Processing of frost- damaged beet remains a significant topical issue for the sugar industry. The growth of microbiological infections in frost-damaged beet leads to several changes in the chemical composition of beet. Microorganisms play a major role in the hydrolysis of sucrose and the production of various metabolites, especially exopolysaccharides. Exopolysaccharides in the raw juice disrupt in normal processing operations, especially purification. The paper shows how exopolysaccharides influence calcium-sludge particles' size distribution, filtration, and sedi- mentation during juice purification. The research was conducted under laboratory conditions using standard dextran and exopolysaccharides extracted from degraded beet of different origins. Findings indicate that the natural exopolysaccharides extracted from the deteriorated sugar beet adversely impacted the purification process more strongly than dextran.
The sugarcane borer Diatraea saccharalis is a major pest of sugarcane (Saccharum spp. hybrids) in the Americas. The insect is partially controlled by cultural, biological, and chemical methods but still causes significant economic losses to sugarcane growers and processors. Currently, one of the most efficient strategies for pest control in other crops is the use of transgenic plants harbouring genes from Bacillus thuringiensis (Bt), which encode crystalline proteins (Cry and/or Vip) with insecticidal activity, known as Bt genes/proteins. In sugarcane, the expression of individual Bt proteins has been previously reported, but not the stacking of two or more Bt proteins. In this study, Bt genes were incorporated by microprojectile bombardment into embryogenic sugarcane calli of the clones TUC 95-10 and TUC 03-12. The presence of the transgenes in 33 transgenic lines was verified by using PCR assays. Subsequently, transgenic lines were acclimated and multiplied in the greenhouse to generate vegetative material for their phenotypic and molecular assessments. The expression levels of transcripts in candidate lines were quantified by real time quantitative PCR (qRT-PCR) assays. In conclusion, transgenic sugarcane lines with a higher level of expression of Bt transcripts compared with the control were developed. These promising lines will be used for future phenotypic tests to determine their resistance against D. saccharalis.
In the South African sugarcane industry, as in many countries, poor adoption of irrigation scheduling is common, leading to ineffective use of irrigation water and loss in yield and income. The reasons for the lack of adoption include economic constraints, difficulty with implementation and human perceptions. To demonstrate the benefits of effective irrigation scheduling under local conditions, a demonstration trial was conducted over 5 years at Pongola, South Africa. Here, a fixed irrigation schedule (control) was compared with three scheduling treatments: (1) the MyCanesim® computer model with data from an automatic weather station; (2) soil-water data from a capacitance probe; and (3) a combination treatment, where MyCanesim® was integrated with a capacitance probe. The number of stress days from either under- or over-irrigation, along with the RV (recoverable value) yield, irrigation applied, irrigation water productivity (IWP) and financial benefits was used to assess each treatment. The adoption of irrigation scheduling was also evaluated through farmer surveys before and after the trial. When compared to the fixed-cycle control, the use of irrigation-scheduling techniques resulted in an increase of up to 13% in RV yield, a reduction of up to 58% in irrigation water applied, improved IWP of up to 23.9 t cane/100 mm of irrigation and financial benefits of up to ZAR10,487/(ha · a) (USD698/(ha · a)). The combination treatment incurred the least water-stress days, 79% lower than the control. Farmer surveys showed an increase of 45% in the adoption of irrigation scheduling, from 11% (n = 111) in 2014 to 56% (n = 100) in 2020. Although site-specific, the trial results show substantial benefits that can be realised by scheduling irrigation. The trial results compare well to other similar studies, showing that the results can be used in other areas to promote the adoption of irrigation scheduling.
Digital cameras are widely used tools for plant monitoring in plant science today. Used to track plant growth or even visible symptoms, they are important tools for breeding and plant protection field trials. Nevertheless, its extension to measure the near infrared (NIR) region (700–1000 nm) includes great potential as plants show a higher light reflectance within this spectrum. Various applications have shown its use for disease detection, quantification, virus content estimation, and stress monitoring. As the next step is a comprehensive integration into agricultural routines, this study will show two use-cases with a high technological readiness level. One use-case shows a handheld multispectral sensor, which is used for manual measurements to detect and discriminate different virus types in sugar beet. In contrast, the second use-case shows a transfer to an UAV based disease quantification routine based on spectral imaging for Cercospora leaf spot. In addition, two prototypical workflows are shown for processing non-imaging and imaging spectral data in an agricultural setting. This study shows the state of the art in spectral sensing in the field for the two major sugar beet diseases – virus yellows and Cercospora leaf spot. Furthermore a future perspective for coming technological challenges regarding the integration of AI in sensors or robotic workflows is provided.
Ratoon stunting disease (RSD) is caused by the bacterium Leifsonia xyli subsp. xyli. The disease causes significant yield losses in sugarcane crops (Saccharum hybrids) throughout the world. Three diagnostic techniques for detecting RSD in fields in the Herbert sugarcane region were assessed in 2022: qPCR on leaf sheath biopsy samples (LSB-qPCR); qPCR on expressed xylem sap; and phase-contrast microscopy (PCM) on expressed xylem sap. The LSB-qPCR leaf sheath biopsy is taken from the lowest green leaf sheath of the plant. Differences among techniques were compared for confirmation of the presence or lack of RSD detected, the time required to collect and process samples, the fee to undertake the sampling, safety considerations and transport costs. Differences were identified among the three sampling methods concerning RSD detection, costs associated with sample collection, processing, and some safety related issues. LSB-qPCR was the most efficient and cost-effective diagnostic platform for RSD.
Mill by-products such as mud, ash and mud/ash mixtures are known to increase cane and sugar yields. Traditionally, Australian growers broadcast these by-products in the fallow at rates greater than 150 t/ha. However, growers are now banding by-products at less than 100 t/ha, with few guidelines on how to maximise their returns from this practice. Eight commercial size replicated, randomised strip trials were established in bare fallows between Ingham and Proserpine to investigate the impact of by-products banded between 35 and 100 t/ha and broadcast between 140 and 200 t/ha on cane yield, CCS and grower net revenue compared to standard grower fallow practices. The trials were harvested each year over the crop cycle using a commercial harvester. Tonnes of cane harvested and mill CCS provided by the receiving sugar mill were used to calculate tonnes of cane per hectare and grower net revenue per hectare using the Australian cane payment method for each plot in a trial. The application of mud, mud/ash and ash increased cane yield with ash ≥ mud/ash >> mud. The greater the quantity of by-product applied, the greater the cane yield. Conversely, CCS decreased linearly with the quantity of mud, mud/ash, or ash applied. CCS was lowest in mud << mud/ash ≤ ash. Cumulative grower net revenue at the end of the crop cycle was greatest in ash > mud/ash >> mud and was greatest at application rates of 35–50 t/ha > 70–100 t/ha > 140–200 t/ha. Broadcasting mud at 200 t/ha resulted in the growers not recovering the cost of application. Banding by-products containing mud/ash and ash at 100 t/ha or less resulted in the grower recovering the cost of the product by the second or third ratoon. By-products applied at rates as low as 50 t/ha reduced CCS, and further research is needed to improve guidelines on nutrient and water management so that growers using these by-products can maximize their profitability.
Sugarcane yellow leaf virus (SCYLV) is an economically significant pathogen that can cause yield losses of 11% to 50% in susceptible clones. Clones (1534) in the second clonal stage (Stage 2) of the Canal Point Cultivar Development Program (CPCDP), three reference cultivars, CP78-1628, CP96-1252, and CP00-1101, and three disease-spreader cultivars, CP88-1762, CPCL02-6848, and CP01-2390, were screened to determine SCYLV infection using tissue-blot immunoassay. One hundred seventy-three clones (11%) were infected with the SCYLV, 29 had 100% SCYLV infection, 19 had 80%, 30 had 60%, 38 had 40%, 57 had 20% of SCYLV infection, and 1361 clones had no SCYLV (0%) infection. The 1534 test clones were derived from 400 crosses that utilized 127 female and 86 male parents in various combinations; 70% of these crosses, 46% of the males, and 54% of the females were related to SCYLV-free clones. The reference and disease-spreader cultivar CPCL02-6848 had 48% infection, followed by CP88-1762 with 38% infection, CP96-1252 with 13% infection, CP01-2390 with 6% infection, CP00-1101 with 5% infection, and CP78-1628 with 3%. The results show that SCYLV can infect many susceptible clones within 3 years of exposure from seed germination to Stage 2. However, the effect of SCYLV infection on yield was not significant in this study. Therefore, the yield losses from SCYLV should be limited by planting virus-free seed cane and good agronomic practices in Florida.
Sugar factory management usually focuses on two important goals: to increase the daily processing capacity and reduce energy consumption. Both targets are connected and cannot be evaluated separately. Many aspects affect this dual target, such as raw juice draft, retention times, process control techniques, equipment capacities, evaporation capability, etc. How do we overcome the problem to make an assessment easier and not to recalculate many balances repeatedly? This study introduces a comprehensive approach where a model and simulation of the whole sugar process is created and evaluated, involving heat & mass balance sheets, KPI and capacity checks of the main equipment. Software like SUGARSTM is mainly used to calculate an exact model of the sugar plant. However, this study involves a summarized and quick approach to check the status of the process, where, finally, comprehensive data on the evaluation of the sugar process is provided.
A microscope system, the Crystobserver (supplied by ITECA, France), was installed on the C seed evaporating crystallizer at Condong Mill, Australia, to monitor the crystal development in real-time. The system provides a high-quality image and measures important parameters such as average crystal size and number of crystals in the image. Analysis of data collected over two seasons confirms that the system is reliable in obtaining images with sufficient clarity to assist the operators in remotely monitoring the crystal development from shortly after slurry addition. The reliability of the measurements is satisfactory once the crystals are larger than 30 µm through to near the end of the C seed when the crystal density in the screen is high. The operators have found the Crystobserver to be very beneficial, allowing them to take corrective actions such as changing the amount of slurry addition or the purity of the feed syrup more quickly. The software in the system stores historical data from several strikes, including images and key parameters that can be accessed readily. The installation, microscope and software features and potential benefits to a raw sugar mill are described.
Wireworms (Coleoptera: Elateridae) are the main soil insect pests of sugarcane (Saccharum spp. hybrids) in Florida. Melanotus communis (Gyllenhal) is the most abundant wireworm in Florida sugarcane fields, reducing stalk populations by feeding on buds of sugarcane seed pieces and on young sugarcane plants. At-planting use of the organophosphate insecticide phorate is the main wireworm management tactic in Florida; however, phorate is a hazardous and relatively expensive insecticide. Thiamethoxam is a neonicotinoid insecticide that has potential to become registered for use on sugarcane in the United States. Previous studies suggested that thiamethoxam decreases wireworm injury to sugarcane seed pieces but does not increase wireworm mortality. The present study conducted between 2018 and 2022 aimed to comprehensively evaluate thiamethoxam for wireworm control under laboratory, outdoor, and field conditions. In two laboratory bioassays, M. communis mortality associated with thiamethoxam (3–20%) was not different than mortality for the non-treated check (0–7%), whereas mortality associated with phorate attained 93–100%. In three large container experiments conducted outdoors with controlled M. communis infestations, thiamethoxam and phorate generally protected young sugarcane plant populations at comparable levels. Insecticide efficacy was mainly associated with the protection of seed-piece buds. However, the number of recovered live wireworms was 2.7–8.0 times greater in thiamethoxam treatments than in phorate treatments. In three field experiments, young sugarcane plant populations in thiamethoxam- and phorate-treated plots were not different than those in non-treated plots. However, the at-planting application of thiamethoxam decreased the number of sugarcane thrips, Fulmekiola serrata (Kobus), by 67–89% in two experiments with thrips infestations 12 weeks after planting. Although the evaluation of insecticide efficacy under natural wireworm infestations was inconclusive, this study confirmed that thiamethoxam should be considered as an alternative to phorate if registered. However, the long-term effects of low wireworm mortality associated with thiamethoxam use should be studied.
In recent years, sugar factories have experienced problems in slicing, extraction and pulp pressing, the cause of which was suspected to be a change in the texture of the sugar beet. In order to analyse the influence of sugar beet texture, processing trials were carried out on a laboratory scale. For this purpose, three sugar beet cultivars with different marc content and corresponding differences in texture were grown in 2020. In 2021, two of the cultivars were included, which were then exposed to either frost (–15 °C, 7 days) or heat (30 °C, 7 days). Consistently, very clear differences between cultivars in processing were evident regardless of treatment. Although there was little difference in cossette quality or pressing, the cultivar with the higher marc content had larger cossette bed and thus better flowability (percolation flow rate) than the cultivar with low marc content in the extraction. Cossettes from frozen beet had much lower percolation flow rate due to destruction of the cell structures but were easier to press than without prior freezing. Moderate heat had no effect on processing. Thus, beet with a higher marc content and thus higher root strength have advantages for processing. It is expected that there is an optimum for root strength. Further trials will investigate how severe heat stress affects the root strength and processability of beet.
A 4-year study tested the feasibility of using bagasse as a soil amendment in sugarcane production on a commercial field with mineral soil in Florida. The experiment was established as a completely randomized design trial with three rates of fresh bagasse applications: approximately 5 cm of bagasse, 10 cm of bagasse, and 10 cm of bagasse + nitrogen (N), which are equivalent to 85 t ha–1, 170 t ha–1, and 170 t ha–1 + 336 kg ha–1 ammonium nitrate, respectively. A control (no bagasse and no N added) was also included. As each treatment and the control had three replicates, there were 12 plots (6.5 ha each in size) totaling over 77 ha. The high pH of the soils is a result of years of mixing underlying limestone (calcium carbonate) bedrock with the topsoil. Overall results indicate that bagasse application positively affected the accumulation of soil organic matter during a short-term period, resulting in higher water-holding capacity and lower bulk density. The high rate of bagasse application had a positive effect on N accumulation, extractable phosphorus (P) and potassium (K) contents during the short term. One single application of bagasse significantly increased the first-year sugarcane biomass and sugar yield by approximately 23%. An overall higher application rate of bagasse (10 cm) was recommended as it showed significantly positive effects on soil health indicators and had a longer effect on increasing sugarcane biomass and sugar yield. There is potential to incorporate bagasse into commercial sugarcane production grown on mineral soils in Florida.
During evaporation, the loss of sucrose can occur due to acid-catalysed hydrolysis to glucose and fructose, a reaction that is exponential with temperature. This paper reviews non-thermal methods for concentrating juices, mainly focusing on the developments of forward osmosis (FO) membranes for juice processing, detailing the benefits and limitations of this technology. A laboratory FO membrane was used in this preliminary study to concentrate pure sucrose solutions and clarified juice from similar to 10 to 45% rds using a calcium chloride draw solution. A small amount of reverse salt flux was observed. The non-sucrose substances in factory juices had little impact on flux performance, with the flux reducing inversely with the volumetric concentration factor. By concentrating to a limit of 45% rds, concentration polari-sation factors that can have a detrimental impact on the flux were not realised. Possible strategies were also explored for the integration into the sugar-manufacturing process.
The 2021 beet campaign in Zeitz, Germany, was the longest in the sugar factory’s history at 177 days, while the 2022 campaign was 144 days. Both campaigns faced challenges with beet storage and supply, as well as climatic conditions causing damage to harvested beets. These challenges resulted in a reduction in the purity and pH value of the raw juice, and increased lime salts and turbidity in the thin and thick juice. Südzucker AG, to which the Zeitz factory belongs, implemented several measures, including technological adjustments, the use of dextranase, increased washing cycles, and filter sleeve changes. The high juice volumes from the campaigns led to year-round sugar production but also required blending lower quality juices with good quality ones. The long production periods resulted in short shutdowns used for maintenance and investment measures.
By-products from the sugar industry (e.g., blackstrap molasses) can be a source of bioactive compounds (e.g., phenolics) known to have antimicrobial, antioxidant, anticancer, and anti-inflammatory properties. These bioactive molecules can be used in the green synthesis of metal nanoparticles. Metal nanoparticles have gathered attention because of their novel physico-chemical properties and potential biological applications (e.g., biocides, fungicides, pesticides, targeted drug and gene delivery, biosensing, medical implants, and plant biostimulants). Gold, silver, iron, and copper nanoparticles are of particular interest as they can be easy to operate and are cost effective, and biocompatible, and their biological activities can be enhanced by surface modifications. In this study, the reducing potential of the phenolic compounds in molasses was investigated for the synthesis of silver nanoparticles without the external addition of reducing agents. The reddish color formation and peak appearance at 420 nm were indications of the successful synthesis of the silver nanoparticles. The synthesized nanoparticles and reducing biomolecules were further characterized by microscopy (SEM, TEM, EDS) and spectroscopy (FTIR) techniques indicating nanoparticles of spherical shape and with particle sizes ranging from 15 nm–45 nm. Their antimicrobial activity was evaluated against several Gram-positive and Gram-negative bacteria. The synthesized nanoparticles showed a biocidal effect, further confirmed by microscopy techniques. It appears that the nanoparticles are interacting with the cell surface of bacteria, penetrating the cell and also causing the disruption of intracellular organelles.
A pre-evaporator is installed in an existing evaporator station with co-current juice flow without adding a new evaporator vessel. The mass and heat balances are compared for both cases. The analysis shows that with such a change the parameters (temperature, flow rate) of the bleed vapors of the 3rd, 4th and 5th effects will result in the need to enlarge the heating surface of several juice heaters. It will also be necessary to increase the vapor parameters of the effect supplying the evaporating crystallizers either by increasing the pressure of the exhaust steam supplying 1st effect or by relieving pre-evaporator through switching the supply of the juice heater from this effect to bleed vapors of another effect.
Sugarcane (Saccharum spp. hybrids) is a major row crop in Florida. The effect of row-spacing on total row length per hectare can significantly effect the cost of major farm operations, including planting, harvesting and fertilizer application. In Florida, sugarcane is commonly planted at 1.5 m row-spacing. There is little information available on the effect of relatively narrow or wide spacing on the growth and yield of sugarcane, especially in new high-biomass cultivars. To determine sugarcane growth response to different row-spacing, a field trial was conducted in organic soil (Histosols) with four different row-spacings (1.2, 1.5, 1.8 m and a double row on a 1.5 m bed) and three sugarcane cultivars (CP 96-1252, CP 00-1101 and CP 01-1372). Data showed differential row-spacing effects on plant cane versus the first ratoon. In plant cane, depending on the cultivar, double row and 1.2 m spacing produced 17–46% and 23–42% greater sugar yield per hectare (TSH) than the current 1.5 m spacing, respectively. Overall, the combined average TSH of plant cane and the first ratoon in double and 1.2 m spacing was 20% and 26% greater than 1.5 m spacing. However, the yields in 1.5 m and 1.8 m row-spacing were similar. There was no significant effect in the first ratoon. There was no row-spacing effect on sucrose concentration. A similar response of cultivars to the tested row-spacings suggests that selecting cultivars for different row-spacings may not potentially show any yield improvements. Compared to the current 1.5 m spacing, narrow-spacing (1.2 m and double row) may potentially increase yields and wide (1.8 m) spacing reduce the production cost but further research is needed to understand the economic feasibility of different row configurations.
The SIX EASY STEPS (TM) nutrient-management program encourages a process of ongoing refinement, and any change to a nutrient-management program should be based on evidence. This may include leaf testing, farm records, on-farm evaluation or a combination of these and other factors. Crop response to applied fertiliser should be one of the main factors assessed when refining a nutrient-management program. Crop response to applied nitrogen (N) may be reduced on sodic soils, associated with a reduced crop-N requirement where growth is constrained. However, the sodic conditions may also limit the crop's ability to acquire N. A trial was established in the Central Region to investigate crop response to fertiliser N on sodic soil. N rate treatments (0, 50, 100, 150 and 200 kg N/ha as urea) were established in the first-ratoon crop and repeated for the remainder of the crop cycle. The trial contained two zones, one with low yield potential and high electrical conductivity (LYHEC) and a second zone with higher yield potential and low electrical conductivity (HYLEC). Both zones were highly sodic (ESP > 15%) at depth. An N deficiency developed over the crop cycle, with the 0N and 50N treatments showing lower leaf %N and reduced cane and sugar yield. Optimum N fertiliser rates increased from the first ratoon (18 kg N/ha) to the third ratoon (109 kg N/ha) but declined in the fourth ratoon (85 kg N/ha). Nitrogen-use efficiency declined with the N application rate, and the highest N uptake efficiency of fertiliser N was 27% at the 50N rate. Overall, the trial showed that a small reduction (similar to 20 kg N/ha or 14%) from the recommended rate of 140 kg N/ha would have been appropriate at this site. The results support the recently developed SIX EASY STEPS Toolbox guidance for refining nutrient inputs for specific on-farm circumstances, including sodic soils. This guidance encourages amelioration of the sodic soil condition as the grower's priority before the amendment of nutrient inputs is considered.
The use of clarification/filter aids for polarimetric measurements of cane products is still an acute problem in many countries due to the toxicity and environmental concerns of lead acetate, the availability of other non-lead aids, and concerns with any metal salts advocated as lead acetate substitutes. A systematic study was undertaken comparing various amounts of two commercial clarification aids (Octapol and Clearpol) and Diatomaceous Earth (DE) on the filtration of Louisiana factory juices through coarse filter paper (27 µm pore size) for their effect on the accuracy of polarimetric measurement at 589 nm, and how they compare to HPLC (high-performance liquid chromatography) values. Octapol had a significantly (P < 0.05) higher density (0.615 g/cm3) than Clearpol (0.440 g/cm3); thus, for the same volume, slightly less mass of Clearpol is added. The amounts of total salts (av. 17.6%) in Octapol were higher (P < 0.05) than in Clearpol (av. 5.3%), with a much greater batch-to-batch variability. Excess amounts of Octapol caused an increase in the filtrate dry substance content and decreased polarimetric and HPLC sucrose contentss; this phenomenon also occurred for Clearpol but to a much lesser extent. The dry substance increase in the filtrate juice was due to soluble mineral salts from the aids dissolving. Overall, this study highlights the importance of standardizing clarification aids for polarimetric measurement and the need for batches or lots of such aids to be monitored for critical components affecting the polarimeter readings, e.g., total salts. A greater risk is being taken when using aids that contain relatively high amounts of salts (>~6%) because results are more susceptible to inaccuracy when excessively dosed.
Falling-film evaporators (FFE) have been adopted as a standard feature for juice evaporation in beet sugar factories for decades. In recent years, cane sugar factories have accepted FFE as an alternative technology for the juice evaporation station. Operational experience and exclusive investigations in recent years on the use of falling-film evaporators in the cane sugar industry clearly show the advantages for sustainable sugar production. Recent findings regarding heat-transfer coefficients k of individual FFEs, the effect of scale deposition on the k of first-effect FFE, reduction in exhaust steam demand and lower sucrose losses for evaporator stations comprising entirely of falling-film type evaporators are summarised and discussed.
