Sugarcane Management Research Articles

Driving sustainability in the sugarcane industry: Life Cycle Assessment of conventional and emerging spraying technologies in Tanzania

Sugarcane dominates global sugar and bioethanol production, involving extensive cultivation and supply chain activities. The sugarcane development encounters challenges, such as climate change, diseases, pests, and water scarcity, affecting growth and yields. Sugarcane management often involves the use of pesticides, which risk soil and water contamination. It also leads to biodiversity loss, high water use, greenhouse gas emissions, and energy consumption. This study conducted a life cycle assessment to compare the environmental impacts of cropdusters and drones in ripener application for sugarcane farming. The life cycle assessment enables informed decisions on sustainable practices by providing a holistic view of environmental impacts, facilitating comparisons, and identifies hotspots. The analysis examined the impacts of machinery, ripener compounds, and spraying operations. It explored using sugarcane waste (bagasse) as bioenergy for drone batteries or cropdusters. Results show that drones minimize environmental impacts by 11,557 kgCO2eq, 128,079 MJ, and 103 m3 for 40 ha farm compared to using cropdusters. Also, bagasse from a 40-ha farm can generate 1.93E+09 Wh of bioenergy, enough to charge drone batteries for spraying over approximately 4.9 million ha or to fuel cropdusters for 0.04 million ha of sugarcane. Conclusively, emerging technologies help to reduce environmental impacts and align with sustainable development goals, SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation, and Infrastructure), SDG 12 (Responsible Consumption and Production), and SDG 15 (Life on Land). These goals promote renewable energy, enhance agricultural efficiency, and ensure sustainable resource management, fostering a global transition to sustainable practices.

Effect of crop management and climatic factors on weed control in sugarcane intercropping systems

ContextCover crops in intercropping systems have a high potential to manage weeds in tropical agroecosystems as an herbicide alternative. However, it still needs to be better investigated in sugarcane cropping systems. ObjectiveThis study assesses the weed control ability of cover crops in sugarcane intercropping systems depending on crop management and climate in tropical conditions. MethodsThis study was based on a set of eight experiments, including ten cover crop species, performed from 2012 to 2021 in three areas in Reunion Island (France) and comparing three inter-row management treatments: i) chemical weed control, ii) cover crops sown in the inter-row, and iii) low weed control. Mean weed and cover crop ground cover were measured during the entire crop cycle, and the complementary weed management practices (herbicide, manual weeding) were also recorded. Sugarcane yield and crop management were evaluated to assess the economic impact of a change in practice. ResultsMean weed ground cover was reduced by 51 % in the cover crop and chemical treatments compared to low control. Additionally, the cover crop treatment had an herbicide treatment frequency index lower by 37 % compared to chemical treatment but a higher number of manual weedings. In all treatments, weed cover increased with rainfall and temperature. In the cover crop treatment, a structural equation modeling approach allowed us to highlight the influence of cover crop (sowing date and species) and sugarcane management (crop cycle - plant or ratoon crop) on weed cover. Weed cover decreased with an increase in cover crop ground cover, which was higher for the early sowing date. Additionally, weed cover was lower in ratoon crops than plant crops but increased over time since intercropping was implemented. Finally, sugarcane yield was lower by 6 % in cover crop treatment compared to chemical treatment. The change in operating costs and revenues between these crop management induced a decrease in profits in intercropping compared to chemical cropping systems, variable according to the degree of mechanization. ConclusionsThis study highlights the predominance of management factors, compared with climate, to explain the effectiveness of weed control in sugarcane intercropping systems. ImplicationsDue to the change in weed cover over time, there is a need to assess the long-term sustainability of this practice and the potential change in weed communities.

Fate and toxicity of 2,4-D and fipronil in mesocosm systems

2,4-D and fipronil are among Brazil's most used pesticides. The presence of these substances in surface waters is a concern for the aquatic ecosystem health. Thus, understanding the behavior of these substances under environmentally relevant conditions is essential for an effective risk assessment. This study aimed to determine the degradation profiles of 2,4-D and fipronil after controlled application in aquatic mesocosm systems under influencing factors such as environmental aspects and vinasse application, evaluate pesticide dissipation at the water-sediment interface, and perform an environmental risk assessment in water and sediment compartments. Mesocosm systems were divided into six different treatments, namely: control (C), vinasse application (V), 2,4-D application (D), fipronil application (F), mixture of 2,4-D and fipronil application (M), and mixture of 2,4-D and fipronil with vinasse application (MV). Pesticide application was performed according to typical Brazilian sugarcane management procedures, and the experimental systems were monitored for 150 days. Pesticide dissipation kinetics was modeled using first-order reaction models. The estimated half-life times of 2,4-D were 18.2 days for individual application, 50.2 days for combined application, and 9.6 days for combined application with vinasse. For fipronil, the respective half-life times were 11.7, 13.8, and 24.5 days. The dynamics of pesticides in surface waters resulted in the deposition of these compounds in the sediment. Also, fipronil transformation products fipronil-sulfide and fipronil-sulfone were quantified in water 21 days after pesticide application. Finally, performed risk assessments showed significant potential risk to environmental health, with RQ values for 2,4-D up to 1359 in freshwater and 98 in sediment, and RQ values for fipronil up to 22,078 in freshwater and 2582 in sediment.

Exposure to fipronil, 2,4-D and vinasse influences macroinvertebrate assemblage structure: An experimental mesocosm approach

Sugarcane is one of the main monocultures in Brazil and widely uses herbicide 2,4-D and fipronil insecticide. In addition, vinasse can be mentioned as it is widely used in this plantation. These compounds occurring simultaneously in the aquatic environment can potentiate the deleterious effects on organisms. Thus, this study aimed to evaluate the composition, abundance and ecological indices of the benthic macroinvertebrate community, as well as its ability to reestablish itself considering environmental contamination by the pesticides Regent® 800WG (active ingredient - a.i. fipronil) (F) and DMA® 806BR (a.i. 2,4-D) (D) and vinasse (V), alone and in mixtures: pesticides - M and the three contaminants - MV. The study was conducted using open-air mesocosms. The macroinvertebrate community was monitored by colonization structures, the physical-chemical parameters, metals and pesticides were determined and the effects of contaminants were evaluated over the exposure time in 1, 7, 14, 28, 75 to 150 days. A multiple regression was performed between the water parameters and significant relationships were found between parameters associated with vinasse contamination (pH, total nitrogen, turbidity, and dissolved oxygen) and concentration of fipronil and the ecological variables studied. Over time, changes were observed in the composition of the community. The dominance and richness increased in treatments V and MV. The family Chironomidae and subclass Oligochaeta were more sensitive to the treatment V and MV, while individuals from the families Phoridae, Ephydridae and Sciomyzidae were occasionally found (depending on the experimental time) in these treatments. The insects were sensitive to treatments F and M, disappearing in these mesocosms after contamination, reappearing only after 75 days. The results reveal that sugarcane management practices associated with the use of pesticides and vinasse as fertilizer pose risks to the macroinvertebrate community with consequences for the trophic chains, given its importance in freshwater ecosystems and adjacent terrestrial environments.

Farmers’ Perspectives on Sugarcane Management in Nepal: Empirical Evidence from Logistic Regression Model

he majority of rural poor in this country, as in most developing countries including Nepal, is dependent upon agriculture. In spite of sugarcane is a major economic crop, Nepalese sugarcane growers are getting problem day by day. The study was undertaken to analyze the viewpoints, attitudes, and perspectives of sugarcane growers on sugarcane cultivation and management among Nepalese farmers. The cognitive behavioral theory was applied to better understand how farmers’ behaviors and decision-making are influenced by their ideas, thoughts, and attitudes towards the industry. The study is based on explanatory research design and collected primary data using structured questionnaire. Following probability sampling techniques, cluster sampling is used to select 280 sugarcane farmers from at ward no. 3,8,9, and 10 of Kabilashi Municipality, a most sugarcane growers in Sarlahi. Data collection was made using kobo toolbox and observation methods. The Binary Logistic Model was used for analyzing farmers’ perspectives on sugarcane management. Results indicate that (80%) sugarcane growers are not getting paid on time and in full. Similarly, the logit model revealed that farmers are well aware of sugarcane management since factors were found to be statistically significant at a desirable probability level in the logit model. The study concludes that although Nepal has a lot of potential to enhance sugarcane production, but the full potential has not yet been fully realized. In this context, the findings of this research will be beneficial for the Ministry of Agriculture, policymakers, and the government to understand the challenges and issues faced by sugarcane growers and to develop policies and solutions to address these issues. How to Cite: Niranjan Devkota, Alika Kumari, Sahadeb Upretee, Devid Kumar Basyal, Surendra Mahato, Deependra Karki, Udaya Raj Paudel, Seeprata Parajuli, Krishna Dhakal, 2023. "Farmers’ Perspectives on Sugarcane Management in Nepal: Empirical Evidence from Logistic Regression Model." Journal of Agriculture and Crops, vol. 9, pp. 222-232.

Productivity and penalty in sugarcane from three meteorological databases in Jataí-GO

The agroecological zone model proposed by FAO (ZAE/FAO) is an important tool in agricultural planning and can be used in Jataí, which has been gaining space in the production of sugarcane. The objective of this study was to compare the observed meteorological databases (BDMEP) with the estimated ones (Xavier and NASA POWER), in the estimation of potential productivity (PP) and attainable (PA) of sugarcane and its penalties for management (PMJ) and water deficit (PDF), using the ZAE/FAO model in the municipality of Jataí - GO. To this end, the BDMEP, Xavier and NASA POWER database, 33 years old (1984-2017), were used. Using BDMEP, Xavier and NASA POWER as input in the ZAE model, we observed an average PP of 259±11, 275±10 and 267±11 Mg ha-1 as, respectively. PA reaches 200 Mg ha-1 when using BDMEP in ZAE, with 50% of the crop year with PA above 180 Mg ha-1. There was an average penalty of 114.01±6.9 for management and 85.67±4.08 Mg ha-1 in stem yield. The meteorological variables of Xavier's database can be used in the ZAE model in the prediction of productivity penalty for water deficit and sugarcane management, with 63% and 88% adjustment to BDMEP, respectively. NASA POWER can be used in the simulation of penalty for failures in sugarcane management, with up to 87% approximation of those observed. Both sources when used in the prediction model assist in agricultural planning.

A review on integrated disease management of red rot of sugarcane caused by Colletotrichum falcatum

Red rot of sugarcane caused by Colletotrichum falcatum Went is one of the devastating diseases of sugarcane, causing significant loss to sugarcane production in India and other countries. However, varietal breakdown to red rot caused severe epiphytic in countries, particularly in Asia, where resistant varieties fail on a regular basis. In India between 1932 and 1942, a virulent strain of red rot materialized, which resulted in the withdrawal of numerous susceptible types and finally endangered the sugar industry. Among the pathogens of sugarcane Colletotrichum falcatum causes the most substantial economic loss (5-50%) in sugarcane. Because of the pathogen’s highly variable nature, which breaks red rot resistant varieties in a short period of time, breeding resistant varieties is the major challenge for sugarcane breeders. Currently, there is no feasible way to prevent the disease from spreading, so we need to follow integrated disease management. The red rot of sugarcane management will benefit from integration of cultural practices, resistant varieties, physical practices, biocontrol practices and chemical practices.

Carbon uptake of the sugarcane agroecosystem is profoundly impacted by climate variations due to seasonality and topography

Sugarcane is an economically important crop whose growth and carbon uptake play vital roles in the carbon cycle, food security, and global trade development. However, the response of the carbon uptake of sugarcane to climate variations and the influencing factors are still unclear. In this study, seven sugarcane plantation distribution maps during 2000 and 2018 in Guangxi, China, were generated using time series Landsat and Sentinel-2 imagery, and these maps were used to produce stable sugarcane sites by identifying pixels without land cover transformation. Time series gross primary production (GPP) and climate datasets were used to analyze the response of annual GPP to temperature, precipitation, and their interacting effects under different landforms (rugged ground and flat ground) and growing periods. The results showed a significantly positive correlation between annual GPP change and temperature variations. Extreme precipitation, including extreme drought and extreme wetness, caused the annual GPP to decrease sharply, except for extreme wetness in the early growing period. The decrease in annual GPP mainly appeared when extreme drought and hot conditions or extreme wet and cold conditions coexisted, ranging from −20.37% to −0.23%, while the increase in annual GPP especially appeared when non-extreme precipitation and high temperature co-occurred, ranging from 0.02% to 8.44%. In addition, the responses of sugarcane annual GPP change to extreme temperature and precipitation were significantly different between rugged and flat ground. Overall, this study indicated that spatiotemporal heterogeneities existed in the response of sugarcane carbon uptake to climate variations. In the future, effective measures should be adopted in sugarcane management and cultivation to reduce the negative effects of climate change on crop production. • Sugarcane’s carbon uptake response discrepantly to heat and water stresses. • Impacts of climate variations on sugarcane GPP varied with growing stages. • Rugged grounds change the response of sugarcane GPP to extreme climates.

Responses of Chironomus sancticaroli to the simulation of environmental contamination by sugarcane management practices: Water and sediment toxicity

Sugarcane management practices include the application of pesticides, including the herbicide 2,4-D and the insecticide fipronil. In addition, a by-product from the ethanol industry, called vinasse, is commonly applied to fertilize sugarcane areas. The potential risks of these practices to the edge-of-field aquatic ecosystems were assessed in the present study. This was done by contaminating mesocosms with (single and mixtures of) both pesticides and vinasse and evaluating the effects on the midge Chironomus sancticaroli through in-situ and laboratory bioassays. To this end, outdoor mesocosms were treated with fipronil (F), 2,4-D (D), and vinasse (V) alone and with the mixture of fipronil and 2,4-D (M), as well as with both pesticides and vinasse (MV). C. sancticaroli was deployed in mesocosms before contamination in cages, which were taken out 4- and 8-days-post-contamination. Water and sediment samples were also taken for laboratory bioassays on the first day of contamination, as well as 7-, 14-, 21-, 30-, 45-, and 75-days post-contamination. The responses assessed in subchronic assays (8-day) were survival, growth, head capsule width, development, and mentum deformities. Low survival occurred in the in-situ experiments of all treatments due to the low oxygen levels. In the laboratory tests, effects on survival occurred for F, V, and M over time after exposure to both water and sediment. All organisms died post-exposure to water samples from the MV treatment, even 75-days-post-contamination. Impairments in body length and head capsule width occurred for F, V, and M for water and F, V, M, and MV for sediment samples over time. All treatments increased mentum deformities in exposed larvae for any of the sampling periods. The negative effects observed were more significant in the mixture mesocosms (M and MV), thus indicating increased risks from management practices applying these compounds together or with a short time interval in crops.

Spatial Analysis of Soil Available Potassium and Plant Brix Content for Site Specific Nutrient Management in Sugarcane

There has been a tendency of decreasing sugarcane productivity (Saccharum officinarum Linn) in Indonesia due to poor soil available potassium. There has also been evidence that available soil potassium relates directly to soil condition. For this reason, the management of sugarcane engaging Site Specific Nutrient Management (SSNM) must be pursued. The first and most important stage in SSNM is assessing variability, which can be used to recommend particular fertilizer. This research’s main aim is to assess the variability of Potassium and Brix content for uses in the Potassium (K) fertilizer recommendation. The methodology used in this research is collecting data in the field, analyzing with Geographical Information Systems (GIS) using Kriging techniques, and developing a site-specific K prescription map. The results show that (1) spatial analysis assisted in developing a prescription map for K management in sugarcane; (2) spatially, the area can be classified into three classes (low, medium, and high) of K with the recommendation of 300 kg/ha (low), 200 kg/ha (medium) and 0 kg/ha (high) respectively. The results suggest that spatial analysis of soil available potassium and Brix content can provide a whole and specific picture of the area studied, which is beneficial for SSNM.

Effect of Trash Management of Sugarcane on Soil Organic Carbon Buildup and Sustaining Yields of Successive Ratoon Crop in Khammam District of Telangana

Effect of Trash Management of Sugarcane on Soil Organic Carbon Buildup and Sustaining Yields of Successive Ratoon Crop in Khammam District of Telangana

Vegetation indices as a Tool for Mapping Sugarcane Management Zones

In precision agriculture, the adoption of management zones (MZs) is one of the most effective strategies for increasing agricultural efficiency. Currently, MZs in sugarcane production areas are classified based on conventional soil sampling, which demands a lot of time, labor and financial resources. Remote sensing (RS) combined with vegetation indices (VIs) is a promising alternative to support the traditional classification method, especially because it does not require physical access to the areas of interest, is cost-effective and less labor-intensive, and allows fast and easy coverage of large areas. The objective of this study was to evaluate the ability of the normalized difference vegetation index (NDVI) and the two-band enhanced vegetation index (EVI2) to classify sugarcane MZs, compared with the conventional method, in the Brazilian Cerrado biome (savannah), where about half of Brazil´s sugarcane production takes place. This study used historical crop production data from 5,500 production fields in three agricultural years (2015 to 2018) and NDVI and EVI2 values of 14 images acquired by the Landsat 8 satellite from 2015 to 2018 in Google Earth Engine (GEE). Although improvements are still necessary and encouraged, a new methodology of classifying MZs according to VIs was proposed in this study. The NDVI was not correlated with MZs classified using the conventional method, whereas EVI2 was more sensitive to biomass variations between MZs and, therefore, could better discriminate between MZs. The EVI2 values measured in crops aged 180 to 240 days in the rainy season proved to be the best strategy for classifying MZs by RS, where MZ A, for example, had EVI2 of 0.37, compared to MZ E, which had an EVI2 of 0.32.

Diversity of ground-dwelling ants in sugarcane plantations under different management systems

AbstractIn this study, we compared the richness of ground-dwelling ants among three different sugarcane management systems (with the application of the insecticide fipronil and the addition of vinasse; with fipronil and no vinasse; and with vinasse and no fipronil, i.e., an organic production system) to evaluate whether the feeding/foraging types vary according to the management system. We tested the hypothesis that organic management increases species diversity because there is no use of chemical inputs. Estimated species richness was significantly higher in the organic management system than in the systems that used fipronil with vinasse. Generalists species were prevalent in all sugarcane fields, regardless of the production system, whereas predatory and fungivorous species were infrequent. However, the organically managed field had many predatory species. Our results suggest that fipronil with vinasse in sugarcane cultivation alters the ant community, possibly disrupting the functions performed by the edaphic fauna, such as control of arthropod crop pests, due to reduced predator species richness.

Development of a Phenology-Based Method for Identifying Sugarcane Plantation Areas in China Using High-Resolution Satellite Datasets

Sugarcane is an important sugar and biofuel crop with high socio-economic importance, and its planted area has increased rapidly in recent years. China is the world’s third or fourth sugarcane producer. However, to our knowledge, no study has investigated the mapping of sugarcane cultivation areas across entire China. In this study, we developed a phenology-based method to identify sugarcane plantations in China at 30-m spatial resolution from 2016–2020 using the time-series of Landsat and Sentinel-1/2 images derived from Google Earth Engine (GEE) platform. The method worked by comparing the phenological similarity in normalized difference vegetation index (NDVI) series between unknown pixels and sugarcane samples. The phenological similarity was assessed using the time-weighted dynamic time warping method (TWDTW), which has less sensitivity to training samples than machine learning methods and therefore can be easily applied to large areas with limited samples. More importantly, our method introduced multiple and moving time standard phenological curves of sugarcane to the TWDTW by fully considering the variable crop life-cycle of sugarcane, particularly its long harvest season spanning from December to March of the following year. Validations showed the method performed well in 2019, with overall accuracies of 93.47% and 92.74% for surface reflectance (SR) and top of atmosphere reflectance (TOA) data, respectively. The sugarcane maps agreed well with the agricultural statistical areas from 2016–2020. The mapping accuracies using TOA data were comparable to SR data in 2019–2020, but outperformed SR data in 2016–2018 when SR data had lower availability on GEE. The sugarcane maps produced in this study can be used to monitor growing conditions and production of sugarcane and, therefore, can benefit sugarcane management, sustainable sugarcane production, and national food security.

Irrigated sugarcane crops improve the quality of soil organic carbon over time

The substitution of native vegetation in agricultural systems can cause several changes in the chemical and physical soil attributes, and in the dynamics of soil organic carbon. This study aimed to evaluate changes in soil physical attributes and carbon stock in soil organic matter fractions in irrigated sugarcane crops, as a function of land use and straw management practices over time, in the North of Minas Gerais State, Brazil. Four sugarcane fields with different ages and management systems were studied: Cane 6, Cane 7, Cane 8, and Cane 10. The data obtained were compared with a native vegetation area located near the sugarcane fields, and used as reference for unmanaged soil. In each system, soil samples were collected in the 0-10, 10-20, and 20-30 cm depth layers, to determine the physical attributes, the total organic carbon, and the physical fractions of the soil organic matter. We found that the sugarcane management with the maintenance of a part of the straw on the soil surface contributes to the preservation of the soil structure and the most stable fractions of organic carbon over time. However, in the regions with high annual mean temperature and in the irrigated systems, the soil tillage for the renewal of the sugarcane fields significantly decreases the total soil organic carbon.

CLASSIFICATION OF SUGARCANE YIELDS ACCORDING TO SOIL FERTILITY PROPERTIES USING SUPERVISED MACHINE LEARNING METHODS

Action planning and decision-making in the sugarcane management chain depend on yield estimates, which, in turn, vary with the soil. This study aimed to describe an applicable method of classifying sugarcane productivity into three categories, based on soil properties (medium, low, and high), determining which is most associated with biomass production. To this end, we applied the machine learning methods Naïve Bayes, Decision Trees, and Random Forest, as they proved to be useful tools for faster and more accurate results. Our results indicate that Random Forest is the most suitable for classifying all yield categories, and Naïve Bayes had good results for classification into “medium” and “low” and potential for solving multiclass problems in agriculture. Organic matter was the property most closely related to sugarcane biomass yield by the Random Forest and Decision Trees algorithms. The methods described can be used to obtain subsidies for sugarcane chain management, contributing to more sustainable decisions.

Remote Sensing Applications in Sugarcane Cultivation: A Review

A large number of studies have been published addressing sugarcane management and monitoring to increase productivity and production as well as to better understand landscape dynamics and environmental threats. Building on existing reviews which mainly focused on the crop’s spectral behavior, a comprehensive review is provided which considers the progress made using novel data analysis techniques and improved data sources. To complement the available reviews, and to make the large body of research more easily accessible for both researchers and practitioners, in this review (i) we summarized remote sensing applications from 1981 to 2020, (ii) discussed key strengths and weaknesses of remote sensing approaches in the sugarcane context, and (iii) described the challenges and opportunities for future earth observation (EO)-based sugarcane monitoring and management. More than one hundred scientific studies were assessed regarding sugarcane mapping (52 papers), crop growth anomaly detection (11 papers), health monitoring (14 papers), and yield estimation (30 papers). The articles demonstrate that decametric satellite sensors such as Landsat and Sentinel-2 enable a reliable, cost-efficient, and timely mapping and monitoring of sugarcane by overcoming the ground sampling distance (GSD)-related limitations of coarser hectometric resolution data, while offering rich spectral information in the frequently recorded data. The Sentinel-2 constellation in particular provides fine spatial resolution at 10 m and high revisit frequency to support sugarcane management and other applications over large areas. For very small areas, and in particular for up-scaling and calibration purposes, unmanned aerial vehicles (UAV) are also useful. Multi-temporal and multi-source data, together with powerful machine learning approaches such as the random forest (RF) algorithm, are key to providing efficient monitoring and mapping of sugarcane growth, health, and yield. A number of difficulties for sugarcane monitoring and mapping were identified that are also well known for other crops. Those difficulties relate mainly to the often (i) time consuming pre-processing of optical time series to cope with atmospheric perturbations and cloud coverage, (ii) the still important lack of analysis-ready-data (ARD), (iii) the diversity of environmental and growth conditions—even for a given country—under which sugarcane is grown, superimposing non-crop related radiometric information on the observed sugarcane crop, and (iv) the general ill-posedness of retrieval and classification approaches which adds ambiguity to the derived information.

Effects of Sugarcane and Soybean Intercropping on the Nitrogen-Fixing Bacterial Community in the Rhizosphere.

Intercropping between sugarcane and soybean is widely used to increase crop yield and promote the sustainable development of the sugarcane industry. However, our understanding of the soil microenvironment in intercropping systems, especially the effect of crop varieties on rhizosphere soil bacterial communities, remains poor. We selected two excellent sugarcane cultivars, Zhongzhe1 (ZZ1) and Zhongzhe9 (ZZ9), from Guangxi and the local soybean variety GUIZAO2 from Guangxi for field interplanting experiments. These two cultivars of sugarcane have good drought resistance. Rhizosphere soil samples were collected from the two intercropping systems to measure physicochemical properties and soil enzyme activities and to extract total soil DNA for high-throughput sequencing. We found that the diversity of the rhizosphere bacterial community was significantly different between the two intercropping systems. Compared with ZZ1, the ZZ9 intercropping system enriched the nitrogen-fixing bacteria, increasing the available nitrogen content by 18% compared with that with ZZ1. In addition, ZZ9 intercropping with soybean formed a more compact rhizosphere environment than ZZ1, thus providing favorable conditions for sugarcane growth. These results provide guidance for the sugarcane industry, especially for the management of sugarcane and soybean intercropping in Guangxi, China.

Avoiding burning practice and its consequences on the greenhouse gas emission in sugarcane areas southern Brazil.

There is a growing need of sustainable solutions for balancing agricultural production with the reduction of its environmental impacts. The rapid increase in sugarcane cultivation and the progressive conversion of pre-harvest burning (BH) to green harvest (GH) have brought into debate the contribution of agricultural sector to the greenhouse gas (GHG) mitigation. This study focused on the estimated GHG emission from sugarcane cultivation during years in which sugarcane areas in southern Brazil expanded and passed throughout an important transition, from 2006 to 2012, when harvest adopted was changed from burned to not-burned based. Sugarcane management and harvest were mapped through visual interpretation of Landsat-type satellite images, and the areas under sugarcane cultivation were distinguished according to each agricultural phase and harvest regime (i.e., manual harvest with burning vs. green mechanized harvest). Based on a broad data review and applying the IPCC (2006) methodologies, the results were expressed in terms of kilograms of carbon dioxide equivalent (kg CO2eq ha-1). Avoiding burn prior to harvest, even during expansion of sugarcane areas, promoted a mean reduction of GHG emission from 901 to 686 kg CO2eq ha-1 relative to harvest phase (24% lower) and an increase from 1418.3 to 1507.9 kg CO2eq ha-1 related to the ratoon maintenance phase (6% higher). Analyzing the total GHG emission per unit of cultivated sugarcane area (hectare), it was observed a decrease from 2275 to 2034 kg CO2eq ha-1 (11% reduction). The gradual transition of pre-harvest burning on that period has contributed to the reduction of GHG emission associated with sugarcane production being an important step towards GHG mitigation while still providing more sustainable sugar and ethanol production in southern Brazil.

A low cost method for early detection of airborne Puccinia rust spores using glass slides and foldscope in the sugarcane field

The rust pathogens (Puccinia spp.) affect many cereals, pulses and sugar crops causing a major threat to crop production and productivity throughout the world. The sugarcane crop is being affected by Puccinia melanocephala and P. kuehnii causing brown and orange rust respectively. Sugarcane rust is an important constraint in popularizing the new and high potential varieties due to its appearance on the foliage. Under the changing climatic conditions many popular cultivars are showing rust infection from mild to severe form depending on the weather conditions during the crop seasons. Being an obligate pathogen, the rust is present on sugarcane throughout the year but the appearance and severity is highly influenced by the weather parameters such as temperature, relative humidity and the physiological maturity of the crop. Trapping the uredospores using Vaseline coated microscopic glass slides helped to determine the inoculum load at various time intervals in the air. The uredospores can be observed with the help of Foldscope, which broadens the scope of detection of uredospores without depending on the compound microscope in remote areas. By connecting with the mobile phone, the spores can be photographed and digital pictures can be shared for further confirmation. The frequency and quantity of the uredospores trapped will help in quantifying the spores in the field for management of sugarcane rust well in advance before the appearance of the symptoms in hot spot areas. This simple tool will be a boon for detection of rust spores in the field during the latent period before the appearance of the symptoms thus enabling management of rust in time.