scholarly journals Assessment of soil clogging and seed productivity of weeds on poplar black landings

2020 ◽  
pp. 17-20
Author(s):  
S. Remeniuk ◽  
N. Smolkova

Goal. Determination of soil contamination of plots planted for planting black poplar and evaluation of seed productivity of weeds. Methods. The level of seed productivity of the weeds was determined by the weighting method in the following sequence. In the experiment, 10 plants of one weed species were cut and manually threshed on a tarpaulin. The purified seeds were weighed and, after determining the mass of 1000 seeds, the average amount (thousand units /plant) of seeds per plant was converted. Results. The problem with perennial plantations of bioenergy crops is that the plants are grown for 10—15 years in monoculture on the same section of the field. Consequently, large stocks of certain weeds in the soil can significantly affect the growth and development and productivity level of cultivated plants. So, before planting a plantation, it is necessary to assess the clogging of the plots for the presence of problematic weed species, which can potentially breed on black poplar plantings and impede effective plant care. Virtually all arable land is mothballed with a different weed seed bank. Weed seed stocks depend on the direction of use of the plot, the culture of agriculture, the quality of agricultural operations on care, crop rotation, culture, etc. However, two areas with the same seed reserves in the soil are difficult to find, although the percentage of the main weed species may be identical. Conclusions. Weeds traditionally have high seed productivity and form large seed banks in the arable soil, reaching 1.5—2.0 million units / ha. Bioenergy crops, especially perennial species, are extremely sensitive to weeds in the first year of growing season. Because they form rather modest growths of vegetative mass and can not receive photosynthetically active energy to the soil, and therefore it is important to ensure the purity of the field from weeds during the first year of vegetation.

Author(s):  
Y.Р. Makukh

The structure of the weed and seed productivity of weeds in plantings of willow energy the first year of life. It is established that the greatest number of weed species are presented in families of grass: Graminеае, Chenopodiaceae, Polygonaceae, Solanaceae, Rubiaceae.


2020 ◽  
pp. 1-22
Author(s):  
Michael J. Walsh ◽  
Annie E. Rayner ◽  
Annie Rutledge ◽  
John C. Broster

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).


Weed Science ◽  
1999 ◽  
Vol 47 (2) ◽  
pp. 175-183 ◽  
Author(s):  
George O. Kegode ◽  
Frank Forcella ◽  
Sharon Clay

Approaches to crop production that successfully reduce weed seed production can benefit farming systems by reducing management inputs and costs. A 5-yr rotation study was conducted in order to determine the effects that interactions between crop rotation, tillage, and amount of herbicide and fertilizer (management inputs) have on annual grass and broad-leaved weed seed production and fecundity. There were 10 crop rotation and tillage system combinations and three levels of management inputs (high, medium, and low). Green and yellow foxtail were the major weed species, and together they yielded between 76 and 93% of collected weed seeds. From 1990 to 1994, average grass weed seed productions were 7.3 by 103, 3.7 by 1036.1 by 103and 5.7 by 103seeds m−-2, whereas average broad-leaved weed seed productions were 0.4 by 103, 0.4 by 103, 1.4 by 103, and 0.4 by 103seeds m−-2in crop rotations using conventional tillage (moldboard plow), conservation tillage, no tillage, and ridge tillage, respectively. Crop rotations using conventional or ridge tillage consistently produced more grass and broad-leaved weed seeds, especially in low-input plots. There was little difference in weed seed production among input levels for crop rotations using conservation tillage. Comparing rotations that began and ended with a corn crop revealed that by increasing crop diversity within a rotation while simultaneously reducing the amount of tillage, significantly fewer grass and broad-leaved weed seeds were produced. Among the rotations, grass and broad-leaved weed fecundity were highly variable, but fecundity declined from 1990 to 1994 within each rotation, with a concomitant increase in grass and broad-leaved weed density over the same period. Crop rotation in combination with reduced tillage is an effective way of limiting grass and broad-leaved weed seed production, regardless of the level of management input applied.


Weed Science ◽  
2016 ◽  
Vol 64 (4) ◽  
pp. 551-561 ◽  
Author(s):  
Javid Gherekhloo ◽  
Mostafa Oveisi ◽  
Eskandar Zand ◽  
Rafael De Prado

Continuous use of herbicides has triggered a phenomenon called herbicide resistance. Nowadays, herbicide resistance is a worldwide problem that threatens sustainable agriculture. A study of over a decade on herbicides in Iran has revealed that herbicide resistance has been occurring since 2004 in some weed species. Almost all the results of these studies have been published in national scientific journals and in conference proceedings on the subject. In the current review, studies on herbicide resistance in Iran were included to provide a perspective of developing weed resistance to herbicides for international scientists. More than 70% of arable land in Iran is given over to cultivation of wheat, barley, and rice; wheat alone covers nearly 52%. Within the past 40 years, 108 herbicides from different groups of modes of action have been registered in Iran, of which 28 are for the selective control of weeds in wheat and barley. Major resistance to ACCase-inhibiting herbicides has been shown in some weed species, such as winter wild oat, wild oat, littleseed canarygrass, hood canarygrass, and rigid ryegrass. With respect to the broad area of wheat crop production and continuous use of herbicides with the sole mechanism of action of ACCase inhibition, the provinces of West Azerbaijan, Tehran, Khorasan, Isfahan, Markazi, and Semnan are at risk of resistance development. In addition, because of continuous long-term use of tribenuron-methyl, resistance in broadleaf species is also being developed. Evidence has recently shown resistance of turnipweed and wild mustard populations to this herbicide. Stable monitoring of fields in doubtful areas and providing good education and training for technicians and farmers to practice integrated methods would help to prevent or delay the development of resistance to herbicides.


1988 ◽  
Vol 2 (4) ◽  
pp. 499-504 ◽  
Author(s):  
Randall S. Currie ◽  
Thomas F. Peeper

Seed of three weed species collected from the grain bins of combines while standing hard red winter wheat was harvested germinated better than hand-harvested seed. Combine-harvested curly dock seed germinated from 4 to 24% more than hand-harvested seed. Curly dock seed harvested with a commercial-type combine germinated better than those harvested with a small-plot combine. Harvesting slimleaf lambsquarters and Venice mallow seed with a commercial-type combine also enhanced germination compared to hand-harvested seed.


2021 ◽  
Vol 901 (1) ◽  
pp. 012046
Author(s):  
A A Ivanova

Abstract The studies were carried out in the Moscow region in 2019-2021. In order to create a new breeding material for creeping hay-pasture clover, samples of the Lodian type (giganteum variety), characterized by high peduncles and longer leaf petioles, and a low content of hydrocyanic acid (0.3 mg%), were selected as parental forms. Reciprocal crossing was carried out. Hybrids F1 and F2 in the first year of life were assessed by the main economic and biological characteristics: the length of the peduncles, the number of inflorescences on the plant, fodder and seed productivity, early maturity, winter hardiness and other indicators. Based on the assessment results, the best hybrids and individual biotypes were identified.


Author(s):  
Michaela Kolářová ◽  
Luděk Tyšer ◽  
Josef Soukup

The aim of this study was to explore the composition of weed vegetation on arable land in selected areas of the Czech Republic and to determine the level of γ-diversity. Our survey was conducted at 27 conventional and 35 organic farms from 2006–2008. In each sampled field, one phytocoenological relevé of a standard size of 100 m2 was recorded in the central part of the field. The species cover was estimated. The total γ-diversity was expressed as the total number of weed species recorded. γ-diversity of different farming systems, altitudes and crops was calculated. Subsequently, the species were divided on the basis of their perenniality. In total, 172 weed species were found – 123 and 162 in conventional and organic farming, respectively. The highest number of species was found in winter cereals and at medium altitudes. Chenopodium album was recorded as the species with the highest constancy in both types of farming. In total, 89 annuals, 17 biennials and 15 perennials were observed in conventional farming, and 109 annuals, 23 biennials, 28 perennials and 2 semiparasitic annuals were found in organic farming.


Author(s):  
B. V. Proshkin ◽  
A. V. Klimov

The research explores the seed productivity and plantlets growth in the free pollination of the natural hybrid taxon P. × jrtyschensis. Fruits of P. × jrtyschensis were selected from four plants that grow in the collection ofResearchCenter“EducationalBotanical Garden” ofKemerovoStateUniversity. Four P. nigra model trees, randomly selected from theTomRiverfloodplain population, were applied as a control group. The authors used 30 fruit-bearing amentumsfrom each model. The researchers measured set of fruit (capsule); number of ovules per fruit; number of seeds per fruit; set of seeds.. Laboratory germination was determined by sowing Petri dishes on wet filter paper. The authors found out sowing germination by sowing 100 seeds in a box with soil and drainage. The energy of germination was determined on the second day while germination - on the fifth day. P. × jrtyschensis is characterized by a lower level of seed productivity (15-30%) compared to P. nigra. In terms of laboratory germination of seeds, the descendants of hybrids surpassed many P. nigra models, but their soil germination was 20-30% lower than that of black poplar. The observed variability in reproductive indices of both P. × jrtyschensis and P. nigra is mainly caused by specific features of their genotypes. Plantlets being developed, the authors observed no significant differences among the descendants of P. nigra and hybrids. The researchers highlighted plantlets that can stop growing and even more abnormal plants with one, three or four seeds in P. × jrtyschensis. This may be caused by underdevelopment of hypocotyl or germ root. The authors observed breaches in development of P. nigra just once. They outline high plantlets destruction when sowing hybrids on the first day after germination The share of destructed plants within a month (from the beginning of the experiment) reaches 66,0 %, and in P. nigra it does not exceed 40,0 %.


2020 ◽  
Vol 10 ◽  
pp. 1-14
Author(s):  
Charles N. Nyamwamu ◽  
Rebecca Karanja ◽  
Peter Mwangi

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.


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