Herbicide application has long been considered the most efficient weed control method in agricultural production worldwide. However, long-term use of agrochemicals has numerous negative effects on crops and the environment. Bearing in mind these negative impacts, the EU strategy for withdrawing many herbicides from use, and modern market demands for the production of healthy and safe food, there is a need for developing new effective, sustainable, and ecological weed control measures. To bring a fresh perspective on this topic, this paper aims to describe the most important non-chemical weed control strategies, including ecological integrated weed management (EIWM), limiting weed seed bank, site-specific weed management, mechanical weeding, mulching, crop competitiveness, intercropping, subsidiary crops, green manure, and bioherbicides.

Sorghum halepense (L.) Pers is a common and noxious worldwide weed of increasing distribution in many European countries. In the present review, information on the biology, ecology, agricultural, economic and environmental impact of johnsongrass is given, and the current status of this weed in Europe is discussed. Furthermore, special attention is given to the important role of field trials using glyphosate to control weeds in arable and perennial crops in many European countries. Some of the factors which affect control efficacy and should be taken into account are also discussed. Finally, several non-chemical alternative methods (cultural, mechanical, thermal, biological, etc.) for johnsongrass management are also presented. The adoption of integrated weed management (IWM) techniques such as glyphosate use, crop rotation, and deep tillage is strongly recommended to control plant species that originate from both seed and rhizomes.

Flame weeding is an alternative method of weed control. Essentially, it is a supplement to other physical and mechanical processes used in organic production. Weed control costs have a large share of the total cost of crop production. This study aimed to investigate hand weed hoeing’s cost-effectiveness, accompanied by inter-row cultivation and flame weeding applied in organic maize production using two different machines to determine the economically best solution. For this purpose, the prototype flame weeder and commercial flame-weeding machinery were used. Designed primarily for smaller fields, the prototype flame weeder was equipped with a cultivator and a 70 kg propane bottle. Commercial Red Dragon flame weeder, fitted with an 800 kg propane tank and featuring no cultivation implements, is designed for larger areas. The analysis has shown that hand hoeing produced a higher yield (8.3 t/ha in total), but it contributed significantly to the production costs. The costs per hectare decreased when the prototype flame weeder and the commercial Red Dragon flame weeder were used compared to hand hoeing. More beneficial economic impacts were recorded when the prototype flame weeder was used (489.39 €/ha) than in applying the Red Dragon flame weeder (456.47 €/ha). The efficacy of flame weeding is somewhat limited and could be enhanced by additional hand hoeing, if the effect of the machine in terms of weeding is observed. However, the analysis has shown that, in this case, investments in additional hand hoeing are not economically justified because the operating costs incurred therein (168 €/ha) were not met by a yield increase of 500 kg/ha, i.e., a surplus revenue of 100 €/ha. Moreover, the economic impacts of flame weeding would be considerably more significant in larger fields.

The main objective of this study was to identify optimal burner orientation for a newly designed flame cultivator by quantifying the flame temperature distributions of cross, back, and parallel position of burners at different heights of the soybean canopy (distance from the soil surface). Flame temperatures were measured within-row for three burner orientations at seven propane doses (20–100 kg/ha) and eight different canopy heights (0–18 cm above soil surface). Soybean plants in V3 growth stage were flamed with the same doses and burner orientations, and 28 days after treatment (DAT) crop injury (0%–100%), plant height (cm), dry matter (g) and grain yield (t/ha) were assessed. All three burner orientations had high flame temperatures at lower canopy heights (<6 cm high) that gradually decreased with increasing canopy height (6–18 cm). Measured temperatures ranged from 33 to 234 ℃ for cross flaming, 29 to 269 ℃ for back flaming and 23 to 155 ℃ for parallel flaming, with high variability in temperature patterns. Back flaming generated flame temperatures above 100℃ at a lower propane dose (27 kg/ha) compared to cross and parallel flaming (40 and 50 kg/ha). For all tested parameters, parallel and cross flaming had better impact on soybeans than back flaming, but for weed control in crop rows, cross flaming is recommended.

The crop yield can be affected by many factors, including various levels of weed presence. Therefore, we conducted a study to evaluate the effect of time of weed removal in combination with planting pattern and pre-emergence-applied herbicides on maize yield and yield components in 2015, 2016 and 2017. The experiments were designed in a split–split plot arrangements with three replications, which consisted of the two main plots (standard/conventional and twin-row planting pattern), two subplots (with and without pre-emergence herbicide application) and seven sub-subplots (seven weed removal timings). In the dry season of 2015, maize yield was much lower (413–9045 kg ha⁻¹) than in the wet 2016 seasons with yields of 5759–14,067 kg ha⁻¹ across both planting patterns. Yield and yield components were inversely correlated with the time of weed removal. The application of pre-emergence herbicides delayed the critical time for weed removal (CTWR), which ranged from V4 to V10 and from V3 to V11 for standard and twin-row planting patterns, respectively. Herbicides also protected various yield components, including 1000 seeds weight and number of seeds per cob.

The breeding of herbicide-tolerant crops (HTC) has been going on in Serbia for almost three decades, and cultivation has been a tradition for two decades. In Serbia, it is allowed to cultivate plants that are tolerant to certain herbicides and have been obtained using conventional breeding methods without the use of genetic engineering. These are sunflowers, oilseed rape and sugar beet, which are tolerant to some ALS inhibitors, as well as maize, which is tolerant to cycloxydim. With the exception of sunflower, which is tolerant to tribenuron-methyl and imidazolinone and occupies over 80% of the arable land of this crop in the Republic of Serbia, the other HTC are represented on smaller areas (1-17%). The potential of these crops is often not used in the best way, and the main challenge and threat are weeds that are resistant to herbicides to which these crops are tolerant. A big problem for the sustainability of growing these crops in Serbia is that growers of these crops rely mainly on herbicides to which they are tolerant and neglect other measures of integrated weed management (IWM). In order to protect these resources as part of IWM, growers' knowledge of best cultivation practices, their benefits and risks must be improved. As a double-edged sword, HTCs allow growers to improve the rotation of herbicides with different modes of action and the control of certain herbicide-resistant weeds, but they can also lead to overuse of herbicides to which they are tolerant and influence the selection of resistant weeds and the shift in weed flora. flora. Herbicides and HTC are very important resources of modern crop production, but only in the context of IWM and without excessive use of these crops and herbicides to which they are tolerant.