Milka Brdar-Jokanović, Milan Ugrinović, Branka Ljevnaić-Mašić, Anamarija Stojanović and Jasmina Zdravković
An increasing interest in organically grown vegetables has led to an increasing demand to select cultivars meeting the requirements of the production system. This two-year field study was undertaken to assess the effects of organic and conventional nutrient regimes on onion (Allium cepa L.) yield and several yield contributing characters, as well as to identify the traits that could be important when selecting genotypes attended for different production systems. The trial involved five commercially grown onion cultivars and four nutrient regimes: bacterial fertilizer, fully decomposed farmyard manure, without fertilization (organic) and NPK fertilization (conventional). Onion yield, bulb weight, number of bulbs plot−1, number of days from sowing to emergence, vegetation period, plant height, neck diameter, neck length, bulb diameter, bulb height and bulb index have been analyzed. Significant differences concerning all analyzed traits have been found among the cultivars, treatments and years, with significant corresponding interactions. The obtained results imply the specific adaptation to the particular treatments and weather conditions and therefore the possibility to select onion cultivars performing well in organic environments. Path coefficient analysis revealed positive direct effects of bulb weight and number of bulbs plot−1 on yield, as well as negative direct effects of plant height and number of days from sowing to emergence; therefore, those traits should be considered when selecting genotypes attended for different production systems. Other traits affected yield indirectly, mostly positively via bulb weight.
The objective of the study, conducted in Vojvodina a northern part of the Serbia Republic, was to analyse the effect of drip irrigation on yield, evapotranspiration and water productivity of watermelon (Cirullus lanatus Thunb.) grown with plasticulture. Irrigation was scheduled on the basis of water balance method. Daily evapotranspiration was computed using the reference evapotranspiration and crop coefficient. The yield of watermelon in irrigation conditions (37,28 t/ha) was significantly higher compared to non irrigated (9,98 t/ha). Water used on evapotranspiration in irrigation conditions was 398 mm and 117 mm on non irrigated variant. The crop yield response factor of 1,04 for the whole growing season reveals that relative yield decrease was nearly equal to the rate of evapotranspiration deficit. The values of irrigation water use efficiency and evapotranspiration water use efficiency were 9,93 kg/m3 and 10,29 kg/m3 respectively. The determined results could be used as a good platform for watermelon growers in the region, in terms of improvement of the optimum utilization of irrigation water.
Milka Brdar-Jokanović, Branka Ljevnaić-Mašić, Dejana Džigurski, Anamarija Koren, Larisa Merkulov-Popadić, Ljiljana Nikolić and Dušan Adamović
The aim of this study was to examine weed flora occurring in an organic common mallow (Malva sylvestris L.), a newly established crop at the experimental field Bački Petrovac, Institute of Field and Vegetable Crops, Novi Sad, during the growing season of 2014. The weed flora consisted of six species, with even a half being invasive for Vojvodina region (Sorghum halepense, Amaranthus retroflexus, Datura stramonium). The observed low floristic diversity may be related to unbalanced ecological conditions in a newly established crop, invasive species, comparatively low fertilization, allelopathic relations, and possibly robust habitus of the main crop. However, although the flora was low in diversity, both narrow and broadleaf species were represented, with the average infestation as high as 16 individuals per m2. In addition, since the recorded weeds flower from Mart to November, until the development of more efficient methods that are in compliance with the principles of organic agriculture, mechanical weeding should be performed at least three times during the growing season. To our knowledge, this is the first such report on organic common mallow in agro ecological conditions of Serbian province Vojvodina and represents the first step in establishing the adequate weed control measures.