Kuorihumus kasvualustana: Alustavia kokeita

Authors

• Irma Suhonen Helsingin yliopiston puutarhatieteen laitos, Viik

DOI: https://doi.org/10.23986/afsci.71702

Abstract

Disposal of barking waste has been in recent years the most difficult waste problem of the sawmill industry. The possibilities of using barking waste as growing substrata for greenhouse plants have been discussed (ISOMÄKI 1967). At Viik preliminary growing experiments on composted barking waste (= bark humus) were made in 1967. The bark humus in tests was 3—4 years old barking waste of conifer wood which had been in compost until spring 1967. At this stage, lime chalk, nitrogen and bacteria were added. The soil testing results of the bark humus after treatment are shown in Table 1, column C. In the first experiment at Viik, tomato was grown on unmixed bark humus and on unmixed peat. The growing methods of tomato were ordinary and the rates of store fertilizing of both growing substrata are shown in Table 2. The soil tests were made by Viljavuuspalvelu Oy (Soil Testing Service) every second week and the test results are presented in Table 3 and in Figures 1—4. During the experiments top dress fertilization was given according to the data from soil tests and recommended standard values for greenhouses (Table 1, column B). The yield of tomato was 12—15 kg/m2 (Table 4). In another test balsam (Impatiens balsamina) was grown in unmixed bark humus. In this experiment different amounts of phosphorus and potassium were given as store fertilizing (Table 5), and during the growth 0.2 % Ca (NO3)2 solution was given every week. The results are given in Table 6. According to the results, the investigated bark humus contained very little phosphorus available for the plants. During the growth, bark humus needed much nitrogen for the decomposing process. The humus was spacious and the roots in bark humus developed well (Figure 5). The yield of tomato grown on bark humus was similar to tomatoes grown on peat.