Varying Soil Conditions Research Articles

Exploring Diversity in Neolithic Agropastoral Management in Mainland Greece Using Stable Isotope Analysis

ABSTRACT New stable carbon (δ13C) and nitrogen (δ15N) isotope values of charred plant and bone collagen remains from 6th mill. BCE Halai, central Greece, together with datasets from 6th mill. BCE Kouphovouno, southern Greece, and later 6th/early 5th mill. BCE Makriyalos, northern Greece, demonstrate how early farming communities in mainland Greece adapted mixed farming strategies to distinct local environmental and cultural settings. Intra-site similarities and differences in δ13C and δ15N values of distinct crop species, along with the intra-species variabilities in stable isotopic values, are used to assess the cultivation choices that farmers at the three sites made to fulfil distinct economic goals. At Halai, farmers cultivated multiple crops under variable soil conditions, a strategy likely geared towards minimising overall risk in a relatively arid coastal setting. At better-watered Kouphovouno, by contrast, farmers practiced strategic manuring to maximise the yield of free-threshing wheat, likely grown exclusively for human consumption and rotated with nitrogen-fixing pulses. At Makriyalos, the limited sample size of cereal remains suggests a lack of intensive manuring, in contrast to the two other sites. Assessment of which crops may have been consumed by livestock sheds further light on symbiotic relationships between crop cultivation and animal husbandry.

WITHDRAWN: Earth quake analysis of regular and irregular structures for all the soil types in seismic zone V

Abstract There has been a remarkable advancement in the research on design in the scope of engineering in the last couple of decades. There are many studies that contribute to better performance of buildings. Herein, to understand the seismic effects on a building when one of the design parameters is varying while others remaining constant, this study is conducted. The lateral forces at different levels of a structure in seismic zone V in all of the soil types are studied. The seismic loading with a varying soil conditions in the seismic zone is applied on all the structures. Both regularly and irregularly planned buildings are incorporated which are of varying heights (G + 3, G + 6, G + 9, and G + 12). The structure’s response in terms of lateral forces at all storey levels is analyzed varying the parameters. While the pattern observed is similar in regular and irregular cases, the soft soil type had higher storey shear when the storey levels increased.

Assessing Cover Crop and Intercrop Performance Along a Farm Management Gradient

The impacts of crop diversity on ecosystem functioning may vary depending on farms’ baseline environmental conditions and management histories. We conducted a two-year experiment to assess the effects of two diversification practices—vetch-oat cover cropping and cucumber-snow pea intercropping—on nitrogen (N) cycling and productivity across a farm management gradient. The field experiment spanned 14 farms in southern Brazil with different long-term management histories, from conventional tobacco to agroecological mixed crop-livestock systems. As predicted, soils with longer histories of agroecological management had higher levels of soil organic carbon, potentially mineralizable carbon, and extractable phosphorus, captured by a principal component reflecting “biological soil fertility”. In the study’s second year, the vetch-oat cover crop doubled N inputs to soil compared to fallows across all farms. Nitrogen mineralization following cover crop incorporation was twice as high on agroecological farms as on transitioning or conventional farms. Structural equation modeling revealed that after accounting for variation in background fertility, cover crop mixtures explained a further 67% of the variation in soil N availability at vegetable planting. Consequently, benefits of diversification practices for soil N cycling were ecologically relevant across farms within the span of our experiment, with the greatest performance overall on agroecological farms. Low soil pH was the strongest constraint on vetch N fixation and on intercrop yield (Land Equivalent Ratio, LER). Overall, the vegetable intercrop overyielded relative to monocrops across farms and years (mean LER=1.19), with stronger overyielding in the second year (mean LER=1.27). Though prior research has emphasized facilitation with greater crop diversity in lower fertility soils, our results suggest that benefits for nutrient cycling and productivity are robust to varied soil conditions and accrue over the course of transitions to agroecological management.

GENETIC DIVERSITY IN SELECTED PROGENY OF PLUM CULTIVAR ‘TULEU GRAS’

Becoming from several species and influenced by the very varied climate and soil conditions that characterize the Romanian territory, the plum has developed in this area numerous biological forms with a wide range of characters and characteristics. Taking into account these realities, fruit growers have selected valuable forms with an amazing diversity in terms of taste, size, productivity, ripening season, resistance to biotic and abiotic factors. Of these, the 'Tuleu gras' variety, due to its high plasticity and fruit quality, was very widespread in orchards in Romania and was used as parent in the autochthonous plum breeding since the second half of the last century, representing a numerous source of genes. Thus, by using this variety in breeding works, so far 23 varieties with a great genetic diversity have been registered. The aim of this paper was to study the phenotypic variability of some of these descendants. Thus, many varieties created in this way from 'Tuleu gras' (‘Piteștean’, ‘Centenar’, ‘Tita’, ‘Roman’) certainly recorded a genetic gain in almost all objectives, being in turn used as parents in the current works plum improvement.

Species interactions under climate change in mixed stands of Scots pine and pedunculate oak

Mixed-species forests have become widely studied in the recent years because of their potential to mitigate risks associated with climate change. However, their growth dynamics are often difficult to predict because species interactions vary with climatic and edaphic conditions, stand structure and forest management. We examined species interactions in mixtures of Scots pine (Pinus sylvestris) and pedunculate oak (Quercus robur) under climate change and for varying soil conditions in the Netherlands, over a period of 30 years. We parameterized, calibrated and validated the 3-PGmix model for mixing effects in Scots pine and oak mixtures and analysed these effects under climate change. 3-PGmix performed well for the variety of forest stands examined throughout the Netherlands. Furthermore, it was also able to reproduce mixing effects for each species in mixtures compared to monocultures for the growing conditions examined. Simulated climate change resulted in lower productivity of oak and higher productivity of Scots pine, compared to the current climate. This was observed for both monospecific stands and mixtures. The mixture of Scots pine and oak showed clear but limited overyielding (mixture yield greater than the mean of the monocultures), which was mainly attributed to oak. This was maintained under the most extreme climate scenario for 2050, implying that for oak, increased growth due to mixing with Scots pine was larger than the reduction in productivity under the future climate. On resource-limited soils, Scots pine competitiveness was increased, and this was maintained under a warmer and drier climate. Our results suggest that projected changes in climate will influence species interactions and result in increased Scots pine productivity, notably on poor sandy soils, which are typical of the Netherlands.

Fusion of ground penetrating radar and laser scanning for infrastructure mapping

Abstract Mobile mapping vehicles, equipped with cameras, laser scanners (in this paper referred to as light detection and ranging, LiDAR), and positioning systems are limited to acquiring surface data. However, in this paper, a method to fuse both LiDAR and 3D ground penetrating radar (GPR) data into consistent georeferenced point clouds is presented, allowing imaging both the surface and subsurface. Objects such as pipes, cables, and wall structures are made visible as point clouds by thresholding the GPR signal’s Hilbert envelope. The results are verified with existing utility maps. Varying soil conditions, clutter, and noise complicate a fully automatized approach. Topographic correction of the GPR data, by using the LiDAR data, ensures a consistent ground height. Moreover, this work shows that the LiDAR point cloud, as a reference, increases the interpretability of GPR data and allows measuring distances between above ground and subsurface structures.

The Comparison Between 2-D and 3-D Slope Stability Analysis Based on Reinforcement Requirements

The landslides in the field often do not have an infinite length, making 3-dimensional assumptions more appropriate for the design. Meanwhile, they are mostly analyzed in design by assuming the landslides occur infinitely with plane strain in a 2-dimensional approach. This assumption becomes less precise due to the consideration of the safety factor based on 2-dimensional conditions while the landslide happens 3-dimensional, and this has further effects on the need for reinforcement. This research was conducted to determine the level of influence 2-dimensional and 3-dimensional landslide safety factors have on the number of reinforcements required. A limit equilibrium method was used in the study. The number of geotextile reinforcement needs with a 3-dimensional sliding model is calculated based on existing research results. The results are then compared with the amount of geotextile reinforcement required with a 2-dimensional sliding model. The results showed the possibility of having the same amount of reinforcement under 2-D and 3-D assumptions in the homogeneous soil, while different results were found with heterogeneous soil layers due to the variations in soil conditions. Comparison of the number of geotextile reinforcement requirements between 2 dimensions and three dimensions still needs to be further developed by using more varied soil data. This is done considering that existing studies are only limited to soil, which tends to be homogeneous.

Influence of basalt fiber reinforcement to improve flexural strength of single piles installed in varying ground conditions subjected to combined static and lateral loading – A numerical case study

Pile foundations are usually treated as a compression member and its probability of getting failed due to bending seems negligible. But, in many cases, due to the movement of tectonic plates or vibrations caused by heavy machineries, these foundation systems are subjected to combined effects of axial and lateral loading, which results in devastative failure of the whole structure resting on it. In the present study, the influence of incorporating the Basalt fiber as a reinforcement to the conventional concrete in enhancing the flexural capacity of the piles are analyzed and compared with the ordinary Reinforced cement concrete (RCC) piles, subjected to combined loading using Abaqus finite element software. Fiber reinforced concrete (FRC) contains homogenously dispersed and unsymmetrical oriented fibers that are responsible for the advancement of mechanical properties such as toughness, ductility, tensile strength, shear resistance and load carrying capacity. The efficiency of the Basalt fiber reinforced concrete piles (BFRC) when compared to conventional RCC piles under different ground conditions were also analyzed using the same software following the Mohr-Coulomb constitutive model. The parameters such as the shear strength and the deflection of the pile were compared and analyzed for both the cases of piles installed under varying soil conditions. The results show interesting patterns of stress–strain curves which thereby prove the efficiency of Basalt fiber reinforced piles over the conventional piles in resisting combined loadings. There were drastic reductions in the deflection of the BFRC piles due to the effects of fibers interlocking mechanism, when related with the ordinary RCC piles.

Dung beetle species introductions: when an ecosystem service provider transforms into an invasive species.

Dung beetle introduction programmes were designed to accelerate exotic livestock dung degradation and to control dung breeding pestiferous flies and livestock parasites. The introduction programmes provided exotic dung beetle species with an opportunity to cross natural barriers and spread beyond their native range. There are no reports that explain what probable adaptation mechanisms enable particular dung beetle species to be the most successful invader. Here we identify the morphological, biological, physiological, ecological and behavioural attributes of the four most widespread and successful dung beetle species in introduced areas on a global scale in relation to the assumption that these species are different from other exotic and native dung beetles. We have recognised Digitonthophagus gazella (Fabricius), Onthophagus taurus (Schreber), Euoniticellus intermedius (Reiche) and Aphodius fimetarius (Linnaeus) as the most successful invaders based on their spread, predominance, distribution range and the reports of invasion. Each of these four species has different natural history traits that increase their fitness making them successful invaders. D. gazella has high fecundity and spreading ability, can instantly locate and colonise fresh and nutritious dung, and has a broad thermal window. O. taurus has morphological plasticity, high fecundity, high brood survival rate due to bi-parenting, and is adapted to extreme thermal and moisture conditions. E. intermedius has remnant-dung feeding abilities, a wide thermal window, functioning best at upper-temperature levels, and successful breeding and survival abilities at extremely low soil moisture conditions. A. fimetarius is small-sized, has high breeding and dispersal abilities, and is adapted to lower thermal and upper moisture extremes and variable soil conditions. Discussed here are perspectives on adaptive attributes of dung beetle species that are important to consider during their selection for redistributions. We have elaborated on the fitness and success characteristics of the four species individually. Further, we recommend a prior-introduction baseline monitoring of native dung beetle assemblages so as to evaluate the future impact of exotic dung beetle introductions on the recipient ecosystem.

A geospatial approach for estimating hydrological connectivity of impervious surfaces

Recent studies have reported that connected impervious areas – those impervious surfaces that contribute directly to runoff in a storm network or stream – are a better indicator of hydrologic response, stream alteration, and water quality than total impervious area. However, most methods for quantifying connected impervious areas require major assumptions regarding the definition of ‘connection’, potentially over-simplifying the role of variable climates, slope gradients, soils conditions, and heterogeneous flow paths on impervious surface connectivity. This study presents a new conceptual model and method for estimating hydrologically connected impervious areas (HCIA) that explicitly considers the effect of landscape and storm variability. The model separates impervious surfaces into two categories: directly or physically connected (Aphys) and variably connected (Avar) (impervious that drains to pervious). Of these categories, we investigated the sensitivity of Avar connectivity to varying soil conditions, slope gradients, rainfall properties, and hillslope geometry using PySWMM (a python interface for SWMM5). Simulations spanned a large parameter space with varying soil, slope, rainfall properties and geometries (i.e., relationships between the impervious and downslope pervious areas). PySWMM simulations were used to train and test a regression tree that predicts infiltration and connectivity of runoff from Avar surfaces, which provides excellent fidelity with PySWMM outcomes. To enable use of these methods in practice, we developed an ArcGIS tool that (1) delineates subcatchments; (2) extracts the impervious surface categories Aphys and Avar; (3) applies the regression tree algorithm to predict the fraction of incident rainfall that produces runoff across Avar; and (4) summarizes the resulting HCIA by subcatchment. Analysis of the regression feature importance shows that, in general, Avar connectivity is highly sensitive to the soil type, rainfall depth, area fraction, and antecedent soil moisture conditions of the downslope pervious area. We find that temporally varying parameters (e.g., rainfall and antecedent soil moisture) control Avar connectivity in areas with low permeability soils, while spatial flow path variability (e.g., relative quantity of disconnecting pervious area) controls Avar connectivity in areas with highly permeable soils. The methods developed in this study can be used to identify impervious surface connectivity more accurately in urban watersheds, representing an important step forward for incorporating spatial heterogeneity in stormwater modeling and planning.

Root-Associated Mycobiome Differentiate between Habitats Supporting Production of Different Truffle Species in Serbian Riparian Forests.

Balkan lowlands bordering with the Pannonia region are inhabited by diverse riparian forests that support production of different truffle species, predominantly the most prized white truffle of Piedmont (Tuber magnatum Pico), but also other commercial species (T. macrosporum Vitt., T. aestivum Vitt.). Surprisingly, little is known about the native root-associated mycobiome (RAM) of these lowland truffle-producing forests. Therefore, in this study we aim at exploring and comparing the RAMs of three different truffle-producing forests from Kolubara river plane in Serbia. Molecular methods based on next generation sequencing (NGS) were used to evaluate the diversity of root-associated fungal communities and to elucidate the influence of environmental factors on their differentiation. To our knowledge, this is the first study from such habitats with a particular focus on comparative analysis of the RAM in different truffle-producing habitats using a high-throughput sequencing approach. Our results indicated that the alpha diversity of investigated fungal communities was not significantly different between different truffle-producing forests and within a specific forest type, while the seasonal differences in the alpha diversity were only observed in the white truffle-producing forests. Taxonomic profiling at phylum level indicated the dominance of fungal OTUs belonging to phylum Ascomycota and Basidiomycota, with very minor presence of other phyla. Distinct community structures of root-associated mycobiomes were observed for white, mixed, and black truffle-producing forests. The core mycobiome analysis indicated a fair share of fungal genera present exclusively in white and black truffle-producing forest, while the core genera of mixed truffle-producing forests were shared with both white and black truffle-producing forests. The majority of detected fungal OTUs in all three forest types were symbiotrophs, with ectomycorrhizal fungi being a dominant functional guild. Apart from assumed vegetation factor, differentiation of fungal communities was driven by factors connected to the distance from the river and exposure to fluvial activities, soil age, structure, and pH. Overall, Pannonian riparian forests appear to host diverse root-associated fungal communities that are strongly shaped by variation in soil conditions.

Soil P reduces mycorrhizal colonization while favors fungal pathogens: observational and experimental evidence in Bipinnula (Orchidaceae).

Little is known about the soil factors influencing root-associated fungal communities in Orchidaceae. Limited evidence suggests that soil nutrients may modulate the association with orchid mycorrhizal fungi (OMF), but their influence on non-mycorrhizal fungi remains unexplored. To study how nutrient availability affects mycorrhizal and non-mycorrhizal fungi associated with the orchid Bipinnula fimbriata, we conducted a metagenomic investigation within a large population with variable soil conditions. Additionally, we tested the effect of phosphorus (P) addition on fungal communities and mycorrhizal colonization. Soil P negatively correlated with the abundance of OMF, but not with the abundance of non-mycorrhizal fungi. After fertilization, increments in soil P negatively affected mycorrhizal colonization; however, they had no effect on OMF richness or composition. The abundance and richness of pathotrophs were negatively related to mycorrhizal colonization and then, after fertilization, the decrease in mycorrhizal colonization correlated with an increase in pathogen richness. Our results suggest that OMF are affected by soil conditions differently from non-mycorrhizal fungi. Bipinnula fimbriata responds to fertilization by altering mycorrhizal colonization rather than by switching OMF partners in the short term, and the influence of nutrients on OMF is coupled with indirect effects on the whole fungal community and potentially on plant's health.

Present Status Of Medicinal and Aromatic Plants of Jammu, Kashmir and Ladakh region of Himalayas

The conservation and cultivation of medicinal and aromatic plants (MAP) are getting more importance. MAPs in India are being collected/cultivated in diverse climatic conditions starting from seacoast to high Himalayas in varied soil conditions. Among them temperate, alpine and cold arid regions of country have vital importance for MAPS. The Northern region Himalayas viz. Jammu, Kashmir and Ladakh which represents temperate, alpine and cold arid region zone finds first place in medicinal and aromatic plants conservation/cultivation. It has more than 300 MAP and out of them around 16 very important and prioritized medicinal plants viz., Aconitum heterophyllum, Artemesia absinthium, Picrorhiza kurroa, Swertia chirayita, Saussurea costus, Withania somnifera, Acorus calamus, Atropa acuminata, Berberis aristata, Cathranthus roseus, Dioscorea deltoidea, Taxus wallichiana. Podophyllum hexandrum, Hippophae rhamnoides, Dactylorhiza hatagirea and Arnebia benthamii and aromatic plants viz. Levandula officinalis, Rosmarinus officinalis, Organium vulgare . Thymus serpyllum are exclusive aromatic crops of temperate region with potential to be commercialized. Most of these plants are extracted from wild and have very high demand.

Human encroachment, climate change and the loss of our archaeological organic cultural heritage: Accelerated bone deterioration at Ageröd, a revisited Scandinavian Mesolithic key-site in despair.

Ancient organic remains are essential for the reconstruction of past human lifeways and environments but are only preserved under particular conditions. Recent findings indicate that such conditions are becoming rarer and that archaeological sites with previously good preservation, are deteriorating. To investigate this, we returned to the well-known Swedish Mesolithic site Ageröd I. Here we present the result of the re-excavation and the osteological analyses of the bone remains from the 1940s, 1970s and 2019 excavation campaigns of the site, to document and quantify changes in bone preservation and relate them to variations in soil conditions and on-site topography. The results indicate that the bone material has suffered from accelerated deterioration during the last 75 years. This has led to heavily degraded remains in some areas and complete destruction in others. We conclude that while Ageröd can still be considered an important site, it has lost much of the properties that made it unique. If no actions are taken to secure its future preservation, the site will soon lose the organic remains that before modern encroachment and climate change had been preserved for 9000 years. Finally, because Ageröd has not been subjected to more or heavier encroachment than most other archaeological sites, our results also raise questions of the state of organic preservation in other areas and call for a broad examination of our most vulnerable hidden archaeological remains.

Maize root biomass and architecture depend on site but not on variety: Consequences for prediction of C inputs and spread in topsoil based on root-to-shoot ratios

Abstract Knowledge about the response of root biomass and root system architecture (RSA) to soil conditions would increase efficiency in selecting high performance crop varieties and predicting the impact of rotations on long-term soil organic matter (SOM) stock. We evaluated the effect of variety and site on maize (Zea mays L.) root growth. Two-dimensional (2D) and 3D techniques were used to quantify changes of RSA. Commercial maize varieties were grown in three sites with typical soil types for maize cultivation in Belgium. We observed that at Merelbeke, above- and belowground biomass and root-to-shoot ratios (R/S) were larger compared to those at Ravels. Both factors interactively influenced an index of biological stability (ISB) based on biochemical quality of the roots. There were also more fine roots at Merelbeke than at Bassevelde and Ravels. Together with a lower ISB value, this suggests that site had an inherent effect on root biochemical quality. We conclude that a strong impact of site exists on both above- and belowground biomass; however, they are not necessarily correlated. With a fixed R/S, predictions of root biomass were misestimated in one half of the cases. This complex response of root phenotyping to varying soil conditions should not be overlooked.

Evaluation of sustainability of microgrid grounding grid design under varying soil conditions through estimation of touch, step voltages and novel methods of earthing

This study examines the sustainability of uniform as well as an optimal grounding grid (GG) design for the microgrid (MG), in terms of variations in the top layer (TL), middle layer (ML), and bottom layer (BL) soil resistivities ( ρ 1 , ρ 2 , and ρ 3 , respectively) along with change in a thickness of TL and ML. GG design is highly dependent on ρ 2 , as it helps in determining the density of conductors at grid extremities. With an increase in ρ 2 , touch voltage (TV) crosses its tolerable limit, but step voltage (SV) remains within its limit. However, with a simultaneous increase in the thickness of ML (MLT), SV also crosses its limit. For ρ 2 higher than ρ 3 , with an increase in MLT, TV, and SV increase, while in the reverse case, they decrease. For the given MLT, ρ 3 is crucial in determining GG burial depth. Validation of results is done by comparing them with the IEEE standard. Also, the optimal compression ratio of GG with an increase in MLT is analysed. TVs can be reduced to a great extent, with the application of distinctive methods of earthing (TT-GG system, TN-S-GG system, and TN-C-S-GG system) in MG. This study also reveals that an increase in GG resistance leads to a reduction in TV.

Application of machine learning to the identification of quick and highly sensitive clays from cone penetration tests

Geotechnical classification is vital for site characterization and geotechnical design. Field tests such as the cone penetration test with pore water pressure measurement (CPTu) are widespread because they represent a faster and cheaper alternative for sample recovery and testing. However, classification schemes based on CPTu measurements are fairly generic because they represent a wide variety of soil conditions and, occasionally, they may fail when used in special soil types like sensitive or quick clays. Quick and highly sensitive clay soils in Norway have unique conditions that make them difficult to be identified through general classification charts. Therefore, new approaches to address this task are required. The following study applies machine learning methods such as logistic regression, Naive Bayes, and hidden Markov models to classify quick and highly sensitive clays at two sites in Norway based on normalized CPTu measurements. Results showed a considerable increase in the classification accuracy despite limited training sets.

A Note on the Application of an AgLeader® Cotton Yield Monitor for Measuring Peanut Yield: An Investigation in Two US states.

ABSTRACT Previous researchers demonstrated the ability to adapt an AgLeader® Cotton Monitor to a peanut combine. It was demonstrated that the field weight could be accurately predicted with average errors of less than 10% across all trials when at least five calibration loads are applied. This project focused on expanding previous work performed at the University of Georgia and other peanut optical yield monitor work by incorporating a protective deflector plate for the sensors, obtaining multiple field weights, and using the peanut sale sheets to correlate yield monitor yield to sale weight. This study was a two-university, two-state effort, including Oklahoma State University (Oklahoma), and Mississippi State University (Mississippi). Data collected during this study included multiple loads which included yield monitor weight, field weight, field moisture content, and all the information presented on the standard USDA peanut grade sheet, when available. The multi-state effort allowed for the incorporation of the two major peanut types and for the incorporation of different soil types. The goal of this study was to develop guidelines for using, calibrating, and adapting the AgLeader® Cotton Monitor for peanut harvest. Five calibration loads referenced to buy-point net weight were typically needed to bring error within acceptable limits. Results indicated that multiple local calibrations were needed to ensure high data validity and yield estimation across multiple harvest environments. The data showed that peanut type (virginia, runner and spanish) and variable soil conditions impacted yield estimation.

Extracellular Ca2+ induces desensitized cytosolic Ca2+ rise sensitive to phospholipase C inhibitor which suppresses root growth with Ca2+ dependence

Calcium (Ca) is an essential element for all organisms. In animal cells, the plasma membrane-localized Ca receptor CaSR coupled to a phospholipase C (PLC)-dependent signaling cascade monitors extracellular Ca2+ concentrations ([Ca2+]ext) and responds with increases in cytosolic calcium concentrations ([Ca2+]cyt). Plant roots encounter variable soil conditions, but how they sense changes in [Ca2+]ext is largely unknown. In this study, we demonstrate that increasing [Ca2+]ext evokes a transient increase in [Ca2+] in the cytosol, mitochondria, and nuclei of Arabidopsis thaliana root cells. These increases were strongly desensitized to repeat applications of [Ca2+]ext, a typical feature of receptor-mediated cellular signaling in animal and plant cells. Treatment with gadolinium (Gd3+), a CaSR activator in animal cells, induced concentration-dependent increases in [Ca2+]cyt in roots, which showed self-desensitization and cross-desensitization to [Ca2+]ext-induced increases in [Ca2+]cyt (EICC). EICC was sensitive to extracellular H+, K+, Na+, and Mg2+ levels. Treatment with the PLC inhibitor neomycin suppressed EICC and Ca accumulation in roots. The inhibitory effect of neomycin on root elongation was fully rescued by increasing [Ca2+]ext but not [Mg2+] or [K+] in the growth medium. These results suggest that [Ca2+]ext and the movement of Ca2+ into the cytosol of plant roots are regulated by a receptor-mediated signaling pathway involving PLC.

Variations in Root Distribution Patterns and Cane Yield of 16 Elite Sugarcane Clones Grown Under Varied Soil Conditions

Response to drought of sugarcane for root traits is considered to be an important mechanism in which the crop can maintain cane yield under drought conditions. The objective of this study was, therefore, to investigate root distribution patterns of sugarcane and their relationships with cane yields under rain-fed conditions. Thirteen elite sugarcane clones (KK06-501, KK07-478, NSUT08-22-3-13, RT2004-085, CSB06-2-15, CSB06-2-21, CSB06-4-162, CSB06-5-20, TBy27-1385, TBy28-0348, MPT02-458, MPT03-166 and 91-2-527) and three check varieties (KK3, LK92-11 and Kps01-12) were planted in a randomized complete block design with four replications at two locations. Root length density (RLD) was measured via the auger method at 4, 6 and 8 months after planting (MAP) at two positions between plants and between rows. Cane yield was measured at 12 MAP. RLD in the upper soil layers was measured at 0–20 cm and 20–40 cm below the soil surface, whereas RLD in the lower soil layers was measured at 40–60, 60–80 and 80–100 cm below the soil surface. Sugarcane genotypes were significantly different for RLD and cane yield in both locations, and the RLDs of the 13 sugarcane varieties grown under rain-fed conditions were classified into four patterns. The sugarcane varieties changed their root distribution patterns when evaluated at 6 and 8 MAP. KK3 was predominant and most interesting as it had consistently high yield in both locations and high root length density in the lower soil layers in response to drought.