Search

Trailing bindweed (Convolvulus arvensis) was the main weed on the fields sown with winter wheat variety ‘Povolzhskaya 86’. The article considers the effect of various degrees of weediness by trailing bindweed (sparsae, copiosae1, copiosae3) on the main elements of winter wheat productivity. The estimation of the weediness degree has been carried out by the Drude method. The largest losses of yields (15.0-28.0% depending on the year of study) occur with heavy weediness (copiosae3). All three degrees of weediness reduce the main elements of productivity. But the indexes of such elements of productivity as ‘number of kernels per head’ and ‘kernels weight per head’ have increased from 2.6% till 18.0%. Such increase has happened due to the increase of area of nutrition of one plant. The weediness had the largest negative effect on ‘number of productive stems’ and ‘dry tops’ (17.0-28.0%). The weediness by trailing bindweed had an effect on density of winter wheat, on formation of the elements of productivity. Trailing bindweed had a smaller effect on the elements of productivity in the year with optimal stand than in the year with spaced sowings (sparsae). The correlation coefficient for each year of study has been estimated. The dispersion analysis which shows true difference between the control and the variants of the experiment has been conducted. The largest decrease of the indexes occurred in 2014, as the sowings were spaced because of bad wintering; it resulted in weak competitiveness of winter wheat to weeds. Weak competitiveness of winter wheat to trailing bindweed had a negative effect of the main elements of productivity.

This study has been aimed to determine degree of weediness, grain yield and yield components of winter barley, as affected by fertilization system and liming. For that reason, the field trial with three fertilization variants and four barley cultivars was carried out during 2009, in the Center for Agricultural and Technological Research at Zaječar. First fertilization variant included NPK nutrients (120:80:53), in the second one phosphorus amount was doubled, and in the third one were applied 5 t ha' 1 of lime fertilizer "Njival Ca" and 20 t ha' 1 of manure together with mineral fertilizers. The following four winter barley cultivars were involved in the trial: Jagodinac, Record, Premium and Crystal. The trial was set on vertisol soil type, in random complete block design with three replications. This study results show that the highest weediness degree (3.8) was observed at the control variant (without fertilization), while it was lower at the fertilized variants. The highest average grain yield (4340 kg ha'1) was reached at the variant with manure, NPK and lime fertilizers, and the lowest one (3303 kg ha'1) at the first variant. Similarly, the greatest 1000 grain mass and hectoliter mass were also observed at the variant where NPK fertilizer, lime fertilizer and manure were applied. Application of fertilizers with increased amount of phosphorus, as well as lime and manure combination, significantly decreased degree of weediness and increased grain yield of winter barley.