THE PROBLEM OF ESTABLISHING PROPER AGRICULTURAL TECHNICS IN THE INTENSIVE GROWING OF MUSHROOM CROPS
In all experiments we used horse manure as a nutritive medium, composted for 17 days. Overlaying was done every 20–21 days after planting in a mixture of sand, peat and turf soil (pH 7–7.3). The mushrooms were grown in wooden cases of 50 kg each, ranged in 4 stages, one over the other, in premises with technical regulation of the heat and air exchange. Selected strains 155 II and 190 II of the Psalliota hortensis Cooke and the Ps. Bispora (Lange) Sing spp. were utilized as biological materials. Mycelium grown on horse manure was used, and only in one case mycelium was used, grown on barley grain (granulated mycelium).
The studies for establishing the quantity of substratum showed that the highest earliness (first picking on the 28th day after planting) can be obtained from the largest quantity of substratum. In small quantities of substratum the first picking is retarded to 35 days after planting. The total yield obtained during a period of 60 days increased more than three times from beds with the greatest quantity of substratum. The same phenomenon was observed in studying the effect of small quantities of substratum. In these conditions the mycelium reached the fruit-bearing stage 5 days earlier using the maximum quantity (600 g) of substratum, in comparison to the minimum (100 g). Table 1 illustrates the effect of the quantity of substratum on the development of the buds, the average weight and the habit of the mushrooms of two different kinds, and table 2 gives data only of the growth of the convex cap (pileus).
From studying the effectiveness of the different quantities of substrata, it was established that although there is a marked increase in the yields (up to the 60th day) (relationship of a kilogram mushrooms to a ton of substratum) the productivity of the substratum increased only to 115 kg per 1 m2. The yield then was 19.3 kg per m2, respectively 167 kg per ton. With a greater quantity of substratum the yield gradually decreased, which indicated the ineffectiveness in the utilization of larger quantities substrata, as had been recorded by Ganser and Sinden in 1964. The mushroom production grew in direct proportion to the quantity of substratum. Very authentic differences were obtained through statistical calculations in the variants 230 and 269 kg per m2, rather reliable differences in the