen neuvonta otettiin vastaan nopeammin kuin vaikeatajuinen. Neuvonnassa tulisi kiinnittää enemmän huomiota tilakohtaiseen neuvontaan. Syysvehnälohkoilta tavattiin 130 rikkaruoholajia, joista 26 esiintyi yli 16 %:lla peltolohkoista. Rikkaruohoja oli keskimäärin 257 yksilöä tai versoa/ m2. Tiheimmässä kasvoivat syysyksivuotisista Viola arvensis, Matricaria spp., Stellaria media, Lapsana communis ja Myosotis arvensis, kevätyksivuotisista Galeopsis spp., Chenopodium album, Erysimum cheiranthoides, Polygonum aviculare, Myosurus minimus, Gnaphalium uliginosum ja Polygonum convolvulus, ja monivuotisista Agropyron repens. Rikkaruohokoostumus poikkesi ruispeltojen rikkaruohokoostumuksesta joten neuvonnan tulisi kohdistua viljelykasvikohtaiseen neuvontaan. Rikkaruohojen tiheyteen vaikuttivat mm. lohkon etäisyys talouskeskuksesta, lohkon ikä peltona, maalaji, maaperän kosteus, leikkuupuintikertojen määrä, herbisidikäsittelyjen määrä, esikasvi, kylvöaika, kasvukauden vaihe ja viljan peittävyys. Tekijät eivät aina vaikuttaneet suoranaisesti vaan olivat todellisten tekijöiden indikaattoreita.


2010 ◽  
Vol 61 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Krzysztof Heller

„Flax specialists”-weed species extinct in Poland? The results of a research on segetal weed communities in fibre flax in Poland are presented, with respect to different regions of cultivation, and changes in the level of infestation during the past forty years. Observations on composition and abundance of weed infestations were made in fields in six experimental farms at the Institute of Natural Fibres and Medicinal Plants. The observations conducted in the period 1967-2008 did not show the occurrence of weed species from the group of so-called "flax specialists": Lolium remotum Schrank, Spergula arvensis L. subsp. maxima (Weiche) O. Schwarz, Camelina alyssum (Mill.) Thell. and Cuscuta epilinum Weihe Ex Boenn. In Poland, weed populations in fibre flax consist of species typical for cereals and root crops: Chenopodium album L., Polygonum convolvulus L., Viola arvensis Murr., Stellaria media Vill., Lamium amplexicaule L., Thlaspi arvense L., Elymus repens (L.) Gould, and Polygonum nodosum Pers.


1980 ◽  
Vol 28 (4) ◽  
pp. 199-210
Author(s):  
F.T.J.M. Fortuin ◽  
S.W.P. Omta

The cultivation of S. nigrum was studied in West Java. Growth analysis showed that individual plant weight reached 1070 g 113 days after planting. When fruits and leaves were harvested the total yield was 580 g berries/plant (16.5 t/ha) and 28 g leaves/plant (0.8 t/ha). Picking the leaves influenced plant shape, relative growth rate and net assimilation rate. Shading caused a decline in total plant weight and changes in the distribution of biomass; the production of fruits was strongly affected, whereas the production of edible leaves was not affected by 35-60% shade and only moderately affected by 75-85% shade. Leaves from plants grown in shade were larger and thinner than those from plants in full light. There was no indication that the berries were toxic. (Abstract retrieved from CAB Abstracts by CABI’s permission)


Author(s):  
Piotr Markowski ◽  
Adam Józef Lipiński ◽  
Zdzisław Kaliniewicz ◽  
Andrzej Anders ◽  
Elwira Ślesicka ◽  
...  

This study investigates the effect of the seeding rate of two hybrid cultivars of maize harvested for silage on selected, i.e.: physical parameters (stem length, stem diameter, total plant weight and weight of ears with husks), fresh weight yield and ear yield of maize plants. A field experiment was carried out in 2011-2013 on soil of weak rye complex (cv. Kosmo) and a good rye complex (cv. Kixxo). The results were processed by one-way analysis of variance, correlation analysis and regression analysis. The analyses revealed that at constant inter-row spacing of 0.75 m, seeding rate (6.5 to 11.9 seeds∙m-2 for cv. Kosmo and 8 to 12∙m-2 for cv. Kixxo) significantly (&alpha;=0.05) influenced the evaluated parameters. Higher plant density lowered the weight of plants and ears and resulted in lower stem diameter. Plants grown in treatments with lower seeding rates were larger and heavier. In cv. Kosmo, the highest total yield and ear yield were noted at the seeding rate of 11∙m-2. Maize plants cv. Kixxo sown at the rate of 12∙m-2 were characterized by the highest fresh weight yield and the highest yield of ears with husks. A set of equations were developed to analyze the correlations between seeding rate and the physical parameters of maize plants and between seeding rate vs. green fodder yield and ear yield.


2004 ◽  
Vol 18 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Diego J. Bentivegna ◽  
Osvaldo A. Fernández ◽  
María A. Burgos

Chemical weed control with acrolein has been shown to be a lower cost method for reducing submerged plant biomass of sago pondweed in the irrigation district of the Lower Valley of Rio Colorado, Argentina (39°10′S–62°05′W). However, no experimental data exist on the effects of the herbicide on plant growth and its survival structures. Field experiments were conducted during 3 yr to evaluate the effect of acrolein on growth and biomass of sago pondweed and on the source of underground propagules (i.e., rhizomes, tubers, and seeds). Plant biomass samples were collected in irrigation channels before and after several herbicide treatments. The underground propagule bank was evaluated at the end of the third year. Within each treatment, plant biomass was significantly reduced by 40 to 60% in all three study years. Rapid new plant growth occurred after each application; however, it was less vigorous after repeated treatments. At the end of the third year at 3,000 m downstream from the application point, plant biomass at both channels ranged from 34 to 3% of control values. Individual plant weight and height were affected by acrolein treatments, flowering was poor, and seeds did not reach maturity. After 3 yr, acrolein did not reduce the number of tubers. However, they were significantly smaller and lighter. Rhizomes fresh weight decreased by 92%, and seed numbers decreased by 79%. After 3 yr of applications, operational functioning of the channels could be maintained with fewer treatments and lower concentrations of acrolein.


1990 ◽  
Vol 70 (4) ◽  
pp. 1215-1221 ◽  
Author(s):  
IRIS BITTERLICH ◽  
MAHESH K. UPADHYAYA

Field experiments were conducted in 1987 and 1988 to study the effect of lamb’s-quarters (Chenopodium album L.) interference on broccoli (Brassica oleracea L. var. botrytis ’Emperor’) growth and yield. Broccoli growth was initially affected by weed interference at 28–36 d after seeding. Generally, the negative effect of weed interference on broccoli growth increased with increasing weed density and time after seeding. Interference by 15 lamb’s-quarters plants m−2 reduced the biomass of broccoli plants by 71–73% compared to the weed-free control at 57–58 d after seeding. Weed density-crop yield relationship curves showed that one lamb’s-quarters plant m−2 decreased total yield by 18–20% and marketable yield by 22–37%. Lamb’s-quarters reduced the total yield per plot by decreasing the average head weight of broccoli. The number of heads per plot was not affected. Weed interference also reduced the weight of heads classified as marketable (> 10 cm across). However, in 1987 more heads failed to reach a marketable size which resulted in a much smaller marketable yield than in 1988.Key words: Brassica oleracea var. botrytis, broccoli, Chenopodium album L., weed density, weed interference, cole crop


Author(s):  
Г. М. Козелець

Наведено результати досліджень впливу норми висіву і ширини міжрядь на продуктивність коріандру за підзимового та ранньовесняного строків сівби.Встановлено, що кращим строком сівби для коріандру є підзимовий, за якого врожайність плодів становила 1,21 т/га, що більше порівняно із ранньовесняним на 0,30 т/га, або 24,7 %. Для коріандру в умовах північного Степу оптимальною є норма висіву 2,0–2,5 млн сх. нас. на 1 га, яка забезпечила урожайність 1,14–1,15 т/га. Сівба з шириною міжрядь 0,45 м сприяла отриманню врожайності 1,09 т/га, що більше ніж при 0,15 м на 0,06 т/га, або 8,0 %. Вищий рівень врожаю (1,39 т/га) отримано за підзимового строку сівби з шириною міжрядь 0,45 м та нормою висіву 2,0 млн сх. нас. на 1 га. The results of investigations of the effect of seed rate and row spacing on the productivity of coriander on the podzim and early spring yields are given.It was established that the best seeding period for coriander is the podzimovy, in which the fruit yield was 1.21 t / ha, which is more compared to the early spring by 0.30 t / ha, or 24.7%. For a coriander in the conditions of the northern steppe, the seeding rate of 2.0-2.5 million cu is optimal. us. per 1 hectare, which yields 1.14-1.15 t / ha. A seam with a width of 0.45 m row spacings contributed to yielding 1.09 t / ha, which is more than 0.15 m at 0.06 t / ha, or 8.0%. The highest level of harvest (1.39 t / ha) was obtained for the podium seeding period with a width of rows of 0.45 m and a seeding rate of 2.0 million growing seeds per 1 hectare.


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