engleski

The effect of time of ploughing on the yield and quality of flue-cured tobacco

The effect of time of ploughing on the yield and quality of flue-cured tobacco was studied from 1986 to 1989 at the Experimental Station of Tobacco Institute, Zagreb in Pitomaca. The trial soil was luvisol, of acid reaction, with a low content of colloids and organic matter. This soil is characteristic for the flue-cured tobacco growing area in North Croatia (Yugoslavia) where this type of tobacco is grown on about 12000 ha. There were three treatments in the experiment : 1) autumn ploughing, 2) spring ploughing and 3) autumn + spring ploughing. The treatments were randomized on the block method with four repetitions. The fertilization (300 kg 7:14:21) and other growing conditions were standard for all treatments of the experiment. The flue-cured tobacco variety Drava was used. The soil density was measured during tobacco flowering. The soil ploughed in autumn and spring gave higher yields of flue-cured tobacco in comparison with autumn ploughing. The soil ploughed structure in autumn became compact to settling down during winter and spring because of the unstable and unfavourable texture. By measuring mechanical soil resistance different soil density was established. The soil ploughed in spring was less compact. The soil ploughed in autumn had the highest density. Higher density resulted in slighter development of the roots and lower tobacco yield. The soil ploughed in spring had higher yields and the tendency to higher nicotine content. The ratio of the nicotine and the sugars was dependent on the amount and distribution of precipitation in tobacco vegetation.

flue-cured tobacco; time of ploughing; yield; unit value; nicotine; reducing sugars

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