INFLUENCE OF THE IRRIGATION REGIME ON THE YIELD OF DRY BIOMASS IN GRASS MIXTURES OF ENGLISH RYEGRASS (LOLIUM PERENNE L.) AND RED FESCUE (FESTUCA RUBRA L), GROWN FOR THE PURPOSES OF LANDSCAPING

摘要

The aim of the experiment was to investigate the influence of the irrigation regime on the productivity of the grass mixture of English ryegrass and red fescue grown for the purpose of landscaping.The experiment was performed in the period 2009 - 2011 at the University of Forestry - Sofia The following variants were tested. 1 - without irrigation, 2, 3 and 4 - irrigation by a rate of 40% m 60% m and 100% m. "m" being the maximum for the conditionsof the experimental irrigation rate. At the variant of 100% the soil moisture was maintained above 80% of the Limit Field Moisture Capacity (LFMC) for the layer 0-30 cm. For the conditions of the experiment, the best growth, development and high yield were created with optimal irrigation, by maintaining the soil moisture over 80% of the LFMC for the layer of 0-30 cm. the differences compared to all other options were substantial and statistically proven. Under non irrigation conditions the yield was very low (about 18% of that of the optimal irrigation), the growth was very weak, and the quality of the grass carpet was bad. The irrigation with small watering rates (40% m) is not recommended, due to the large losses of around 50%. In the absence of sufficient water for irrigation or the presence of any other reason, deterring the optimal watering, irrigation could be made with reduced irrigation rate, but not less than 60% m. At this irrigation regime the losses were about 25%. with relatively good quality of the grass carpet Irrigation with optimum irrigation rates (60 to 100% m) leaded to a stabilization of the yields from the individual undergrowth, the differences being less than 5%.