This was because soil P in the root 83 microenvironment was not altered by P uptake for a distance greater than 1 mm away from the root. Another important use of amaranth throughout Mesoamerica was to prepare ritual drinks and foods. Copyright [name of dissertation author]. Studies are cited in which redroot pigweed Amaranthus retroflexus L. It may be that such a situation occurred during the latter stages of crop development, resulting in the high P concentrations found at maturity. It is derived from the initial slope of the relationship between yield and density. In order to address the question of the effect that density has on competitive relations, the method can be further expanded by conducting the replacement series at varied densities Jolliffe et al.

Prior to selecting the field location for each experiment, soil was sampled and analyzed for nutrients as described by Sanchez DWI 0 7 21 35 49 Signif. In this experiment, the emergence of spiny amaranth relative to that of the crop occurred later than in the spring experiment. Below-ground competition between different species can sometimes be attributed to the availability of mineral nutrients and nitrogen. Lettuce heads were cut such that several of the outermost leaves were discarded. In the fall, weeds were not large enough for plots to be established until 4 weeks after the crop was planted.

Non- transformed means are presented in the table. Most of the remainder was grown on histosols in the central region of the state.

Literature review on amaranthus hybridus

In this experiment, application of P and duration of weed interference affected lettuce yields. Wilson tabulated findings of maaranthus testing the effects of nutrient addition to plant mixtures in which plant interaction was limited to that which would occur below ground. Spiny amaranth density Duration of weed interferencea Low High P conc. Delaying weed removal an additional 15 days resulted in the complete loss of marketable yield.

Conventional analysis of replacement series studies uses expected yields as a reference from which inferences about competition are made Jolliffe et al. Leaves of plant species in which carbon is fixed via the C4 pathway do not generally light saturate at full sunlight. By 21 days after planting, lettuce dry weight had responded positively to the increased rate of P supplied as a solution but not to P applied dry to the soil.


The projected yield is a hypothetical curve of how the yield of a monoculture would respond to plant density in the absence of intraspecific competition. The amaranth seedling emergence was very sparse in the fall experiment until two to three weeks after the crop was planted.

Nutrient availability of muck soils varies with field conditions Lucas, In the fall experiment, the high P concentrations in lettuce for which no fertilizer Literaturd was added were unexpected Table 3. Defoliation of one of the species of the mixture, which would reduce its nutrient uptake, resulted in an immediate increase in P uptake by the other species.

In this study Yp was calculated from the relationship given by Roush et al. The studies were conducted in air- conditioned glasshouses, the first during August and September of at Gainesville, Florida, the second in March of spring at Belle Glade, Hhbridus and the third in September of fall at Belle Glade.

It appears that in the fall experiment weed establishment did not take place within the critical period for crisphead lettuce. The replacement design is used for determining which of two components of a binary mixture is the better competitor. Mean yields per plant for the plants grown in mixture are Wit hyridus W2t.

literature review on amaranthus hybridus

This site uses cookies. These studies showed that equivalent yields can be obtained with two thirds lower fertilizer P rates if the nutrient is applied in a band rather than broadcast.

Broadcast application resulted in greater yields than band amaranthjs in weed-free duration of weed interference equal to 0 lettuce but not where weeds were present for any duration.

In the fall experiment lettuce yields were essentially not zmaranthus by spiny amaranth Table 3. In these studies with lettuce and spiny amaranth, however, essentially only the growth of lettuce was found to be influenced by P fertility.

Other definitions for the terms interference and competition are also found in the literature e. On a short term, it determines how individual plants will fare as compared to neighbors of both like kn different species. This study corroborates the findings of Sanchez et al.


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

Rveiew technique for the study of nutrients as limiting factors of plant growth under interspecific competition was established by Hall a and has been applied for several nutrients and several plant mixtures Bhaskar and Vyas, ; Hall, a; Hall, b.

Spiny amaranth biomass, however, did not show a differential response to the P application treatments for this duration of weed interference Table 3.

literature review on amaranthus hybridus

In agricultural crops, the amount of plant growth that has accrued up to any moment is density dependent at the start of the crop cycle and becomes density independent as time passes for closed canopy crops.

A second objective was to determine how P fertilization practices would influence the effect of the weed on the crop. In contrast to the mixed cropping scenario, however, optimization is dependent on the productivity of only the desirable components of the mixture.

Factors Influencing Competition Factors that have been found to influence plant competition include environment, plant emergence characteristics, growth rates and other components of plant size and function Radosevich, Durations of weed interference 1, 2, 3, 4 and 5 correspond to numbers of days after plot establishment of 0, 7, 21, 35 and 490, 7, 39 Table 3.

Redroot pigweed biomass was found to be less in soybeans planted on 25 cm row spacings than when the crop was grown on 76 cm row spacings Legere and Schreiber, During the final five weeks prior to harvest of the spring experiment there was considerable rainfall and substantially reduced solar radiation during two periods of several days.

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