Separating the Effects of Sorghum (Sorghum bicolor) and Rye (Secale cereale) Root and Shoot Residues on Weed Development

Weed Science ◽  
1996 ◽  
Vol 44 (2) ◽  
pp. 402-407 ◽  
Author(s):  
Melinda L. Hoffman ◽  
Leslie A. Weston ◽  
John C. Snyder ◽  
Emilie E. Regnier
Keyword(s):  
Cover Crop ◽  
Early Growth ◽  
Light Transmittance ◽  
Stem Length ◽  
Combined Effects ◽  
Surface Residue ◽  
Weed Growth ◽  
Shoot Tissue ◽  
Delayed Emergence ◽  
Crop Root

Greenhouse experiments that used capillary mat subirrigation to maintain constant soil moisture and to supply fertilizer continuously were conducted to evaluate the effects of sorghum or rye residue on early growth of barnyardgrass and velvetleaf. The separate effects of root residue and of shoot residue were compared to the combined effects of root plus shoot residues and to an uncovered soil control. Residues included as nontoxic controls were leached shoot tissue and poplar excelsior. Shoot residue, leached shoot tissue, and poplar excelsior were surface-applied on an equal light transmittance basis such that mass of poplar excelsior > shoot residue > leached shoot tissue. The presence of rye root residue delayed emergence of barnyardgrass. Surface-applied residues tended to decrease barnyardgrass height, but velvetleaf stem length was greater in treatments with surface residue. Although cover crop shoot residues had little effect on weed growth after 18 d, weed growth decreased in the presence of cover crop root residues and poplar excelsior.

scholarly journals Inhibitory Effects of Brassicaceae Cover Crop on Ambrosia artemisiifolia Germination and Early Growth

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 794
Author(s):  
Maja Šćepanović ◽  
Marija Sarić-Krsmanović ◽  
Valentina Šoštarčić ◽  
Ema Brijačak ◽  
Josip Lakić ◽  
...  
Keyword(s):  
Cover Crops ◽  
Syringic Acid ◽  
Early Growth ◽  
Ambrosia Artemisiifolia ◽  
Aqueous Extracts ◽  
Inhibitory Effects ◽  
Weed Growth ◽  
Liquid Chromatography Tandem Mass ◽  
Allelopathic Effects ◽  
Vanilic Acid

Several cover crops (CCs) exert allelopathic effects that suppress weed growth. The aim of the present study was to evaluate the effects of aqueous extracts containing different concentrations [0, 0.5, 1, 2.5, 5, 7.5 and 10% (w/v)] of Brassicaceae CCs (Sinapis alba, Raphanus sativus, Camellina sativa) and of the CCs Fagopyrum esculentum and Guizotia abyssinica on germination and early growth of Ambrosia artemisiifolia L. The allelopathic effects were species and concentration-dependent. C. sativa, for example, caused the greatest potential to inhibit germination, shoot, radicle length and fresh seedling weight, whereas S. alba and R. sativus inhibited germination and early growth of A. artemisiifolia only at concentrations ≥7.5%. In contrast, no inhibition was observed when aqueous extracts of F. escultneum and G. abyssinica were added at any of tested concentration. Liquid chromatography-tandem mass spectrometry detected 15 phenolic compounds in Brassicaceae CCs with the highest content (µg/g) of vanillin (48.8), chlorogenic acid (1057), vanilic acid (79), caffeic acid (102.5) and syringic acid (27.3) in C. sativa. Our results suggest that C. sativa is the most allelopathic CCs and that the fruits of C. sativa are the plant organs richest in allelochemicals.

scholarly journals Estimation of runoff mitigation by morphologically different cover crop root systems

2016 ◽  
Vol 538 ◽  
pp. 667-676 ◽  
Author(s):  
Yang Yu ◽  
Willibald Loiskandl ◽  
Hans-Peter Kaul ◽  
Margarita Himmelbauer ◽  
Wei Wei ◽  
...  
Keyword(s):  
Cover Crop ◽  
Root Systems ◽  
Crop Root

Cereal cover crops for weed suppression in a summer fallow-wheat cropping sequence

2000 ◽  
Vol 80 (2) ◽  
pp. 441-449 ◽  
Author(s):  
J. R. Moyer ◽  
R. E. Blackshaw ◽  
E. G. Smith ◽  
S. M. McGinn
Keyword(s):  
Winter Wheat ◽  
Weed Control ◽  
Cover Crops ◽  
Soil Conservation ◽  
Cover Crop ◽  
Wheat Yield ◽  
Weed Suppression ◽  
Wheat Crop ◽  
Weed Growth ◽  
Summer Fallow

Cropping systems in western Canada that include summer fallow can leave the soil exposed to erosion and require frequent weed control treatments. Cover crops have been used for soil conservation and to suppress weed growth. Experiments were conducted under rain-fed conditions at Lethbridge, Alberta to determine the effect of short-term fall rye (Secale cereale L.), winter wheat (Triticum aestivum L.) and annual rye cover crops in the fallow year on weed growth and subsequent wheat yield. Under favorable weather conditions fall rye was as effective as post-harvest plus early spring tillage or herbicides in spring weed control. Winter wheat and fall rye residues, after growth was terminated in June, reduced weed biomass in September by 50% compared to no cover crop in 1993 but had little effect on weeds in 1995. Fall-seeded cover crops reduced the density of dandelion (Taraxacum officinale Weber in Wiggers) and Canada thistle [Cirsium arvense (L.) Scop.] but increased the density of downy brome (Bromus tectorum L.), wild buckwheat (Polygonum convolvulus L.), and thyme-leaved spurge (Euphorbia serpyllifolia Pers.) in the following fall or spring. Wheat yields after fall rye and no cover crop were similar but yields after spring-seeded annual rye were less than after no cover crop. Spring-seeded annual rye did not adequately compete with weeds. Cover crops, unlike the no cover crop treatment, always left sufficient plant residue to protect the soil from erosion until the following wheat crop was seeded. Key words: Allelopathies, fall rye, nitrogen, soil conservation, soil moisture, weed control, spring rye, winter wheat

Variations in cell length and frequency of anticlinal division in the vascular cambium throughout a white spruce tree

1970 ◽  
Vol 48 (7) ◽  
pp. 1363-1371 ◽  
Author(s):  
M. W. Bannan ◽  
M. Bindra
Keyword(s):  
Negative Relationship ◽  
Ring Width ◽  
Early Growth ◽  
Cell Length ◽  
Stem Length ◽  
Cell Multiplication ◽  
Great Length ◽  
Vascular Elements ◽  
Anticlinal Division ◽  
Late Growth

In the early growth of the stem, branches, and roots, the vascular elements are relatively short and the frequency of anticlinal division involved in cambial cell multiplication is high. As growth sheaths are added in the stem, length of cell increases and rate of multiplicative division declines. A similar trend occurs upward through the lower quarter to half the height of the stem. In the root system, the later growth of vertical roots is characterized by shortness of cell and high frequency of anticlinal division, and conversely, that of horizontal roots by great length of cell and low rate of anticlinal division. Although a general negative relationship exists between rate of anticlinal division and cell length throughout much of the tree, these features sometimes vary independently, and length of cell seems to be more closely related to amount of yearly radial accretion. Through the middle to late growth of the stem a negative relationship obtains between length of cell and width of annual ring, cell length maximating at a ring width of 1–2 mm. At this stage, frequency of division may fluctuate only narrowly over a considerable range of ring width. A continued decline in ring width to less than 0.5 mm, such as may occur on senescence, is accompanied by decreased cell length and accelerated anticlinal division. Length of the cell plate in anticlinal division, relative to that of the dividing cell, is greater in the early growth of the stem and branches and throughout horizontal roots than elsewhere in the tree. Most of the anticlinal divisions are pseudotransverse. The proportion of lateral divisions ranges from about 1% in the late growth of stems to 11% in horizontal roots.

Effects of competition with weeds on the growth, development and yield of sorghum

1993 ◽  
Vol 120 (2) ◽  
pp. 187-196 ◽  
Author(s):  
A. P. Everaarts
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Canopy Structure ◽  
Ground Cover ◽  
Stem Length ◽  
Yield Reduction ◽  
Area Index ◽  
Weed Growth ◽  
Competition For Light ◽  
Number Of Leaves

SUMMARYIn two field experiments in Suriname, competition between weeds and sorghum (Sorghum bicolor(L.) Moench) was studied in the rainy seasons of 1982 and 1983. The crop was kept either weed-free or without weed control for each of six different periods of time from planting. Observations made at the end of each period allowed an analysis to be made of the growth and development of a crop with and without weed control.Due to the crop canopy structure and fertilizer placement near the row, weed growth was concentrated in the rows. Starting atc.20–30 days after planting, competition with weeds reduced ground-cover and leaf area index of the crop. Competition reduced growth rates, leading to lower yields. Plant population density was not affected, but competition reduced the number of leaves present. Stem length initially increased with competition in one season, but was retarded in another. Competition for nutrients was strong and was found as early as 15 days after planting. Nitrogen was the element most competed for initially. Competition for water occurred, but competition for light seemed unlikely. About 20 weed-free days after planting were necessary to avoid yield losses and around 30 weed-free days to attain negligible weed growth at harvest. Yield reduction was mainly due to a decrease in number of grains per panicle. Competition during floret establishment (c.30–40 days after planting) should be avoided.

scholarly journals Effect of Winter Cover Crop Residue on No-till Pumpkin Yield

HortScience ◽  
2007 ◽  
Vol 42 (7) ◽  
pp. 1568-1574 ◽  
Author(s):  
E. Ryan Harrelson ◽  
Greg D. Hoyt ◽  
John L. Havlin ◽  
David W. Monks
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Crop Residues ◽  
Fruit Size ◽  
Vegetable Production ◽  
Surface Residue ◽  
No Till ◽  
Wide Range ◽  
Winter Cover Crop ◽  
Winter Cover

Throughout the southeastern United States, vegetable growers have successfully cultivated pumpkins (Cucurbita pepo) using conventional tillage. No-till pumpkin production has not been pursued by many growers as a result of the lack of herbicides, no-till planting equipment, and knowledge in conservation tillage methods. All of these conservation production aids are now present for successful no-till vegetable production. The primary reasons to use no-till technologies for pumpkins include reduced erosion, improved soil moisture conservation, long-term improvement in soil chemical and microbial properties, and better fruit appearance while maintaining similar yields compared with conventionally produced pumpkins. Cover crop utilization varies in no-till production, whereas residue from different cover crops can affect yields. The objective of these experiments was to evaluate the influence of surface residue type on no-till pumpkin yield and fruit quality. Results from these experiments showed all cover crop residues produced acceptable no-till pumpkin yields and fruit size. Field location, weather conditions, soil type, and other factors probably affected pumpkin yields more than surface residue. Vegetable growers should expect to successfully grow no-till pumpkins using any of the winter cover crop residues tested over a wide range in residue biomass rates.

INFLUENCE OF THE ESTER OF 2,4-D APPLIED AT VARIOUS GROWTH STAGES FOR THE CONTROL OF RUSSIAN THISTLE (SALSOLA PESTIFER NELS.) IN FLAX

1959 ◽  
Vol 39 (4) ◽  
pp. 458-465
Author(s):  
J. J. Sexsmith
Keyword(s):  
Butyl Ester ◽  
Early Growth ◽  
Growth Stages ◽  
Harvest Time ◽  
Flax Seed ◽  
Full Bloom ◽  
Weed Growth ◽  
Naturally Occurring ◽  
Second Peak ◽  
Better Than

Linseed flax, growing with naturally occurring infestations of Russian thistle at Lethbridge, Alta., was treated with three rates (2, 3, and 6 oz. acid equivalent per acre) of the butyl ester of 2,4-D at 5-day intervals from the seedling stage to boll formation in each of the 5 years 1952 to 1956, inclusive.Two peaks of weed control were determined, the first being at the early growth stages between 19 and 35 days after crop seeding when some measure of weed stand reduction was obtained. The second peak occurred from 45 to 60 days after seeding when the Russian thistle plants were 6 to 8 in. tall, the control being characterized by a "curl-down" of weed growth which persisted to harvest time. Mature flax height was relatively unaffected except when the crop was treated at or near the first-bud stage of growth. Height of flax above the weed mass was 9.7 and 13.2 in. in 1954 and 1955, respectively, as a result of the best-timed 6-oz. treatment. Such height differences would make it possible to combine-harvest flax seed containing a minimum of weed material. Maturity delays of only 2 or 3 days resulted from treatments made within 1 month after seeding, whereas delays of up to 33 days resulted from treatments made when the flax was in full bloom. On the average for all three treatment rates, flax yields equal to or better than those from untreated weedy plots were obtained in each of the 5 test years when the 2,4-D was applied prior to 36 days after seeding. Thus, for adequate control of a Russian thistle infestation and the undelayed harvest of a good yield of flax seed, it would appear that, 25 to 30 days after seeding, the crop should be treated with a 6-oz. rate of the butyl ester of 2,4-D. Slightly earlier treatment is indicated if cool, wet conditions prevail after seeding.

scholarly journals The value of calcium nitrate and urea for main-crop potatoes and kale

1960 ◽  
Vol 55 (1) ◽  
pp. 1-10 ◽  
Author(s):  
F. V. Widdowson ◽  
A. Penny ◽  
G. W. Cooke
Keyword(s):  
Ammonium Sulphate ◽  
Calcium Nitrate ◽  
Early Growth ◽  
Plant Establishment ◽  
N Fertilizers ◽  
Main Crop ◽  
Delayed Emergence ◽  
Crystalline Urea

1. Twenty-two experiments on main-crop potatoes in 1955–7 compared calcium nitrate and ammonium sulphate applied to the seedbeds before planting. Urea was also tested in fifteen of the experiments in 1956–7. The three fertilizers were compared at rates that supplied 0·5, 1·Oand 1·5 cwt. N/acre.2. Seven experiments on kale in 1955–8 compared seedbed dressings of calcium nitrate and ammonium sulphate. Urea “was also tested in. five of the experiments in 1956–8. The rates used were 0·6, 1·2 and 1·8 cwt. N/acre in 1955 and 1·0 and 2·0 cwt. N/acre subsequently. Single dressings applied to the seedbed were also compared with divided dressings applied partly to the seedbed and partly in mid-season.3. Generally the potatoes gave only small responses to N; there was no worthwhile gain from applying more than 1·0 cwt. N/acre in 1955 and 0·5 cwt. N in 1956 and 1957. Nitrogen gave much larger proportionate increases in yields of kale, at several of the centres crops continued to respond up to dressings of 2·0 cwt. N/acre.4. Calcium nitrate generally gave lower yields of potatoes than ammonium sulphate and the superiority of ammonium sulphate was greater with the higher dressings. Losses in yield with the nitrate were usually associated with a severe check to early growth occurring in dry springs and with dressings concentrated close to the seed, but lower yields were also obtained at some centres where early growth was not damaged. Calcium nitrate and ammonium sulphate were roughly equivalent for kale when the nitrate did not damage germination; heavy seedbed dressings of the nitrate reduced kale plant numbers severely unless there was adequate rain after sowing.5. Granulated urea tested in 1956 contained 4·5% of biuret, it delayed emergence and reduced plant establishment seriously in several of the potato experiments; damage increased with the level of manuring and was accentuated when dressings were broadcast over furrows before hand-planting. Yields given by this batch of urea were less than with other N fertilizers and when 1·5 cwt. N/acre was applied they were less than with no nitrogen at all. Purer crystalline urea (having less than 1% of biuret) used in the 1957 experiments caused no damage to emergence of potatoes and gave yields similar to those obtained with ammonium sulphate. There were similar effects in the kale experiments; granulated urea containing much biuret damaged germination severely in 1956; the purer products containing little biuret used in later years reduced plant numbers at one centre in 1957 and at the single 1958 centre. Where there was no damage to the establishment of kale, urea and ammonium sulphate gave similar yields.6. Dressings applied partly to the seedbed and partly in mid-season gave slightly higher average yields of kale than an equivalent total amount of nitrogen all applied before sowing.

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