FIELD AND GREENHOUSE VEGETABLE PRODUCTION ON PEAT AND BROWN COAL DUST
The peat soil of these experiments had the pH value (in water) of 6. 1 and the degree of its decomposition was 74%. The peat layer is 1. 85 m deep. Nitrogen in the form of ammonium nitrate was applied on all plots in equal amounts of 50 kg N/ha. Phosphorus and potassium were applied in two different doses, one being 3 times the other. The single dose of phosphorus was 80 kg of P2O5 in the form of the 18% superphosphate and that of potassium was 160 kg of K2O ha in the form of potassium sulfate. Copper in the form of copper sulfate in the amount of 100 kg/ha was used evenly on all plots. Molybdenum, also the subject of the experiment was applied on some plots. The addition of manganese to the peat was not necessary, because chemical analyses and the previous pot experiments have shown that the amount of this microelement in the soil was sufficient for the plants. Every fertilizer treatment was repeated four times. Liro - CIPC was used as a herbicide in onions (twice) and Gesagard in carrots.
Experimental results for onions, sown in the field, are presented in table 1. For clarity we are giving here results only from the first year of the experiment and the average yields for the years 1968, 1969 and 1970. The size of plots harvested was 12 m2, but the yields in table 1 are given in quintals per hectare.
The figures in table 1 show, that the highest yield in 1968 (total and marketable) was obtained with Lot 6, i. e. from plots fertilized with a triple amount of phosphorus (N 3 P K Cu Mo). This lot brought the highest yield in every year of the experiment, as is evident from the average yields for the three year period. The figures of yields have been analysed statistically (Duncan test with P = 0. 95). The difference in yields between Lot 6 and Lot 2, with a single dose of phosphorus, proved to be highly significant. From the comparison of the yields of the Lots 5 and 6 it is evident that molybdenum was also essential for onions, grown on