Sugarcane Monoculture Research Articles

Sugarcane-Peanut Intercropping System Enhances Bacteria Abundance, Diversity, and Sugarcane Parameters in Rhizospheric and Bulk Soils.

Sugarcane–legume intercropping systems can effectively control pests and diseases as well as improve the fertility and health of farmland soil. However, little is known about the response of bacterial abundance, diversity, and community composition in the rhizosphere and non-rhizosphere soils under the sugarcane–peanut farming system. A field experiment was conducted with two treatments: sugarcane monoculture and sugarcane–peanut intercropping to examine the response of sugarcane parameters and edaphic factors. We also deciphered bacterial abundance, diversity, and community composition in the root endosphere, rhizosphere, and bulk soil by leveraging Illumina sequencing to conduct the molecular characterization of the 16S rRNA gene and nitrogenase (nifH) gene. We observed that sugarcane–peanut intercropping exhibited the advantages of tremendously increasing cane stalk height, stalk weight, and millable stalk number/20 m, and edaphic factors, namely, pH (1.13 and 1.93), and available phosphorus exhibited a fourfold and sixfold increase (4.66 and 6.56), particularly in the rhizosphere and bulk soils, respectively. Our result also showed that the sugarcane–peanut intercropping system significantly increased the bacterial richness of the 16S rRNA gene sequencing data by 13.80 and 9.28% in the bulk soil and rhizosphere soil relative to those in the monocropping sugarcane system, respectively. At the same time, sugarcane intercropping with peanuts significantly increased the Shannon diversity of nitrogen-fixing bacteria in the sugarcane rhizosphere soil. Moreover, most edaphic factors exhibited a positive regularity effect on bacterial community composition under the intercropping system. A linear discriminant analysis with effect size analysis of the 16S rRNA sequencing data revealed that bacteria in the root endosphere of the intercropped cane proliferated profoundly, primarily occupied by Devosia, Rhizobiales, Myxococcales, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Bradyrhizobium, and Sphingomonas. In conclusion, our findings demonstrated that sugarcane–peanut intercropping can enhance edaphic factors, sugarcane parameters, and bacterial abundance and diversity without causing adverse impacts on crop production and soil.

Formicidae fauna in pig carcasses contaminated by insecticide: implications for forensic entomology

Corpses in Brazil are commonly hidden in sugarcane plantations in the attempt to delay their finding and hinder the solution of the crime. On the other hand, these plantations are regularly sprayed with insecticides for pest control. Until now no study has reported the effects of insecticides on ant fauna. This study aimed to test the hypothesis that if a body hidden in a monoculture is accidentally contaminated by an insecticide, both the carcass decomposition pattern and the Formicidae fauna will be affected. To accomplish this, pig carcasses contaminated and non-contaminated were placed in a sugarcane monoculture environment and subsequently examined for data collection every 24 hours. The concentration used to contaminate the carcasses was 20 grams per liter of thiamethoxam. The decomposition patterns of contaminated carcasses were changed, in turn affecting the behavior of Formicidae fauna. A total of 5318 ants were collected, 3397 in contaminated carcasses and 1919 in non-contaminated carcasses, and 30 species of 11 genera were identified. According to the analysis, there are no differences between the composition of species between contaminated and non-contaminated carcasses, however, a significant difference was observed in the composition of species along the stages of decomposition between the two types of carcasses. Therefore, our hypothesis has been confirmed, contaminated carcasses undergo changes in their normal pattern of decomposition and the fauna of ants that act on them. As this group of insects has great importance for forensic sciences, the analysis of the experts should take these results into account.

Incorporation of the Sociocultural Heritage as an Essential Component in the Emergy Asessment Of Agroecological Systems in the Central Region Of Valle del Cauca-Colombia

In Valle del Cauca, a wide range of agroecological production systems havebeen preserved, withstanding the expansionist onslaught of sugar cane monoculture. The study performed the emergy assessment to three agroecological farms in the municipalities of Andalucia, Sevilla and Buga, incorporating a novel flow of emergy called Sociocultural Heritage (H), which is determinant for the functioning of the agroecological farms in the Colombian context, which includes the contribution of internal family labor given by their permanent residence in the agroecosystem, the family's activity to promote agroecological culture with external actors to the farm, the memory of information, and the appropriation of knowledge. The identity architecture and management of the agrosystem were expressed by the total emergy (U), computing the emergy flows of: renewable natural resources (R), nonrenewable (N), Sociocultural Heritage (H), purchased materials (M), and contrated services (S). The efficiency of agroecological farms, involved inclusive emergetic indices that contain the Sociocultural Heritage (H): Percentage of Sociocultural Heritage (%H), Inclusive Renewability (%RH) and Inclusive Environmental Burden Index (ELRH). The H flow gave results between 6,95 and 42,19 E + 17 sej / year, representing 45,47% and 55,07% of total emergy as %H. The %RH index gave values higher than 91%, indicating that the farms have a high renewability. The ELRH index presented values between 0,05 and 0,09, indicating a low environmental load of agroecological systems and low pressure of agroecological farms on local ecosystems. The results of inclusive emergetic indixes from this study show that agroecological systems are more sustainable in the long term. This would not be so evident with results obtained through an emergy assessment without the inclusion of the H.

Sugarcane-Legume Intercropping Can Enrich the Soil Microbiome and Plant Growth

Soil microbes have a direct impact on plant metabolism and health. The current study investigates the comparative rhizobiome between sugarcane monoculture and sugarcane–soybean intercropping. A greenhouse experiment was performed with two treatments: (1) sugarcane monoculture and (2) sugarcane–soybean intercropped. We used a high-throughput sequencing (HTS) platform to analyze the microbial community. We used the 16S rRNA gene and internal transcribed spacer region primers to identify the microbial diversity. HTS results revealed that a total of 2,979 and 124 bacterial and fungal operational taxonomic units (OTUs) were observed, respectively. Microbial diversity results concluded that the intercropping system has a beneficial impact on soil microbes. The highest numbers of bacterial and fungal OTUs were found in the intercropping system, and these results also collaborated with quantitative PCR results. Additionally, intercropped sugarcane plants showed a higher weight of above- and below-ground parts than the monoculture. Soil chemical analysis results also complemented that the intercropping system nourished organic carbon, total nitrogen, and soil enzyme activities. Correlation analysis of the diversity index and abundance concluded that soil nutrient content positively influenced the microbial abundance that improves plant growth. The present study frames out the profound insights of microbial community interaction under the sugarcane–soybean intercropping system. This information could help improve or increase the sugarcane crop production without causing any negative impact on sugarcane plant growth and development.

La tierra y la sombra: cine háptico, violencia ambiental y desplazamiento forzado en Colombia

The film Land and Shade (2015) by César Acevedo (Colombia, 1984) tells the story of a family that refuses to leave a territory from which all the other peasants have been displaced due to the imposition of the sugar cane monoculture in Valle del Cauca. The main question of this paper is what are the causes and consequences of forced displacement that the film presents and what do they have to do with ecological territories? I argue that through haptic film techniques (Marks 2000), which use vision as a sense of touch, the film makes viewers experience some of effects of the environmental violence that Rob Nixon (2011) calls slow violence. I argue the film not only explores the peasant migration from one rural space to another, but also deals with the movement of political borders on ecological territories caused by the extractivism of the sugar cane monoculture. I claim that slow violence is also exercised against non-human beings and ecosystems and I explore how the film exposes different types of precariousness and turns the viewer into a witness of this type of political violence.

Comparison of Soil Biological Properties and Bacterial Diversity in Sugarcane, Soybean, Mung Bean and Peanut Intercropping Systems

Sugarcane intercropping with soybean [Glycine max (Linn.) Merr.], mung bean [Vigna radiata (Linn.) Wilczek] and peanut (Arachis hypogaea Linn.) as well as a sugarcane monoculture were conducted to study the impacts of intercropping on soil biological characteristics and bacterial diversity. The results showed that soil cultivable microorganisms, the activities of soil enzymes and microbial biomass carbon, nitrogen, and phosphorus were all significantly improved by intercropping with soybean and mung bean. Additionally, soil bacterial diversity and richness in sugarcane fields were also significantly enhanced by intercropping with soybean and mung bean. In addition, soil bacterial community structures in sugarcane fields can be altered by intercropping with different legumes. Proteobacteria, a high-nutrient-tolerant bacterial assemblage, became the dominant bacteria in the sugarcane-soybean and sugarcane-mung bean intercropped soils. Twenty four, 28, 26 and 27 dominant soil bacterial genera were found after the sugarcane-soybean, sugarcane-mung bean, sugarcane-peanut and sugarcane monoculture treatments, respectively. Sugarcane-mung bean intercropping being the most promising system for regaining and improving soil fertility and soil heath and facilitate agriculture intensification of sugarcane.

Sugarcane monoculture drives microbial community composition, activity and abundance of agricultural-related microorganisms

Sugarcane monoculture (SM) often leads to soil problems, like soil acidification, degradation, and soil-borne diseases, which ultimately pose a negative impact on agricultural productivity and sustainability. Understanding the change in microbial communities' composition, activities, and functional microbial taxa associated with the plant and soil under SM is unclear. Using multidisciplinary approaches such as Illumina sequencing, measurements of soil properties, and enzyme activities, we analyzed soil samples from three sugarcane fields with different monoculture histories (1-, 2-, and 4-year cultivation times, respectively). We observed that SM induced soil acidity and had adverse effects on soil fertility, i.e., soil organic matter (OM), total nitrogen (TN), total carbon (TC), and available potassium (AK), as well as enzyme activities indicative for carbon, phosphorus, and nitrogen cycles. Non-metric multidimensional scaling (NMDS) analysis showed that SM time greatly affected soil attribute patterns. We observed strong correlation among soil enzymes activities and soil physiochemical properties (soil pH, OM, and TC). Alpha diversity analysis showed a varying response of the microbes to SM time. Bacterial diversity increased with increasing oligotrophs (e.g., Acidobacteria and Chloroflexi), while fungal diversity decreased with reducing copiotrophs (e.g., Ascomycota). β-Diversity analysis showed that SM time had a great influence on soil microbial structure and soil properties, which led to the changes in major components of microbial structure (soil pH, OM, TC, bacteria and soil pH; TC, fungi). Additionally, SM time significantly stimulated (four bacterial and ten fungal) and depleted (12 bacterial and three fungal) agriculturally and ecologically important microbial genera that were strongly and considerably correlated with soil characteristics (soil pH, OM, TC, and AK). In conclusion, SM induces soil acidity, reduces soil fertility, shifts microbial structure, and reduces its activity. Furthermore, most beneficial bacterial genera decreased significantly due to SM, while beneficial fungal genera showed a reverse trend. Therefore, mitigating soil acidity, improving soil fertility, and soil enzymatic activities, including improved microbial structure with beneficial service to plants and soil, can be an effective measure to develop a sustainable sugarcane cropping system.

Alluvial Soil Quality Indicators As Affected By Different Land-Uses. مؤشرات جودة التربة الطمييه تحت تأثير الاستخدامات المختلفة للأراضي.

Soil deterioration and yield decline are the main factors affecting the environmental sustainability of long-term irrigated sugarcane monoculture. This research was conducted to detect changes of soil physical, chemical and physicochemical quality parameters associated with intensive irrigated sugarcane monoculture with groundwater for long term. Sugarcane monoculture resulted in a severe impact on some soil physical indicators of soil quality as increased the soil bulk density and reduced soil clay content, decreased soil aggregate stability and the water content at the field capacity causing decreases in soil porosity and decline in soil fertility. Significant impacts on some soil chemical indicators of soil quality were also recorded as reduced soil organic matter content and increased soil pH and EC producing soil salinity. Fields under long-term irrigated sugarcane monoculture had low OM values ranged from 2.09 to 2.61% while areas under crop rotation had the highest OM values ranged from 2.62 to 3.39%. Fields under sugarcane monoculture system had higher pH, EC and SAR values ranged from 7.96 to 8.41, from 2.98 to 4.22 dS m-1 and from 7.75 to 11%, while fields under crop rotation system had the lowest pH, EC and SAR values ranged from 7.64 to 7.92, 1.41 to 2.42 dS m-1 and from 4.51 to 5.86%, respectively. From these results, it could be concluded that long term sugarcane monoculture has significantly deteriorated soil physical and chemical properties indicating the urgent demand for more sustainable management practices to preserve soil quality.

Reconstructing the history of environmental impact in a tropical mangrove ecosystem: A case study from the Suape port-industrial complex, Brazil

Mangrove ecosystems can record biogeochemical and sedimentary signatures in their stratigraphic column. This study examines a mangrove sediment core to evaluate the potential environmental impact of a large-scale port-industrial construction in a tropical lagoonal–estuary near Recife, NE Brazil. Here, we measure sediment accretionrate (SAR), carbon and nitrogen stable isotopes (δ13C and δ15N), total organic matter (TOM), total nitrogen (TN), total organic carbon (TOC), and carbonate content (CaCO 3) to determine the impact of Suape’s Port-Industrial Complex in the adjacent estuarine system. We identify a high SAR (1.37 cm yr −1) and propose three main depositional phases in the 82 cm sediment core. The first phase (circa 1956–1973) corresponds to the period prior to the installation of the Suape port complex, where the sediments are characterized by containing sand and organic material derived from terrestrial sources. The second phase (c. 1976–1986) shows signatures that reflect the installation of the Suape port complex and the intensification of the sugarcane monoculture in the catchment area. This phase shows an increase of mud and carbonate content, interpreted as a predominance of marine sediment source due to the morphological changes along the estuary. The third and final phase (c. 1986–2015) contains fluctuating results, reflecting an increase of land use, but not as intense as the period after the installation of the port complex (phase 2). Our results show a biogeochemical and sediment signature shifts directly related to anthropogenic impacts and natural factors. Overall, this study reveals a shift in the sediment sources and composition in the Suape estuarine system as a consequence of human development adjacent to estuarine areas and the resilience of mangrove ecosystems to adapt to anthropogenic impact.

Heavy Metals and Microbial Activity in Alluvial Soils Affected by Different Land-Uses

Soils must receive maximum protection to assure sustainable agriculture and quality food production. Heavy metals tend to accumulate in the soil rather than decompose and at a certain limit of their content, toxic consequences for living organisms occur. This research was conducted to survey the contamination status of Cd, Cr, Ni, and Pb and microbial activity in soils affected by long-term sugarcane monoculture in Upper Egypt. The rise of diacetate fluorescein hydrolysis (FDA) ranged from 86.25 to 201.25 mg kg-1 soil·h-1 in sugarcane monoculture fields, while the increase under crop rotation fields showed higher and significant values ranged from 207.25 to 266.67 mg kg-1 soil·h-1. In this study, generally soil microbial biomass and enzymatic activity was usually and significantly higher under crop rotation than sugarcane monoculture. The highest potential ecological risks were found in soils under long-term irrigated sugarcane monoculture, while being moderate for crop rotation. Under both sugarcane monoculture and crop rotation farming systems, cadmium Cd was observed to be the urgency pollutant with the highest degree of contamination even though Cd had the lowest average concentration (Cd 27.03 mg kg-1) in sugarcane monoculture fields, and Cd (10.46 mg kg-1) in crop rotation. In view of the impacts of these potentially toxic elements of cadmium (Cd), chromium (Cr), nickel (Ni) and lead (Pb), on the ecological system and public health, the introduction of new management practices in sugarcane monoculture fields are essential to protect the environment and to achieve future sustainability in sugarcane production in Upper Egypt.

Communitarian weavings: Agrarian commons of the Maya-Q’eqchi’ against the expansion of monocultures in the Polochic Valley, Guatemala

ABSTRACT The Maya-Q’eqchi’ are the people that occupy the most territory in Guatemala and that historically, like other indigenous peoples, have resisted multiple waves of dispossession through ‘communitarian weavings’ and by maintaining their sacred relationship with the land and maize. In this article, I analyze how and why temporary and long-lasting ‘agrarian commons’ are created and reproduced as part of the communitarian weavings of the Maya-Q’eqchi’ in the Polochic Valley, Guatemala. I show how the reproduction of the Maya-Q’eqchi’ agrarian commons has been, and still is today, the basis of resistance to the new wave of dispossession caused by the expansion of sugarcane and oil palm monocultures owned by oligarchic families of German descent. Despite the commons being the reproduction of a form of struggle characteristic of the Maya-Q’eqchi’, there are multiple differences of functioning and structure of the agrarian commons between territories inhabited by the Maya-Q’eqchi’, as well as within the same territory. These differences are conditioned by the different identities reconfigured by history and by socio-economic and environmental dynamics, as well as by the structure and operation of the commons itself.

Dinâmica socioespacial e produção agrícola nos acampamentos rurais Sapucaia e Caípe, União dos Palmares, Alagoas - Brasil

ABSTRACT: The Zona da Mata of Alagoas is a region of the state strongly marked by the creation of beef cattle and sugarcane monoculture, the latter practice being an influence of the sugar and alcohol establishments that for many decades dictated the state's agricultural production. For some years, this scenario has been modified due to the closure of sugar and alcohol mills and some properties changing their production method. However, many areas previously cultivated by the aforementioned crop have had production pauses. Thus, some, through social movements fighting for land, started to be occupied and claim the right to land through agrarian reform. Thus, the objective of this study was to understand the socio-spatial dynamics of the Sapucaia and Caipe campsites, located on the margins of BR-104 in the municipality of Uniao dos Palmares, Alagoas, Brazil, as well to understand the agricultural production of these rural camps. Thus, a qualitative and quantitative research was carried out through interviews. The research provided an understanding of the constitution of the families that make up the camps, which demonstrated the existence of a still patriarchal mode of organization with the invisibility of women. In addition, there are also subhuman conditions regarding infrastructure. In addition to these aspects, there is a lack of technical assistance, which is fundamental in the process of contemplating and implementing land reform. KEYWORDS: land reform, housing structure, rural camp.

Short Communication: Investigating environmental impacts of long-term monoculture of sugarcane farming in Indonesia through DPSIR framework

Abstract. Putra RP, Ranomahera MRR, Rizaludin MS, Supriyanto R, Dewi VAK. 2020. Short Communication: Investigating the environmental impacts of long-term monoculture of sugarcane farming in Indonesia through DPSIR framework. Biodiversitas 21: 4945-4958. An increasing trend of sugar demand in Indonesia due to the rising population has forced the government to boost its national sugarcane production through intensification program. Long-term monoculture system has long been practiced by sugarcane growers in Indonesia, particularly by large sugar companies for more than 30 years. This farming method bolsters the government’s program in scaling-up national sugar production. Through a literature study, the present study analyzed the impacts of long-term sugarcane monoculture in Indonesia on agroecosystem functions by using the Driver-Pressure-State-Impact-Response (DPSIR) framework. Results showed that long-term sugarcane monoculture leads to decreased soil quality, lowered hydrological functions, reduced agrobiodiversity, and increased greenhouse gas emissions. Those conditions corresponded to reduced sugarcane yield and productivity, increased pests and diseases, decreased income gained by growers, higher dependencies on chemicals, and higher cultivation costs. In the end, we proposed several sustainable crop management to mitigate the detrimental effects of sugarcane monoculture practice in Indonesia. These include performing crop break or rotation with legume or the other cash crop, intercropping, green harvesting and trash blanket, precision agriculture methods, and soil amendment with organic matters. However, some constraints in implementing those sustainable crop management, such as inadequate knowledge and capital, should be considered. The information given in this study can be used by sugarcane growers or companies, policymakers, and sugarcane-related stakeholders as considerations to improve sugarcane productivity while at the same time minimizing its impact on the environment.

O processo de expansão urbana e seus impactos na Estação Ecológica de Ribeirão Preto, SP

Although the normative instruments of urban planning include the environmental impact assessment, there is a loosening of these laws due to public and private interests that have purposes contrary to environmental policies. In the municipality of Ribeirão Preto, coffee and sugarcane monocultures have contributed to the fragmentation of native vegetation, reducing it to 6% of the municipal area (4,200 ha). The Ecological Station of Ribeirão Preto (ESRP) is the larger native remnant (155 ha) and suffers pressures for being located in the urban environment. This work investigated the urban pressure in the Buffer Zone (BZ) and its relation to the changes in the Master Plan (MP) and complementary laws. The land cover maps (2010 and 2017) were also analyzed in order to quantify the conversion of native forests to anthropic uses, showing an intense urban expansion in the BZ over the period analyzed. On the other hand, municipal urban environmental legislation has evolved seeing that the previous MP (dated from 1995) approached the environment in a very specific way, which was modified in the 2018 law, which attempts to integrate the urban zoning to the buffer zone in order to make land use compatible with the ESRP Management Plan.

Life-History Traits Response to Effects of Fish Predation (Kairomones), Fipronil and 2,4-D on Neotropical Cladoceran Ceriodaphnia silvestrii.

Aquatic environments are constantly exposed to a cocktail of contaminants mainly due to human activities. As polluted ecosystems may simultaneously present other multiple natural stressors, the objective of the present study was to evaluate joint effect of stressors (natural and anthropogenic) on life history traits of the Neotropical cladoceran,Ceriodaphnia silvestrii. For this purpose, the effects of water conditioned with predator kairomones (fish) and environmental concentrations (sublethal) of two pesticides widely used in sugarcane monoculture in Brazil, the insecticide Regent® 800 WG (active ingredient-a.i. fipronil) and the herbicide DMA® 806 BR (a.i. 2,4-D) were evaluated using chronic toxicity testing, isolated and in mixture, for this cladoceran species. The environmental risks of pesticides for tropical freshwater biota were also estimated from the risk quotient MEC/PNEC. Among the characteristics of the life history ofC. silvestriievaluated after 8days of exposure, compared with the mean value of control, the age of primiparous females was not affected by any evaluated treatment. However, species average survival decreased in the treatment of kairomones mixed with fipronil (FK) and in the treatment with a mixture of fipronil, 2,4-D, and kairomones (MFKD). The body length of maternal females was shorter than in the control after exposure in treatments with only kairomones (K) and FK. Fecundity of this cladoceran was reduced when exposed to FK and MFKD treatments, and the intrinsic rate of population increase significantly decreased for organisms exposed to treatment with fipronil (F) and to mixtures of fipronil and 2,4-D (MFD), MFDK, and FK. The results indicated that the combination of anthropogenic and natural stressors causes changes in C. silvestrii life history traits, which can contribute to the decline in populations, and our preliminary risk assessment results are a matter of concern regarding biota conservation.

A GÊNESE E A DINÂMICA RURAL-URBANA DO MUNICÍPIO DE CANITAR - SP

O objetivo do trabalho é apresentar a gênese da pequena cidade de Canitar, cuja origem remete ao período cafeeiro, porém, presentemente pauta a economia municipal quase exclusivamente no cultivo de cana-de-açúcar, discutindo alguns elementos resultantes desse processo. A emancipação de Canitar, em 1993, insere-se no processo de desmembramentos de municípios, após a promulgação da Constituição Federal de 1988. Para a realização do trabalho, consultou-se as referências bibliográficas, dados censitários e foi realizado um levantamento de campo em junho de 2018, com o objetivo de coletar informações não discutidas pela bibliografia consultada. Compreendeu-se que a dinâmica rural-urbana de Canitar pauta-se atualmente na monocultura da cana-de-açúcar, sendo que aproximadamente 90% da área municipal é dedicada a esse cultivo e por outro lado, as atividades econômicas urbanas são pouco relevantes.

INOVASI TEKNOLOGI PENERAPAN KOMPOS BLOTONG UNTUK PERBAIKAN KESUBURAN TANAH DAN PENINGKATAN PRODUKTIVITAS TANAMAN TEBU

Sugarcane (Saccharum officinarum L.) is a variety of sources of carbohydrate as sugar production. Planting of sugar cane monoculture and continuously in dry land causes degradation of soil fertility. One effort to improve soil fertility is the addition of organic matter. through the use of blotong compost. The purpose of this paper is to provide information on blotong compost technology innovation in improving soil fertility and increasing sugarcane productivity.Blotong has potential as a source of organic material from the residual waste from sugarcane crop yields. The macro and micro nutrient content of compost in blotong compost plays an important role in supporting plant growth. Blotong compost application in the long term can increase the physical, biological and chemical fertility of degraded land. Blotong compost application with inorganic fertilizer can reduce the use of inorganic fertilizer. Blotong application can increase the nutrient content of N, P and micro elements in the soil and can increase the growth and productivity plant sugarcane.

Urban or rural fragments: which soil use in forest surroundings induces greater litter deposition?

The soil use in surroundings of forest remnants, as well as, variations in seasonality and rainfall totals from each year might influence the composition, structure, and ecophysiological responses of vegetation and, thus, cause differences in litter deposition. For this reason, the present study proposes to verify which soil use in the surroundings of forest fragments induces greater litter deposition. Study areas were defined after mapping and quantification of urban and rural occupations around the remnants (buffer up to 3 km), based on satellite images. In each fragment were installed 36 collectors of 0.25 m2. Litter deposition after 2 years was 434.73 t in the urban fragment and 513.32 t in the rural area. GLM analysis showed that the total litter mass and fractions (leaf, twig, and seed) were significantly higher in the rural fragment and dry season, excepting for the seed fraction in the urban area, which did not present seasonal variation. Simple Linear Regression test showed that leaf deposition in the rural and urban fragments increased with the reduction of water availability, and increasing in seed deposition was also observed with the reduction in precipitation in the urban fragment. Our results suggest that soil use in the rural fragment vicinity may have provided changes in the local abiotic characteristics within the rural fragment which should have induced a greater intensity in litter deposition. Therefore, the sugar cane monoculture surrounding the rural fragment induced the greatest intensity of litter deposition, and possibly reflects the effects of the fire use on sugarcane management.

Nesting biology and flower preferences of Megachile (Sayapis) zaptlana

Megachile zaptlana is a solitary cavity-nesting leafcutter bee widely distributed in Brazil. Using two models of trap nests in sugarcane monoculture and agroecosystem environments in Pernambuco, northeastern Brazil, we studied the nesting biology of this species. We obtained 193 nests, 39.4% in the monoculture and 60.6% in the polyculture site. The nests consisted of a linear series of brood cells coated with a mixture of chewed leaves with sand, often followed by a long empty vestibular cell and an operculum at the entrance. A nest contained on average 2.4 (± 1.3) brood cells. Emergence patterns indicate that the species has a multivoltine life cycle without diapause and a peak emergence in the drier months from October to December. The sex ratio females: males, was 1:0.43. Females founded their nests in holes with diameters of 5–10 mm, with a preference for 6 mm (68%). Pollen analysis of larval diet showed that the species is polylectic, and brood cells contained pollen from 19 plant species, especially from the families Asteraceae, Rubiaceae, Plantaginaceae, and Fabaceae. In the studied agroecosystems, ruderal plants were the most important nectar and pollen sources for Megachile zaptlana. Given that Megachile zaptlana is polylectic and multivoltine, it might be a good candidate for future use as a managed pollinator.

Composition of organic C fractions in soils of different texture affected by sugarcane monoculture

ABSTRACT Sugarcane is a strategic commodity in Indonesia. It is usually raised in a monoculture system. There is a lack of information about the effects of extended sugarcane monoculture on the soil carbon fraction. The aim of this study was to determine the relative changes in the soil organic C fractions in response to the duration of sugarcane monoculture on Entisols, Inceptisols, and Vertisols. The measured variables were the percentages of sand, silt, and clay, organic matter (OM), total nitrogen (TN), pH (H2O), cation exchange capacity (CEC), NH4 +, NO3 -, labile carbon fraction (soil carbon mineralization (C-Min), soil microbial carbon (C-Mic), and carbon particulate organic matter (C-POM)), and stable carbon fraction (humic and fulvic acids). Soil type with sugarcane monoculture period had significant influences on the percentages of clay, sand, silt, CEC, and pH (H2O). Soil type and sugarcane monoculture period had no apparent significant effect on C-Min or C-POM but did significantly influence C-Mic. The humic and fulvic acid levels in all three soil types were affected by the duration of sugarcane monoculture. To establish the impact of long-term sugarcane monoculture on the physicochemical properties of soils with various textures, it is more appropriate to measure the soil stable carbon fractions such as humic and fulvic acid rather than the soil labile carbon fractions such as C-Min, C-POM, or C-Mic.