Weed Competition, Yield and Tuber Size of Potato as Affected by Herbicides Under Sudanese Conditions

1986 ◽  
Vol 22 (1) ◽  
pp. 59-65 ◽  
Author(s):  
A. I. Mohamed ◽  
M. O. M. Nour
Keyword(s):  
Unit Area ◽  
Potato Crop ◽  
Dry Weight ◽  
Potato Yield ◽  
Tuber Size ◽  
Weed Competition ◽  
Hand Weeding

SUMMARYThe effects on the potato crop of the herbicides metribuzin, linuron and metobromuron, singly and in combination with each other and with hand weeding, were investigated and compared with cropped and uncropped weedy controls. Weed competition was determined by measuring weed dry weight. When the three herbicides were applied singly metribuzin gave the lowest weed dry weight, while the combination of metribuzin, metobromuron and hand weeding gave the lowest weed dry weight per unit area of all treatments in both seasons. However, the best potato yield was obtained from the combination of metribuzin and hand weeding. Metobromuron consistently reduced yield through reduction of tuber size irrespective of its effect on weed competition. Metribuzin was the best herbicide for the control of broad leaved weeds and many grasses.

scholarly journals Functional ecology of the biological soil crust in semiarid SE Spain: sun and shade populations of Diploschistes diacapsis (Ach.) Lumbsch.

2005 ◽  
Vol 37 (5) ◽  
pp. 425-432 ◽  
Author(s):  
Ana PINTADO ◽  
Leopoldo G. SANCHO ◽  
T. G. Allan GREEN ◽  
José Manuel BLANQUER ◽  
Roberto LÁZARO
Keyword(s):  
Water Content ◽  
Chlorophyll Content ◽  
Unit Area ◽  
Biological Soil Crust ◽  
Dry Weight ◽  
Mean Annual Precipitation ◽  
Plant Colonization ◽  
Soil Crust ◽  
Active Time ◽  
Exposed Population

The Tabernas badlands in semiarid south-east Spain is one of the driest regions in Europe with a mean annual precipitation of c. 240 mm. The landscape is deeply dissected, with canyons, ramblas and sparsely vegetated eroded badland slopes. The vegetation is predominantly a biological soil crust consisting of different types of lichen-rich communities, one of the more conspicuous being dominated by Diploschistes diacapsis (Ach.) Lumbsch. This lichen is mainly restricted to the north- facing slopes, where it forms extensive whitish carpets and probably plays an important role in preventing erosion of the slopes and allowing plant colonization. South-facing slopes are much more eroded and generally lack vegetation. %The photosynthetic performance of north (shade) and south-facing (sun) populations of D. diacapsis was studied to determine if these different populations showed any adaptations to the microclimatic conditions of their individual habitats. The response of CO2 exchange to light intensity, temperature and water content was measured under controlled conditions in the laboratory. Dry weight-based net photosynthetic rates were higher in the southern-exposed population but quantum efficiency, and light compensation points were similar. Thallus weight per unit area (LMA) was considerably higher for shade specimens but maximum water content and optimal water content were very similar and chlorophyll content on a dry weight basis was also similar. Chlorophyll content on an area basis was higher in the northern-exposed population and always much larger than those reported in other studies on the same species (up to 8 times larger) with the result that NP values on a chlorophyll basis were relatively low. The larger LMA meant that shade thalli stored more water per unit area which should ensure longer active periods than sun thalli. The results support a strategy pair of high NP and short active time versus low NP and long active time, both having been reported for other soil crust species. However, the visibly larger biomass of the shade D. diacapsis suggests that the lichen is at the limit of its adaptability in these habitats.

scholarly journals Effect of duration of weed competition and weed control on the yield of Indian spinach

1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Agricultural Research ◽  
Cyperus Rotundus ◽  
Weed Competition ◽  
Weed Species ◽  
Maximum Benefit ◽  
Hand Weeding ◽  
Crop Weed Competition

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008

The effects of the growth-regulating compounds methyl decanoate and 2, 3, 5-triiodobenzoic acid on potato tuber size

1976 ◽  
Vol 86 (2) ◽  
pp. 251-255
Author(s):  
D. C. E. Wurr
Keyword(s):  
Potato Tuber ◽  
Size Distribution ◽  
Tuber Yield ◽  
Potato Crop ◽  
Total Yield ◽  
Tuber Size ◽  
Tuber Initiation ◽  
Triiodobenzoic Acid ◽  
Tuber Size Distribution ◽  
Methyl Decanoate

SummaryApplication of methyl decanoate to a potato crop about the time of tuber initiation reduced the total yield and the yield of tubers in the grade 2·5–5·5 cm though neither of these reductions were significant. However, application of 2,3,5-triiodobenzoic acid increased the yield of tubers 2·5–5·5 cm by up to 20% while having no significant effect on total tuber yield. This change in the tuber size distribution was due to a more even partition of photosynthate between tubers and not to an increase in the total number of tubers.

Economic and interference threshold densities of quackgrass (Elytrigia repens) in potato (Solanum tuberosum)

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 176-180 ◽  
Author(s):  
Régis Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Yield Loss ◽  
Dry Weight ◽  
Field Studies ◽  
Potato Yield ◽  
Hyperbolic Function ◽  
Yield Losses ◽  
Economic Threshold ◽  
Elytrigia Repens ◽  
Shoot Number ◽  
Dry Biomass

Field studies were conducted in 1989 and 1990 at St-Augustin, Quebec, Canada, to determine the economic threshold density of quackgrass in potato. Potato yield losses due to quackgrass interference increased with quackgrass population density. Potato yield ranged from 33 to 73% in 1989, and from 19 to 44% in 1990. The relationship between potato yield losses and quackgrass densities was described by a rectangular hyperbolic function. Dry weight of quackgrass proved to be the best predictor of potato yield loss compared to shoot number. The interference thresholds for 10% potato yield loss amounted to 25 shoots m−2or 20 g total dry biomass m−2. The economic threshold varied between 0.04 and 2 shoots m−2or 0.0165 and 1.5 g total dry biomass m−2, depending on the variables considered.

Effect of Duration of Green Foxtail (Setaria viridis) Competition on Potato (Solanum tuberosum) Yield

1990 ◽  
Vol 4 (3) ◽  
pp. 539-542 ◽  
Author(s):  
David A. Wall ◽  
George H. Friesen
Keyword(s):  
Solanum Tuberosum ◽  
Tuber Yield ◽  
Total Yield ◽  
Potato Yield ◽  
Average Weight ◽  
Weed Competition ◽  
Setaria Viridis ◽  
Marketable Tuber ◽  
Green Foxtail

The effects of different periods of green foxtail competition on the components of potato yield were investigated. Delaying the removal of green foxtail for 2 wk following crop emergence reduced total and marketable tuber yield by 19 and 29%, respectively, when averaged over 2 yr. Similarly, the number and average weight of marketable tubers were reduced by 24 and 6%, respectively. The proportion of unmarketable tubers comprising the total yield increased as the duration of weed competition was increased. Successively longer periods of green foxtail competition further decreased the measured parameters.

Effect of Corn (Zea mays) Seeding Date on the Growth of Yellow Nutsedge (Cyperus esculentus)

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 572-575 ◽  
Author(s):  
Zain Ghafar ◽  
Alan K. Watson
Keyword(s):  
Zea Mays ◽  
Large Population ◽  
Dry Weight ◽  
Tuber Size ◽  
Corn Yield ◽  
Cyperus Esculentus ◽  
Above Ground Biomass ◽  
Yellow Nutsedge ◽  
Seeding Date ◽  
Tuber Production

Major differences in above- ground biomass and tuber production of yellow nutsedge (Cyperus esculentusL. # CYPES) were not observed when corn (Zea maysL. “CO-OP S265”) was seeded on different dates (1st, 2nd, 3rd and 4th week of May; and 1st week of June). The final seedbed was prepared just prior to each seeding date and this cultivation stimulated dormant tubers to sprout. As a result, a large population of yellow nutsedge emerged with the corn at all seeding dates. Because fertilizer was banded near the corn row, yellow nutsedge biomass, tuber dry weight and number of tubers were higher within corn rows than between rows. Tuber size was affected by seeding date and shifted toward smaller tubers within corn rows and larger tubers between the rows as the corn was sown late. The optimum seeding date of corn was in the 3rd week of May when the highest corn yield was obtained and yellow nutsedge growth was generally reduced.

scholarly journals Light Use, Water Uptake and Performance of Individual Components of a Sorghum/Groundnut Intercrop

1990 ◽  
Vol 26 (4) ◽  
pp. 413-427 ◽  
Author(s):  
S. N. Azam-Ali ◽  
R. B. Matthews ◽  
J. H. Williams ◽  
J. M. Peacock
Keyword(s):  
Dry Matter ◽  
Unit Area ◽  
Dry Weight ◽  
Performance Ratio ◽  
Sole Crop ◽  
Conversion Coefficients ◽  
Proportional Increase ◽  
Total Dry Weight ◽  
And Performance ◽  
Intercepted Radiation

SUMMARYThe productivity of each component of a sorghum/groundnut intercrop and its constituent sole crops is determined in terms of a ‘Crop Performance Ratio’ (CPR) defined as the productivity of an intercrop per unit area of ground compared with that expected from sole crops sown in the same proportions. The CPR allows productivity, intercepted radiation and seasonal transpiration to be compared so that conversion coefficients for radiation (e; g MJ−1) and dry matter/water ratios (q; g kg−1) can be calculated for each intercrop component and its constituent sole crops. In this experiment, CPR for total dry weight in the intercrop was 1.08 and that for reproductive yield was 1.27. These advantages in overall productivity and yield were typical of those reported elsewhere for sorghum/groundnut intercrops. The proportional increase in total dry matter in the intercrop was largely a result of its greater interception of radiation. The further advantage in reproductive yield was a consequence of an improved harvest index in the sorghum component of the intercrop (0.64) compared with that of its sole crop counterpart (0.55).

Effects of Barnyardgrass (Echinochloa crus-galli) on Growth, Yield, and Nutrient Status of Transplanted Tomato (Lycopersicon esculentum)

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 775-778 ◽  
Author(s):  
Prasanta C. Bhowmik ◽  
Krishna N. Reddy
Keyword(s):  
Unit Area ◽  
Tomato Fruit ◽  
Growth Yield ◽  
Dry Weight ◽  
Nutrient Status ◽  
Field Studies ◽  
Fruit Weight ◽  
Fresh Weight ◽  
Shoot Dry Weight ◽  
Marketable Fruit

Field studies were conducted to determine the effects of various barnyardgrass populations on growth, yield, and nutrient concentration of transplanted “Jetstar’ tomato. Barnyardgrass densities at 16, 32, and 64 plants/m tomato row were tested in 1982 and 1983. Barnyardgrass shoot fresh weights/unit area increased as density increased. Fresh weight of barnyardgrass shoots ranged from 17 100 kg/ha at 16 plants/m of row to 35 500 kg/ha at 64 plants/m of row. At the vegetative stage, tomato shoot dry weight was unaffected by barnyardgrass. As crop growth progressed, tomato shoot dry weight decreased at all barnyardgrass densities. Season-long interference of barnyardgrass reduced marketable tomato fruit number and fruit weight at all densities compared to weed-free plots. Reductions in marketable fruit weight ranged from 26% to 16 plants/m row to 84% at 64 plants/m row. In 1982, concentrations of N, P, K, Ca, and Mg in tomato shoots were unaffected by season-long interference of barnyardgrass at all densities. However, in 1983, concentrations of N and K decreased and concentration of P increased in tomato leaves as the density of barnyardgrass increased. Concentrations of Ca and Mg in tomato leaves were unaltered by barnyardgrass density.

Effect of herbicides and herbicide mixtures on weeds in wheat

2016 ◽  
Vol 50 (2) ◽  
Author(s):  
Dhirender Choudhary ◽  
P. K. Singh ◽  
N. K. Chopra ◽  
S. C. Rana
Keyword(s):  
Triticum Aestivum ◽  
Weed Control ◽  
Harvest Index ◽  
Dry Weight ◽  
Field Investigation ◽  
Weed Density ◽  
Metsulfuron Methyl ◽  
Weed Control Efficiency ◽  
Herbicide Mixtures ◽  
Hand Weeding

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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