INFLUENCE OF FERTILIZATION AND HERBICIDES APPLICATION ON SOIL MICROFLORA AND ELEMENTS OF SUGAR BEET YIELD

Two-year sugar beet trials were set up on two localities: akovo (Stagnic Luvisol) and Osijek (Dystric Cambisol). The soils showed acid environment respond (pHKCL 4.9 – 5.4) and low humus contents (1.3 –1.6%). The trial aimed to investigate use possibility of carbocalc (CC) – pressed saturated silt (30% CaO) and 40 t/ha stable manure in amendment of already determined unfavourable soil properties, increasing number of soil benefit microorganisms, as well as influence of obtained changes in weed control, sugar beet yield and quality. The weeds were controlled once with full-dose herbicides, repeated low-doses and by hoeing. Weed types, their number and weight were determined on 1 m2in the July second decade. The investigation results show that carbocalc application (CC) brought about increased pHKCL to 7.12 – 7.18 whereas stable manure one resulted in humus increased to 1.73 – 1.95%. It was resulted in increasing of number of bacteria, actinomycetes as well as aerobic asimbiotic nitrogen fixing bacteria – Azotobacter chroococcum. Weed prevailed were as follows : Ambrosia artemisiifolia L., Polygonum persicarie L., Amaranthus retroflexus L. and Echinochloa crus galli L. Total number of weeds without protection application was on the average 83.2 weeds/m2and weight 4012 g. Hoeing resulted in decreased number of weeds to 2.9 weeds/m2– weight 111 g, repeated herbicides application to 6.3 weeds/m2 – weight 294 g whereas the worst results , at weeds control, were obtained by the once herbicides control variant (9.1 weed/m2i.e. 534 g). Low- dose herbicide application variants resulted in higher root yield (48.5 t/ha) compared to the once application (45.1 t/ha). However, hoeing brought about the highest root (50.8 t/ha) and sugar yield (6.2 t/ha). Root yield was very significantly increased and sugar yield significantly by carbocalc (CC) application compared to the control.