Interrelationship of Soil Tillage and Fertilizing in Growing Sugar Beet on Lessive Pseudogley of the Lower Podravina

Na lessive pseudogleju donje Podravine provedena su trogodišnja istraživanja osam različitih varijanata obrade u kombinaciji sa četiri varijante mineralne gnojidbe. U ovom se radu iznose rezultati za šećernu repu. Varijante obrade tla u kombinaciji s četiri razine mineralne gnojidbe (niska, srednja, visoka i vrlo visoka) bile su sljedeće: oranje na 20, 30, 40, 50 i 60 cm, te oranje na 20 cm s podrivanjem na 50 i 70 cm i oranje na 30 cm s podrivanjem na 50 cm. Druge i treće godine istraživanja pratio se rezidualni učinak duboke obrade i mineralne gnojidbe, pa su stoga oba zahvata bila uniformna. Duboka je obrada tla u pravilu pozitivno djelovala na prinos korijena šećerne repe i šećera. Gnojidba je u osnovi bila vrlo neučinkovita u sve tri godine, što posebno vrijedi za vi.e doze. U skladu s pojedinačnim djelovanjem obrade i gnojidbe tla, interakcijsko djelovanje oba čimbenika javilo se u ograničenom opsegu. Pri tome je značajniji bio kompenzacijski učinak obrade.Three-year investigations of eight different tillage treatments, combined with four mineral fertilizer rates, were carried out on luvic pseudogley in lower Podravina. The results referring to sugar beet are presented in this paper. The following ploughing treatments combined with four mineral fertilizer rates (low, medium, high and very high) were applied: ploughing at 20, 30, 40, 50 and 60 cm, ploughing at 20 cm with subsoiling at 50 and 70 cm, and ploughing at 30 cm with subsoiling at 50 cm. Residual effects of deep ploughing and mineral fertilization were followed up in the second and third trial years, hence both practices were uniform. As a rule, deep ploughing had a positive effect on the yield of sugar beet roots and sugar. Fertilization was generally inefficient in all three years, which particularly holds for higher rates. In accord with the individual effects of ploughing and fertilization, there was rather restricted interaction of these factors, with a more pronounced compensation effect of ploughing