RESPONSE OF CONIFER SEEDLINGS AND WEEDS TO SEEDBED FUMIGANTS

1968 ◽  
Vol 48 (2) ◽  
pp. 189-196
Author(s):  
R. Grover

Four soil fumigants at three rates each were field-tested in nursery seedbeds as pre-sowing treatments for effectiveness in controlling weeds and for tolerance of Scots pine (Pinus sylvestris L.), Colorado spruce (Picea pungens Engelm.) and white spruce (Picea glauca (Moench) Voss). The fumigants were: allyl alcohol, dazomet (3,4,5,6-tetrahydro-3,5-dimethyl-2-thio-2H-1,3,5-thiadiazine), metam (sodium N-methyldithiocarbamate) and methyl bromide containing 2% chloropicrin.Most of the fumigant treatments, especially at medium and high rates, provided 80 to 90% control of weeds, irrespective of the weed density. However, the weeds that escaped the treatment grew well. Hand-weeding stimulated the germination of more weed seeds.Most of the fumigant treatments, in 1963 or 1964, did not affect the emergence and stands of the three conifer species. The fresh weight of conifer seedlings in most instances was equal to or better than the weight of seedlings in the hand-weeded check plots. However, the emergence of the two spruce species tended to be reduced in non-weeded as well as in hand-weeded check plots when the weed density was high, and this was attributed to competitive effect of high weed-seedling emergence.

Author(s):  
T. Ganapathi ◽  
M. R. Ravikumar ◽  
G. R. Rajakumar

A field experiment was conducted during 2015-16, 2016-17 and 2017-18 at Agricultural Research Station, Hanumanamatti, Ranebennur (Tq), Haveri (Dist.) Karnataka, to study the effect of chemical herbicides on weed management in garlic. The treatments consisted of pre emergent application of Pendimethalin, Oxyfluorfen, Quizalofop ethyl and Butachlor. The pooled mean results indicated that, pre-emergent  application of Butachlor 50 EC @ 1.0 kg ai/ha + one  hand weeding + second spray at 30 days after planting (B1HW2S:T7) recorded the least weed density (82.83, 89.67 monocot weeds and 8.15, 6.34 dicot weeds), weed bio-mass (80.99g, 93.33g fresh weight of  monocot weeds and 8.48g, 1.82g fresh weight of dicot weeds, 32.40g, 37.33g dry weight of monocot weeds and 3.39g,  0.73g dry weight of dicot weeds), the highest garlic plant height  (4.34cm, 16.17 cm), number of leaves (3.55, 6.57) at 30 and 60 days after planting respectively. Treatment with Butachlor 50 EC @ 1.0 kg ai/ha + one  hand weeding + second spray at 30 days after planting (B1HW2S:T7) also recorded the highest hundred bulb weight (912.98 g), yield per plot (2056.63g) and yield/ha (41.13 Q) followed by Oxyflurofen 23.5 EC @  0.15 kg ai /ha + one hand weeding + second spray at 30 Days after planting (O1HW2S:T4) compared to farmer’s practice (2HW:T8) and untreated control (WC:T9).


2020 ◽  
Vol 23 (1) ◽  
pp. 47-58
Author(s):  
SS Tanu ◽  
P Biswas ◽  
S Ahmed ◽  
SC Samanta

A field experiment was conducted at Agronomy Field Laboratory, Patuakhali Science and Technology University, Dumki, Patuakhali from July 2018 to November 2018 to evaluate the effect of sunflower residues and herbicides on the yield and economic performance of transplanted Aman rice. Weed control methods tested were T1 = weedy check (Unweeded control), T2 = Weed-free check by hand weeding twice, T3 = Pendimethalin, T4 = Pretilachlor, T5 = Butachlor, T6 = Pyrazosulfuron ethyl, T7 = Bensulfuron methyl + Acetachlor, T8 = Bispyriback sodium, T9 = 2,4-D amine, T10 = MCPA, T11 = Sunflower residues, T12 = Sunflower residues + 100% Pyrazosulfuron ethyl, T13 = Sunflower residues + 75% Pyrazosulfuron ethyl, T14 = Sunflower residues + 50% Pyrazosulfuron ethyl. The experiment was laid out in a randomized complete block design with fourteen treatments replicated thrice. Weedy check registered significantly the highest total weed density (354.67 m-2) and total weed dry matter (51.81 g-2) while weed-free treatment by hand weeding twice recorded significantly the lowest total weed density (6.67 m-2) and total weed dry matter 0.49 g-2) . Weedy check produced the highest weed index (34.24%) and hand weeding produced the lowest. Among different herbicides applied alone, butachlor had the lowest total weed density (15 m-2) and total weed dry matter (6.43 g-2) after hand weeding. Hand weeding recorded the highest grain yield (5.14 t ha-1) which was statistically similar to pendimethalin, pretilachlor, butachlor, bensulfuron methyl + acetachlor and sunflower residues + 100% pyrazosulfuron ethyl. Higher grain yield was attributed to a higher number of panicle m-2, number of filled grains panicle-1 and 1000-grain weight. The highest gross margin (22955 Tk. ha-1) and benefit-cost ratio (1.32) were obtained from butachlor. Integration of sunflower residues with pyrazosulfuron ethyl produced effective weed suppression and satisfactory yield comparable to butachlor. Although the integration is less profitable than butachlor the farmers can use this technology as a feasible and environmentally sound approach in transplanted Aman rice field. Bangladesh Agron. J. 2020, 23(1): 47-58


1968 ◽  
Vol 46 (7) ◽  
pp. 921-928 ◽  
Author(s):  
D. J. Durzan

In late August during the onset of dormancy in spruce, seasonal levels of soluble nitrogen, rich in arginine, were high. On a fresh weight basis, diurnal levels of total soluble nitrogen and most component amino acids in roots, buds, and leaves showed maxima, one at sunrise and another in the afternoon or near sunset.Arginine and glutamine in the different plant parts contributed 44 to 83% to the alcohol-soluble nitrogen. In buds and leaves, percentage of arginine remained high and decreased slightly at midday, whereas in roots a continual drop occurred. In all organs examined, changes in glutamine reflected the double maxima of total soluble nitrogen and were greatest in roots.On a fresh weight basis, most amino acids accumulated at sunrise and near sunset; however a few especially in leaves, increased at midday, e.g. glutamic and aspartic acid, lysine, γ-aminobutyric acid, and serine.Comparison of levels of free guanidino compounds in different organs showed remarkable out-of-phase patterns. Levels of these compounds are known from 14C-arginine studies to be closely related to the metabolism of arginine.


2008 ◽  
Vol 48 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Maxwell Handiseni ◽  
Julia Sibiya ◽  
Vincent Ogunlela ◽  
Irene Koomen

Comparative Study of the Effect of Different Weed Management Strategies on Disease Severity and Marketable Yield of Paprika (Capsicum AnnuumL.) in the Smallholder Farming Sector of ZimbabweOn-farm trials were conducted in the Chinyika Resettlement Area of Zimbabwe under dryland conditions to investigate the effects of different weed management methods on disease incidence, severity and paprika (Capsicum annuum) pod yield. The weed control treatments included hand weeding at 2 and 6 weeks after transplanting (WAT); ridge re-moulding at 3,6 and 9 WAT; application 4l/ha Lasso (alachlor) immediately after transplanting, and Ronstar (oxidiazinon) at 2l/ha tank mixed with Lasso at 2l/ha one day before transplanting. The herbicide-water solution was applied at the rate of 200l/ha using a knapsack sprayer. Major diseases identified were bacterial leaf spot (Xanthomonas campestrispv.vesicatoria), cercospora leaf spot (Cercospora unamunoi), grey leaf spot (Stemphylium solani) and powdery mildew (Leveillula taurica) in both seasons. For the 2000/2001 season hand weeding at 2 and 6 WAT and ridge re-moulding at 3, 6 and 9 WAT had the greatest reduction effect on the area under disease progress curve (AUDPC) and the highest marketable fruit yield. In the 2001/2002 season, both herbicide treatments had the same effect as hand weeding and ridge re-moulding on AUDPC and marketable fruit yield. The least weed density was obtained by ridge re-moulding at 3, 6, and 9 WAT in the 2000/2001 season. Weed density was statistically the same across all treatments except the check treatment in 2001/2002 season. Hand weeding operations were significantly (p < 0.05) effective and consequently gave the highest added profits mainly because of their effect on major weeds such asDatura stramonium.


2003 ◽  
Vol 83 (3) ◽  
pp. 519-524 ◽  
Author(s):  
A. G. Xue

The efficacy of seed treatments with bioagent ACM941 (a strain of Clonostachys rosea), its formulated products GB116 and ACM941-Pro, and common fungicides for the control of pea root rot complex were examined in six field trials in western Canada from 1996 to 2000. The effects on seedling emergence, root rot severity, and yield varied among years. In trials 1 and 2 (1996–1997), none of the treatments significantly reduced root rot severity or increased yield. ACM941 + Thiram 75WP was the most effective treatment, increasing emergence by 17.4% and was significantly better than that of the untreated controls. In trials 3 and 4 (1997–1998), Apron FL alone and ACM941 + Apron FL were significantly better than the untreated control, increasing emergence by 6.2 and 7.7%, and yield by 10.8 and 11.5%, respectively. In trials 5 and 6 (1999–2000), AC M 941 and GB116 were equally the most effective treatments, increasing emergence by 11.5 and 12.2%, and yield by 8.2 and 6.3%, respectively. These effects were significantly greater than that of the untreated control, but not significantly different from those of Apron FL or Vitaflo-280. ACM941-Pro was developed and tested in 2000 only, and it increased emergence by 17.1% and reduced root rot severity by 29.6%. Key words: Bioagent, Clonostachys rosea, field pea, Pisum sativum, pea root rot complex (PRRC), seed treatment, fungicide


1994 ◽  
Vol 24 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Hans Winsa ◽  
Urban Bergsten

Direct seeding of Pinussylvestris L. is a regeneration method, with potential for development considering scarification, microsite preparation, seed invigoration, and seed quality. Three seed lots of different quality concerning seed weight, germination percent, and mean germination time were used on two sites in northern Sweden. Microsite preparation, 2 cm deep pyramidal indentations, of the mineral soil improved seedling emergence on the two sites by 48 and 62%, respectively, compared with seeding without preparation other than removal of the humus layer. Microsite preparation in combination with invigorated seed, i.e., seed incubated at 30% moisture content for 7 days at 15 °C, resulted in seedling emergence of about 85% for the highest and about 50% for the lowest seed quality at both sites. Noninvigorated seed, seeded without microsite preparation, reached about 55% for the highest and 22% at one and 43% at the other for the lowest seed quality. Without microsite preparation there was no, or a negative, effect of seed invigoration on seedling emergence. Seedling survival after the first winter improved significantly with better seed quality. Survival averaged 92 and 72% at the two sites, with frost heaving causing most mortality. Seedlings from invigorated and redried seed survived better than seedlings from untreated seed. Seedlings from the best seed quality had higher values in seedling height, about 35%, shoot length, about 60%, and needle length, about 30%, after two growing seasons than seedlings from lower seed qualities. Invigoration and microsite preparation had no effect on measured growth characteristics.


2016 ◽  
Vol 8 (1) ◽  
pp. 59
Author(s):  
Valentín A. Esqueda ◽  
Arturo Durán ◽  
Ernesto López

Three experiments were carried out in the central area of the state of Veracruz, Mexico, during the Fall-Winter seasons of 1989-90, 1991-92 and 1992-93. The main objective was to determine the effect of the time and type of weeding on the yield of residual moisture growing beans. Twelve treatments, arranged in a CRBD with four replications were evaluated. Treatments consisted in hoeing at different times. In some treatments, hoeing was complemented with hand-weeding. The highest grain yields were obtained when the weeds were eliminated at least in two ocations during the early stages of development of the crop. The yield of these treatments was significantly higher than that obtained with the traditional weeding practice (hoeing at 25 days after emergence).Handweeding after hoeing increased grain yields at high weed densities,but when the weed density was not very high, handweeding after hoeing made no difference. The increase in grain yield obtained when two weeding operations were performed instead of one, was sufficient to cover for the expenses of this additional practice and to generate economic profits.


2012 ◽  
Vol 92 (2) ◽  
pp. 267-269 ◽  
Author(s):  
Cheryl R. Hampson ◽  
Paul Randall ◽  
Peter Sholberg

Hampson, C. R., Randall, P. and Sholberg, P. 2012. Short communication:Tolerance of Vineland apple rootstocks to waterlogging and Phytophthora infestation. Can. J. Plant Sci. 92: 267–269. The Vineland (V) apple (Malus) rootstock series has displayed a range of dwarfing potential and fire blight resistance in research test plots. Knowledge of their resistance to crown and root rot, incited by Phytophthora spp., is desirable before recommending them for on-farm testing, but information on this subject is lacking. Therefore, we tested the response of V.1, V.2, V.3 and V.4 clonal rootstocks to Phytophthora (P. cactorum and P. cryptogea) and waterlogging (0, 24 or 48 h per week for 4 mo) in a factorial greenhouse experiment on potted plants, using M.9 (moderately resistant to Phytophthora) and MM.106 (susceptible) as standards for comparison. Root fresh weight was reduced equally by both pathogens relative to uninoculated controls; rootstocks differed in their response to flooding but not to pathogen treatment. Shoot fresh weight was depressed by flooding in a rootstock- and pathogen-dependent manner. In general, all four V rootstocks had better root and shoot growth than MM.106 in the flooding treatments, and all grew as well as, or better than M.9.


1969 ◽  
Vol 47 (11) ◽  
pp. 1693-1700 ◽  
Author(s):  
James W. Hanover ◽  
Ronald C. Wilkinson

Controlled pollinations were made within and between blue spruce (Picea pungens Engelm.) and white spruce (Picea glauca (Moench) Voss) in 1967 and 1968. Interspecific hybrids were obtained and verified by comparative measurements of several traits. The cross was successful when either species was used as the female parent. Hybrid seed germinated more rapidly than that of either species and hybrid seedlings showed some heterosis for early growth. Also, hybrid seedlings had needles intermediate between, and significantly different from, the parental seedlings. Growth form of the hybrid was quite variable compared with that of either species. Further evidence for the successful crossing of blue spruce and white spruce was provided by biochemical analyses of monoterpene compounds in the parents and progeny.


2016 ◽  
Vol 50 (2) ◽  
Author(s):  
Dhirender Choudhary ◽  
P. K. Singh ◽  
N. K. Chopra ◽  
S. C. Rana

A field investigation was carried out to evaluate the effect of herbicides and their mixtures on weeds in wheat (<italic>Triticum aestivum</italic> L.) cv. PBW-343. Minimum weed density per m<sup>2</sup> and weed dry weight (5.13 and 17.31g) was recorded with sulfosulfuron at 25g ha<sup>−1</sup> followed by clodinofop at 60g + metsulfuron methyl at 4g ha<sup>−1</sup> (5.19 and 18.45g), metribuzin at 200gha<sup>−1</sup>(5.85 and 25.98g), pendimethalin at 1000g fb 2,4-Dat400g ha<sup>−1</sup> (6.49 and 31.73g) and hand weeding twice(7.01 and 35g), respectively. Also, maximum weed control efficiency was recorded under sulfosulfuron at 25g ha<sup>−1</sup> (83.85%) followed by clodinofop at 60g + metsulfuron methyl at 4g ha<sup>−1</sup> (83.17%) and metribuzin at 200g ha<sup>−1</sup> (75.85%), respectively. All the weed control treatments recorded significantly higher harvest index than the weedy check (40.24). Among various herbicidal treatments, application of clodinofop at 60g + metsulfuron methyl at 4g ha<sup>−1</sup> recorded highest harvest index (41.91) followed by sulfosulfuron at 25 gha<sup>−1</sup> (41.83) and pendimethalin at 1000g fb2,4-Dat 400gha<sup>−1</sup> (41.25) respectively. The harvest index recorded under clodinofop at 60g + metsulfuron methyl at 4g ha<sup>−1</sup> and sulfosulfuron at 25 g ha<sup>−1</sup> was significantly at par with weed free (42.06).


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