Sugarcane Production Areas Research Articles

Agent-Based Spatial Dynamic Modeling of Diatraea saccharalis and the Natural Parasites Cotesia flavipes and Trichogramma galloi in Sugarcane Crops

In recent years, sugarcane production areas in Brazil have experienced a slower evolution in productivity, and one of the reasons for this is related to the increase in phytosanitary problems, such as the presence of pests. Nevertheless, limited attention has been paid to the development of tools for simulating the spatial dynamics of pests, including their impact on production. This study aims to simulate the potential population growth and dispersal of Diatraea saccharalis (sugarcane borer) in sugarcane crop fields and its estimated impacts on this crop production and to simulate biological control strategies. We developed an agent-based model to simulate the pest population and its dispersal in a one-hectare sugarcane crop field in Pederneiras, São Paulo, Brazil, delimited with the aid of satellite imagery, considering two scenarios: the first without biological control and the second with biological control using the parasites Trichogramma galloi and Cotesia flavipes. The model was developed using the NetLogo 6.3.0 software. The results indicate that the model accurately reproduced the infestation rates reported in the literature. Additionally, it provided insights into expected pest dispersal, potential production losses, and how the use of T. galloi in association with C. flavipes could mitigate production losses. We believe that the model can be used to simulate different biological control strategies and the implementation of integrated pest management (IPM) to achieve adequate control levels and greater productivity in sugarcane production.

Endophytic Beauveria bassiana in sugarcane and associated Eldana saccharina host plants in South Africa

Eldana saccharina Walker is a problematic sugarcane stalk borer pest in South Africa. Twenty-eight sugarcane genotypes (Saccharum spp. hybrids) and seven different species of host plants of E. saccharina were surveyed for the presence of endophytic Beauveria bassianasensu lato (s.l.). Collectively, 326 plant samples (roots, stems, or leaves) were collected from five locations in sugarcane-producing areas (KwaZulu-Natal; South Africa). Following plant surface disinfection, 128 fungal colonies morphologically resembling Beauveria spp. were isolated from internal plant tissues. The sequence analysis of the internal transcribed spacer region confirmed that 13 representative isolates were B. bassiana.s.l. Eight B. bassiana isolates were recovered from E. saccharina natural host plants, and 120 from different sugarcane stem parts (top node, top internodes, bottom node, and bottom internode). Endophytic B. bassiana isolates were recovered from 22 of 28 sugarcane genotypes surveyed. The number of B. bassiana isolates obtained from different sugarcane parts differed significantly, with more B. bassiana isolates obtained from the top than the bottom internodes. Furthermore, sugarcane genotypes N31 and N41 yielded B. bassiana from all plant parts sampled, while five sugarcane genotypes harbored no B. bassiana isolates. This study demonstrates for the first time the natural occurrence of endophytic B. bassiana strains in sugarcane plants and E. saccharina host plants in South Africa.

Combined effect of silicon and nitrogen doses applied to planting furrows on sugar, biomass and energy water productivity of sugarcane (Saccharum spp.)

Brazil has the largest cultivated area for sugarcane in the world, with a predominance of rain-fed production systems (64%) and marginal areas that are subject to frequent water deficits. The remaining 36% under cultivation is equipped with irrigation systems; however, a significant portion of these irrigation systems (76%) is dedicated to crop maintenance. Their primary purpose is to provide water for initial plant maintenance during planting and regrowth of ratoons, which helps to alleviate drought stress caused by water scarcity during dry periods. The remaining 24% of the irrigated sugarcane production areas use deficit and full irrigation strategies to partially (50%) and fully (100%) meet the plants’ water demands, respectively. Therefore, a large part of the cultivated area for sugarcane in Brazil is subject to a water deficit at one or more stages of the crop's development cycle, which can retard plant growth, nutrient use and productivity. One potential strategy for mitigating these harmful effects is the application of silicon (Si) in the furrow at planting, which can also increase crop water productivity (WPc). The objective of this research was to determine the effects of different applications of Si and nitrogen (N) on WPc, in terms of sugar (SWPc), biomass (BWPc) and energy (ENWPc) for sugarcane crop. The research was conducted at the University of São Paulo (USP/ESALQ), Piracicaba, São Paulo State, Brazil. The experimental design involved randomized blocks, with four blocks and 12 treatments. The treatments consisted of three applications of Si, 175, 350 and 525 kg·ha−1 and four N treatments of 15, 30, 60 and 90 kg·ha−1. Biometric responses, effects on juice quality, and indices related to yield and WPc were determined. The water consumption and agricultural yield (AY) of sugarcane were clearly influenced by the treatments. The lowest water consumption was obtained with the 15Nx350Si treatment, 561 mm per year. The treatment with the highest AY value was 60Nx350Si (162.3 Mg·ha−1). The SWPc, BWPc and ENWPc of the sugarcane crop were affected by the different application rates of N and Si. In general, the highest average WPc values were obtained with the 15Nx350Si treatment (SWPc=2.6 kg·m−3, BWPc=10 kg·m−3 and ENWPc=224.5 MJ·m−3). The different N and Si treatments did not significantly affect biometric variables (except for fresh biomass and leaf area) or juice quality; therefore, Si application did not compromise the quality of the end-product.

A protective foliar complex boosts sugarcane quality and energy yield by reducing oxidative stress under drought

AbstractWater stress negatively impacts plant morphology and physiology by inducing metabolic oxidative stress, which leads to cellular damage. Applying nutrients and/or organic molecules, such as amino acids, may mitigate the effects of drought stress. In the present study, the effects of a protective foliar complex (PFC) on late‐harvest sugarcane (Saccharum spp L.) (dry season) were evaluated. Four field experiments were carried out in commercial areas of sugarcane production in the central‐south region of Brazil using sugarcane variety CTC4: in the fourth and second ratoons in 2019 and in the fifth and third ratoons in 2020. The treatments consisted of foliar application or no application of the PFC at the beginning of the dry period in June. The PFC was applied at a dose of 10 L ha−1 in a water volume of 100 L ha−1. PFC application increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in sugarcane leaves. PFC application also reduced leaf levels of malondialdehyde and hydrogen peroxide (H2O2). On average, PFC application increased sucrose accumulation by 2.26 and 1.74 Mg ha−1 in 2019 and 2020, respectively, indicating improved raw material quality. In addition, PFC application mitigated damage caused by drought, with average increases in stalk productivity of 10.7 and 7.6 Mg ha−1 in 2019 and 2020, respectively. The positive effects of PFC application on plant antioxidant enzymes enabled greater biomass accumulation and, in turn, higher energy cogeneration.

Predicting Sugarcane Yield via the Use of an Improved Least Squares Support Vector Machine and Water Cycle Optimization Model

As a raw material for sugar, ethanol, and energy, sugarcane plays an important role in China’s strategic material reserves, economic development, and energy production. To guarantee the sustainable growth of the sugarcane industry and boost sustainable energy reserves, it is imperative to forecast the yield in the primary sugarcane production regions. However, due to environmental differences caused by regional differences and changeable climate, the accuracy of traditional models is generally low. In this study, we counted the environmental information and yield of the main sugarcane-producing areas in the past 15 years, adopted the LSSVM algorithm to construct the environmental information and sugarcane yield model, and combined it with WCA to optimize the parameters of LSSVM. To verify the validity of the proposed model, WCA-LSSVM is applied to two instances based on temporal differences and geographical differences and compared with other models. The results show that the accuracy of the WCA-LSSVM model is much better than that of other yield prediction models. The RMSE of the two instances are 5.385 ton/ha and 5.032 ton/ha, respectively, accounting for 7.65% and 6.92% of the average yield. And the other evaluation indicators MAE, R2, MAPE, and SMAPE are also ahead of the other models to varying degrees. We also conducted a sensitivity analysis of environmental variables at different growth stages of sugarcane and found that in addition to the main influencing factors (temperature and precipitation), soil humidity at different depths had a significant impact on crop yield. In conclusion, this study presents a highly precise model for predicting sugarcane yield, a useful tool for planning sugarcane production, enhancing yield, and advancing the field of agricultural production prediction.

Climate Variations in the Low-Latitude Plateau Contribute to Different Sugarcane (Saccharum spp.) Yields and Sugar Contents in China.

In China, the main sugarcane (Saccharum spp.) planting areas can be found in the low-latitude plateau (21° N-25° N, 97° E-106° E), which has most of the natural ecological types. However, there is limited information on the climate conditions of this region and their influence on sugarcane yield and sucrose content. Monthly variations in the main climate factors, namely, average air temperature (AAT), average relative humidity (ARH), average rainfall amount (ARA), and average sunshine duration (ASD), from 2000 to 2019 and sugarcane yield and sucrose content of 26 major sugarcane-producing areas from 2001/2002 to 2018/2019 were collected from the low-latitude plateau in Yunnan for studying the impact of climate variations on sugarcane yield and sucrose content. The results showed that AAT in the mid-growth season had a significant positive correlation with sucrose content (p < 0.05), and AAT in the late-growth season had a very significant positive correlation with sucrose content (p < 0.01). ARH in the mid-growth season had a significant positive correlation with sugarcane yield (p < 0.05). ARA in the early-growth season showed a significant positive correlation with sugarcane yield (p < 0.05). ASD in the late-growth season had a significant positive correlation with sugarcane yield (p < 0.05) and sucrose content (p < 0.01). The rainy and humid sugarcane areas were characterized by high ARA and ARH during the entire growth period, low AAT and ASD in the mid-growth season, and low AAT in the late-growth season, contributing to a high sugarcane yield, but not a high sucrose content. The low temperature and sunshine semi-humid sugarcane areas were characterized by the lowest AAT in the early and middle stages of sugarcane growth, less ASD in the early and middle stages, and less ARA in the early and late stages, which are unfavorable for sugarcane yield and sucrose content. The high temperature and humidity sugarcane areas were characterized by higher AAT and ARA, and moderate ASD during the entire growth period, resulting in good sugarcane growth potential and contributing to the sugarcane yield and sucrose content. The semi-humid and multi-sunshine sugarcane areas were characterized by the lowest ARH in the entire growth period, the lowest ARA in the middle and late seasons, and the longest ASD, contributing to an increase in sucrose content. The humid and sunny areas were characterized by the longest ASD and high ARH in the early and late seasons of sugarcane growth and moderate AAT and ARA during the entire growth season, which are beneficial for high sugarcane yield and sucrose content. Overall, these findings suggest that the sugarcane variety layout should be based on the climate type (of which there are five in the plateau), and corresponding cultivation practices should be used to compensate for the climatic conditions in various growth stages.

Mucuna pruriens cannot develop phytoremediation of tebuthiuron in agricultural soil with vinasse: a morphometrical and ecotoxicological analysis.

Pesticides offer stakeholders cost-effective solutions to control weeds. Nevertheless, such active compounds can manifest as severe environmental pollutants when escaping from agroecosystems into surrounding natural ecosystems, driving the need to remediate them. We, hence, analyzed whether Mucuna pruriens can develop a potential phytoremediator for treating tebuthiuron (TBT) in soil with vinasse. We exposed M. pruriens to microenvironments containing tebuthiuron at 0.5, 1, 1.5, and 2 (standard dose) Lha-1 and vinasse at 75, 150 (industrial recommendation), and 300m3·ha-1. Experimental units without organic compounds represented controls. We assessed M. pruriens for morphometrical features, such as plant height and stem diameter and shoot/root dry mass, over approximately 60days. We obtained evidence for M. pruriens not effectively removing tebuthiuron from the terrestrial medium. Such a pesticide developed phytotoxicity, significantly limiting its germination and growth. The higher the dose, the more negatively the tebuthiuron impacted the plant. In addition, introducing vinasse into the system, irrespective of volume, intensified the damage to photosynthetic and non-photosynthetic structures. Equally important, its antagonist action further decreased the production and accumulation of biomass. As M. pruriens could not effectively extract tebuthiuron from the soil, it could allow neither Crotalaria juncea nor Lactuca sativa to grow on synthetic media containing residual pesticide. An atypical performance of such testing (tebuthiuron-sensitive) organisms over independent ecotoxicological bioassays validated inefficient phytoremediation. Hence, M. pruriens could not offer a functional remediative option to treat environmental pollution by tebuthiuron in agroecosystems where vinasse occurs, such as sugarcane-producing areas. Although M. pruriens considered a tebuthiuron phytoremediator as cited in the literature, satisfactory results did not occur in our research due to high concentrations of vinasse in the soil. Therefore, this information requires more specific studies about the influence of high concentrations of organic matter on M. pruriens productivity and phytoremediation performance.

Mulched and soil-incorporated sugarcane greenchop residue and compost: effects on selected soil components, sugarcane nutrients, Mexican rice borer injury, and yield

Burning sugarcane, Saccharum spp., fields to remove leaves before harvest is a routine practice in many sugarcane production areas, including the United States. The method is environmentally deleterious and has been discontinued in some parts of the world. Alternatively, excised preharvest leaf residue, or greenchop, is used as mulch. This field study examined the effects of greenchop, applied in several ways to sugarcane soil, on soil fertility, selected sugarcane plant physiochemicals, injury inflicted by the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), and sugarcane yield parameters, compared to plots augmented by soil-incorporated compost and a nontreated control. The compost amended soil had elevated concentrations of many nutrients, and in sugarcane leaves, heightened concentrations of certain sugars and free amino acids. None of the greenchop treatments affected soil and sugarcane leaf nutrients. During the first year of the study, E. loftini injury to sugarcane stalks during the first season, however, was generally greater in the greenchop and compost treatments than in the control. In the second growing season, the compost treatment was the only treatment associated with heightened E. loftini infestations. Relationships between soils augmented with organic amendments and E. loftini injury to sugarcane are discussed in terms of mediation through physiochemical changes induced by the amendments.

Compromissos nacionais assumidos na COP21 e seus impactos no setor sucroenergético.

The present work discusses the possible impacts on the sugarcane production area due to the agreement signed at COP21. Energy Security is probably the biggest challenge of our century, mainly because we need clean energy. And this is one of the strongest characteristics of the Brazilian sugarenergy sector, which is largely responsible to produce bioelectricity and, mainly, biofuel, in addition to also producing sugar and other products. Through the analysis of the capacity of sugarcane production facilities, possible cases of increase in area, production, and productivity will be discussed to meet the official commitments assumed at COP21Key-words: rural administration, coffee, management, rural organization.

The influence of sugarcane pre‐harvest fire on hantavirus prevalence in Neotropical small mammals

AbstractThe use of pre‐harvest fire in sugarcane fields surprisingly results in an increase in the abundance of Neotropical Sigmodontinae rodents, which might carry hantavirus. By contrast, fire suspension induces a decline in rodents in the first 5 years. The present study aimed to evaluate the effect of sugarcane harvest regimes on hantavirus prevalence in wild rodents. Field collections were carried out on a sugarcane production area in Northeast São Paulo, which is responsible for 30% of the ethanol production in Brazil. A few years after pre‐harvest fire suspension, a high prevalence of hantavirus was found in small rodents at lower population density, but apparently higher population growth rate. Differences in life cycle between the rodents and their predators may explain such density patterns, as small rodents can breed twice or even three times each year, whereas their predators usually breed only once a year. Similarly, the temporal dynamics of the predator–prey relationship suggests that hantavirus prevalence is related to small rodent's population growth and not density. OnlyAkodon montensis,Calomys tener, andNecromys lasiuruscontained immunoglobulin G antibodies against the recombinant nucleoprotein ofAraraquara orthohantavirus, a genotype ofAndes orthohantavirus, with no interspecific variation in seroprevalence among these species. However, males presented higher prevalence rate than females, possibly due to a male‐biased dispersal pattern and a higher frequency of antagonistic interactions. Governance measures to mitigate the role of small wild rodents on the emergence of hantavirus in agricultural landscapes dominated by sugarcane plantations should include the use of wildlife‐friendly management techniques (e.g., to mitigate the mortality of the predators of small rodents), human capacity building concerning wildlife‐related conflicts, and multifunctionality of agricultural landscapes. Future studies should prioritize the possible relationship between microhabitat structure and hantavirus prevalence in small rodents in agricultural landscapes dominated by sugarcane fields.

Peramalan Jumlah Produksi Tebu Menggunakan Metode Time Series Model Moving Averages

Plantation is all activities that use certain and specific plants with soil or other parts of plants in adapted ecosystems. Other plantation activities also include processing and marketing of these crops. In the plantation sub-sector, sugar cane is an important plantation and national economic development strategy and contributes significantly to the plantation sub-sector. Sugarcane is a plantation crop that is widely grown in Indonesia, such as in Java, North and South Sumatra. One of the sugarcane producing areas in Purworejo Regency is Loano District. There are many sugar factories scattered throughout the sugar cane development area and the leading sugarcane plants are in Purworejo Regency. The purpose of this research is to predict production to meet market demand using the Time Series method with the Moving Average model. This study uses a Moving Average model consisting of: Single Moving Average (SMA) and Weighted Moving Average (WMA) with forecasting accuracy using Mean Square Error (MSE) and Mean Absolute Error (MAE) as the selection of the best model to be used for forecasting. From this study, the results of forecasting the amount of sugarcane production in Loano District for the next 4 periods, after 2015 from the WMA model, are: 113,91 ton; 135,62 ton; 101,96 ton; and 89,88 ton. The best model result is the Weighted Moving Average (WMA) model with the smallest forecasting accuracy value, namely the MSE value of 1.833,07 and the MAE of 36,07.

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.

The Fiji Sugar Industry: Sustainability Challenges and the Way Forward

This paper examines the problems facing the sugar industry in Fiji. It expands on the difficulties of world trade and the macro- and micro-problems that affects the sugar industry sternly. It also discusses local challenges associated with sugarcane crop production and sugar manufacturing in the country. Additionally, it provides an overview of some of the specific issues directly facing smallholder sugarcane growers. This study is based on a customised mixed-methods research conducted in the year 2015 in the sugarcane-producing areas on the islands of Viti Levu and Vanua Levu in Fiji. The 33 farmers and members of their households in the study comprised both descendants of the Girmitiya community brought from India under the colonial rule and the native iTaukei sugarcane farmers, who rely primarily on cash incomes derived from the sale of sugarcane and other diversified farm products. This paper demonstrates that the sugar industry in Fiji is currently facing a ‘perfect storm’—wave after wave of major difficulties coming all at once—and the country is beginning to tackle these problems only as they reach crisis point.

Towards Achieving Sugar Self-Sufficiency in Nigeria: A Review

Sugar is produced in 120 countries with about 110 countries producing from either cane or beet, and eight countries produce sugar from both cane and beet. The global sugar production in 2020/2021 was about 179 million tonnes with Brazil as the highest producer with 42 million tonnes. Sugarcane, on average, accounts for nearly 80% of global sugar production. Nigeria’s sugar industry has always faced challenges with national sugar requirements met through imports of raw sugar for local refining. The National Sugar Development Council (NSDC) was therefore set up in 1993 to catalyze the development of the sugar industry with a view to ensuring that Nigeria attains at least, 70% self-sufficiency in sugar requirement within the shortest possible time. Despite efforts by the Sugar Council, Nigeria still ranks among the top 10 sugar importing countries. The National Sugar Master Plan (NSMP) was launched in 2013 by the NSDC as a 10-year plan designed to transform the Nigerian sugar industry. This paper is aimed at reviewing the implementation of the Plan 8 years down the line. The efforts of the government to attain self-sufficiency in sugar through the National Sugar Master Plan have yielded little result. Production of sugar in Nigeria is yet to meet domestic demand thereby creating a huge supply gap that is met through import. According to NSDC data, sugar import increased from 955,675 tonnes in 2010 to 1,531,471 tonnes in 2020. The country spent an estimated USD 433.4 million on sugar importation in 2020, an increase from USD 382.3 million in 2019. Challenges of raw materials production include environmental constraints, lack of quality seed cane and suitable varieties, poor irrigation, lack of farm mechanization and poor capital. To improve sugarcane productivity, the cane industry should be restructured to improve efficiency and yields. Measures should also be put in place to promote the establishment of cane mills around the sugar estates and across the sugarcane producing areas. Keywords: Sugar, Sugarcane, Self-Sufficiency, Domestic demand, import, Master Plan DOI: 10.7176/JRDM/82-02 Publication date: January 31 st 2022

Molecular Detection and Quantification of Xanthomonas albilineans in Juice from Symptomless Sugarcane Stalks Using a Real-Time Quantitative PCR Assay.

Leaf scald, a bacterial disease caused by Xanthomonas albilineans (Ashby) Dowson, is a major limiting factor for sugarcane production worldwide. Accurate identification and quantification of X. albilineans is a prerequisite for successful management of this disease. A sensitive and robust quantitative PCR (qPCR) assay was developed in this study for detection and quantification of X. albilineans using TaqMan probe and primers targeting a putative adenosine triphosphate-binding cassette (ABC) transporter gene (abc). The novel qPCR assay was highly specific to the 43 tested X. albilineans strains belonging to different pulsed-field gel electrophoresis groups. The detection thresholds were 100 copies/µl of plasmid DNA, 100 fg/µl of bacterial genomic DNA, and 100 CFU/ml of bacterial suspension prepared from pure culture. This qPCR assay was 100 times more sensitive than a conventional PCR assay. The pathogen was detected by qPCR in 75.1% (410/546) of symptomless stalk samples, whereas only 28.4% (155/546) of samples tested positive by conventional PCR. Based on qPCR data, population densities of X. albilineans in symptomless stalks of the same varieties differed between two sugarcane production areas in China, Beihai (Guangxi Province) and Zhanjiang (Guangdong Province), and no significant correlation between these populations was identified. Furthermore, no relationship was found between these populations of the pathogen in asymptomatic stalks and the resistance level of the sugarcane varieties to leaf scald. The newly developed qPCR assay proved to be highly sensitive and reliable for the detection and quantification of X. albilineans in sugarcane stalks.

Association between awakening cortisol levels and cardiovascular performance in sugarcane rural workers.

Sudden deaths without known causes have been reported among rural workers in the last decade, especially in low and middle-income countries. The current study aimed to analyse the association between awakening cortisol response and cardiovascular performance in rural workers before and after the harvesting period. Fifty-four rural male workers and 48 residents were included (non-rural workers) from a sugarcane production area in São Paulo, Brazil. Morning salivary cortisol were analysed before and 7 months after the beginning of burnt sugarcane harvesting. Cardiovascular performance (blood pressure, pulse pressure and heart rate HR) was evaluated using the Incremental Shuttle Walking Test (ISWT). Our findings revealed a negative association between CAR and cardiovascular performance in rural workers at the harvesting period. Specifically, morning cortisol levels significantly increased after seven months of intense harvesting activity, allied to improvements in physical performance, systolic blood pressure and heart rate reactivity to a cardiopulmonary task. No association was observed in the resident group. Altogether, these findings suggest that, at least in the short-term, rural workers presented an adaptive response to the physical demands of sugarcane harvesting work. Longitudinal studies are essential to investigate the long-term effects of harvesting activity on rural workers' health.

Taxonomic and nitrogen-cycling microbial community functional profiles of sugarcane and adjacent forest soils in Southeast Brazil

Nowadays, due to the expansion of agricultural borders, it is highly desirable to increase the sustained productivity of sugarcane cultivars using the knowledge of soil microbial communities. In this study, twelve shotgun metagenomic datasets based on genomic DNA from soil were analyzed using the Metagenomics Rapid Annotation using Subsystem Technology (MG-RAST) and Statistical Analysis of Metagenomic Profiles (STAMP) to assess differential responses for the total soil bacterial community composition and nitrogen-cycling microbial community functional potential in soils from sugarcane field with pre-harvest burning and adjacent forest in dry and wet seasons in Southeast Brazil. The soil bacterial community revealed higher abundance for Actinobacteria in forest soil than sugarcane soil in dry and wet seasons, and an opposite pattern for Proteobacteria and Planctomycetes in these soils in both seasons. The results obtained in this study based on the KEEG map suggest that the forest soil has a higher nitrogen-cycling microbial community functional potential compared to the sugarcane soil, independently of the season. The gene sequences associated with carbohydrate metabolism were the most frequent in all soil metagenomes. Taken together, the results confirm previous findings regarding the effects of forest conversion to sugarcane production area, providing new insights regarding to this conversion through the prism of the seasonality and pre-harvesting method on microbially mediated nitrogen cycle in sugarcane production fields.

Spatial variability of soil physical attributes in sugarcane using different row spacings

The aim of this study was to determine the impact of harvesting traffic by evaluating the spatial variability of soil physical attributes on a clayey Oxisol under sugarcane cultivation using different row spacing. Two areas of sugarcane production (RB855156 genotype) were planted in autumn 2013, both using conventional planting systems. Treatments were either sugarcane cultivated using: (i) single-row spacing (SR) of 1.50 m; or (ii) double-row spacing (DR) of 0.40 × 1.50 m. Areas using SR spacing occupied a total of 6 ha areas using DR spacing occupied a total of 2 ha. Assessments of soil physical attributes were performed during the summer of 2016 after the second harvest. Soil measurements in each area were done at 100 points using a grid design with dimensions of 10 m long by 5 m wide. Soil sampling was taken from the 0.00-0.10 m layer, from points distributed along the planted row and the machine’s wheel track. The following soil physical attributes were assessed: bulk density, total porosity, macroporosity, microporosity, soil penetration resistance, and water contentat field capacity. Bd and PR in the single-row spacing showed critical values for adequate sugarcane root development. The highest spatial variability of PR and Ma was found in double-row spacing, however, this spacing arrangement promoted a better soil physical conditions.

Odorant-binding proteins involved in sex pheromone and host-plant recognition of the sugarcane borer Chilo infuscatellus (Lepidoptera: Crambidae).

Pheromone-binding proteins (PBPs) are responsible for transporting sex pheromones and general odorant-binding proteins (GOBPs) have been proposed to transport host-plant volatiles. A large number of OBPs have been identified from Lepidoptera species. However, olfactory molecular biology and physiology studies on PBP and GOBP in sugarcane pests are limited. Chilo infuscatellus is one of the most widely distributed pests in sugarcane-producing areas. Three PBPs (CinfPBP1, CinfPBP2 and CinfPBP3) and two GOBPs (CinfGOBP1 and CinfGOBP2) were identified, and five olfactory gene transcripts were abundantly expressed in antennae of C. infuscatellus. Binding assays showed that CinfPBP1-3 exhibited strong binding affinity for the sex pheromone components Z11-16:OH and 16:OH of C. infuscatellus. Meanwhile, CinfGOBP1-2 had high binding affinity with host-plant volatiles from sugarcane (Saccharum officinarum). Field-trapping results suggested that four volatile components, octadecane, (Z)-3-hexen-1-ol, α-terpineol and hexadecane from host plants and sex pheromone mixed baits have synergistic roles in attracting C. infuscatellus adult moths. Functional characterization of CinfPBPs and CinfGOBPs in C. infuscatellus could help us find new environmentally friendly alternatives to conventional pest control using pesticides in sugarcane fields. © 2020 Society of Chemical Industry.

Farmland size increase significantly accelerates road surface rill erosion and nutrient losses in southern subtropics of China

Farmland size increase (FSI), which is an increase in operational size and consolidation of fragmented croplands, is considered an effective scheme to improve agricultural productivity and reduce fertilizer use with environmental protection benefits. But FSI involving road extension can enhance rill formation on road surfaces, and increase road erosion and associated nutrient losses in a watershed. These effects have not been experimentally quantified yet. Thus, we determined the changes in road surface rill erosion and associated nutrient losses in response to FSI before (2017) and after (2018), in an intensive sugarcane production area within Nala watershed, in southern subtropics of China. We divided the watershed into three sub-watersheds (lower (S1), left (S2) and right upper (S3) regions), and surveyed three categories of roads: (i) old roads (existing roads before 2017), (ii) new roads (constructed in 2018), and (iii) old-new roads (repaired and extended old roads in 2018). The road surface rill erosion and associated nutrient losses were much higher in the lower region (S1) than the upper regions (S1 and S2) of the watershed due to variations in field density (number of farms per unit area) and traffic intensity. Field density reduced by 53 % while traffic intensity increased by 41 % after FSI. Following FSI, annual road surface rill erosion, nitrogen, phosphorus and organic carbon losses increased by 88 %, 79 %, 67 %, and 46 %, respectively. Road surface rill erosion had a significant inverse relationship with field density (R² = 0.535, P < 0.05) but positively correlated with traffic intensity (R² = 0.728, P < 0.01). The accelerated N and P losses offset the decrease in fertilizer use by 5–22 % due to FSI. Our results highlight the significance of including soil erosion in FSI scheme for environmental protection. Accelerated road erosion following FSI should be minimized by integrated soil and watershed management practices.