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The intensification of global climate change has made the study of greenhouse gas (GHG) emissions increasingly important. To gain a deeper understanding of the emission characteristics and driving factors of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) from rubber plantation soils, this study conducted a 16-month continuous observation in a rubber plantation in Danzhou, Hainan, employing the static chamber method for the monthly sampling and measurement of GHG emissions while analyzing the soil's physical and chemical properties. The results indicated that the N2O flux exhibited no significant diurnal variation between the dry and rainy seasons, with an average emission rate of 0.03 ± 0.002 mg·m−2·h−1. A clear seasonal trend was observed, with higher emissions in summer than in winter, resulting in an annual flux of 3 kg·hm−2·a−1 (equivalent to 1.9 kg N·hm−2·a−1). N2O emissions were significantly correlated with soil temperature and moisture, explaining 46% and 40% of the variations, respectively, while soil ammonium nitrogen content also significantly influenced N2O and CO2 emissions. The rubber plantation soil acted as a source of N2O and CO2 emissions and a sink for CH2, with lower emissions of N2O and CO2 during the daytime compared to nighttime, and higher CH4 uptake during the daytime. In the dry season, there was a significant positive correlation between N2O and CO2 emissions (R2 = 0.74, p < 0.001). This study reveals the diurnal and seasonal patterns of GHG emissions from rubber plantation soils in Hainan and their interrelationships, providing a scientific basis for the low-carbon management of rubber plantations and GHG mitigation strategies, thereby contributing to attempts to reduce the impact of rubber cultivation on climate change. [ABSTRACT FROM AUTHOR]

Human activities have both positive and negative impacts on forests, altering the extent and composition of various forest vegetation types, and increasing uncertainty in ecological management. A detailed understanding of the historical distribution of forest vegetation is crucial for local conservation efforts. In this study, we integrated phenological features with climatic and terrain variables to enhance the mapping accuracy of forest vegetation in Yunnan. We mapped the historical distributions of five forest vegetation type groups and nine specific forest vegetation types for 2001, 2010, and 2020. Our findings revealed that: (1) rubber plantations can be effectively distinguished from other forest vegetation using phenological features, coniferous forests and broad-leaved forests can be differentiated using visible spectral bands, and environmental variables (temperature, precipitation, and elevation) are effective in differentiating forest vegetation types under varying climate conditions; (2) the overall accuracy and kappa coefficient increased by 14.845% and 20.432%, respectively, when climatic variables were combined with phenological features, and by 13.613% and 18.902%, respectively, when elevation was combined with phenological features, compared to using phenological features alone; (3) forest cover in Yunnan increased by 2.069 × 104 km2 (10.369%) between 2001 and 2020. This study highlights the critical role of environmental variables in improving the mapping accuracy of forest vegetation in mountainous regions. [ABSTRACT FROM AUTHOR]

Ants have a very important role in an ecosystem. The insects act as decomposers, pollinators, soil aerators, pest controllers, and predators. Their role is very varied so that they can be easily found in various ecosystems, one of which is the rubber and oil palm ecosystem. The ant’s diversity in this forest eventually will affect the productivity of the land. The aim of this study is to determine the diversity and role of ants in the rubber and oil palm plantations in Sungai Merah Village. Both of the plantations dominate the industrial forest in Jambi. The method used in this study was purposive random sampling. Observation plots were installed in the ecosystem of rubber and oil palm plantations; each ecosystem had 4 plots consisting of 9 units of pitfall traps, and 9 units of bait traps. The results of this study show that 15 species of ants are found in the ecosystem of rubber and oil palm plantations. Furthermore, the collected ants consisted of 39.972 individual ants belonging to 12 genera and 5 subfamilies. Ants establish in the ecosystem of rubber and oil palm plantations in Sungai Merah Village have an important role either as predators (Crematogaster spp., Odontomachus rixosus, Odontoponera tranversa, Pheidole huberi, Tetraponera rufonigra, Tapinoma melanocephalum, Camponotus spp. and Colobopsis moeschi), or foragers such as ants from the genera Anoplolepis, Camponotus, Monomorium and Polyrhachis. As predators, Oecophylla smaragdina, Camponotus spp. and Crematogaster spp. also play a role as biological control agents in the ecosystem. [ABSTRACT FROM AUTHOR]

The Latex Diagnosis (LD) is performed through the determination of dry rubber (DRC), sucrose (Suc), inorganic phosphorus (Pi) and thiol (RSH) contents. It is carried out through the colorimetric method using a single cuvette spectrophotometer, which is time-consuming and requires a high volume of chemicals. It also needs to be executed as soon as the samples are collected so that limits the adoption of LD. The adaptation of the protocol to a multiplate reader and suitable conservation aimed to overcome the limitations. The experiments were carried out at the Indonesian Rubber Research Institute, Sembawa, Palembang, and Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta. Various combinations of solution volumes, adapted from standard protocol, were tested. The closest slope of the standard curve to control was then applied to 7 randomly selected trees. The result showed that for Suc, the composition of 10 µL samples, 30 µL of 2.5 % TCA and 210 µL anthrone reagent was suitable for determination using a multiplate reader. The combination of 40 µL of sample, 85 µL of 2.5 % TCA and 125 µL mL FeSO4 solution was suitable for Pi determination, while 100 µL samples, 5 µL DNTB and 100 µL Tris is recommended for RSH. The measurement using a multiplate reader resulted in comparable contents (average deviations were 1.83, 2.69 and 3.51 % for Suc, Pi, and RSH, respectively), lower time and chemicals consumptions, and a larger number of sample handling compared to single cuvette method. This study also tested the effect of freeze-drying for sample conservation. The result indicated that freezedrying was able to maintain the Pi level (deviation 0.93 %). However, it increased Suc (deviation 19.43 %) and decreased ascorbate (AsA) significantly (deviation 43.60 %); therefore, freeze-drying might not be suitable for conserving serum samples in the LD method. [ABSTRACT FROM AUTHOR]

Background and Aim: The productivity of sheep in humid tropical plantation areas relies on their ability to adapt. Oil palm plantations serve as potential grazing lands for livestock. This study aimed to identify Garut sheep adaptations in oil palm and rubber plantations of the Garut district, West Java, Indonesia. Materials and Methods: The total number of sheep used was 103 as the object of this study. Each individual of sheep was used for several different observations, including: Physiological assessment using 24 sheep of various ages, molecular analysis of heat stress using 31 sheep, worm egg count using 59 sheep, and for morphological assessment using 98 sheep. A general linear model was employed to analyze rectal temperature (RT), heart rate (HR), respiratory rate, number of eggs in each gram of sample feces, body weight (BW), body condition score, and morphometric measurements according to age and sex. Forage was compared between oil palm and rubber plantations during the vegetation analysis. Results: RT, HR, and panting frequency were significantly (p < 0.05) affected by the age and sex of the sheep. The mutation was found in the coding region of the HSP70 gene, which is approximately 232 bp long. Fecal eggs were found in 99% of the fecal samples, consisting of 100% Strongyle eggs and 1.75% Moniezia eggs. BW, body condition score, shoulder height, body length, pelvic height, chest circumference, and number of eggs were significantly affected (p < 0.05) by the age and sex of the sheep. The average fresh matter of vegetation under the plantation was 248.69 ± 120.94 g/m² and 718.15 ± 249.93 g/m² for oil palm and rubber plantations, respectively. Conclusion: Garut sheep were adapted to oil palm and rubber plantations in the humid tropical region. Plantations are potential sources of sheep grazing and roughage. Further research is needed regarding the consumption of forages in oil palm and rubber plantations. [ABSTRACT FROM AUTHOR]

The precise acquisition of phenotypic parameters for individual trees in plantation forests is important for forest management and resource exploration. The use of Light-Detection and Ranging (LiDAR) technology mounted on Unmanned Aerial Vehicles (UAVs) has become a critical method for forest resource monitoring. Achieving the accurate segmentation of individual tree crowns (ITCs) from UAV LiDAR data remains a significant technical challenge, especially in broad-leaved plantations such as rubber plantations. In this study, we designed an individual tree segmentation framework applicable to dense rubber plantations with complex canopy structures. First, the feature extraction module of PointNet++ was enhanced to precisely extract understory branches. Then, a graph-based segmentation algorithm focusing on the extracted branch and trunk points was designed to segment the point cloud of the rubber plantation. During the segmentation process, a directed acyclic graph is constructed using components generated through grey image clustering in the forest. The edge weights in this graph are determined according to scores calculated using the topologies and heights of the components. Subsequently, ITC segmentation is performed by trimming the edges of the graph to obtain multiple subgraphs representing individual trees. Four different plots were selected to validate the effectiveness of our method, and the widths obtained from our segmented ITCs were compared with the field measurement. As results, the improved PointNet++ achieved an average recall of 94.6% for tree trunk detection, along with an average precision of 96.2%. The accuracy of tree-crown segmentation in the four plots achieved maximal and minimal R2 values of 98.2% and 92.5%, respectively. Further comparative analysis revealed that our method outperforms traditional methods in terms of segmentation accuracy, even in rubber plantations characterized by dense canopies with indistinct boundaries. Thus, our algorithm exhibits great potential for the accurate segmentation of rubber trees, facilitating the acquisition of structural information critical to rubber plantation management. [ABSTRACT FROM AUTHOR]

It is well known that long-term chemicalised agricultural practices harmfully affect soil health and prevent sustainable management of fertility in crop fields, including that of plantation crops. Accordingly, an investigation was carried out to check how soil fertility characteristics such as soil pH, soil mineral nutrient and organic carbon content are altered in long-term chemicalised rubber plantations of Kerala, located in the ecologically sensitive Western Ghats of South India. Soil fertility status concerning soil types in the Rubber fields (USDA soil orders - suborders) such as Inceptisols - Oxic Dystrudepts (IOD), Ultisols - Ustic Haplohumults (UUH), Ultisols - Typic Kandiustults (UTK) and Mollisols - Pachic Argiustolls (MPA) involving six soil series are critically analysed. A negative impact of long-term chemicalised agriculture was visible in low soil pH and nutrient levels. In general, rubber fields in the region, even in the generally alkaline Mollisols, showed a pH of 6.23. The soils showed reduced nutrient and carbon content and a comparatively poor soil fertility index specific to soil types. The soil available NPK and soil total cations were found to be comparatively low and soil specific. However, rubber fields in Mollisols were significantly higher in STK, STMg, STCa, and STNa while those in Ultisols were significantly higher in SAP and SAK than other soil orders. The Inceptisols were significantly higher in SAN, STP, and soil organic carbon than others. Therefore, balanced fertilizer application concerning soil types per proper soil fertility monitoring has become significant to sustainable soil productivity management in rubber plantations. [ABSTRACT FROM AUTHOR]

The rubber tree is an economically important tree planted in many tropical countries. While rubber planting has improved the livelihoods of growers, it has also resulted in soil degradation. However, systematic studies on assessment of soil health and its management in rubber plantations are limited. The present study explored whether intercropping of Michelia macclurei (an ornamental evergreen tree) in rubber plantation could help conserve soil health compared to traditional monoculture practice with randomised complete block design. The rubber tree density was the same in monoculture and intercropping, with the addition of Michelia macclurei in intercropping. The effects of soil properties and microbial communities was used to analyse two different planting patterns of rubber monoculture and rubber intercropping using soil sampling from field plots. The study investigated variation in soil physical structure, soil moisture, soil nutrients, soil microbes, and enzyme activities in two types of rubber plantations viz. a monoclonal plantation without intercrop (RM) and a plantation with Michelia macclurei as an intercrop (RAS). The results from above study showed an increase in soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (AN), available phosphorus (AP), nitrate nitrogen (NN) and total potassium (TK) in plantation with intercrop as compared to monoclonal plantation without intercrop. When comparing the corresponding values of RM to RAS, bacteria and total microbial abundance of RAS increased on average by 75.51% and 48.42%, respectively. In addition, after the transition from rubber monoculture to rubber agroforestry, the annual average of SOC, TN, AP, TK nutrients and pH in soil increased by 10.94%, 4.25%, 14.53%, 1.34% and 9.74%, respectively. Soil water content, soil bulk density and soil porosity were not significantly different between RM and RAS treatments. Sucrase activity and cellulase activity also increased in the RAS intercropping system. These results show that intercropping promotes soil organic matter and microbial communities and enhances soil enzyme activities. These findings indicate that rubber intercropping creates healthy soil environments conducive to tree growth and improves the ecosystem sustainability of rubber plantations. Healthier and stronger rubber trees may increase rubber production and provide sustainable management of plantations in the future. [ABSTRACT FROM AUTHOR]

Rubber plantations are an important component of tropical forest ecosystems and are emerging as crucial contributors to carbon sequestration in the tropics. However, ecosystem respiration (RECO), which constitutes an essential constraint on the carbon fixation capacity of rubber plantations, and its driving mechanisms remains unclear. Therefore, this study developed a data-driven semi-empirical model to simulate rubber plantations RECO utilising eddy covariance flux measurements and was upscaled to Hainan Island using remote sensing images and climatic data. Numerical simulations experiments analysed direct and indirect of climatic factors impacts on rubber plantations RECO. The results showed that the model accurately captured RECO trends and seasonality (R2 = 0.87, RMSE = 1.27 g C m−2 d−1); in the past 19 years, RECO showed a noticeable increase, particularly in the late rainy season and the seasonality of RECO has shown a delayed pattern. The RECO in the central region (52% area) exhibited multimodal enhancement while northern and southern regions (37% area) showed oscillations or decreases. Temporally, RECO is higher in the rainy season compared to the dry season, and spatially, RECO is higher in the southern region than in the northern region. Among the climatic factors, water conditions (rainfall and air humidity) have been emerged as dominant factors (5.38%) influencing RECO, surpassing temperature (3.96%) and radiation (3.81%). In addition, climatic factors make a positive overall contribution during the dry season but perform oppositely in the rainy season. This study offers theoretical and technical insights into high carbon sink management in rubber plantations and carbon sequestration in tropical forests ecosystems. [ABSTRACT FROM AUTHOR]

Rubber plantations are among the most important in the world's tropical regions. They play a positive role in carbon sequestration and in delaying climate change, supplying strategic resources of natural rubber (NR), and aiding in poverty alleviation and rural revitalisation. This paper reviews six methods of research on carbon sinks in rubber plantations: the biomass inventory method, the biomass conversion factor continuous function method, the trade potential of carbon sinks method, the calculation method for carbon storage of rubber latex, the eddy covariance method, and the remote sensing image model method. This study clarifies the carbon sink assessment and enhancement model for rubber plantations and describes the composition of the carbon pool, which includes the aboveground and belowground vegetation biomass carbon pools, litter carbon pool, latex carbon pool, and soil carbon pool. It also examines influencing factors such as tree age, global climate change, and human disturbance, as well as improvement pathways including afforestation, fertilisation, irrigation, and tapping, and evaluation methods like field surveys, positional observations, remote sensing monitoring, and model simulation. Research on carbon sequestration in rubber plantations faces challenges, including the unclear dynamics of carbon sources and sequestration, uncertain spatial and temporal patterns, and the long-term lack of accurate monitoring of carbon sinks and technologies for increasing sinks and reducing emissions. Future research should focus on the methodology of rubber plantation carbon sequestration projects, the dynamics of carbon sequestration, and the spatial allocation pattern of carbon sequestration in rubber plantations. [ABSTRACT FROM AUTHOR]

Natural rubber is one of the four main raw materials of industry and a globally important strategic material. Rubber plantations with agroforestry attributes have undergone rapid growth in the northern part of mainland Southeast Asia (including Xishuangbanna) since the 1990s, leading to a series of eco-environmental effects on biological diversity, climate change, carbon stocks, and hydrological processes. Accurate, detailed, and updated spatial information on rubber plantations, therefore, is fundamental for developing efficient management strategies. Currently, the booming rubber plantations are being experienced new changes in Xishuangbanna. The commonly used coarser spatial resolution satellite data (e.g., 250-m MODIS and/or 30-m Landsat) have limited applications because most plantations are often small and scattered, especially in the mountainous areas. Here, we developed a straightforward and effective re-normalization of red green normalized difference vegetation index (ReNDI) approach based on finer resolution (10-m) Sentinel-2 imagery, and then mapped the first annual 10-m rubber plantations in the entire Xishuangbanna during 2018–2021. Interestingly, rubber plots no longer expanded as rapidly as in past decades and even decreased slightly. The latest area of rubber plantations was 2514.7 km2, a decrease of 31.9 km2 comparing since 2018, with an average overall accuracy and kappa coefficient of four-year reached up to 95.37 % and 0.90, respectively. Among them, Jinghong city and Menghai county increased by 52.4 km2 and 14.8 km2 respectively, and Mengla county decreased by 99.1 km2. The main area of rubber expansion was around the Jinghong city, where rubber was initially planted. More importantly, owing to pursuing increased economic benefits and requirements of environmental protection, a considerable portion of the rubber encroachment has disappeared, particularly near roads and rivers. Our phenology-based ReNDI algorithm not only enriches the remotely-sensed methods for other industrial plantations mapping, but also provides a new chance to understanding the current patterns of rubber plantations (i.e., increase and decrease), which will contributed to rational planting planning and agroforestry management in the future, especially in the tropics. [ABSTRACT FROM AUTHOR]

This study was designed to estimate the land snail diversity of coastal Karnataka, India, and to compare it with that of the Western Ghats mountain range. Altogether, 23 species of land snails were recorded, of which 18 species were found in coastal Karnataka and 3 species were confined only to Western Ghats. The highest number of land snails were found in national parks, followed by plantations, and the lowest in open areas. Rhachistia praetermissus was confined to the nagabana of Harekala and Rishetia sp. was only seen in home gardens. Among the plantations, land snail diversity was higher in arecanut plantations and lower in rubber plantations. Land snails such as Mariaella dussumieri and Macrochlamys indica were common to most of the visited habitats. Significant correlation between humidity and species richness of land snails indicates that humidity determines the land snail diversity in coastal Karnataka. Reserve forests/National Parks studied encompass more land snail diversity as they provide heterogeneous habitats and suitable ecological niches. Lower diversity of land snails in plantations and open areas compared to the reserve forests can be attributed to lower habitat complexity and anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

Scientific manuring, by adopting balanced nutrition in perennial plantations is the need of hour for increased productivity and addressing global warming by adopting 4 R nutrient stewardship. Continuous use of NPK in perennial crops can lead to deficiency of micronutrients. Therefore, a study was carried out to understand nutrient status of major rubber growing tracts and to formulate a customized nutrient mixture for rubber. A detailed soil fertility assessment and leaf tissue analysis of mature rubber plantations of age group 11-15 years in five agro ecological units (AEU) in Thiruvananthapuram were conducted during the study. Based on this, a multi micronutrient mixture was formulated for rubber and the composition of the mixture was Zn -3.64 %, B -8.04 %, Fe- 2.01 %, Cu- 2.55 % and Mn-3.25 %. For accessing the effect of the mixture, a field experiment was conducted in existing rubber plantation of RRII 105 replanted in 2005 at Aryanad (AEU 14) in randomized block design with seven treatments and three replications, namely general recommendation of NPK at 30:30:30 kg ha-1year-1, soil test based recommendation of NPK at 22:8:21 kg ha-1 year-1, application of multi micronutrient mixture along with soil test based recommendation of NPK at varying levels from 5 to 15 kg ha-1year-1. The treatments had a significant effect on dry rubber content (DRC). For the post monsoon, summer, and annual period, the highest DRC was noticed in 15 kg ha-1 of the mixture applied plot which was on par with 7.5 kg ha-1 applied plot. Application of micronutrient mixture resulted in enhancement of different micronutrient pools and enriched nutrient storehouse. It was also observed that available micronutrients were within sufficiency level even after application of the mixture. Multi micronutrient mixture application at 7.5 kg ha-1 along with soil test based recommendation of NPK can be considered for future studies. [ABSTRACT FROM AUTHOR]

[Objective) The present study aimed to construct and develop rubber-based agroforestry systems for increasing total production and ecological benefit, thus ensuring the sustainable development of natural rubber cultivation in Hainan province. (Method) The research focused on the starch crops Maranta arundinacea L. (arrowroot), which were intercropped in immature conventional single-row rubber plantation (6-year old), immature (6-year old) and mature (20-year old) double-row rubber plantations. Its feasibility of intercropping in different rubber plantation was assessed based on its light condition, soil nutrient content, productivity, economical benefit and greenhouse gases emission. [Result] The light condition in the immature conventional single-row rubber plantation was the poorest. Yield of arrowroot inter-cropped in this rubber plantation was only 4750 kg/hm², while the yield of arrowroot intercropped in the immautre and mature double-row rubber plantations were 27 470 and 11 190 kg/hm², respectively, which light conditions were better (P<0.05). The variation of arrowroot biomass between different treatments was consistent with the yields. Totally, the nutritional ingredient (starch, crude protein and soluble sugar) did not differ significantly between treatments. The economical benefits of arrowroot intercropped in immature and mature double-row rubber plantation were 86 185 and 9285 Yuan/hm², respectively, while arrowroot intercropped in immature single-row rubber plantation was -21 415 Yuan/hm². In terms of net greenhouse gas emission, only the treatment intercropped in immature double-row rubber plantation was a sink with a potential of 368 kg/hm², while the other treatments were source of greenhouse gas emission. [Conclusion] The highest productivity and economical benefit are found in treatment of arrowroot intercropped in immature rubber plantation. Meanwhile, ecological benefit is also obtained. This type of rubber-based agroforestry system is suitable and recommended for popularization in Hainan province. [ABSTRACT FROM AUTHOR]

Powdery mildew significantly impacts the yield of natural rubber by being one of the predominant diseases that affect rubber trees. Accurate, non-destructive recognition of powdery mildew in the early stage is essential for the cultivation management of rubber trees. The objective of this study is to establish a technique for the early detection of powdery mildew in rubber trees by combining spectral and physicochemical parameter features. At three field experiment sites and in the laboratory, a spectroradiometer and a hand-held optical leaf-clip meter were utilized, respectively, to measure the hyperspectral reflectance data (350–2500 nm) and physicochemical parameter data of both healthy and early-stage powdery-mildew-infected leaves. Initially, vegetation indices were extracted from hyperspectral reflectance data, and wavelet energy coefficients were obtained through continuous wavelet transform (CWT). Subsequently, significant vegetation indices (VIs) were selected using the ReliefF algorithm, and the optimal wavelengths (OWs) were chosen via competitive adaptive reweighted sampling. Principal component analysis was used for the dimensionality reduction of significant wavelet energy coefficients, resulting in wavelet features (WFs). To evaluate the detection capability of the aforementioned features, the three spectral features extracted above, along with their combinations with physicochemical parameter features (PFs) (VIs + PFs, OWs + PFs, WFs + PFs), were used to construct six classes of features. In turn, these features were input into support vector machine (SVM), random forest (RF), and logistic regression (LR), respectively, to build early detection models for powdery mildew in rubber trees. The results revealed that models based on WFs perform well, markedly outperforming those constructed using VIs and OWs as inputs. Moreover, models incorporating combined features surpass those relying on single features, with an overall accuracy (OA) improvement of over 1.9% and an increase in F1-Score of over 0.012. The model that combines WFs and PFs shows superior performance over all the other models, achieving OAs of 94.3%, 90.6%, and 93.4%, and F1-Scores of 0.952, 0.917, and 0.941 on SVM, RF, and LR, respectively. Compared to using WFs alone, the OAs improved by 1.9%, 2.8%, and 1.9%, and the F1-Scores increased by 0.017, 0.017, and 0.016, respectively. This study showcases the viability of early detection of powdery mildew in rubber trees. [ABSTRACT FROM AUTHOR]

• First report of RNA- seq analysis of Hevea clones in response to abnormal leaf fall (ALF) disease caused by Phytophthora. • A comparative transcriptome analysis of resistant and susceptible clone performed to gain insights into its resistance mechanism against ALF. • Compared to a susceptible clone, several differentially expressed genes were found in the resistant clone. • Several signalling pathways and transcription factors were also expressed during infection. Rubber is an important industrial commodity and Hevea brasiliensis is the commercial source of natural rubber (NR). Abnormal Leaf Fall (ALF) disease caused by Phytophthora meadii is one of the major diseases affecting yield of NR. Understanding Hevea-Phytophthora interaction mechanism is essential to manage this devastating disease. Transcriptome analysis was employed to gain an understanding on the molecular mechanisms that confer resistance to Phytophthora that would facilitate development of disease-tolerant Hevea clones. As our current understanding of Hevea-Phytophthora interaction is limited, an attempt was made to analyze and compare the transcriptomes of tolerant and susceptible clones of H. brasiliensis in response to P. meadii infection (in healthy and Phytophthora challenge-inoculated condition) during early, middle and late phases of infection by using the RNA-Seq technology. The transcriptome sequencing generated an average of 19,000 differentially expressed genes (DEGs) in both clones. When comparing the tolerant clone to the susceptible clone, there was an overall increase in the number of DEGs and a progression in the number of DEGs, indicating a more active engagement of transcriptional activity in the tolerant clone. Functional annotation, KEGG analysis and enrichment analysis revealed that the major pathways enriched for the DEGs were involved in plant hormone signal transduction and plant-pathogen interaction. An analysis of DEGs during each phase showed that the most active transcripts involved in defense mechanisms were activated during mid-phase and in the case of susceptible clone least transcripts were induced during mid-phase than in any other phase in both the clones. Many DEGs belonging to the MYB, NAC, WRKY and AP2/ERF transcription factor families were observed in both clones. Comparative studies revealed their differential involvement in tolerant and susceptible clones against Phytophthora infection. These findings may facilitate further exploration of Hevea-Phytophthora interaction and in cloning for defense related genes. [ABSTRACT FROM AUTHOR]

Corynespora leaf fall disease caused by the fungus Corynespora cassiicola is a major leaf disease of Hevea brasiliensis, the commercial source of natural rubber. Different clones of H. brasiliensis show varying levels of sensitivity towards different strains of C. cassiicola. The genetic mechanism behind the differential sensitivity of H. brasiliensis clones has to be identified in order to develop clones resistant to wider range of C. cassiicola strains. The available information on the sensitivity of H. brasiliensis clones is based on the observation of natural infection or infection of detached leaves. In the present study, the sensitivity of seven H. brasiliensis clones towards two strains of C. cassiicola belonging to two different races was determined using a more precise method by artificial infection of the plants under controlled conditions. Strain CLN 16 was found to be more virulent compared with CSB 16, as it induced more severe symptoms in a shorter period. Among the four different stages of leaves, Stage II leaves with copper brown to apple green colour showed higher sensitivity to both strains followed by Stage III leaves with apple green appearance. Among the clones, RRIM 600 had a higher susceptibility towards CSB 16; however, it was the most resistant clone towards CLN 16. Clone PB 350 showed the highest susceptibility towards CLN 16 whereas RRIM 928 showed the highest resistance towards CSB 16. The present study provides a platform for further studies leading to the development of H. brasiliensis clones with resistance towards wider range of C. cassiicola strains. [ABSTRACT FROM AUTHOR]

Background and aims: There is still limited knowledge regarding the dynamics of soil microbial community structures and functional groups during forest secondary succession after rubber monocultures (RP) abandonment. Methods: Bacterial and fungal communities and functions were investigated for the soil from six forest stands with three replicate plots. Selected stands included an RP, four spontaneous secondary forest stands that formed after RP abandonment at 1 (SF_1), 10 (SF_10), 20 (SF_20), and 40 (SF_40) years, as well as a primary forest (PF, approximately 100 years). Results: After RP abandonment, the alpha-diversity metrics of soil microbial communities increased during the first 40 years of succession but decreased in PF. The biomarkers Proteobacteria and Mortierellomycota increased significantly (P < 0.05) by 84% and 633% in PF, respectively, while Firmicutes showed a significant decrease of 89% in comparison with SF_1. Secondary succession increased the relative abundance of bacterial functional groups related to carbon cycling and fungal functional groups (especially ericoid mycorrhizal). Soil pH was the main edaphic factor in shaping microbial communities and functions. In addition, soil moisture and seasonal variations had direct impacts on fungal communities and bacterial functions. Conclusions: Collectively, these findings suggest that different successional trajectories occur in bacteria and fungi, owing to their divergent responses to the changes in season, soil moisture, and nutrients. Specifically, the frequent shifts in bacterial dominant phyla during succession, as well as the increased susceptibility of diversity and functional groups to season, indicate that bacteria respond more quickly to disturbances compared to fungi. [ABSTRACT FROM AUTHOR]

Aims: Termites function as "soil engineers" in tropical agroforestry ecosystems. However, of their role in phosphorus (P) cycling little is known. We aimed to investigate the impact of termite activity on soil aggregate stability and P fractions at the aggregate level in a tropical rubber plantation. Methods: Fungus-growing termite mounds (active and abandoned) involving both above- and belowground locations were studied in a 24-year-old rubber stand. The mass percentage and stability of aggregates, P fractions contents and other major chemical properties of soil aggregates were measured. Aggregate-associated P preservation capacity was also calculated. Results: More aggregates < 1 mm in size were concentrated in active aboveground mounds than active belowground chambers, thus resulting in weaker stability and erosion resistance, whereas the opposite trend occurred in abandoned mounds. The concentrations of labile P (in > 2 mm aggregate size), moderately labile P (0.25–1 mm), and non-labile P (0.053–1 mm) in active aboveground mounds were significantly higher than other types. The changes in specific P forms enriched TPi in aggregates > 2 mm and TPo in 0.053–1 mm size of active aboveground mounds relative to others, implying the importance of Po storage in microaggregates induced by termite activity involved in long-term P transformation. Furthermore, middle-sized (0.25–2 mm) aggregates stored more P and represented the highest P storing capacity, especially for active belowground chambers. Conclusions: These results suggest that in the presence of termite activity, P cycling is greatly enhanced in aboveground mounds despite the poor aggregate stability, whereas P forms are stable after mound abandonment, except for a higher H2O-Pi concentration aboveground. Our study provides an important reason why mound soils can be considered as fertility amendments for agroforestry practices in P-deficient tropical soils. [ABSTRACT FROM AUTHOR]

Enhanced rock weathering (ERW) has been proposed as a measure to enhance the carbon (C)‐sequestration potential and fertility of soils. The effects of this practice on the soil phosphorus (P) pools and the general mechanisms affecting microbial P cycling, as well as plant P uptake are not well understood. Here, the impact of ERW on soil P availability and microbial P cycling functional groups and root P‐acquisition traits were explored through a 2‐year wollastonite field addition experiment in a tropical rubber plantation. The results show that ERW significantly increased soil microbial carbon‐use efficiency and total P concentrations and indirectly increased soil P availability by enhancing organic P mobilization and mineralization of rhizosheath carboxylates and phosphatase, respectively. Also, ERW stimulated the activities of P‐solubilizing (gcd, ppa and ppx) and mineralizing enzymes (phoADN and phnAPHLFXIM), thus contributing to the inorganic P solubilization and organic P mineralization. Accompanying the increase in soil P availability, the P‐acquisition strategy of the rubber fine roots changed from do‐it‐yourself acquisition by roots to dependence on mycorrhizal collaboration and the release of root exudates. In addition, the direct effects of ERW on root P‐acquisition traits (such as root diameter, specific root length, and mycorrhizal colonization rate) may also be related to changes in the pattern of belowground carbon investments in plants. Our study provides a new insight that ERW increases carbon‐sequestration potential and P availability in tropical forests and profoundly affects belowground plant resource‐use strategies. [ABSTRACT FROM AUTHOR]

Agroforestry combines trees and crops for sustainable benefits. We explore rubber and canna integration into agroforestry, emphasizing sustainability, biodiversity, and carbon sequestration. This study assesses C. indica's viability beneath 7-8-year-old rubber plantations, examining its impact on soil, microbial communities, and latex production. The research site in Subang, Indonesia, features, at the beginning, six-year-old rubber trees with variations in sunlight under canopies. Wild C. indica rhizomes from Mid Java are planted beneath rubber trees and open ground. No significant difference was found in plant height, rhizome weight, leaf area, number of leaves, r/s ratio, SLA, LWR, and LAR between C. indica cultivated beneath rubber trees (RC agroforestry) and on open ground. Although not significant, RC soil had higher N, P, K, and organic C levels than rubber monoculture (RM) soil two years after adopting the rubber-canna agroforestry system. After six years, RC soil had a greater pH, C, N, P, and K, clay and silt content, and Shannon E index than RM soil. Analysis of soil metagenomics showed the phylum Proteobacteria dominates and enhances soil fertility, particularly in RC soils. These results increase latex output at the RC site over the RM location. In conclusion, the Rubber-Canna agroforestry system enhances sustainability, soil fertility, and crop yield, addressing food security and environmental concerns. The primary novelty of this six-year study lies in the integration of C. indica into Southeast Asia's rubber agroforestry systems, highlighting its unique characteristics such as low-light survival, which can contribute to food security and soil protection. [ABSTRACT FROM AUTHOR]

Melastoma malabathricum L. (Melastomataceae) is a widely distributed tropical shrub that grows in Southeast Asia. Recent research found that M. malabathricum has a bioremediatory potential that can accumulate high concentrations of toxic metals such as Al, Pb, As, and Cr. Thus, this study aimed to investigate the metal hyperaccumulation in M. malabathricum from various populations and their relation to soil edaphic factors. We collected mature leaves and soils of M. malabathricum from 15 different populations in Negeri Sembilan, Selangor, and Pahang in Peninsular Malaysia. These 15 populations consist of lowland forests, dump sites, riparian, oil palm and rubber plantations, paddy fields, and mining sites. We found that M. malabathricum accumulated high concentrations of Al (3.45±1.58 to 8.697±1.61 mg g-1) followed by Fe (1.02±0.02 to 1.07±0.04 mg g-1), Pb (0.013±0.001 to 0.016±0.001 mg g-1), As (0.008±0.005 to 0.23±0.004 mg g-1), and Cr (0.005±0.0003 to 0.02±0.01 mg g-1). The highest concentration of soil Al was 85.95±5.00 mg g-1, Fe with 69.960±7.47mg g-1, Pb with 0.192±0.03 mg g-1, As with 0.156±0.06 mg g-1 and Cr with 0.133±0.03 mg g-1. We found no significant association between high foliar metal concentrations of the metals (Al, Pb, As & Cr) with the soil chemical properties but some soil metal elements were intercorrelated with foliar metal concentrations. Understanding the potential of M. malabathricum in accumulating high levels of metal elements, provides useful information for phytoremediation works. Further research is required to investigate the mechanism uptake and tolerance of heavy metals in M. malabathricum. [ABSTRACT FROM AUTHOR]

This study aims to get an insight into the major sectors with a green job potential in Delta State and to further analyze the argument that job creation is one of the important benefits of green growth policies - that is, policies to foster economic growth and development while ensuring that natural assets continue to provide the resources and environmental services on which our well-being relies (Bowen and Kuralbayeva, 2015). The claims that the greening of economies is a net generator of decent jobs - good jobs that offer adequate wages, safe working conditions, job security, reasonable career prospects and worker rights (UNEP (2011). There is a great need to promote and create lots of green jobs to make Delta State a better place for future generations. The potential areas of green jobs in Delta State has revealed by the studies include among others: Rubber plantations, cassava (manioc), fish, palm oil and kernels, yams, and plantains, flour-milling plant, sawmilling, solar, wind, geothermal, biomass and water, tourism, building sectors, forestry activities, waste management, railways, health sector, government bodies, education sector, Escravos Gas-to-Liquids (EGTL) plant, an integrated steel plant in Aladja, small enterprises and the market within SMEs. The study recommends that for green jobs to thrive in Delta State, there needs to be an increased appreciation for green and sustainable practices; Individualistic efforts from different agents, like governmental agencies, private sector, policymakers, employers, and employees are very important towards the creation of a Green Economy; better integration of employment needs and research programs; and a specific regulatory framework to promote green businesses, and a competitive ecosystem that creates green jobs. [ABSTRACT FROM AUTHOR]

The article "Scales and scaling in Tree Physiology" explores the concept of scaling in tree physiology research. Scaling involves studying processes and phenomena at different levels, from molecular to whole-plant studies. The article provides examples of downscaling, such as examining gene expression and physiological responses to stress, and upscaling, such as mathematical modeling of gas transport and analyzing tree-ring data. The article highlights the need for researchers to consider scaling in their studies to gain a comprehensive understanding of tree physiology. It also discusses specific studies that use a mechanistic approach to understand processes and their consequences at higher scales. Overall, the article emphasizes the importance of identifying relevant scales of study and conducting scaling of mechanisms and processes in tree physiology research. [Extracted from the article]

Background: Studying green manure decomposition in various returning methods can establish a scientific foundation for farmland nutrient management. Methods: In a rubber plantation on Hainan Island, China, utilized the nylon mesh bag method to imitate the decomposition of kudzu (whole plant, stem, and leaf) under two returning methods (mulching and burying) in two different sites (young and mature rubber plantations). The study examined the decomposition rate and nutrient release dynamics of kudzu, as well as the effects of kudzu reintroduction on several soil properties including soil pH, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), nitrate nitrogen (NO3−-N), ammonium nitrogen (NH4+-N), available phosphorus (AP), and enzyme activities. Results: Compared with mulching, the burying returning method significantly increased the kudzu decomposition rate and nutrient release proportions. After 270 days, more than 80% of the C, N, and P in different components of kudzu were released. The decomposition rate was found to be more affected by the initial soil factors than by the endogenous nutrients of kudzu. Compared with CK, all kudzu treatments led to significant increases in soil enzyme activities and soil pH, SOC, NO3−-N, and AP concentrations in two rubber plantations. The TN and NH4+-N concentrations were significantly increased in mature rubber plantations, while the TP was the opposite. Conclusion: The kudzu returned can effectively alleviate soil acidic, improve soil nutrient availability, regulating soil enzyme activities of the rubber plantation in the short-term. These results provide a scientific basis for the rational application of kudzu in rubber plantations. [ABSTRACT FROM AUTHOR]

Pestalotiopsis leaf fall disease (PLFD) has emerged as a significant and detrimental foliar disease affecting Hevea brasiliensis in Malaysia since 2017. The disease poses a severe threat to rubber plantations, leading to economic losses and impacting the country's rubber industry. Understanding the factors contributing to lesion incidence and the potential presence of a fungal complex is crucial for effective disease management. This study aimed to address key objectives, including the identification of primary fungal pathogens responsible for lesion development and examination of the role of co-infections in lesion incidence. To achieve these objectives, five fungal isolates (Neopestalotiopsis surinamensis, Colletotrichum conoides, Lasiodiplodia theobromae, Phyllosticta fallopiae and Letendraea cordylinicola) previously identified through the Internal Transcribe Spacer (ITS) regions were subjected to in vitro artificial inoculation experiments on detached rubber leaves. Various combinations of these fungal isolates were tested to evaluate their interactions as possible causal pathogens of PLFD. Three variables were assessed, viz. type of water source (sterile distilled water and rainwater), presence of leaf wounds, and inoculation techniques (conidial suspensions and mycelial agar plugs). Lesion incidence was evaluated based on sporulating occurrences on the detached leaves, recorded seven days after inoculation. Statistical analysis, including non-parametric Pearson's chi-square tests revealed that the fungal isolates Lasiodiplodia theobromae, Colletotrichum conoides and Neopestalotiopsis surinamensis were the primary contributors to lesion incidence, accounting for 83%, 69%, and 57% of cases, respectively. The study also revealed that lesion incidence was not significantly influenced by inoculation techniques or type of water source but was greater in wounded leaves compared to unwounded leaves. Co-inoculation experiments demonstrated increased lesion incidence, highlighting the role of co-infections in disease severity. Importantly, this study elucidated a potential fungal complex associated with PLFD and provided insights into its epidemiology. The findings contribute to deeper understanding of the disease, offering valuable guidance for effective disease management strategies in H. brasiliensis cultivation in Malaysia. [ABSTRACT FROM AUTHOR]

Rubber (Hevea brasiliensis) is a priority tree crop that produces natural rubber (NR), making it an important plantation commodity in the Philippines. However, NR production is confronted with major constraints, including rubber diseases resulting in low latex yield. Twenty-five rubber farms located in five major rubber-producing municipalities (Kidapawan, Antipas, Makilala, Matalam and President Roxas) of Cotabato, Philippines, were surveyed for prevalence of major rubber leaf diseases. Information on farm practices and environmental variables was collected. The majority of rubber farmers were smallholders with hectarage planted ranging between 1 and 15 hectares. The most planted clones are RRIM 600 and PB 260, which are high-yielding yet susceptible to many foliar pathogens. Six leaf diseases, viz. Oidium powdery mildew, Colletotrichum leaf disease, Corynespora leaf fall/spot, Phytophthora leaf blight, bird's eye spot and algal spot, were documented in this study. Powdery mildew was the most prevalent in Cotabato with the highest percentage and severity of infections in all plantations, followed by Colletotrichum leaf disease. Information on disease prevalence in surveyed areas is important for disease management actions. [ABSTRACT FROM AUTHOR]

【Objective】In order to provide scientific basis for the optimization of intercropping patterns and the management of intercropping under rubber plantations in the future, the effects of different intercropping patterns on the functional diversity of soil microbial communities in mature rubber plantations were studied. 【Method】Biolog-ECO technology was used to study the characteristics of soil microbial functional diversity, and the differences of soil microbial metabolic activity and diversity on carbon sources in different intercropping plantations were analyzed. 【Result】Soil microbial carbon utilization was stable at 216 hours, and the average light absorption value AWCD of different treatments was in the order of rubber-kinggrass intercropping＞rubber-coffee intercropping＞rubber-puzzle intercropping＞rubber.The intercropping pattern not only increased the types of carbon sources utilized by soil microorganisms, but also enhanced the metabolic activity of carbon sources.The metabolic capacity of soil microorganisms to carbohydrates, amino acids, phenolic acids, carboxylic acids and polymers was the strongest in rubber-kinggrass intercropping, and the metabolic capacity of amines was the strongest in rubber-coffee intercropping.There were significant differences in soil microbial carbon source utilization between intercropping patterns and rubber plantation by PCA （principal component analysis), significant differences between rubber-kinggrass and rubber-coffee, rubber-puzzle, but no significant differences between rubber-coffee and rubber-puzzle intercropping.The research showed that different intercropping modes could improve the soil microbial diversity index, and there were significant differences in AWCD value and McIntosh index among different treatments, but no significant differences in Shannon index and Simpson index.Correlation analysis showed that the metabolic function of soil microbial carbon source was closely related to soil environmental factors, and soil water content, pH and organic matter were the main factors affecting the differences of soil carbon source metabolism. 【Conclusion】Intercropping for kinggrass, puzzle and coffee can improve soil ecological environment, promote the utilization of soil carbon sources, and enhance the functional diversity of soil microbial community in rubber plantation. [ABSTRACT FROM AUTHOR]

Hevea brasiliensis is the greatest source of natural rubber and raw material in several industrial products manufacture. In Colombia, it has been commercially established in five productive units; however, the genetic basis is limited and foliar diseases have influenced the development and the production. In La Libertad Research Center (Villavicencio) and Taluma Experimental Field (Puerto López) of the Corporación Colombiana de Investigación Agropecuaria – AGROSAVIA, clonal trials, at small-scale and large-scale, were established to evaluate the performance assessment, associated with growth, of seven clones from CIRAD-Michelin selection Collection series CDC, FDR, MDF y PMB, and FX 3864 and RRIM 600 as well. In juvenile stage, the trunk circumference (CIRC) was measured every six months, and the annual increase average (IMA-CIRC) was calculated. Variance analysis and means comparison were carried out. At eight years of age, the FDR 5788 clone showed IMA-CIRC of 8.20 cm year-1 and 6.87 cm year-1 in La Libertad and Taluma, respectively; differences in growth between clones were observed. In the Piedemonte llanero (La Libertad), the FDR 5788 and RRIM 600 clones were notable for their growth, whereas in the Altilllanura (Puerto López) PMB 1 and FDR 5788 were remarkable. In La Libertad, the FDR 5788, RRIM 600 and CDC 312 clones exceeded the CIRC of 50 cm at sixth year, in contrast to Taluma, where it occurred at seventh year for PMB1 and DFR 5788. [ABSTRACT FROM AUTHOR]

A large-scale rubber plantation in Southern Thailand is expected to capture a significant amount of carbon dioxide from emissions through carbon sinks in the vegetation and soil. The goal of this research is to create a carbon offset assessment for rubber plantations lasting for 30 years using a voluntary market contract approach. To evaluate the area of large-scale rubber plantations, this study evaluated major growing regions in five provinces in the middle-south region of Thailand (Nakhon Si Thammarat, Phatthalung, Songkhla, Satun and Trang) using an integrated RS-GIS technique that incorporated biomass allometric equations, soil series databases, and object-based classification. The classification of rubber plantation areas and the mapping of rubber stand ages were conducted to estimate the above-ground biomass of the rubber tree. Texture analysis was used in the rubber classification process, and normalised difference vegetation index (NDVI) was combined with texture analysis to separate vegetation areas from other land cover. Four groups of varying ages (1–6, 7–13, 14–20 and 21–30 years old) were evaluated for their capacity to generate carbon offsets. The equations of voluntary market contract revenue according to the contract method of the CCX were applied for this case study. This evaluation was used to estimate their annual value, total and net incomes in the carbon market price regarding the RGGI Allowance (RGA). Carbon offset income was then used to estimate the potential income (over a 30-year period) of the life of the contract. The results showed that the carbon stock potential of rubber plantations depended on the age of the trees and the soil carbon stock. The total carbon stock in the rubber plantations varied from 249.73 to 301.48 Mg C/ha (or equivalently 916.49 to 1,106.44 Mg CO2 e/ha). Furthermore, the potential net income of the contract was estimated to be between USD5,378.32 and USD5,930.38 Mg CO2 e/ha over a 30-year period according to the voluntary market contract revenue. These results suggest that the large agricultural land plot policy could create opportunities for carbon offsetting. The policy of large-scale rubber areas could be used as a tool and mechanism for farmers who are considering participating in carboncrediting mechanisms. Then, farmers could use voluntary market contracts as a guide and foundation for their decision-making. The carbon offset credit strategy could assist Thailand in achieving its climate goals of transitioning to a low-carbon agriculture sector. [ABSTRACT FROM AUTHOR]

Powdery mildew is one of the most significant rubber tree diseases, with a substantial impact on the yield of natural rubber. This study aims to establish a detection approach that coupled continuous wavelet transform (CWT) and machine learning for the accurate assessment of powdery mildew severity in rubber trees. In this study, hyperspectral reflectance data (350–2500 nm) of healthy and powdery mildew-infected leaves were measured with a spectroradiometer in a laboratory. Subsequently, three types of wavelet features (WFs) were extracted using CWT. They were as follows: WFs dimensionally reduced by the principal component analysis (PCA) of significant wavelet energy coefficients (PCA-WFs); WFs extracted from the top 1% of the determination coefficient between wavelet energy coefficients and the powdery mildew disease class (1%R2-WFs); and all WFs at a single decomposition scale (SS-WFs). To assess the detection capability of the WFs, the three types of WFs were input into the random forest (RF), support vector machine (SVM), and back propagation neural network (BPNN), respectively. As a control, 13 optimal traditional spectral features (SFs) were extracted and combined with the same classification methods. The results revealed that the WF-based models all performed well and outperformed those based on SFs. The models constructed based on PCA-WFs had a higher accuracy and more stable performance than other models. The model combined PCA-WFs with RF exhibited the optimal performance among all models, with an overall accuracy (OA) of 92.0% and a kappa coefficient of 0.90. This study demonstrates the feasibility of combining CWT with machine learning in rubber tree powdery mildew detection. [ABSTRACT FROM AUTHOR]

This article analyzes the history of the natural rubber industry in the Brazilian Amazon, including the colonialist involvement of the British Empire and the industrial heritage of rubber. It provides an overview of the natural rubber species, tapping and extraction systems, and the establishment of rubber plantations that entangled and modernized the world. The present article considers the role of actants and entanglements between human and non-human agencies in the forest as coproducers of knowledge and resistance. In conclusion, the wide variety of works and approaches on the archaeology of rubber and its industrial heritage is presented and offers perspectives for new debates. [ABSTRACT FROM AUTHOR]

Background: The present study was conducted with an aim to study the socio-economic and livelihood of the rubber growers in Mokokchung district, further main objective is to provide extra income as well as generating more employment through rubber plantation. Methods: For the present research study a total of 160 respondents were selected from 8 villages, out of which, 94 respondents (58.75 per cent) were small, 50 respondents (31.25 per cent) were marginal and 16 respondents (8.00 per cent) were medium farms, respectively. Result: Gross income for marginal, small and medium farmers was ₹ 2,48,400, ₹ 6,21,000 and ₹ 9,93,600 and net income was ₹ 95,300, ₹ 4,10,797.88 and ₹ 7,46,600. About 52.50 per cent respondents were employed in government sector with an average annual income of ₹ 1,01,70,021, followed by 38.75 per cent respondents with an average annual income of ₹ 31,00,016, 5 per cent respondents were daily wage earners with an average annual income of ₹ 2,10,002 and 3.75 per cent respondents were working in private sectors with an annual income of ₹ 5,40,000. Maximum required trained labourers and hired labourers, 89.00 per cent had permanent workers and 29.00 per cent had contract labourers. Total two marketing channels were involved viz; channel I: Producer-Processor, channel II: Producer-Agent-Processor. In channel I, the marketing cost incurred by the producer was ₹ 38/kg and the marketing cost incurred by the agent was ₹ 27/kg. In channel II the marketinpg cost incurred by the producer was ₹ 3/kg and the marketing cost incurred by the agent was ₹ 36/kg. The major cconstraints were lack of local trained labourers, lack of government funding, lack of market, price instability, lack of training programmes and road condition. [ABSTRACT FROM AUTHOR]

Rongalite whose chemical structure was discovered in 1905, is an inexpensive, easily assessable, and copious industrial product, which has significantly been used for a long time in rubber, dye, and veterinary industries. Moreover, it has also been used as an antidote against several heavy metals poisoning, in addition to its applications in the photographic developer and veterinary medicines. Gratifyingly, Rongalite has also shown its uses as the fungicidal, bactericidal and antioxidant in pharmaceutical formulation. Besides, it has also been used in material sciences, and also as a viable cosmetic hair‐dye‐color removers. Interestingly, in past decade, it has shown its high‐impact in the arena of synthetic organic chemistry serving as SO22− equivalent, C1 synthon donor, reducing agent/radical initiator or proton source ‐ to assemble diverse intricate organic molecules under operationally simple yet efficient conditions. However, the services of multiple features of Rongalite in synthetic chemistry are still at the research stage, and needs to be sophisticated to a higher level in many years to come. Considering the synthetic importance of this valued reagent, this review article presents the advancement made in the field of Rongalite chemistry in the past three years. This review article will update the researchers working in this arena about the advancement of Rongalite in the synthetic organic transformations as well as it will help readers wishing to deal with this easy‐to handle and eco‐friendly low‐cost commodity chemical. This review article updating the rongalite chemistry will be useful to the chemical community in general and synthetic chemists in particular. [ABSTRACT FROM AUTHOR]

Developing rubber agroforestry systems is crucial to ensure the sustainable development of natural rubber cultivation. This study focuses on the starch crop Maranta arundinacea (arrowroot) and assesses its productivity and influencing factors when intercropped in 6–7-year-old conventional single-row and double-row rubber plantations. We analyze various aspects, including light resources, root distribution, soil nutrients, arrowroot growth characteristics, and product quality. The results indicate that the daily average photosynthetically active radiation (PAR) in the double-row rubber agroforestry system intercropping area ranges from 896.4 to 940.2 μmol·m−2·s−1. Additionally, the rubber tree roots near the intercropping area are less dense (107.0 g cm−3). In contrast, the conventional single-row rubber agroforestry system has a significantly lower daily average PAR of only 145.7 μmol·m−2·s−1, and the nearby rubber tree roots are more abundant (616.2 g cm−3). Although soil nutrient levels were slightly lower in the intercropping area on the double-row treatment compared to the single-row treatment, there was no statistical difference (p < 0.05). Arrowroot's photosynthetic capacity in the double-row rubber agroforestry system intercropping area is significantly greater than in the single-row rubber agroforestry system intercropping area. The yield per unit area in the former (23.46–27.47 t·ha−1) is also significantly higher than in the latter (2.87–4.75 t·ha−1, p < 0.05), with higher starch content. Therefore, arrowroot exhibits higher productivity when intercropped in double-row rubber agroforestry systems, making it suitable for establishing a "rubber–arrowroot" agroforestry model to enhance the yield per unit area of rubber plantations. [ABSTRACT FROM AUTHOR]

Rubber (Hevea brasiliensis) latex production is crucial to the local economy, yet Xishuangbanna's climate is considered sub-optimal for rubber cultivation. The prevalence of the powdery mildew disease (Oidium heveae) in this region has decreased the annual latex yield by 20%. Rubber latex yield is influenced by several factors, including temperature, disease, other biotic conditions, and plantation management. However, the interrelationships and potential influencing networks between rubber latex yield and these factors are rarely quantitatively assessed, and understanding their impacts on latex yield could inform better management practices. To address this gap, we investigated the effects of temperature, phenology, and powdery mildew disease on rubber latex yield in March using observational data on daily rubber latex yield combined with detailed phenology, powdery mildew, and temperature data from 2004 to 2010 in a state farm in the Xishuangbanna, Yunnan, China. We found that the critical influencing periods of daily temperature difference (or diurnal temperature difference) on the rubber latex yield were during Nov 27–Jan 19 and Jan 21–Mar 17. Partial least square regression analysis and variance partitioning analysis were conducted on the 35 phenological variables, eight powdery mildew-related variables, and two climatic variables. The most influential factors were identified as the factors of the daily temperature differences during Jan–Mar, the duration of leaf flushing phenology, and mean and maximum percentage of leaves infected by powdery mildew. Subsequent canonical correlation analysis and linear regression found that temperature difference directly affected the rubber latex yield and indirectly affected the yield through phenology and powdery mildew disease. Raised daily temperature differences from Jan to Mar had the greatest impact, leading to a higher rubber latex yield. Our comprehensive quantitative assessment revealed the relative importance of antecedent daily temperature differences, phenology, and powdery mildew disease as well as their complex interconnections in influencing rubber latex yield. Our findings are essential to future studies on both powdery mildew disease and rubber latex yield, and also develop rubber latex models. [ABSTRACT FROM AUTHOR]

This is the first multiple months study on home range and habitat use by a small group of bushmaster (Lachesis spp.). Five snakes (natives and translocated) were intensively radio tracked in a mosaic of plantations and small fragments of Atlantic Forest in the Reserva Ecologica Michelin in Bahia, Brazil. The average home range was 9.47 ha (MCP 95%) and 44.11 (Kernel 95%) for bushmasters tracked for more than 6 months. The macrohabitats used were primarily composed of disturbed primary (partially logged) and secondary (originally cleared) forests, but also of rubber tree plantations with a dense understory vegetation. Activity centres were closer to the forest edge (~ 22 m) than the core of the small forest fragments. The snakes mainly occupied wooded microhabitats with complex vegetation structures, around 50% under- and mid-story cover. Nocturnal ambush differed from diurnal resting microhabitats on the surface mainly by being significantly closer to mammal trails and a more open understory space. While mammal burrows and refuges under roots and rocks have been used, diurnal resting was primarily on the forest floor (75%). Translocation from sites > 20 km outside the study site has produced little evidence of negative effect, as all individuals grew impressively, continued an apparently normal life and established a home range similar to native bushmasters. [ABSTRACT FROM AUTHOR]

Rubber tree powdery mildew, caused by the obligate pathogen Erysiphe quercicola, is a major threat to rubber tree plantations worldwide. To investigate the temporal changes in the population structure of E. quercicola, diseased samples were collected at three disease epidemic stages (overwinter, early epidemic and late epidemic) from three counties in Hainan, China. Population structure was assessed using 16 polymorphic microsatellite markers. Both permutational multivariate analysis of variance (PERMANOVA) and analysis of molecular variance (AMOVA) indicated that there were significant differences among the population structure of E. quercicola at different epidemic stages. Furthermore, the late epidemic populations had higher genetic diversity than the other two stages. Discriminant analysis of principal components (DAPC) and STRUCTURE analysis showed that E. quercicola samples grouped into four clusters. One of the clusters included only samples from the late epidemic stage, while the other three clusters included samples from all three sample stages. Further analysis confirmed that there were significant (p = 0.001) genetic differences among these four clusters. As the teleomorph stage of E. quercicola has not yet been reported on rubber tree, these findings suggest that the epidemic of rubber tree powdery mildew is not only established by local inoculum sources, but also may be by inoculum drifting from other plantations or through host jumps from other hosts. [ABSTRACT FROM AUTHOR]

Polycaprolactone-based polyurethane coated urea ( PCU1 'PCU2 'PCU3) with 4 '6 and 8 coating materials were prepared by using biodegradable polycaprolactone polyol. In order to explore the controUed release properties' the coatings structure' nutrient release rate and longevity of polycaprolactone- based polyurethane coated urea were determined by using scanning electron microscopy' static pure water incubation method and soil incubation method. The results showed that the surface of the coated urea was covered with polycaprolactone-based polyurethane coating' and created a physical barrier' so that coated urea had better nutrient controlled release effect. With the increase of the amount of coating material the longevity of coated urea was prolonged. The longevity of PCU1 'PCU2 and PCU3 were 31.60'86.65 d' and 260. 11 d in static pure water' respectively. The nutrient release pattern of polycaprolactone-based polyurethane coated urea in static pure water and rubber plantation soil are similarity' but the soil incuba¬tion method significantly shorted the longevity of PCU3 ' the longevity of PCU3 in soil was 206.54 d' which was 53.57 d shorter than that in static pure water. [ABSTRACT FROM AUTHOR]

Agricultural commodity production is a major driver of tropical deforestation and biodiversity loss. Natural rubber from Hevea brasiliensis, a valuable commodity without viable substitutes, has recently been included in the European Union (EU) deforestation regulation that aims to halt imports of goods containing embedded deforestation. Sustained growth in demand for rubber is driven by increasing tire production, caused by rising transport flows and personal car ownership. We show that average natural rubber yields remain static, meaning 2.7–5.3 million ha of additional plantations could be needed by 2030 to meet demand. A systematic literature search identified 106 case studies concerning transitions to and from rubber, revealing that substantial rubber plantation area expansion since 2010 has occurred at the expense of natural forest. Eliminating deforestation from rubber supply chains requires support for millions of smallholder growers to maintain or increase production from existing plantations, without land or water degradation. Supply chain traceability efforts offer opportunities to deliver such support. While the inclusion of rubber in EU legislation is a positive step, it is critical to ensure that smallholders are not marginalized to avoid exacerbating poverty, and that other markets follow suit to avoid displacement of rubber‐driven deforestation to unregulated markets. [ABSTRACT FROM AUTHOR]

To address the practical navigation issues of rubber-tapping robots, this paper proposes an active navigation system guided by trunk detection for a rubber-tapping robot. A tightly coupled sliding-window-based factor graph method is proposed for pose tracking, which introduces normal distribution transform (NDT) measurement factors, inertial measurement unit (IMU) pre-integration factors, and prior factors generated by sliding window marginalization. To actively pursue goals in navigation, a distance-adaptive Euclidean clustering method is utilized in conjunction with cylinder fitting and composite criteria screening to identify tree trunks. Additionally, a hybrid map navigation approach involving 3D point cloud map localization and 2D grid map planning is proposed to apply these methods to the robot. Experiments show that our pose-tracking approach obtains generally better performance in accuracy and robustness compared to existing methods. The precision of our trunk detection method is 93% and the recall is 87%. A practical validation is completed in robot rubber-tapping tasks of a real rubber plantation. The proposed method can guide the rubber-tapping robot in complex forest environments and improve efficiency. [ABSTRACT FROM AUTHOR]

Rubber is currently the second major industrial crop in Malaysia after oil palm. The use of bokashi fertilizer (BF) on industrial crops is still not popular, and farmers rely mostly on chemical fertilizers (CFs) that are costly and hazardous to the environment. This research was conducted at Hevea plantation, Universiti Putra Malaysia, between August 2020–October 2021. The study was to assess the short-term effects of BF with reduced NPK fertilization on soil fertility, growth, and yield of rubber. Seven treatments (T) were involved. T1, T2, and T3 denote 4, 8, and 12 kg BF per pit. T4 was 1 kg NPK as control, whereas T5, T6, and T7 denote 4, 8, and 12 kg BF + 500 g NPK per pit, respectively. The variables observed included total nitrogen (TN%), total phosphorus (TP%), organic carbon (OC%), organic matter (OM%), exchangeable cations, microbial counts, tree girth, and dry rubber yield. The major findings indicated that applying 12 kg BF has raised the soil’s TN%, OC%, and OM% by 165, 171.4, and 172.0%, respectively, compared to NPK control. Also, adding 4 kg BF + 500 g NPK has increased the soil’s cation exchange capacity and TP% values by 107.8 and 42.9%, respectively, compared to the control. Adding sole bokashi increased the bacterial population by 22.2–133.3%. Rubber yield was better on trees treated with 12 kg BF, though this did not differ significantly from other treatments. Therefore, applying 12 kg BF or 4 kg BF + 500 g NPK can improve soil fertility and save costs from using inorganic fertilizer by at least 50%. [ABSTRACT FROM AUTHOR]

Climate change is visible as climatic events like flood and drought. Floods have a major impact on soil properties by altering them through dilution, transporting and deposition of minerals. Kerala had a flood on August 2018 with a different duration or temporal variation from three to seven days due to heavy and unexpected rain from June to mid of August 2018, that triggered large landslides on that month. The current study was focussed on the impact of flood on soil chemical properties (pH, soil EC, organic carbon, available NPK) at Thrissur district of Kerala in forest, rubber, nutmeg (homegarden), coconut and open land use systems. Soil samples were collected from flood affected and adjacent non flood affected of these land use systems from 0–20 cm depth after six months of flood and analysed chemical properties according to standard methods. The result of soil pH analysis showed a greater significant decrease in coconut plantation (6.28 to 4.94) after flood. Forest, rubber and homegarden showed an increase in organic carbon (OC) (0.22, 0.77, 0.45% respectively), available P (36.85, 32.6, 38.42 kg/ha respectively). Forest showed a higher amount of available N (84 kg/ha) after flood while rubber, nutmeg and open land use systems showed a decrease in available nitrogen (201.6, 107.1, and 207.9 kg/ha decrease respectively. Forest (196.6 kg/ha), rubber plantation (299.4 kg/ha), nutmeg plantation (292 kg/ha), coconut plantation (421.4 kg/ha) and open condition (125.7 kg/ha) showed a decrease in available K content after flood. Tree based land use systems showed a remarkably better resilience or masked the ill effect of flood very quickly compared to other systems. Integration of shade tolerant species (Grewia robusta, Ailanthus triphysa and Vateria indica) in coconut plantation would help the plantation to adapt flood like situation from soil nutrient loss, also it would increase the productivity of land by maximum utilisation of land resources. [ABSTRACT FROM AUTHOR]

Rubber (Hevea brasiliensis Muell.) plantations are among the most critical agricultural ecosystems in tropical regions, playing a vital role in regional carbon balance. Accurate large-scale biomass estimation for these plantations remains a challenging task due to the severe signal saturation problem. Recent advances in remote sensing big data, cloud platforms, and machine learning have facilitated the precise acquisition of key physiological variables, such as stand age (A) and canopy height (H), which are critical parameters for biomass estimation but have been underutilized in prior studies. Using Hainan Island—the second-largest rubber planting base in China—as a case study, we integrated extensive ground surveys, maps of stand age and canopy height, remote sensing indicators (RSIs), and geographical and climate indicators (ECIs) to ascertain the optimal method for estimating rubber plantation biomass. We compared different inputs and estimation approaches (direct and indirect) using the random forest algorithm and analyzed the spatiotemporal characteristics of rubber plantation biomass on Hainan Island. The results indicated that the traditional model (RSIs + ECIs) had low accuracy and significant estimation bias (R2 = 0.24, RMSE = 38.36 mg/ha). The addition of either stand age or canopy height considerably enhance model accuracy (R2 = 0.77, RMSE ≈ 21.12 mg/ha). Moreover, incorporating the DBH obtained through indirect inversion yielded even greater predictive accuracy (R2 = 0.97, RMSE = 7.73 mg/ha), outperforming estimates derived from an allometric equation model input with the DBH (R2 = 0.67, RMSE = 25.43 mg/ha). However, augmenting the model with stand age, canopy height, or their combination based on RSIs, ECIs, and DBH only marginally improved the accuracy. Consequently, it is not recommended in scenarios with limited data and computing resources. Employing the optimal model, we generated biomass maps of rubber plantations on Hainan Island for 2016 and 2020, revealing that the spatiotemporal distribution pattern of the biomass is closely associated with the establishment year of the rubber plantations. While average biomass in a few areas has undergone slight decreases, total biomass has exhibited significant growth, reaching 5.46 × 107 mg by the end of 2020, underscoring its considerable value as a carbon sink. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to investigate the effect of super absorbent polymers (SAP) on soil biological activities, and dry rubber yield of rubber plantations and find out the optimal application dosage for rubber plantions of dorught-prone regions. This can provide some theoretical basis for the rubber tree drought resistance cultivation technology. [Method] A fifteen-year-old rubber plantion with the clone Reyan 7-33-97 was used to set out a field randomized block experiment and compare the application of different dosages of SAP (0, 60, 120, 180, 300 g/tree) on soil moisture, nutrients, microbial quantity, enzyme activities and the dry rubber yield of the rubber plantation. [Result] The application of super absorbent polymers increased the soil water content and available nutrient content of rubber plantations, but it had no effect on soil pH. At the same time, it significantly promoted the soil bacteria quantity, actinomycetes quantity and total microorganisms, but did not change the overall proportion of bacteria, actinomycetes and fungi in the soil. Soil enzyme activity and rubber latex yield showed a unimodal curve trend with the increase of SAP dosage. The soil bacteria quantity, actinomycetes quantity, soil urease acvitity, invertase acvitity, catalase acvitity, ammonia nitrogen content, available phosphorus content and the yield of dry rubber showed a trend of firstly increase and then decrease with the increase of SAP amount. The T2 treatment was the most effective, in which the soil microorganisms, enzymatic activity and dry rubber yield showed the best. Compared with CK, the quantity of soil bacteria and actinomycetes increased by 346.42% and 191.48%, respectively, while the quantity of soil fungi decreased by 15.31%, and the soil urease activity, invertase activity, and catalase activity increased by 40.01% and 15.74%, 31.44%, respectively, and the yield of the latex increased by 11.99%. [Conclusion] The recommended SAP applicationdosage for the tapping rubber trees is 120 g/tree, which is beneficial to the increase of soil water content, soil microorganisms quantity and soil nutrient contents, as well the promotion of dry rubber yield. [ABSTRACT FROM AUTHOR]

Gutta percha, natural rubber, and balata are latexes produced by tropical trees that since the mid-nineteenth century have been extensively used commercially and in the creation of artworks and daily use objects. All three latexes are stereoisomers of polyisoprene that differ in their molecular structure. In gutta percha and balata, the molecular functional group is in the trans- position; in natural rubber, it is in the cis- position. This difference in their molecular structure affects the physical properties of these materials and their aging, turning natural rubber tacky and gutta percha brittle. Commercially focused analysis of natural polyisoprenes has typically used chemically modified materials. The present study characterizes natural, chemically unadulterated latex harvested from trees, aiming to differentiate the cis- and trans-forms. The analysed materials comprised fresh latexes harvested in Malaysia and Indonesia, naturally aged botanical samples, some over 100 years old, and minimally processed 10-year-old commercial stock; a total of 50 samples were examined, out of which 23 are discussed in detail. The harvesting practices of latexes were recorded during fieldwork in Southeast Asia in 2015–2019, in Cipetir (Tjipetir), on Lingga Island in Indonesia, and in Malay rubber plantations. The harvesting methods are the first indicators as to the type of latex harvested based on the pattern of incisions and time of coagulation upon exposure to air. The interviews of tappers, especially of gutta percha and balata, serve as a record of a disappearing craft. Therefore, this fieldwork report contributing to a general knowledge of working methods with natural latexes is of particular value considering the scarcity of published records. The laboratory analytical study of trans- and cis- forms relied on nuclear magnetic resonance (NMR) spectroscopy, which is the most accurate method to unambiguously determine the stereo chemistry of each polyisoprene. The characteristic spectroscopic features of cis- and trans-positions were clearly shown in all samples, in fresh latex, in over 100-year-old material, and in early twentieth century artifacts. This result indicated that the aging of the polyisoprenes does not prevent the identification of their stereochemistry. This analytical work is the first thorough examination of gutta percha, natural rubber and balata in the context of cultural heritage to guide preservation strategies for objects made of these materials. [ABSTRACT FROM AUTHOR]