Monoculture

Current production of NR is about 5.2 X 10 tonnes. For some years it has enjoyed a premium price over SBR because of its desirable characteristics described above and, compared with other large tonnage polymers, a somewhat restricted supply. Clearly it is difficult to substantially increase the production of such a material in a short period of time and indeed the attractions of other crops such as palm oil as well as the desire to move away from a monoculture economy mitigate against this. The indications are that, unless there is undue intervention of political factors, the future of natural rubber as a major elastomer remains secure. 

Crop Rotations and Diversification. For thousands of years farmers have known that planting their crops in a new location about every 2 years helped reduce Insect, disease, and weed problems. Indeed, crop rotations are effective in reducing many pest problems and are often highly cost effective (15, 16). Unfortunately for many crops, the trend has been toward abandonment of rotations and increased monocultures. Where rotations are not practiced, certain pests tend to multiply as the crops are cultured on the same land year after year (23). As a result, the density of pest populations increases to levels that necessitate heavy pesticide applications. 

Unfortunately the long-term nature and extent of the leaf-miner infestations are not known. What is clear is that the (likely) combination of weevil infestation in a virtual monoculture of hard beech, with a period of drought in the early 1970s, has led to a continuous decline in the growth of hard beech at the site of dieback (Fig. 126). At the other site, with lower levels of weevil infestation, the plants have recovered, somewhat, after the drought (Fig. 12a). 

Microbes of differing physiologic types, acting in consortia, appear to be more destructive than monocultures. Methods for examining consortia are based on the detection of lipid biomarkers that are characteristic for different classes of microbes. These can be analyzed by gas chromatography coupled with mass spectrometry [512]. 

Pesticides used on crops grown on the test site in previous seasons may also have an impact on the outcome of a field residue trial. Carryover of prior pesticide applications could contaminate samples in a new trial, complicate the growth of the crop in a trial, or cause interference with procedures in the analytical laboratory. For this reason, an accurate history of what has transpired at the potential test site must be obtained before the trial is actually installed. The protocol should identify any chemicals of concern. If questions arise when the history is obtained, they should be reviewed with the Study Director prior to proceeding with the test site. In most annual crop trials, this will not be a significant issue owing to crop rotations in the normal production practices, because the use of short residual pesticides and different chemical classes is often required for each respective crop in the rotation. However, in many perennial crops (tree, vines, alfalfa, etc.) and monoculture row crops (cotton, sugarcane, etc.), the crop pesticide history will play a significant role in trial site selection. 

A sound crop rotational system is of basic importance to the organic farmer. It reduces the risk of diseases and pests associated with monoculture, gives better control of weeds, spreads the labour requirements more evenly over the year, reduces the financial risk if one crop yields or sells badly and provides more interest for the farmer. For instance, take-all is a disease that cannot even be controlled chemically. Winter crops are more susceptible to take-all than spring sown crops and wheat is more susceptible than barley, so the safest position for winter wheat is immediately after a break crop. 

Utilization of beneficial plant associations Practice of mixed cultures, as ccnpared to monoculture adopted in the U.S. due to farm mechanization, could lead to utilizing the beneficial associations for the long-term benefit of agriculture. It has been suggested that such an approach is even more profitable for developing countries. 

Blackledge, A. (2003). Imagining a monocultural community racialization of cultural practice in educational discourse. /. Language, Identity, and Education, 2(4), 331-47. 

NPE or PrEC monocultures IGF-1 increased, CM reduced (NPE), lycopene reduced viability with IGF-1 stimulation but had no effect without it. 

Gamliel A, Stapleton JJ (1997) Improvement of soil solarization by volatile compounds generated from organic amendments. Phytoparasitica 25(S) 315-385 Gamliel A, Hadar E, Katan J (1989) Soil solarization to improve yield of gypsophila in monoculture systems. Acta Hortic. (ISHS) 255 131-138... 

Crop rotation is a system where different plants are grown in a defined sequence. The well-designed crop rotation is the basis of the success in organic farming. Continuous monoculture is unacceptable due to the increased pressure of weeds and pathogens and difficulties with maintaining soil fertility. Diversity of crops in... 

Moyer JL, Coffey KP (2000) Forage quality and production of small grains interseeded into ber-mudagrass sod or grown in monoculture. Agron J 92 748-753 Muller CH (1966) The role of chemical inhibition (allelopathy) in vegetational composition. Bull Torrey Bot Club 93 332-351... 

Teasdale JR, Abdul-Baki AA (1998) Comparison of mixtures vs. monocultures of cover crops for fresh-market tomato production with and without herbicide. Hort Sci 33 1163-1166 Teasdale JR, Daughtry CST (1993) Weed suppression by live and desiccated hairy vetch. Weed Sci 41 207-212... 

Monocultures form the base of most cerebral endothelial cell culture models [105-107], In the case of filter-grown cells, some authors recommend coculture with astrocytes or the use of astrocyte-conditioned media [108-110], The necessity of this approach is presently under discussion, as cells which had been cultured without supplementation with conditioned media show similar features [94, 111],... 

As Samuel Parsons, the Superintendent of Parks for New York for a decade and chief landscape architect for projects in Washington, D.C. and Philadelphia, explains in his popular treatise on gardening from 1891, the home lawn firstly must be open and largely monocultural, in the landscape gardening tradition of previous centuries. 

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