Two field experimental trials were carried out in central Italy, in 2005 and 2006, on biomass sorghum [Sorghum bicolor (L.) Moench] in order to assess weed control efficacy and selectivity to the crop of some pre- and post-emergence herbicides applied at different doses and in different mixtures. All herbicides showed good selectivity to the crop, although postemergence treatments showed higher transitory phytotoxicity effects than pre-emergence treatments, especially when high temperatures occurred after treatments, decreasing the selectivity of leaf herbicides (i.e. MCPA, 2,4-D, bromoxynil and dicamba). Considering pre-emergence applications, terbuthylazine alone against broadleaves or in mixtures at low doses with s-metolachlor against mixed infestations (grasses + broadleaves), seemed to be the best options to obtain a good selectivity to the sorghum and a high weed control level. Aclonifen showed some limits in terms of weed spectrum and could be recommended only against simplified broadleaf weed infestations without the presence of less susceptible weeds, like Amaranthus retroflexus, Portulaca oleracea and Solanum nigrum. Propachlor seemed not to be advisable due to the low efficacy against all the major broadleaf warmseason weed species in the Mediterranean areas. Considering post-emergence applications, all treatments gave quite similar results in terms of weed control, although, the mixture of terbuthylazine + bromoxynil seemed to be the best option due to bromoxinil’s higher efficacy than other foliar herbicides, such as MCPA, 2,4-D and dicamba, which can increase the efficacy of terbuthylazine alone especially under dry weather conditions. There were no significant differences in sorghum biomass between herbicide treatments, although, the more selective pre-emergence treatments showed, on average, a higher biomass yield value than the less selective post-emergence treatments. For these reasons, biomass values seemed to be more related to herbicide selectivity than to herbicide efficacy, especially in cases of scarce competitiveness of weed flora.

Sorghum produces allelopathic compounds, including total phenolic compounds and sorgoleone, which exhibit a phytotoxic effect on weeds. The field study, carried out in 2016-2017, was designed as an one-factor experiment, in the randomized block design, in four replications, with Sucrosorgo 506, Rona 1, KWS Freya, KWS Juno, and KWS Sammos, to assess the impact of allelochemicals on weeds. Weed infestation was determined at the beginning of July. Individual weed species were collected from two random places in each plot and weighed. The aim of the laboratory study was to evaluate the total content of phenolic compounds, and sorgoleone in the early stages of plant development (5, 10, and 15 days after emergence) in varieties Rona 1, KWS Freya, KWS Juno, KWS Sammos, Farmsorgo 180, GK Aron, PR 845F, Sucrosorgo 506 and PR849F. The total content of phenolic compounds was determined using the colorimetric method, and the sorgoleone HPLC technique on a Flexar chromatographic set. The highest value of sorgoleone was observed in 15-day-old seedlings of KWS Juno, the lowest in 5-day-old seedlings of Sucrosorgo 506, the highest levels of total phenolic compounds in 5-day-old seedlings of PR 845F, the lowest in 15-day-old seedlings of Farmsorgo 180. The results do not fully confirm the beneficial effect of allelopathic compounds on reducing weed infestation, however, it is important to emphasize the diversity of cultivars used. The statistically insignificant results indicated that most varieties of sorghum plants do not exhibit a significant decrease in yield.

Easy-to-handle and effective methods of juice clarification and concentration by membrane technologies are still under exploration. The current article presents results of research on the technological development of an alternative natural sweetener of high biological value and improved organoleptic properties. Sorghum saccharatum stem juice is used in research. It is pre-clarified enzymatically with α-amylase and glucoamylase, clarified by ultrafiltration, and concentrated by the direct contact membrane distillation in various temperature ranges. The study shows the efficacy of membrane methods for improving juice purity, total soluble solids ( TSS), and total sugar (TS) content in the syrup obtained. Clarification depends on membrane characteristics at the beginning of the process, as there are no differences at the end of it. Juice concentration at high-temperature differences allows to accelerate the process by approx. 60% comparing to low-temperature differences. A lower temperature difference ( ΔТ = 20–30°С) in the concentration process results in a longer process and syrup acidisation, whereas a higher temperature difference ( ΔТ = 70°С) affects physicochemical properties of syrup due to local overheating and formation of Maillard reaction products. The juice concentration at ΔТ = 50–60°С allows to obtain high values of total soluble solids without significant degradation of physicochemical and organoleptic properties.

As the impact of global climate change increases, the interaction of biotic and abiotic stresses increasingly threatens current agricultural practices. The most effective solution to the problem of climate change and a decrease in the amount of atmospheric precipitation is planting extremely drought-resistant and high-yielding crops. Sorghum can grow in harsh conditions such as salinity, drought and limited nutrients, also it is an important part of the diet in many countries. Sorghum can be introduced in many zones of Kazakhstan. Plant height and yield of green plant biomass of 16 sorghum samples in arid conditions were determined based on a set of agrobiological characteristics for field screening. The height of the studied samples of grain sorghum was 0.47 ±0.03 m, and the height of sweet sorghum was much longer, reaching up to 2.88 ±0.12 m. Also, there was a strong difference in green biomass in cultivated areas under different soil and climatic conditions, the green biomass of sweet sorghum was 3.0 Mg∙ha ^–1, and in grain sorghum, it reached up to 57.4 Mg∙ha ^–1. Based on the data of the field assessment for various soil and climatic conditions, the following samples were identified for introduction into production: samples of sweet sorghum for irrigated and rainfed lands of the Almaty Region and in the conditions of non-irrigation agriculture of the Aktobe Region – a promising line ICSV 93046. For non-irrigation agriculture of the Akmola Region, genotypes of sweet and grain sorghum are ‘Chaika’, ‘Kinelskoe 4’ and ‘Volzhskoe 44’.