Hilly Region Research Articles

Delineating the drought vulnerability zones in Bangladesh

The research aims to explore the vulnerability of Bangladesh to drought by considering a comprehensive set of twenty-four factors, classified into four major categories: meteorological, hydrological, agricultural, and socioeconomic vulnerability. To achieve this, the study utilized a knowledge-based multi-criteria method known as the Analytic Hierarchy Process (AHP) to delineate drought vulnerability zones across the country. Weight estimation was accomplished by creating pairwise comparison matrices for factors and different types of droughts, drawing on relevant literature, field experience, and expert opinions. Additionally, online-based interviews and group discussions were conducted with 30 national and foreign professionals, researchers, and academics specializing in drought-related issues in Bangladesh. Results from overall drought vulnerability map shows that the eastern hills region displays a notably high vulnerability rate of 56.85% and an extreme low vulnerability rate of 0.03%. The north central region shows substantial vulnerability at high levels (35.85%), while the north east exhibits a significant proportion (41.68%) classified as low vulnerability. The north west region stands out with a vulnerability rate of 40.39%, emphasizing its importance for drought management strategies. The River and Estuary region displays a modest vulnerability percentage (38.44%), suggesting a balanced susceptibility distribution. The south central and south east regions show significant vulnerabilities (18.99% and 39.60%, respectively), while the south west region exhibits notable vulnerability of 41.06%. The resulting model achieved an acceptable level of performance, as indicated by an area under the curve value of 0.819. Policymakers and administrators equipped with a comprehensive vulnerability map can utilize it to develop and implement effective drought mitigation strategies, thereby minimizing the losses associated with drought.

Quantitative Tracking of Seasonal River Pollution Sources and Integration of Sustainable Development Goals in Hilly Regions

Quantitative Tracking of Seasonal River Pollution Sources and Integration of Sustainable Development Goals in Hilly Regions

Altitude Distribution Patterns and Driving Factors of Rhizosphere Soil Microbial Diversity in the Mountainous and Hilly Region of Southwest, China

The distribution characteristics of the microbial community in rhizosphere soils of different altitudinal gradients were explored to uncover ecological factors affecting microbial community composition. In this study, the community variations of bacteria and fungi in the rhizosphere soil of Chrysanthemum indicum L. were analyzed. Samples were distributed along an altitudinal gradient of 300–1500 m above sea level in the Fuling watershed of the Three Gorges Reservoir area, China. The analysis was conducted using Illumina MiSeq high-throughput sequencing and bioinformatics analyses. Through correlation analysis with ecological factors, the altitude distribution pattern and driving factors of soil microbial diversity in the mountainous and hilly region of Chongqing were explored. According to the results, the richness and diversity of rhizosphere soil bacteria increased with altitude, while fungi were the richest and most diverse at an altitude of 900 m. The composition of the microbial community differed among different altitudes. Actinobacteria, Proteobacteria, Acidobacteriota, Chloroflexi, Bacteroidota, Ascomycota, unclassified_k_Fungi, Basidiomycota, and Mortierellomycota dominated the microbial community in rhizosphere soil. Correlation analysis showed that the distribution of rhizosphere soil microbial communities correlated with soil ecological factors at different altitudes. Moisture, pH, total nitrogen, total potassium, available potassium, urease, and catalase were significantly positively correlated with rhizosphere soil bacterial α-diversity, while their correlations with fungi were not significant. Variation partition analysis showed that the combined effects of soil physical and chemical factors, enzyme activity, and microbial quantity regulated bacterial community structure and composition. Their combined contributions (19.21%) were lower than the individual effects of soil physical and chemical factors (48.49%), enzyme activity (53.24%), and microbial quantity (60.38%). The effects of ecological factors on fungal communities differed: While the soil physical and chemical factors (44.43%) alone had a clear effect on fungal community structures, their combined contributions had no apparent effect. The results of this study not only contribute to a deeper understanding of the impact mechanism of altitude gradient on the diversity of rhizosphere soil microbial communities, but also provide a scientific basis for the protection and management of mountainous and hilly ecosystems. It lays a foundation for the future exploration of the relationship between microbial communities and plant–soil interactions.

Bioactive phytocompounds profiling and the evaluation of analgesic, anti-inflammatory, and antihyperglycemic potential of Argyreia capitiformis (Poir.) Ooststr.: A combined in vitro, in vivo, and computational investigations

Ethnopharmacological relevanceArgyreia capitiformis (Poir.) Ooststr. (Convolvulaceae) is traditionally used by the Chakma community in the hilly region of Bangladesh to treat minor disorders such as pain. Aim of the studyThis study intended to determine the secondary metabolites to identify bioactive compounds and evaluate antioxidant potential, in vitro anti-inflammatory and in vivo analgesic, anti-inflammatory, and antihyperglycemic activities of A. capitiformis along with in silico investigations. Materials and methodsChemical profiling was carried out using HPLC and GC-MS analysis. The analgesic effect was measured employing tail immersion and acetic acid-induced writhing methods. Following protein denaturation and formalin-induced paw edema, anti-inflammatory activity was studied. The antihyperglycemic potential was assessed using an oral glucose tolerance test (OGTT), while further mechanistic investigation was conducted using an alpha-glucosidase enzyme inhibitory assay. Simulations and molecular docking analyses were performed to ascertain the stability and binding affinities of the drug-protein complex. ResultsA. capitiformis ethanolic extract confirmed the presence of phenolics, alkaloids, flavonoids, terpenoids, tannins, gums, steroids, and reducing sugars. HPLC analysis revealed the presence of eight polyphenolic compounds, the most abundant of which was myricetin (64.10 ± 0.14 mg per 100 g dry extract). Moreover, the GC-MS analysis revealed twenty-four molecules, the most important of which was 2,4-bis (dimethylbenzyl)-6-t-butylphenol (9.19%). The concentrations of total flavonoids, total terpenoids, total phenolics, and total tannins were ascertained to be 142.48 mg QE/g, 173.1 mg UAE/g, 19.35 mg GAE/g, and 13.05 mg GAE/g, respectively. Furthermore, the plant extract had a total antioxidant capacity of 388 mg AAE/g. In the writhing assay, the plant extract suppressed writhing by 59.73% and 76.99% at the doses of 250 and 500 mg/kg, respectively, compared to the standard diclofenac Na 87.17%, and in the tail immersion assay, the plant extract displayed a maximum average reaction time of 1.94 and 2.40 s at the doses of 250 and 500 mg/kg, respectively as compared to the control tramadol 2.84 s at 60 min. In an in vitro anti-inflammatory assay, the plant extract possessed an IC50 of 95.51 μg/ml while diclofenac Na (standard drug) was found to be 69.50 μg/ml. Afterward, in vivo anti-inflammatory activity was observed in mice over a period, particularly after 3 h, the plant extract exerted maximum percent inflammation inhibitions of 36.36% and 45.45% at the doses of 250 and 500 mg/kg, respectively whereas ibuprofen the standard drug (100 mg/kg) exhibited 61.82%. The plant extract demonstrated antihyperglycemic activity, lowering blood sugar levels to 5.7 and 4.62 mM at doses of 250 and 500 mg/kg, respectively, as opposed to 8.58 mM in the control group. Meanwhile, the standard drug glibenclamide (5 mg/kg) dropped blood glucose levels to 2.38 mM in 60 min after glucose administration. Molecular docking (MD) and molecular dynamics simulation (MDS) studies support the stability of the protein complex responsible for exerting pharmacological activities. ConclusionA. capitiformis extract exhibited strong medicinal values supporting its traditional uses.

Applicability of a Modified Gash Model for Artificial Forests in the Transitional Zone between the Loess Hilly Region and the Mu Us Sandy Land, China

Afforestation in the transitional zone between the loess hilly area and the Mu Us Sandy Land of China has reshaped the landscape and greatly affected eco-hydrological processes. Plantations are crucial for regulating local net rainfall inputs, thus making it necessary to quantify the closure loss of plantation species in drought and semi-arid areas. To quantify and model the canopy interception of these plantations, we conducted rainfall redistribution measurement experiments. Based on this, we used the modified Gash model to simulate their interception losses, and the model applicability across varying rainfall types was further compared and verified. Herein, Caragana korshinskii, Salix psammophila, and Pinus sylvestris plantations in the Kuye River mountain tract were chosen to measure the precipitation distribution from May to October (growing season). The applicability of a modified Gash model for different stands was then evaluated using the assessed data. The results showed that the canopy interception characteristics of each typical plantation were throughfall, interception, and stemflow. The relative error of canopy interception of C. korshinskii simulated by the modified Gash model was 8.79%. The relative error of simulated canopy interception of S. psammophila was 4.19%. The relative error of canopy interception simulation of P. sylvestris was 13.28%, and the modified Gash model had good applicability in the Kuye River Basin. The modified Gash model has the greatest sensitivity to rainfall intensity among the parameters of the C. korshinskii and S. psammophila forest. The sensitivity of P. sylvestris in the modified Gash model is that the canopy cover has the greatest influence, followed by the mean rainfall intensity. Our results provide a scientific basis for the rational use of water resources and vegetation restoration in the transitional zone between the loess hilly region and the Mu Us Sandy Land. This study is of import for the restoration and sustainability of fragile ecosystems in the region.

Satellite Based Composite Weather Insurance Product for assessing mid-term adversary

The present study formulated a satellite-based rainfall insurance product (SRIP) at sub-seasonal scale during 2015–2020 by integrating meteorological, geophysical and vegetation index products e.g. rainfall (CHIRPS:Climate Hazards Group InfraRed Precipitation with Station), soil moisture (SMAP), normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) from moderate resolution imaging spectro-radiometer (MODIS). The SRIP was meticulously designed to integrate both cause (rainfall) and impact (NDVI, NDWI, soil moisture) parameters to enhance the assessment of min-season crop risks, with a particular emphasis on deficit rainfall. The performance evaluation of SRIP was conducted in two distinct agro-climatic zones viz. Deoria district of Uttar Pradesh (Upper Gangetic Plain Region) and Krishna district of Andhra Pradesh (Southern Plateau and Hills Region) spanned from June to October, which aligns with the major crop-growing season corresponding to the Southwest monsoon period in India. Three sets of SRIPs were investigated i.e. SRIP with cause parameter (SRIP1), SRIP with cause-impact parameters with no lag response (SRIP2) and SRIP with cause-impact parameters with one-month lag response (SRIP3). The SRIP was structured to provide a numerical index on a scale ranging from 0 to 1, representing poor to good crop-growing conditions that could effectively identify the rainfall deficit threshold (SRIP≤0.43) corresponding to negative percent deviation in rainfall (PDR≤−20%). This threshold level was recognized for compensation of triggers at the multiple crop growth phases during the crop-growing season. The district average of SRIP and PDR showed fair correlation co-efficient (0.77 ≤ r ≤ 0.88). Good correlation between sub-seasonal (monthly, bi-monthly, tri-monthly) SRIP and normalized MODIS Gross Primary Productivity (0.65 ≤ r ≤ 0.98), and SRIP deviation and yield deviation (0.45 ≤ r ≤ 0.97) reflect sensitivity of SRIP to crop carbon productivity and crop yield. The findings of the present study recommend SRIP not only a multi-phase composite index for assessing mid-season crop risks in terms of rainfall deficit for clusters of insurance units, but it has the potential to be used by insurance agencies to settle the claims by farmers in a transparent and faster manner for crop loss due to large-scale rainfall deficits. However, SRIP needs to be customized in future to make it more adaptable to settle insurance claims due to weather adversaries at individual farm level.

Comparative Phenotypic Traits and Performances of Native Sheep in Naikhongchhari Hilly Area of Bangladesh

Background: Many studies have been conducted to investigate the performance of native sheep in plains and coastal regions, but no studies have been conducted in hilly regions of Bangladesh. Considering this fact, Coastal, Barind and Jamuna River Basin sheep were evaluated for their phenotypic traits, productive and reproductive abilities to gain insights into their performance in the hilly region. Methods: The Coastal, Barind and Jamuna River Basin sheep were collected from Bangladesh Livestock Research Institute (BLRI), Savar, Dhaka for the first time to Regional Station, Naikhongchhari, BLRI and separated based on their phenotypic characteristics. A breeding program was established to ensure purity, using independent culling levels and selection indexes. Ewes were allowed to lamb throughout the year, mated with rams in a 15-20 to 1 ratio. The sheep were kept in a semi-intensive system. Result: The highest lamb birth weight was observed in coastal Region sheep, both male (1.43 kg) and female (1.22 kg), followed by Barind males (1.36 kg) and females (1.15 kg), respectively. The highest average daily gain was found in coastal region sheep (41.87 g/d), which was significantly higher compared to others. The lowest age at first heat, gestation length, age at first lambing, post-partum heat period, days open, lambing interval was observed in Barind sheep. Finally, the study offers valuable insights into the potentialities of native sheep in hilly regions, guiding future research and extension efforts for sheep farming in these areas.

Morphometric analysis and LULC change dynamics of Nayar watershed for the sustainable watershed management

The morphometric analysis of the watersheds is essential for the conservation of natural resources, including soil, water, and vegetation. The Morphometric analysis defines the linear, areal and relief aspects of the watershed. It involves the comprehensive analysis of various factors such as drainage network, surface water flow, and other topographical features. The aim of this study is to develop a sustainable watershed management strategy for the Nayar watershed based on morphometry and Land Use Land Cover (LULC) change dynamics. The Nayar watershed has a total area of 1956.33 km2. The multispectral satellite imagery, Digital Elevation Model (DEM) data, and Survey of India (SOI) Toposheets were used for understanding the topographical and morphological characteristics along with the LULC change dynamics. The findings of this research conclude that the Nayar watershed has parallel and dendritic drainage patterns with high relief. According to the LULC change dynamics, the Nayar watershed's area change comprising 57.60 km2 and 57.15 km2, are from Agricultural Land to Wasteland and from Forest Cover to Wasteland, respectively. This shift in the hilly region will increase the risks of landslides and erosion. Furthermore, the change of 110.03 km2 area of Forest Cover to Agricultural Land raises further challenges due to loss of natural vegetation in long run. In summary the change in LULC of Nayar watershed is vulnerable to risk of natural calamities like landslide, erosion. This work would be helpful to many experts and decision-makers for sustainable watershed management and natural resource management.

Rainfall cycle causes the inter-seasonal instability of ecosystem service trade-offs: A case study in the Tana River Basin, Kenya

As a crucial climate condition, the inter-seasonal rainfall cycle directly impacts the livelihoods and productivity of billions residing in monsoon regions. However, there is still limited understanding regarding its effects on trade-offs among ecosystem services (ES). This knowledge gap may impede the sustainable development of human well-being in these regions. In this study focused on Tana River Basin, a representative monsoon region, we assessed the seasonal supply and trade-offs of three ESs including water yield (WY), soil conservation (SC), and net primary production (NPP), which are closely linked to local human well-being. To comprehend the driving mechanism of inter-seasonal variation, the influential factors were identified using the Geographical Detector Model. Furthermore, by quantifying the seasonal trade-off intensity among three ESs, the managemental optimization priority areas were identified.The results showed that (1) all three ES supply presented an increasing trend from 2000-2020. Seasonally, both the supply and trade-offs of ESs were significantly enhanced in the rainy seasons, with spatial heterogeneity observed in the response to inter-seasonal rainfall cycle. (2) Natural condition factors presented stronger influence on the seasonal variation of ES trade-offs, which is crucial to consider the comprehensive hydrological response resulting from vegetation growth as the foundation for these seasonal variations. For the WY-SC trade-off, precipitation was identified as the primary influential factor, while vegetation coverage impact on SC-NPP and WY-NPP trade-offs. Higher precipitation and vegetation coverage would intensify the trade-off between corresponding ESs. (3) Regarding the spatial distribution of seasonal instability, several sub-watersheds aggregated in the midstream hill region were identified as the primary optimized zones, more flexible management strategies should be implemented preferentially. The findings contribute to a better understanding of how the inter-seasonal rainfall cycle impact on the ES trade-offs, supporting effective ecosystem management in monsoon regions.

Influence of Front-Line Demonstrations on Yield, Yield Gap and Economics of Field Pea under Hill Region of Arunachal Pradesh, India

Krishi Vigyan Kendra Yachuli, Lower Subansiri district, gave a front-line field pea demonstration in 06 villages across two blocks with 44 farmers during the 2019-20 and 2020-21 seasons. FLD on the VL Matar 42 variety of field pea was carried out over the course of two years in a 15 ha area using the recommended improved practices. Additionally, a control plot with farmer practices was maintained. The yield in the farmers' plot (1110 kg ha-1) and demonstration plot (1510 kg ha-1) in the year 2020-21 was higher than in the year 2019-20. In the years 2019-20 and 2020-21, respectively, the demonstration plots' mean yield exceeded that of the farmers' plot by 35.23 and 36.03 percent. The VL Matar 42 variety of field pea had a mean yield of 1465 kg ha-1, which was lower than the potential yield of 1868 kg ha-1. The yield gap of 403 kg ha-1 indicates that there is a technology gap. Interestingly, the average extension yield gap was lower (385 kg ha-1) during the study period. The technology index varied from 19.16 to 23.98 percent, showing the feasibility of the evolved technology at the farmer's fields. Cultivating field pea using improved technologies resulted in an average higher net return of Rs. 59,050 ha-1 compared to Rs 34,500 ha-1 from local farming practices. The benefit cost ratio of field pea was higher (2.16) when using improved technologies compared to (1.83) when using farmers' practices.

Examining the Impact of Topography and Vegetation on Existing Forest Canopy Height Products from ICESat-2 ATLAS/GEDI Data

Forest canopy height (FCH) is an important variable for estimating forest biomass and ecosystem carbon sequestration. Spaceborne LiDAR data have been used to create wall-to-wall FCH maps, such as the forest tree height map of China (FCHChina), Global Forest Canopy Height 2020 (GFCH2020), and Global Forest Canopy Height 2019 (GFCH2019). However, these products lack comprehensive assessment. This study used airborne LiDAR data from various topographies (e.g., plain, hill, and mountain) to assess the impacts of different topographical and vegetation characteristics on spaceborne LiDAR-derived FCH products. The results show that GEDI–FCH demonstrates better accuracy in plain and hill regions, while ICESat-2 ATLAS–FCH shows superior accuracy in the mountainous region. The difficulty in accurately capturing photons from sparse tree canopies by ATLAS and the geolocation errors of GEDI has led to partial underestimations of FCH products in plain areas. Spaceborne LiDAR FCH retrievals are more accurate in hilly regions, with a root mean square error (RMSE) of 4.99 m for ATLAS and 3.85 m for GEDI. GEDI–FCH is significantly affected by slope in mountainous regions, with an RMSE of 13.26 m. For wall-to-wall FCH products, the availability of FCH data is limited in plain areas. Optimal accuracy is achieved in hilly regions by FCHChina, GFCH2020, and GFCH2019, with RMSEs of 5.52 m, 5.07 m, and 4.85 m, respectively. In mountainous regions, the accuracy of wall-to-wall FCH products is influenced by factors such as tree canopy coverage, forest cover types, and slope. However, some of these errors may stem from directly using current ATL08 and GEDI L2A FCH products for mountainous FCH estimation. Introducing accurate digital elevation model (DEM) data can improve FCH retrieval from spaceborne LiDAR to some extent. This research improves our understanding of the existing FCH products and provides valuable insights into methods for more effectively extracting accurate FCH from spaceborne LiDAR data. Further research should focus on developing suitable approaches to enhance the FCH retrieval accuracy from spaceborne LiDAR data and integrating multi-source data and modeling algorithms to produce accurate wall-to-wall FCH distribution in a large area.

Efficacy of Different Priming Methods on Germination and Growth of French Bean (Phaseolus vulgaris L.) Under Field Conditions in Mugu, Nepal

Low seed germination and poor growth have been major problems in French bean production in the hilly region of Nepal. An effective solution may lie in seed priming, which enhances rapid and uniform seed emergence, thereby improving yield. A field experiment was conducted to find out the effect of different seed priming methods on various varieties of French beans under field conditions in Chhaayanath Rara-4, Mugu, Nepal. The experiment was conducted in two factorial RCBD with three replications. Factor A was three French bean varieties; black, ghoratte, and red beans, and Factor B included two methods of priming; hydro and halo along with control. The results revealed that the germination parameter was significantly influenced by the method of priming and it was found non-significant in the case of varieties. Maximum germination percentage and higher speed of germination were found in seeds treated with hydro-priming. Similarly, the growth parameter was found significant for both varieties as well as priming methods. Vegetative growth parameters such as plant height, number of leaves, and number of primary and secondary branches were found significantly higher in hydro-primed seeds and ghoratte variety. Likewise, the yield parameters such as days to first flowering, days to 50% flowering, and yield per hectare were found significantly higher in hydro-primed ghoratte beans. Hence, hydro-priming can be used as a simple and cost-effective technique to improve germination and growth of French beans along with suitable variety under field conditions in Mugu district, Karnali province, Nepal. Int. J. Appl. Sci. Biotechnol. Vol 12(3): 137-144.

Evaluation of rabi season sesame productivity from graded nutrient doses and tillage regimes in rice fallows of southern plateau and hills region of the Indian sub-continent.

Only scattered information is available on the tillage and nutrient management information for the sesame crop following rice in the literature. Sesame as an edible oil yielding crop with high levels of unsaturated fatty acids has high international demand due to superior health benefits. Being a small seeded crop, it requires standard tillage and nutrient management to obtain optimum productivity under rice fallow ecologies. As a sequential crop after rice harvest, the tillage and nutrient management practices followed for the preceding rice have astounding effects on the succeeding sesame crop. To better understand and manipulate the agro ecology in the rice fallow culture, it is necessary to study the behaviour of sesame cultivars, in relation to the tillage requirements and macro nutrient factors that have a bearing on the productivity. The aim of this work was to evaluate the productivity of rice fallow sesame in the southern plateau and hills regions of the Indian sub-continent (Tamil Nadu) with a hypothesis that tillage and nutrient management would immensely benefit the sesame crop. Field experiments were conducted at TNAU, Tamil Nadu Rice Research Institute, Aduturai, Tamil Nadu during 2019-2020 and 2020-2021 with tillage practices (reduced tillage, conventional tillage and zero tillage) and fertilizer doses (zero percent RDF, 25% RDF, 50% RDF, 75% RDF and 100% RDF) in a split plot design replicated thrice. The results have clearly indicated that the performance of rice fallow sesame was poor under zero till conditions as the sesame crop is poorly adapted leading to a yield penalty up to 68%. A total of 75% RDF has yielded statistically similar yield to that of 100% RDF to the rice fallow sesame. Further, neither the oil content nor the fatty acid composition was modified by tillage and nutrient management regimes.

Digital mapping of dates of transplanting and accumulated thermal requirement of rice (Oryza sativa L.) in the subtropics of North Eastern Hill Region, India

ABSTRACT Accurate and timely mapping of rice areas is crucial for effective agricultural planning and food security management in the North Eastern Hill Region of India, especially amid changing climate conditions. This study developed a method to estimate rice transplanting dates by utilizing VH polarized backscattering-coefficients rom Sentinel-1A SAR data and also assessed thermal requirements for rice productivity in Ri-Bhoi district, Meghalaya during kharif 2021. The methodology involved 3 steps- (i) preprocessing data to construct time-series SAR images (ii) rule-based classification of SAR data integrating phenological and topographical information to identify transplanting windows (iii) assessing mapping accuracy. The results when compared with field data, revealed five distinct transplanting windows from early June to early August across 9031 ha of rice area. Overall accuracy was 85%, with a kappa coefficient of 0.74. User and producer accuracies ranged from 0.74 to 0.93 and 0.75 to 0.92, respectively for various transplanting windows. GDD varied between 1432.8°C day and 3290.4°C day, with higher values corresponding to earlier planting dates. This study formulates a robust methodology for rice mapping in hilly, small-field landscapes with multiple transplanting dates by integrating Sentinel-1A SAR data with ancillary and crop phenology information, contributing to improved crop management and climate change adaptations.

Regulatory mechanism of soil and water conservation measures on understorey erosion in a subtropical hilly region

Vegetation restoration affects soil erosion by altering near soil-surface characteristics and hydrodynamic mechanisms. However, the regulatory mechanisms of vegetation restoration in reducing soil erosion under forests are not fully clear. Five soil and water conservation measures (SWCM) with different vegetation structures and characteristics were used in the pure forest of Pinus massoniana which included the grass and shrub, grass, grass and shrub + level furrow, grass, shrub and trees and grass + fish-scale pits, to analyze the impact of vegetation restoration on near soil-surface characteristics and soil erosion. The data were analyzed using Structural Equation Modeling (SEM) to find the key indicators affecting soil erosion under forest. The findings revealed that, as opposed to the control plots (CK), there were significant alterations in the near soil-surface attribute following the application of SWCM. These changes were characterized by an increase in soil porosity, soil water content, soil nutrient content, root biomass, litter, and vegetation cover, and a decrease in soil compaction, disintegration coefficient, and bulk density, with the most significant improvement occurring in 0–10 cm soil layer. The SWCM significantly reduced soil erosion, with runoff and soil loss reduction ranging from 60.46 % to 74.09 % and 67.62 % to 79.99 %, respectively. Structural equation models revealed the influence of SWCM on soil erosion. Specifically, soil water content and litter had a favourable influence on reducing soil erosion, root biomass had a direct positive impact on soil erosion, and vegetation cover directly leads to a reduction in soil erosion. Soil physical properties primarily influenced soil erosion through their effect on vegetation cover. Combining bioengineering and vegetation measures is superior at enhancing soil structure, improving nutrient content, and decreasing soil erosion compared to single vegetation measures. It is recommended to combine bioengineering with vegetation strategies to effectively curb understory forest erosion and enhance soil quality in pine forests.

Exploring Farmers’ Perspectives on Ecosystem Degradation and Restoration in Southern Hilly Regions of China

Exploring Farmers’ Perspectives on Ecosystem Degradation and Restoration in Southern Hilly Regions of China

Determination of Critical Crop Water Stress Index of Tea under Drought Stress Based on the Intercellular CO2 Concentration

Climatic changes have caused seasonal drought to occur frequently in tea fields of low-mountain and hill regions over the past decades. This leads to huge losses in the quality and yields of famous tea, which restricts the economic development of the tea industry. It is crucial to implement suitable irrigation scheduling. The crop water stress index (CWSI) is the main index to assess the water status of the crop. When the crop suffers irreversible drought stress, its critical water status cannot be easily evaluated using the CWSI. The change from stomatal limitations (SLs) to non-stomatal limitations (NSLs) of photosynthesis is vital for accurately recognizing crop drought stress. Thus, the objective of this research is to determine the critical crop water stress index of tea based on intercellular CO2 concentration (Ci) dynamic responses to drought stress. During two sensitive periods of water stress (famous tea harvest season and summer drought season, which are from March to April and July to August, respectively), the dynamic changes in the CWSI in tea were calculated and analyzed based on the CWSI theoretical model. The upper and lower baselines were determined on a daily basis and during a certain period. A critical value of the CWSI represents irreversible drought damage. This was determined by the characteristic response of the Ci of tea leaves during extreme drought stress. The results showed the following: (1) during the famous tea harvest season and summer drought season, the daily variation in CWSI was similar. During a certain period, the former maintained a stable fluctuation, while the latter increased in fluctuation. (2) The Ci showed a trend of fluctuating downward to a low point and then upward during extreme drought stress. After reaching the low point, it quickly increased in the former and stabilized for a day in the latter. When the Ci reached the low point, the upper benchmark of this critical point was 13.9 μmol·mol−1, the lower benchmark was 3.4, and the CWSI was 0.27. This critical CWSI could be used as an irrigation threshold point to ensure normal production for tea fields.

Contribution of soil microbial necromass carbon to soil organic carbon in grassland under precipitation change and its influencing factors in loess hilly region, Northwest China.

To investigate the contribution of microbial necromass carbon (MNC) to soil organic carbon (SOC) and its influencing factors under precipitation changes in grassland, we conducted a precipitation experiment with seven different precipitation levels in the Bothriochloa ischaemum restoration area in the loess hilly region. We analyzed the contents and characteristics of fungal necromass carbon (FNC), bacterial necromass carbon (BNC), and MNC in different fractions of SOC under different treatments, including natural precipitation (CK), and increased and decreased 20%, 40%, 60% of natural precipitation (I20, I40, I60, D20, D40, D60) . The results showed that 1) MNC content in mineral organic carbon (MAOC) ranged from 1.62 g·kg-1 to 2.17 g·kg-1, which was higher than that in particulate organic carbon (POC) ranging from 0.69 g·kg-1 to 1.31 g·kg-1. The former was approximately 1.4 to 2.8 times as that of the latter. 2) FNC and MNC exhibited similar changes in both MAOC and POC fractions. BNC content in MAOC was approximately 1-3.1 times as that of FNC. FNC content in POC was generally higher than BNC except for I40 and I60 where BNC exceeded FNC. 3) Overall, both increases and decreases in precipitation resulted in elevated MNC/MAOC and BNC/MAOC ratios, but decreased MNC/POC and FNC/POC ratios. The MNC/MAOC ratios in I60 and D60 were 33.2% and 18.1% higher than CK, respectively. The BNC/MAOC ratios in D60, I40 and I60 were 28.0%, 23.0% and 19.1% higher than those in CK, respectively. Except for D60, the FNC/POC and MNC/POC ratios were significantly lower than CK under other treatments. In terms of POC fractions, the MNC/POC ratios of D40, D20, I20, I40 and I60 were 28.4%, 23.3%, 28.8%, 23.3% and 32.2% lower than that of CK, respectively. The FNC/POC ratio of D40, D20, I20, I40 and I60 was found to be lower by 23.3%, 16.1%, 21.0%, 27.0% and 31.0% compared to that of CK, respectively. 4) NH4+-N and pH were the primary factors influencing the content of MNC in different carbon fractions under varying precipitation conditions. In summary, alterations in precipitation (either increase or decrease) enhanced the contribution of BNC-dominated MNC to MAOC, but reduced the contribution of FNC-dominated MNC to POC. This study was of significance for understanding the distribution of microbial necromass across different organic carbon fractions under precipitation alterations.

Assessment of Impact and Yield Economics of Tomato Hybrid Variety Arka Rakshak under High Hill Region of Arunachal Pradesh

A demonstration (FLD) was conducted by Krishi Vigyan Kendra Yachuli, Lower Subansiri district, Arunachal Pradesh under high hill region during Summer season of 2021-22 and 2022-23 to evaluate the impact of the demonstration of Tomato variety Arka Rakshak for yield and economics at the farmer’s field of four different locations of region. An area of 3.2 ha was covered under FLDs on Tomato variety Arka Rakshak with active participation of 12 farmers during demonstration. The average fruit yield was 372 q/ha during 2021-22 and 410 q/ha during 2022-23 with the increase in percentage of yield ranged between 53.71 to 52.98 during two years of the study. The extension gap ranging 130 to 142 q/ha and technology gap ranging between 308 and 270 q/ha. Decrease in technology index from 45.29 per cent during 2021-22 to 39.70 percent during 2022-23 show the practicality of the demonstrated technology in this region

Risk and vulnerability analysis of road network in landslide prone areas in Munnar region, India

Catastrophes like landslides have the potential to impair critical transportation infrastructure, particularly road networks. The hilly regions in the state of Kerala in India are particularly prone to hazards and changing climate conditions. During the monsoon season, landslides are common in the Western Ghats, and the intensity of adverse impacts is more severe due to its densely populated regions. The study area of this research is in Idukki district of Kerala, where over 60 % of the land is prone to landslides. The monsoon rains bring with them a slew of disastrous landslides in the region. Most of the roadways in the study area are often disrupted due to landslides. Landslide risk assessment (LRA) is a crucial component of research on adverse impacts of landslide. The use of Geographical information System (GIS) and Multi Criteria Decision Analysis (MCDA) using Analytical Hierarchical Process (AHP) for susceptibility mapping and hazard risk assessment assists in the identification of disaster-prone areas. The data collected by field surveys were used to confirm the study results and the high-risk zones of the region were identified and the risk maps are prepared for the region as well as for the road network in the region. The risk of landslides may be described as the possibility of negative repercussions on road network thereby adversely impacting the inhabitants of the region. The landslide risk assessment of the road network in a hilly region is carried out which gives important insights for risk management and for future planning of resilient development in the region. This study enhances the knowledge for management of road network risk and vulnerabilities in intricate hilly region settings by developing a thorough vulnerability analysis framework. The research advances by giving transportation engineers a useful quantitative tool for identifying the risk and vulnerabilities of road network and directing design strategies and mitigation measures to lessen the possible negative effects of disruptive events like landslides on road infrastructure. The research findings could be an input for policy makers to plan for alternative resilient strategies for landslide risk management in road networks. The rational methodology adopted here could be replicated for carrying out risk and vulnerability assessment in other landslide prone areas.