Plant Litter and Establishment of Alien Annual Weed Species in Rangeland Communities

Weed Science ◽  
1970 ◽  
Vol 18 (6) ◽  
pp. 697-703 ◽  
Author(s):  
Raymond A. Evans ◽  
James A. Young

Plant litter that covers the soil surface acts as a layer of insulation moderating temperature and moisture, and creating favorable microsites for germination and the establishment of annual weed species in rangeland communities. Litter cover is an important factor in succession among annual species which culminates in dominance by downy brome (Bromus tectorumL.) and medusahead (Taeniatherum asperum(Sim.) Nevski) in these communities.

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 489-493 ◽  
Author(s):  
Frank L. Young ◽  
David R. Gealy ◽  
Larry A. Morrow

In the greenhouse, glyphosate [N-(phosphonomethyl)glycine] at 0.6 kg ae/ha applied directly to seeds alone or seeds on the soil surface reduced germination and shoot dry weight of common rye (Secale cerealeL. ♯3SECCE). Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) applied similarly at 0.6 kg ai/ha reduced germination and shoot dry weight of downy brome (Bromus tectorumL. ♯ BROTE) and wheat (Triticum aestivumL. ‘Daws' ♯ TRZAX). Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5 (4H)-one] at 0.6 kg ai/ha applied to seeds, soil, or seeds and soil had very little effect on germination, but significantly reduced shoot dry weight of common rye, downy brome, wheat, and jointed goatgrass (Aegilops cylindricaHost. ♯ AEGCY). Pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide] at 0.6 kg ai/ha, and propham (isopropyl carbanilate) at 3.4 kg ai/ha plus extender (p-chlorophenyl-N-methylcarbamate) at 0.4 kg ai/ha substantially reduced shoot height and dry weight of all species, regardless of application method, with pronamide completely inhibiting shoot elongation and dry-weight production in three of the four species.


Weed Science ◽  
1971 ◽  
Vol 19 (1) ◽  
pp. 82-86 ◽  
Author(s):  
G. A. Wicks ◽  
O. C. Burnside ◽  
C. R. Fenster

Downy brome (Bromus tectorumL.) seedling emergence was greatest from soil depths of 1 inch or less, but occasionally seedlings emerged from depths of 4 inches. Downy brome seed covered by soil germinated more rapidly than those seed on the soil surface. More downy brome seedlings emerged, and from greater depths, from coarse-textured soils than fine-textured soils when moisture was not limiting. Soil type did not influence longevity of downy brome seed buried in the soil. Most (98%) 8-month-old downy brome seed buried 8 inches in the soil germinated but did not emerge in 1 year; and none remained viable in the soil after 5 years. The moldboard plow was more effective in reducing downy brome populations than a sweep plow or one-way disk in a continuous winter wheat (Triticum aestivumL.) cropping system.


Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 350-356 ◽  
Author(s):  
Raymond A. Evans ◽  
James A. Young

Seedling emergence and growth of downy brome(Bromus tectorumL.), medusahead(Taeniatherum asperum(Sim.) Nevski), and tumble mustard(Sisymbrium altissimumL.) were favored by seed burial, pitting of the soil surface, and soil movement. These conditions maintained temperatures and soil and atmospheric moisture in the range required for establishment.


Weed Science ◽  
1968 ◽  
Vol 16 (2) ◽  
pp. 255-258 ◽  
Author(s):  
O. C. Burnside ◽  
C. R. Fenster ◽  
C. E. Domingo

Weed control during the fallow year and yields of subsequent winter wheat (Triticum aestivumL.) were lower on unsprayed plots than on plots treated with 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) at 2 lb/A or 3-amino-l,2,4-triazole (amitrole) at 1/2lb/A plus 3-(p-chlorophenyl)-l,l-dimethylurea (monuron) at 1 lb/A. The moldboard plow gave the most effective weed control in the winter wheat-fallow rotation followed by the oneway and the sweep plow. Sweep plow tillage left the greatest amount of plant residues on the soil surface to prevent wind and water erosion, but it did not consistently destroy shallow-rooted downy brome (Bromus tectorumL.) plants. Average downy brome stands in winter wheat on fallow plots tilled with the sweep plow, oneway, and moldboard plow were 331, 114, and 16 plants per 54 sq ft, respectively. Winter wheat yields averaged for the sweep plow, oneway, and moldboard plow treatments were 17, 18, and 20 bu/A, respectively. The most feasible method of controlling weeds in a winter wheat-fallow rotation, found in this study, was oneway tillage in combination with the lower herbicide rates.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.


2013 ◽  
Vol 31 (4) ◽  
pp. 823-832 ◽  
Author(s):  
A. Derakhshan ◽  
J. Gherekhloo

Specific knowledge about the dormancy, germination, and emergence patterns of weed species aids the development of integrated management strategies. Laboratory studies were conducted to determine the effect of several environmental factors on seed germination and seedling emergence of Cyperus difformis. Germination of freshly harvested seeds was inhibited by darkness; however, when seeds were subsequently transferred to complete light they germinated readily. Our results showed that 2 wk of cold stratification overcome the light requirement for germination. Seeds of C. difformis were able to germinate over a broad range of temperatures (25/15, 30/20, 35/25, and 40/30 ºC day/night). The response of germination rate to temperature was described as a non-linear function. Based on model outputs, the base, the optimum and the ceiling temperatures were estimated as 14.81, 37.72 and 45 ºC, respectively. A temperature of 120 ºC for a 5 min was required to inhibit 50% of maximum germination. The osmotic potential and salinity required for 50% inhibition of maximum germination were -0.47 MPa and 135.57 mM, respectively. High percentage of seed germination (89%) was observed at pH=6 and decreased to 12% at alkaline medium (pH 9) pH. Seeds sown on the soil surface gave the greatest percentage of seedling emergence, and no seedlings emerged from seeds buried in soil at depths of 1 cm.


2006 ◽  
Vol 86 (3) ◽  
pp. 875-885 ◽  
Author(s):  
J. R. Moyer ◽  
S. N. Acharya

Weeds, especially dandelion (Taraxacum officinale Weber in F.H. Wigg.), tend to infest a forage alfalfa (Medicago sativa L.) stand 2 to 4 yr after establishment. To develop better weed management systems, experiments were conducted at Lethbridge, Alberta, from 1995 to 2002 and Creston, British Columbia, from 1998 to 2001, which included the alfalfa cultivars Beaver (standard type) and AC Blue J (Flemish type) and annual applications of metribuzin and hexazinone. These herbicides are registered for weed control in irrigated alfalfa in Alberta and alfalfa grown for seed. In addition, two sulfonylurea herbicides, metsulfuron and sulfosulfuron, and glyphosate were included. All of the herbicides except glyphosate controlled or suppressed dandelion and mustard family weeds. Metsulfuron at 5 g a.i. ha-1 almost completely controlled dandelion at both locations. However, after metsulfuron application at Lethbridge, dandelion was replaced with an infestation of downy brome, which is unpalatable for cattle. None of the herbicides increased total forage (alfalfa + weed) yield, and in some instances herbicides reduced forage quality by causing a shift from a palatable to an unpalatable weed species. However, it was observed that AC Blue J consistently yielded more than Beaver, and weed biomass was consistently less in the higher-yielding cultivar. AC Blue J was developed primarily for the irrigated area in southern Alberta and for southern British Columbia. Therefore, additional experiments should be conducted to determine which alfalfa cultivars have the greatest ability to compete with weeds in other regions of western Canada. Key words: Alfalfa yield, dandelion, forage quality, weed control


2010 ◽  
Vol 56 (No. 9) ◽  
pp. 444-450 ◽  
Author(s):  
M. Jursík ◽  
J. Holec ◽  
J. Soukup ◽  
V. Venclová

This study aimed to describe emergence cycles of selected weed species under Central European conditions in relation to cumulative soil temperatures from the start of the vegetation season. Emergence of Chenopodium album, Echinochloa crus-galli, Galinsoga ciliata, and Abutilon theophrasti was observed from March to October during the period 2001–2006 at two locations. The beginning of main field emergence was determined as the day when the sum of effective hour temperatures was achieved, and was detected from the second decade of April to early May for C. album, in the second decade of May for E. crus-galli, from late April to the beginning of May for G. ciliata, and from the end of April to mid-May for A. theophrasti. The relationship between cumulative soil surface layer temperature and weed mass field emergence at the beginning of the growing season is very direct (differences ±7 days) – but only when soil moisture is sufficient. In a drier spring, the beginning of mass field emergence occurs with 1–4 weeks of delay and field emergence is usually slower and protracted.


2015 ◽  
Vol 36 (6Supl2) ◽  
pp. 4377
Author(s):  
Sabino Pereira da Silva Neto ◽  
Antonio Clementino dos Santos ◽  
Raimundo Laerton de Lima Leite ◽  
José Expedito Cavalcante da Silva ◽  
Durval Nolasco Neves Neto ◽  
...  

This study aimed to quantify, describe, and identify plant litter production and nutrient accumulation zones in different forest-pasture integration (FPI) systems and forest strata of the Cerrado-Amazon transition on typical orthic Quartzarenic Neosol using spatial analysis, principal component analysis, and non-hierarchical fuzzy k-mean clustering logic techniques. The evaluations were performed at two FPI systems comprising a combination of Brachiaria brizantha cv. Marandu and thinned native vegetation with 50 and 75% (FPI-I and FPI-II, respectively) shade in an original thinned forest (NFI) and in an original intact forest (NF-II) with 80 and 95% shade, respectively. An area of 4,000 m² (40 x 100 m) that contained 32 sampling points arranged in a 4 x 25 m grid was demarcated for each treatment. Plant litter was collected using 32 collectors installed at equidistant points. Twelve nylon bags were placed on the soil surface at each point to evaluate the plant litter decomposition, totaling 384 bags per treatment. It was possible to quantify, describe, and define plant litter production and nutrient accumulation zones in different FPI systems and forest strata of the Cerrado-Amazon transition on orthic Quartzarenic Neosol using geostatistical analysis, principal components, and non-hierarchical fuzzy k-mean clustering logic procedures.


1992 ◽  
Vol 10 (1) ◽  
pp. 43-45 ◽  
Author(s):  
W.A. Skroch ◽  
M.A. Powell ◽  
T.E. Bilderback ◽  
P.H. Henry

Abstract Five organic mulches (pine bark, hardwood bark, cedar chips, longleaf pine needles, shortleaf pine needles), used alone or in combination with two inorganic mulches (black polyethylene, woven polypropylene), were evaluated over two years for weed control, durability, aesthetic value, and influence upon soil temperature. Organic mulches reduced total weed counts by 50% compared to control plots. and underlaying organic mulches with polyethylene resulted in complete control. Polypropylene, used in combination with organic mulch, was ineffective in controlling perennial weed species. Pine bark was the most durable organic mulch, requiring the least replenishment (70% initial volume) after 630 days. Durability of organic mulches increased when underlaid with polyethylene. Longleaf pine needles were rated most attractive, and underlying organic materials with either polyethylene or polypropylene enhanced appearance. Organic mulches reduced maximum daily temperatures at the soil surface by 2.2–3.3°C (4–6°F) and increased minimum daily temperatures by 1.1–2.2°C (2–4°F). However, the type of organic mulch did not affect temperatures at the soil surface.


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