Edaphic Factors Research Articles

Comparative Study of Community Analysis of Plant Parasitic and Free-living Nemic Fauna around Root Zones of Mango (Mangifera indica) Plant in Hapur Region

Nematodes are tiny rounded body, unsegmented worms. They occupy any niche of the environment, like soil, freshwater, and terrestrial (free-living and parasitic). They constitute a large group of all metazoans in the world: Plant-parasitic and free-living nematodes are well-recognized factors in soil productivity. Phytonematodes feed upon the cell sap of plants with the help of stylet. It causes many abnormalities in plants like gall formation on roots, stunting growth, wilting of plants, and serious damage to crop yield. In the present study, soil samples were collected from (0-30 cm) vertical depth and (30-60 cm) horizontal depth from around the root of the mango plant in the Hapur region from July to November. Nematodes samples were extracted by decanting and sieving Techniques (Cobb1918) were applied. Under the microscope examination nematodes were identified as free-living with minimum percentages of 14.2% and8.88% at both vertical and horizontal depth while plant parasitic nematodes were recorded as a higher percentage(53.90% vertical depth)and(64.91% horizontal depth) away from the host plant. This was variation in communities of plant nematodes at both depths due to seasonal changes, various other edaphic factors such as PH, temperature, moisture emergence of secondary rootlets, and availability on set of monsoon season and unavailability of various food resources.

Effects of humic acid fertilizer on the growth and microbial network stability of Panax notoginseng from the forest understorey

Humic acid (HA) can substantially enhance plant growth and improve soil health. Currently, the impacts of HA concentrations variation on the development and soil quality of Panax notoginseng (Sanqi) from the forest understorey are still unclear. In this study, exogenous HA was administered to the roots of Sanqi at varying concentrations (2, 4, and 6 ml/L). Subsequently, the diversity and community structure of bacteria and fungi were assessed through high-throughput sequencing technology. The investigation further involved analyzing the interplay among the growth of sanqi, soil edaphic factors, and the microbial network stability. Our finding revealed that moderate concentrations (4 ml/L) of HA improved the fresh/dry weight of Sanqi and NO3-−N levels. Compared with control, the moderate concentrations of HA had a notable impact on the bacterial and fungal communities compositions. However, there was no significant difference in the α and β diversity of bacteria and fungi. Moreover, the abundance of beneficial bacteria (Bradyrhizobium) and harmful bacteria (Xanthobacteraceae) increased and decreased at 4 ml/L HA, respectively, while the bacterial and fungal network stability were enhanced. Structural equation model (SEM) revealed that the fresh weight of Sanqi and bacterial and fungal communities were the factors that directly affected the microbial network stability at moderate concentrations of HA. In conclusion, 4 ml/L of HA is beneficial for promoting Sanqi growth and soil quality. Our study provides a reference for increasing the yield of Sanqi and sustainable development of the Sanqi-pine agroforestry system.

Understanding the influence of environmental factors on forest composition along the vertical gradient of Northwestern Himalaya

Temperate and alpine ecosystems are considered the most sensitive and vulnerable region towards climate change in the Indian Himalayan region. The current study investigates forest composition in relation to environmental and edaphic factors, which is critical for determining plant community patterns. The impact of climatic and soil properties was studied to better understand species diversity and composition over an elevational gradient (2500–4800 m) in Beas Valley, Northwestern Himalaya. A total of 181 species from 15 community types, representing 122 genera and 53 families (9 Trees, 13 shrubs, and 142 herbs) were recorded from the valley. Non-metric multidimensional scaling (NMDS) analysis revealed significant compositional dissimilarity (PseudoF = 10.16, R2 = 0.48, p < 0.001) among vegetation types. Structural equation modeling (SEM) results indicated that tree species diversity was significantly influenced by solar radiation (β=0.17, p = 0.001) and winter temperature (β=41.95, p = 0.017). It was observed that solar radiation and winter temperature shape the community types in high elevation temperate regions. In contrast, precipitation, solar radiation along with summer temperature determine the composition of sub-alpine communities, whereas solar radiation, winter temperature and soil pH determine the composition of alpine communities. This indicated that multiple environmental factors are responsible for this diversity. The research findings shed light on crucial factors influencing high elevation plant diversity, emphasizing the significance of understanding environmental correlations for effective conservation. This is pioneer study, which will act as a reference for future studies in Beas valley. This scientific foundation allows for prioritized conservation efforts, focusing on areas with specific environmental conditions influencing forest composition and plant diversity, ultimately contributing to better management and preservation of high elevation plant communities.

Seasonal Fluctuations in Plant-Parasitic Nematode Vertical Distributions and Their Interactions with Edaphic Factors in Vegetable Fields of South Georgia, U.S.A.

Plant-parasitic nematodes (PPNs) can be found deep in the soil profile, compounding nematode management decisions and detection. This study aimed to understand how seasonal fluctuations in edaphic factors are associated with the vertical distribution of PPNs in south Georgia's vegetable cropping systems. Five-core composite soil samples were taken monthly (March 2020 to February 2022) at three random locations in six vegetable fields. Fields represented three cropping systems (vegetable plasticulture, bare ground cucumber, and plastic bed watermelon rotation) and two regions (north and south) sampled from five 15-cm strata (0 to 15, 15 to 30, 30 to 45, 45 to 60, and 60 to 75 cm). Only soil temperatures and precipitation had seasonal fluctuations; the other edaphic factors were vertically stratified. Latitude and stratum had the strongest associations with nematode composition, showing a clear separation between the north and south regions. Variations in soil texture, porosity, moisture, and PPN vertical distribution suggested that the illuvial zone in the north region was the main factor in the differences observed between regions and strata. Seasonal fluctuations in vertical distribution were found among Meloidogyne incognita and Nanidorus spp. Higher abundances of deep-dwelling PPNs were limited to the south region in the winter for deep-dwelling M. incognita and summer and winter for Nanidorus spp., probably due to the illuvial zone barrier in the north region. Because most root-knot nematodes dwell at ≤30 cm during the summer, fumigant/nematicide applications are recommended during this season to minimize the risk of deep-dwelling escapees.

Soil pH and organic matter: Key edaphic factors in sustaining optimum yield and quality of pomelo fruit

Identifying the soil properties associated with crop yield and quality variation is crucial for developing sustainable agronomic strategies. However, such information on pomelo production is scarce. Hence, forty independent sites in the primary pomelo production areas of Pinghe County were selected to investigate the influence of soil properties on pomelo yield and quality, and to provide reference for future soil management strategies. The results showed positive correlations between pomelo yield and soil pH, along with exchangeable calcium and magnesium, but this comes at the expense of fruit flavor quality. Meanwhile, soil organic matter positively influenced fruit flavor quality. Furthermore, a significant positive effect on fruit nutritional quality was noted across various soil properties, except for organic matter and available phosphorus concentration. A random forest model was used to predict pomelo yield, flavor quality, and nutritional quality based on soil properties and yielded R2 values of 0.50, 0.60, and 0.50, respectively. Partial least squares regression and structural equation modeling identified soil pH and organic matter as pivotal pomelo yield and quality determinants. The categorization of samples into four groups based on differences in pH and organic matter highlighted that integrating soil acidification remediation with organic matter increased is essential for sustainable pomelo production. Overall, this study offers comprehensive insights into the effects of holistic soil management on achieving both high yield and quality in pomelo cultivation. Furthermore, these findings serve as valuable reference for advancing sustainable production practices across large fruit types beyond the pomelo.

Urban greenspaces shape soil nematode community across soil depth gradients: Belowground life at The Ohio State University

Urban greenspaces face significant anthropogenic transformation, impacting soil ecosystems, multifunctionality, and global biodiversity. With increasing population and urbanization, understanding the drivers influencing soil nematode communities in urban greenspaces is crucial for sustainable urban ecosystem management. We chose the campus of The Ohio State University (OSU) due to its unique urban settings with minimally disturbed both turf and non-turf ecosystems. This study focuses on nematodes, the often-overlooked ecological engineers which play diverse roles in ecosystem functions. Nematodes were collected from 99 sampling locations across three soil depths to represent two ecosystem types (i.e., turf and non-turf) of the OSU campus. Among plant parasitic nematodes (PPN), Helicotylenchus and Pratylenchus populations were above damage threshold limits. No specific pattern of community composition was observed in the spatial variation map. The presence of rare PPN genera in the lower soil layers had a significant impact on beta diversity. Trophic group abundances displayed distinct patterns, with turf ecosystems exhibiting higher PPN as well as total nematode abundance decreasing with soil depths. In the subsurface layer (10–30 cm), both bacterivores and fungivores were higher in the non-turf than turf ecosystem. Fungal-dominated decomposition of organic matter was observed in both ecosystem types. Soil physiochemical properties, specifically, total organic carbon and soil texture, had a significant impact on PPN community composition. However, nematode trophic group composition was more altered by ecosystem type than edaphic factors followed by soil depths. Together these three explanatory variables explained 27.5 % of the total variance in trophic group composition. Overall, this study provides insights into the complex interactions between PPN, trophic groups, soil properties, and urban ecosystem characteristics, contributing valuable knowledge for sustainable urban greenspace management.

Edaphic Factors Modulating Phosphorus Availability in Lowland Rice Systems, Nigeria

ABSTRACT The low rice production level in Africa is attributed to poor soil fertility despite the potential for rice cultivation in the inland valleys. This study was conducted to evaluate soil characteristics in some lowlands that have been continuously and intensively used for rice production for over two decades in southwestern Nigeria. Soil physical, chemical, and mineralogical properties, as well as phosphorus sorption characteristics, were assessed in soil samples collected from diagnostic horizons of profiles in six benchmark soils. The results show kaolinite, quartz, potassium(K)-feldspars, and mixed-layered smectite as the predominant minerals. The iron oxide fractions indicate that the soils are at varying degrees of development where the soils at the advanced stage of development are predominantly rich in kaolinite and quartz with a high concentration of total pedogenic iron oxide and generally low in soil fertility. Soil phosphorus buffering capacity is low and varies inversely with pH, confirming the deficiency of phosphorus at low pH. Short-range-order (SRO) iron (Fe) oxides show a strong affinity for phosphorus and this is stronger at lower soil horizons and mediated by some redoxomorphic reactions. The SRO iron oxide concentration has more influence on phosphorus retention in soils rather than the absolute concentration of iron oxides. The study concludes that SRO Fe oxides and soil pH are the major edaphic factors playing a prominent role in phosphorus retention and availability in the wetland soils rather than the clay minerals.

IDONEIDAD DEL HÁBITAT Y ETAPAS DE DOMESTICACIÓN DE Heliopsis longipes (ASTERACEAE: HELIANTHEAE)

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; &lt;em&gt;Heliopsis longipes &lt;/em&gt;is an endemic plant with chemical properties and medicinal use, making it a species of biological, economic, and cultural importance. &lt;strong&gt;Objective: &lt;/strong&gt;To determine the habitat suitability of &lt;em&gt;H. longipes&lt;/em&gt; and the domestication stage of the cultivation. &lt;strong&gt;Methodology: &lt;/strong&gt;The presence probability was estimated using the maximum entropy algorithm (MaxEnt), with twenty-three bioclimatic variables as predictors from presence records. For the domestication process, 79 surveys focused on the knowledge of reproductive biology, production, and management of the species were conducted. &lt;strong&gt;Results:&lt;/strong&gt; The habitat suitability is determined by three variables: precipitation seasonality (51%), soil type (26%), and isothermality (22%). Considering the domestication stages, 81% of farmers are in stage five, where the species is cultivated and harvested using traditional practices, and 11% are in stage four, where general features of the reproductive biology are known. &lt;strong&gt;Implications:&lt;/strong&gt; The importance of climatic and edaphic factors in the species distribution and the cultivation's domestication stage are highlighted. This provides a foundation for conservation strategy design. &lt;strong&gt;Conclusions:&lt;/strong&gt; The contribution of specific variables to habitat suitability underscores the importance of climatic and edaphic factors in the species distribution. Three groups of farmers with different knowledge and cultivation practices were identified, placing them in two different stages of the species domestication process. &lt;/p&gt;

Edaphic factors mediate the responses of forest soil respiration and its components to nitrogen deposition along an urban-rural gradient

Exploring the influences of nitrogen deposition on soil carbon (C) flux is necessary for predicting C cycling processes; however, few studies have investigated the effects of nitrogen deposition on soil respiration (Rs), autotrophic respiration (Ra) and heterotrophic respiration (Rh) across urban-rural forests. In this study, a 4-year simulated nitrogen deposition experiment was conducted by treating the experimental plots with 0, 50, or 100 kg·ha−1·year−1 of nitrogen to check out the mechanisms of nitrogen deposition on Rs, Ra, and Rh in urban-rural forests. Our finding indicated a positive association between soil temperature and Rs. Soil temperature sensitivity was significantly suppressed in the experimental plots treated with 100 kg·ha−1·year−1 of nitrogen only in terms of the urban forest Rs and Ra and the rural forest Ra. Nitrogen treatment did not significantly increase Rs and had different influencing mechanisms. In urban forests, nitrogen addition contributed to Rh by increasing soil microbial biomass nitrogen and inhibited Ra by increasing soil ammonium‑nitrogen concentration. In suburban forests, the lack of response of Rh under nitrogen addition was due to the combined effects of soil ammonium‑nitrogen and microbial biomass nitrogen; the indirect effects from nitrate‑nitrogen also contributed to a divergent effect on Ra. In rural forests, the soil pH, dissolved organic C, fine root biomass, and microbial biomass C concentration were the main factors mediating Rs and its components. In summary, the current rate of nitrogen deposition is unlikely to result in significant increases in soil C release in urban-rural forests, high nitrogen deposition is beneficial for reducing the temperature sensitivity of Rs in urban forests. The findings grant a groundwork for predicting responses of forest soil C cycling to global change in the context of urban expansion.

A Comparative Analysis of Bacterial and Fungal Communities in Coastal and Inland Pecan Plantations.

Pecan forests (Carya illinoinensis) are significant contributors to both food and oil production, and thrive in diverse soil environments, including coastal regions. However, the interplay between soil microbes and pecan forest health in coastal environments remains understudied. Therefore, we investigated soil bacterial and fungal diversity in coastal (Dafeng, DF) and inland (Guomei, GM) pecan plantations using high-throughput sequencing. The results revealed a higher microbial diversity in the DF plantation than in the GM plantation, significantly influenced by pH and edaphic factors. The dominant bacterial phyla were Proteobacteria, Acidobacteriota and Bacteroidota in the DF plantation, and Acidobacteriota, Proteobacteria, and Verrucomicrobiota in the GM plantation. Bacillus, Nitrospira and UTCFX1 were significantly more abundant bacterial genera in DF soil, whereas Candidatus Udaeobacter, HSB_OF53-F07 and ADurbBin063-1 were more prevalent in GM soil. Basidiomycota dominated fungal sequences in the GM plantation, with a higher relative abundance of Ascomycota in the DF plantation. Significant differences in fungal genus composition were observed between plantations, with Scleroderma, Hebeloma, and Naucoria being more abundant in DF soil, and Clavulina, Russula, and Inocybe in GM soil. A functional analysis revealed greater carbohydrate metabolism potential in GM plantation bacteria and a higher ectomycorrhizal fungi abundance in DF soil. Significantly positive correlations were detected between certain bacterial and fungal genera and pH and total soluble salt content, suggesting their role in pecan adaptation to coastal environments and saline-alkali stress mitigation. These findings enhance our understanding of soil microbiomes in coastal pecan plantations, and are anticipated to foster ecologically sustainable agroforestry practices and contribute to coastal marshland ecosystem management.

Profile distribution and edaphic controls of soil organic carbon in dominant soil orders of Chitwan, Nepal

Soil profile distribution of soil organic carbon (SOC) in different soil types provides information about the carbon (C) dynamics in terrestrial ecosystems, and is also important for understanding climate feedback mechanisms and for developing a proper farm level SOC management decision. However, there are limited studies on it when we consider soil horizons of dominant soil orders of Nepal, which mostly use a fixed depth approach rather than horizon-based approach while studying profile SOC distribution. We collected soils from master horizons (0 to 100 cm) of three dominant soil orders (Alfisols, Entisols, and Inceptisols) in Chitwan district of Nepal, to understand the controlling factors of SOC accumulation. Dominant soil order regions were identified using a soil map prepared by the National Land Use Planning Project where a pit of 1 m3 was dug for each soil order and replicated four times. The highest SOC concentration (10.1 ± 0.6 g kg−1) was found in Alfisols followed by Entisols (8.8 ± 0.3 g kg−1) and Inceptisols (7.2 ± 8.9 g kg−1). Similarly, the highest SOC stock was found in the soil profile of Alfisols (200.01 ± 15.97 t ha−1) followed by Entisols (124.67 ± 12.20 t ha−1) and Inceptisols (113.27 ± 10.30 t ha−1) horizons. Surface (A) horizons of all three-soil order had significantly higher SOC than sub-surface (B and C) horizons. Regression analysis showed significant variability in SOC to clay content (R2 = 0.45, p < 0.0001), sand (R2 = 0.19, p < 0.001), and total nitrogen (N; R2 = 0.835, p < 0.001). Principal component analysis showed that the controlling edaphic factors differ with the soil types considering SOC change in the whole soil profile. Overall, we found that soil pH, N, clay and sand contents are the major controlling factors that drive the SOC accrual in dominant soil orders of Nepal.Graphical

A comprehensive network meta-analysis to assess the benefit of starter fertilization on yield, nutrient uptake and nutrient use efficiency

BackgroundPlaced starter fertilization, a well-established fertilization practice in agriculture, aims to increase fertilizer use efficiency and yield. So far, numerous studies have proven positive effect on yields. However, the impact on nutrient use efficiency and nutrient uptake was not investigated profoundly. Additionally, diverse unidentified edaphic and environmental factors, and fertilization strategies cause a high uncertainty for the outcome under field conditions. ObjectivesThe aim of this study was to quantify the impact of a placed starter fertilization on yield, N and P uptake as well as N and P use efficiency. Thereby, the importance of influencing environmental factors and management strategies and the magnitude of their impact should be clarified. MethodsWe performed a network meta-analysis including 1158 observations from 57 peer-reviewed studies and provided a holistic investigation on the effect of placed starter fertilization on yield, nutrient use efficiencies, and aboveground nutrient contents compared to fertilizing without starter fertilization. ResultsThis study revealed that placed starter fertilization significantly increased yield by 9.4 %. Especially in warm, arid climates as well as in warm, hyper-humid climates the fertilizer use efficiency gain was most pronounced. While N uptake and N use efficiency could not benefit significantly from a placed starter fertilization, P uptake and P use efficiency were both enhanced. In the future, combining N and P and using ammonium-based fertilizers can guarantee the effectiveness of a placed starter fertilization. ConclusionsIn summary, placed starter fertilization is a potent strategy to increase yield and improve P use efficiency and P uptake. When applied in the right climate, with the right dosage and N compound, additional advantages of a placed starter fertilization can be exploited. ImplicationsThe current study not only deepens our understanding of the connection of fertilization methods and agronomic performance, but also provides a guideline for improving the efficiency of placed starter fertilization.

Impacts of genotype, edaphic factors, and plant nutrients on yield and fruit quality for a perennial specialty crop (Vaccinium macrocarpon Ait.)

AbstractCompared to conventional crops, less is known about how genetic and environmental variability affect the yield and quality of specialty crops like cranberry (Vaccinium macrocarpon Ait.). Herein, we performed a multifaceted analysis of six commercial cranberry beds planted to the Stevens cultivar. The six beds included three with above‐average multiyear yields and three that were lower than average. We considered genotype, edaphic factors, and plant nutrient content as driving variables of yield and fruit quality. We found that genetic purity within beds raised the odds of obtaining above‐average yields over an 8‐year period. The highest levels of genetic contamination (38%–75%) were found at the low‐yield beds, where significant differences in yield and fruit quality were observed between genotypes, within beds. Across all beds, focusing only on plots genetically confirmed to be Stevens cultivar, we also found that plot‐scale yield in 2020 was significantly higher for two of three high‐yield beds, suggesting other factors besides genetic contamination influenced differences in bed‐scale yield. A factor analysis of mixed data that jointly included genotype, edaphic variables, and plant tissue nutrient content revealed complex relations among these variables that were tied to grouping plots based on long‐term yield. Findings highlight the need for further research into the complex genetic and environmental factors that control cranberry yield and fruit quality.

Caracterization of the edaphic factor in which within the Straseni forestry entity

The article presents a comparative study of the vegetation conditions (geomorphological aspects, soils) for the central area of the Republic of Moldova (RM) also called „Central Forests”. The prolonged droughts require a different way of managing both forestry and agriculture. Through this study, we aim to identify comparatively the edaphic conditions in 1985 and 2021, how they evolved over time, but also the capacity of the trees to accommodate over time. The forest soils of the Republic of Moldova have been studied less, with the exception of those in the middle of the Republic of Moldova, which also protected areas, have been more often visited with scientific research (A. Ursu 2005).

Temporal variation of microbial nutrient limitation in citrus plantations: Insights from soil enzyme stoichiometry

Soil enzyme carbon (C): nitrogen (N): phosphorous (P) stoichiometry and their vector model has been widely used to elucidate the balance between microbial nutrient requirements and soil nutrient availability. However, limited knowledge is available on the dynamics of soil enzyme stoichiometry and microbial nutrient limitation following afforestation, especially in the economic forest. In this study, the effects of citrus plantation on C: N: P stoichiometry were assessed through a comparative study between cropland and citrus plantations with varying durations of afforestation (i.e., 3, 15, 25, and 35 years). It was found that the C, N, and P contents in the soil (SOC, STN, and STP), microbial biomass (MBC, MBN, and MBP), as well as the activities of C-, N-, and P-acquiring enzymes (BG, NAG, and AP), were 1.02–2.51 times higher than those in cropland. Additionally, C, N, and P contents in soil and microbial biomass increased consistently with increasing afforestation time. While the activities of C-, N-, and P-acquiring enzymes increased from 3 years to 25 years and then significantly decreased. In addition to NAG: AP, the stoichiometry of C, N, and P in soil (SOC: STN, SOC: STP, and STN: STP) and microbial biomass (MBC: MBN, MBC: MBP, and MBN: MBP), along with BG: NAG, exhibited a decline of 7.69–27.38% compared to cropland. Moreover, the majority of the C: N: P stoichiometry in soil, microbial biomass, and enzymes consistently decreased with increasing afforestation time, except for SOC: STN and NAG: AP, which exhibited an opposite trend. Furthermore, a significant decrease in microbial carbon limitation and an increase in microbial nitrogen limitation were observed with increasing afforestation time. Collectively, the dynamic of microbial nutrient limitation was primarily influenced by the interaction between soil nutrients and edaphic factors. The findings suggest that with the increasing duration of citrus plantation, it is crucial to focus on nitrogen (N) fertilization while maintaining a delicate balance between fertilization strategies and soil acidity levels.

Physiological, molecular, and environmental insights into plant nitrogen uptake, and metabolism under abiotic stresses.

Nitrogen (N) as an inorganic macronutrient is inevitable for plant growth, development, and biomass production. Many external factors and stresses, such as acidity, alkalinity, salinity, temperature, oxygen, and rainfall, affect N uptake and metabolism in plants. The uptake of ammonium (NH4 +) and nitrate (NO3 -) in plants mainly depends on soil properties. Under the sufficient availability of NO3 - (>1mM), low-affinity transport system is activated by gene network NRT1, and under low NO3 - availability (<1mM), high-affinity transport system starts functioning encoded by NRT2 family of genes. Further, under limited N supply due to edaphic and climatic factors, higher expression of the AtNRT2.4 and AtNRT2.5T genes of the NRT2 family occur and are considered as N remobilizing genes. The NH4 + ion is the final form of N assimilated by cells mediated through the key enzymes glutamine synthetase and glutamate synthase. The WRKY1 is a major transcription factor of the N regulation network in plants. However, the transcriptome and metabolite profiles show variations in N assimilation metabolites, including glycine, glutamine, and aspartate, under abiotic stresses. The overexpression of NO3 - transporters (OsNRT2.3a and OsNRT1.1b) can significantly improve the biomass and yield of various crops. Altering the expression levels of genes could be a valuable tool to improve N metabolism under the challenging conditions of soil and environment, such as unfavorable temperature, drought, salinity, heavy metals, and nutrient stress.

Forest Flora of Nichlaul-IV. Trees

This paper enlists the trees found in Nichlaul forest, Gorakhpur Division (U.P.). Geographical limits, topography, edaphic and climatic factors of the area, its vegetational composition, injurious factors, phenological behaviour of the common plants and an artificial key to the families as well as to the species are given. In all, 109 tree species belonging to 91 genera and 44 families are included, giving field observations, local names, habit, habitat, dominance and sociability. Flowering and fruiting seasons as well as collection numbers of plants are indicated.

Flora of Bulandshahr District

The paper gives an account of the vegetation of the district of Bulandshahr in Central Uttar Pradesh. Edaphic, climatic, biotic and other factors determining the floristic composition of the district have been discussed in the paper. Aquatic and cultivated plants, avenue trees and orchard plants have been mentioned. A list of 376 species has been appended to give an idea of the flora of the District. Cuscuta capitata Roxb. and Clinopodium umbrosum (M. Bieb.) Koch have been reported for the first time from the U. P. plains.

High stochasticity in rare bacterial community assembly in rice-wheat rotation soils at a regional scale

A growing body of evidence highlights the important role of both abundant and rare microorganisms in agroecosystem for their respective ecological functioning. However, the ecological processes that govern the assembly of abundant and rare taxa microbial communities in rice-wheat rotation soils at a regional scale have not yet been elucidated. Here, we conducted a comprehensive investigation of bacterial diversity, community structure, and assembly in samples from 238 sites under rice-wheat rotation in eastern China. Soil pH was the most important edaphic factor shaping bacterial diversity and community structure. The Shannon diversity of both abundant and rare bacterial taxa had a parabolic relationship with soil pH, with diversity reaching its peak at pH values of 7.50 and 7.31, respectively. Abundant bacteria displayed greater sensitivity to soil pH than rare taxa. Stochastic processes, especially dispersal limitation, predominantly governed assembly for both abundant and rare bacteria, explaining 80% of observed variation. Remarkably, stochastic processes contributed >90% of variation in the assembly of rare taxa communities, surpassing its importance in abundant taxa community assembly. Moreover, the assembly of specific bacterial phyla was predominantly governed by stochastic processes in the rice-wheat rotation soils. Overall, our findings provide the first data that although soil pH can make an initial assessment of the variation of bacterial communities, the high level of stochasticity in rare taxa community assembly would make them highly unpredictable during agricultural managements in rice-wheat rotation soils. These findings contribute new perspectives to understanding the main processes underpinning the observed bacterial communities, with implications for soil sampling, biodiversity conservation and ecosystem functionality in rice-wheat rotation soils.

Cropping calendar, agroclimatic and agroecological zoning for rainfed maize (Zea mays L.) under different rainfall scenarios in a semi-arid region of Brazil

Context The productivity of crops is influenced by the available net water balance, which relies on a complex interplay of edaphic and climatic factors. In this sense, rainfall is the leading water input for crop growth and yield, especially in water-scarce regions under semi-arid climates worldwide. Aims This study aimed to define the optimum cropping calendar and the agroclimatic and agroecological zones for rainfed maize in the state of Ceará, which is predominantly located within the Brazilian semi-arid region, assuming different rainfall scenarios. Methods We considered the subdivision of the study area into eight homogeneous precipitation regions according to the regional rainfall pattern. The climatic water balance for each region over two decades was calculated from historical weather data series, assuming three rainy scenarios: dry, regular, and rainy. The agroclimatic zoning was defined through the crop water balance results, soil classification, land use and occupation, slope and temperature, weighted through a multi-criteria decision analysis based on the Analytic Hierarchy Process. Key results The recommended planting period was broader in rainy conditions. However, there may be some dry spells between two 10-day intervals of the calendar, which impair plant growth depending on their intensity. For the dry scenario, the agroclimatic zoning showed that the marginal water deficiency covered 96.55% of the study area. Conclusions Rainfed maize cultivated under the semi-arid climate of Ceará state is viable in rainy conditions, partially restricted in regular years, and not recommended in dry years. Implications This study emphasises the importance of climate monitoring in effective planning for rainfed maize cultivation in semi-arid regions.