Search

Crop rotation is known as an eco-friendlier approach, as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. We set out here a study on the farms that have been managed over 50 years of specific continuous crop management programs. The experimental treatments were in a different management system: monoculture of maize, winter wheat, and soybean, 2-year crop rotation (winter wheat–maize) with and without chemical fertilizer, and 3-year crop rotation (winter wheat–soybean–maize) with and without chemical fertilizer and manure. We took soil samples six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. We, upon the data of a long term experiment of crop rotation, could conclude that crop rotations with more crops in the sequence are significantly effective in maintaining weed populations, a low-input crop production could reach a constant low population below an important damaging density, and therefore will be a more sustainable crop production while chemical fertilizers would change the soil’s chemical and structure and imbalance the plant population diversity and manures with high weed seed infestations have the potential to totally eradicate crop rotation effects, Therefore, clean manures or compost are highly recommended.

Long-term monoculture has a de-stroying impact on plant production, while crop rotation is known as a more eco-friendly approach as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. The aim of his research was to answer: How management system over 50 years of specific continuous crop management programs (crop rotation and fertilization) effect on weed populations? This study was conducted in the experimental site of the Institute of Field and Vegetable Crops of “Plodoredi”, Rimski Šančevi, Novi Sad, Serbia. It has been estimated three monocultures of maize, wheat and soybean, 2-year crop rotation (winter wheat-maize) with and without chemical fertilizer and 3–year crop rotation (winter wheat-soybean-maize) with and without chemical fertilizer and manure. Soil samples were taken six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. Mixed model analysis was used to determine the effect of the crop sequence and fertilizers on weed seed bank. To compare the strength of the treatment, it calculated the log-worth with their P-values. Upon the data of a long term experiment of crop rotation, could approve that crop rotations with more crops in the sequence are significantly effective in maintaining weed population. Therefore, will be a more sustainable crop production, chemical fertilizers would imbalance the plant population diversity and manures with high number of weed seeds have potentials to totally vanish crop rotation effects. Mixed model analysis suggests that on over 50 years of the management practices crop sequence × fertilizer interaction had the highest effect (log-worth = 64.7), followed by the triple interactions between crop sequence × fertilizer × soil depth (log-worth = 30.5). The number of seeds in soil sig

Three populations of weedy sunflower were investigated with the aim to assess its population variability. The following parameters were evaluated: vegetative parameters - plant height (cm), leaf lenght (cm), leaf width (cm), number of ray flowers, number of bract; generative parameters - head diametar (cm), mass of achene per head (g), number of achene per head; and achene parameters - achene lenght (µm), achene width (µm), mass of 100 achenes (g). Except that, achene morphology as indicator of population variability was studied. The studied populations significantly differed regarding to most measured parameters, while only plant height and number of ray flowers were similar in all three populations.