Such studies indicate that substantial weed losses will occur if weeds are not controlled. As density is increased, indices that quantify competition in replacement series tend to become less density dependent Cousens, It was argued that these methods have been wrongfully criticized for these limitations. Hoeing requires a high labor input. It is called keerai masial. There was also some indication that broadcast P application resulted in lettuce being more susceptible to weed interference than did band application Figures 3. Duration of weed interference had a significant effect on lettuce where P was applied broadcast but not where it was applied in a band or not applied at all.

Excised shoots were counted and then dried and stored at 60 C. Log transformation was made after adding 1 to data values. These series can be established at each of several levels for the set density component of a series Vleeshouwers et al. Studies specifically concerned with how weeds affect lettuce have also been reported. In agricultural ecosystems, plant competition is commonly viewed as a factor influencing crop productivity Radosevich and Roush, , which implies a shorter term focus than the study of competition in nonagricultural ecosystems would take. In experiment 1 plantings were established at the densities given in Table 4. It thus appears that, in the case of the broadcast treatment, amaranth took up more P than was needed for the biomass accumulation that occurred in these studies.

They found that competitive interference occurred for P with common lambsquarters being more aggressiveand to a lesser extent for N in which case wheat was more aggressive.

Field studies in England showed that densities of 65 weeds per hybrodus resulted in complete loss of marketable yield when weeds were allowed to remain present in the crop Roberts et al.

literature review on amaranthus hybridus

The area of influence approach is applicable for determining the effect of an individual weed on crop plants growing at various distances from the crop plant Gunsolus and Coble, In the spring study there was literatute interaction between density and duration of weed interference Table 3. Studies concerned with how the duration of weed presence affects lettuce have been reported.


In general, the principle revirw affecting spiny amaranth biomass were the length of time it was grown DWI and the density at which it was grown. The weed selected for use in these studies was spiny amaranth Amaranthus spinosus L. You are commenting using your Facebook account.

literature review on amaranthus hybridus

The most pronounced effect of P application was on lettuce P concentrations. Critical concentrations in lettuce tissue have been established for these nutrients Sanchez lierature al.

Literature review on amaranthus hybridus

Bhaskar and Vyas applied the technique to a wheat Triticum aestivum L. The companionship and assistance of the weed science graduate students and staff and the Everglades Research and Education Center staff is appreciated and will long be remembered. Analysis of the spring yield data suggested that slightly greater yields were obtained with the broadcast than the band application. Lettuce leaf samples were collected at midseason from plants in the weed- free plots of this experiment.

Per plant dry weight data were analyzed using analysis of variance with a complete factorial treatment arrangement. In these studies with lettuce and spiny amaranth, however, essentially lierature the growth of lettuce was found to be influenced by P fertility.

literature review on amaranthus hybridus

Alkamper reviewed literature on the combined influence of weeds and fertilization on crop production. Hall b studied the influence of added K on competition between Nandi setaria Setaria anceps cv. With mid- to full-season interference, lettuce yields were reduced more with 4 weeds per 2.

With the earliest barley planting, the crop progressively suppressed the weed. Otherwise cylinders were constructed of hexagonal wire mesh with 2.


These treatments were included for each species in order to show the overall response to CP under the conditions of the study. Duration of weed interference litsrature were analyzed with regression techniques Freund et al. However, if amaranth can be incorporated into a major flour milling blend for large volume uses, then significant expansion could follow.

Falseflax thus hybfidus more strongly for P than flax, both interspecifically and intraspecifically. No meaningful trend over time was found however. However, no information is available concerning the effect P fertility would have on weed interference with lettuce.

Literature review on amaranthus hybridus – Don’t have time to do homework

For gramineous weeds, postemergence herbicides are amaranthuss Stall and Dusky, While K fertilizer can be applied as needed after the crop is planted, the entire amount of P to be used for a crop is applied before planting. Phosphorus applied broadcast as an experimental treatment. Nandi and Greenleaf desmodium Desmodium intortum cv. Relatively large amounts of phosphorus P fertilizer are required to obtain a lettuce lkterature of good quality and yield on high organic matter soils Sanchez and Burdine, Merrill and Florida beggarweed Desmodium tortuosum Sw.

In the spring experiments lettuce yields were reduced most when spiny amaranth was present at high densities throughout the season until the time of harvest of the crop. Copyright literatture of dissertation author]. Calcium concentrations in lettuce ranged from as low as 1.