Agricultural Development and Environmental Research American and Czechoslovak Perspectives: Proceedings of a Bilateral Workshop (1987) / Chapter Skim
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'PROTECTION OF SOIL ORGANISMS AND IMPROVEMENT OF BIOLOGICAL PROPERTIES OF SOIL'
'PROTECTION OF SOIL ORGANISMS AND IMPROVEMENT OF BIOLOGICAL PROPERTIES OF SOIL'
Pages 89-96
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From page 89... ...
For instance, in meadow soils man has influenced some components of soil organisms in a favorable way while he has suppressed others completely. But the deepest negative impact on soil biota has been in arable soils.
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From page 90... ...
90 TABLE 1 Density and biomass of soil organisms Specimens on m 2 Biomass in gm/m Group Average Optimum Average Optimum Microflora (bacteria, aktinomycetes, fungi, algae) 1014 1016 320 2,350 Microfauna 108 1010 5 150 Mesofauna Rotatoria 104 106 0.01 0.3 Nematoda 106 108 5 50 Tardigrada 10S 105 0.01 0.5 Acarina 7 x 104 4 x 105 0.6 4 Entognatha 5 x 104 4 x 105 0.5 4 Macrofauna Enchytraeidae 3 x 103 3 x 104 5 50 Gastropoda 50 1,000 1 30 Aranea 50 200 0.2 1 Isopoda SO 200 0.4 1.5 Myriapoda 230 2,800 4.45 13 Insecta 350 16,600 3.5 50 Megafauna Lumbricidae 100 500 SO 200 Vertebrata 0.01 0.1 0.1 10 TOTAL 375.17 2,914.3
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From page 91... ...
Zooedaphon takes part in soil microstructure formation -- through its excrements, through its active burrowing, and by its transport of particles of organic matter to deeper levels and mineral particles from lower layers toward the surface. Soil microflora are functionally connected with soil animals, and the web of mutual relations among soil organisms is one of the most intricate in terrestrial ecosystems.
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From page 92... ...
Most studies concentrate on the influence of a defined insecticide on a defined species or group of organisms, and there are only limited data concerning the impact on whole communities of soil organisms and on the effect of chemical processes in soil. A positive as well as a negative effect on one species may evoke a set of changes in mutual relations among different soil organisms in the function of the whole soil subsystem.
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From page 93... ...
It appears that different species of soil fauna feed on different species of soil microflora, often on a very narrow species spectrum. For instance, the millipede Glomeris hexasticha feeds on the fungus Botrytis cinerea which attacks the roots of trees in nurseries.
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From page 94... ...
The factors which negatively affect soil organisms can be placed in five main categories: • mechanical soil cultivation; • application of mineral fertilizers in an inappropriate form and at excessively high doses; • pesticide application; • monoculture of the same plant over many years; • incorrect application of irrigation. However, the risks of negative impacts on soil organisms can be restrained by: • eliminating heavy machinery in soil cultivation; • application of mineral fertilizers in combination with organic manures; • introduction of integrated plant control principles; • appropriate crop rotation, including plants supporting development of soil organisms such as alfalfa; • appropriate application of irrigation which does not lead to salinization and compaction of soils.
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From page 95... ...
In recent years there have been many exciting developments in our understanding of how soil physical conditions affect microorganisms (Lynch 1986) and how soil fauna affect nutrient cycling and soil microstructure, but there is still a long way to go.
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From page 96... ...
1983. Synteticka sprava o resenfkontrolovatelne-etapy hlavnfho dkolu SPZU "Vliv herbicidu naedafon a jejich rozklad v pude." Mikrobiologicky ustav CSAV, Praha, 79 pp.
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