I. Nikolova, N. Georgieva, Y. Naydenova*
Institute of Forage Crops, 89 General Vladimir Vazov, 5800 Pleven, Bulgaria
Abstract. The isolated and combined action of organic products Biofa (foliar fertilizer), Polyversum (growth regulator), NeemAzal and Pyrethrum (biological insecticides) on energy and protein feeding value of the dry mass of spring forage pea grown in the conditions of organic farming is studied. As a standard of comparisonthesyntheticproductsFlordimeks(plantgrowthregulator)andNureleE(insecticide)areusedaloneorincombination. Thefieldexperimentis conducted in the period 2011 – 2013 at the Institute of Forage Crops, Pleven, Bulgaria. Treatments are performed once in budding and twice in budding and flowering vegetative stages for control of economically important pests. It is found that treatment with organic products in the budding stage influences the energy feeding value positively, increasing it from 0.6 to 5.2% for UFL and from 0.7 to 7.1% for UFV. The highest energy feeding value distinguished combined introduction of Nimazal and Polyverzum (UFL – 0.850 and UFV – 0.768). Double use of biological preparations is associated with a pronounced increase in forage energy feeding value from 1.1 to 9.2% for UFL and from 0.9 to 11.9% for UFV. Compared to a single treatment, an average five- and four-fold increase is established for UFL and UFV, respectively. The treatment with biological regulator Polyverzum has the greatest impact (0.864 and 0.783 for the UFL and UFV), followed by Polyverzum+NeemAzal (0.856 and 0.773 for the UFL and UFV). Protein feeding value in a single treatment is decreased by 5.6% on average. Only Biofa treatment leads to an increase of 15.3% (PBD – 117.6). Double-application is associated with an increase of the forage protein feeding value from 0.2 to 14.4% for the PBD, from 0.1 to 9.8% for PDIN and from 1.8 to 6.4% for PDIE. The highest values distinguished the treatment with NeemAzal (PBD – 99.1; PDIN – 82.3; PDIE – 91.0), followed by NeemAzal+Biofa (PBD – 99.8; PDIN – 89.7; PDIE – 89.2) and Pyrethrum + Polyverzum (PBD – 97.1; PDIN – 88.1; PDIE – 89.0).Syntheticproducts,irrespectiveofthevegetativestageofsubmission,leadtoanincreaseofparameterswhichcharacterizethe forageenergyfeeding value and protein feeding value, but in a relatively lower degree.