Lucerne cultivation and the rate of activity of the microbial population of the soil
1990
Santrucek, J. (Vysoka Skola Zemedelska, Prague-Suchdol (CSFR))
Before the onset of vegetation of the stands of the Palava and Rambler varieties of lucerne, within two days after every cut, the stands were treated by harrowing, inter-row compacting by the tractor wheels, and manual inter-row loosening to a depth of 100 mm. The highest values of the basal respiration of the soil were recorded in the second and third year of vegetation of the stands in the treatments with inter-row compacting. The lowest values were obtained in soils left without cultivation (0.488 to 0.560 mg CO2 per 100 g dry matter per hour). The samples of soil taken from under the Rambler lucerne variety had a basal respiration higher by 12 per cent, on an average, in comparison with the Palava variety. Inter-row loosening increased the values of potential respiration of the soil. The highest realtive respiration levels were recorded in soils with stands sown in summer and were lower in soils sown in spring (in the Palava variety the difference averaged 15 per cent). The control (no treatment) had the highest activity of cellulolytic soil microflora. Compacting affected the activity of cellulolytic microorganismus. This activity showed the largest fluctuation in the treatments of inter-row loosening and depended on the atmospheric precipitation. Effective loosening had a favourable influence on the rate of proteolysis whereas compacting reduced it. The highest values of CO2 concentration were recorded in the plots with inter-row compacting; in the harrowed plots they were lower by 34 per cent and in the untreated control by 42 per cent. There were substantial differences in the results between the soil treatments, varieties, and seasons of stand establishment (spring and summer), with respect to the weather conditions.
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