Influence of non - chemical weed control methods on sugar beet productivity and quality parameters

Abstract

Weed control in organic farming conditions is complicated and requires extra expenses. There are many different non-chemical weed control methods but some of them are not effective enough. For this reason, a long-term stationary field experiment was carried out at the Experimental Station of Aleksandras Stulginskis University (ASU) in 2017-2018. The following sustainable weed control systems were tested: 1) inter-row loosening (control treatment); 2) inter-row cutting and mulching with weeds; 3) inter-row cutting and mulching with Persian clover; 4) inter-row cutting and mulching with white mustards; 5) inter-row cutting and mulching with spring barley. The fertility of sugar beets was determined by weighing clean roots. Their roots ramification was determined by counting all the branched beets in the sample. Amounts of Na, K, a-amino N and sugar content were determined in the laboratory of Kedainiai sugar factory (the stock company "Nordic Sugar Lietuva"). To determine the photosynthetic parameters, the sugar beet leaves were scanned by the Delta T Scan scanner, taking 3 leaves from each experimental plot. Sugar beet processing parameters, namely, sugar content in molasses, sugar output and white sugar yield were calculated according to standard formulas. The alternatives of weed control often reduced the yields of sugar beet substantially; however, when mulching with white mustard, the decrease in fertility was not essential. In most cases, non-chemical weed control measures had insignificant effect on the parameters of sugar beet quality: the content of Na, K and a-amino N. The most significant sugar output (16.34% and 16.26%) was found in sugar beet roots, which were grown applying inter-row mulch of spring barley and weed (P <0.05). Comparing non-chemical weed control systems, the highest amount of white (crystalline) sugar (4.96 t ha"1) was derived from the sugar beet that was grown using white mustard mulch