Distribution Of Root System Research Articles

Root system of Coffea canephora cv. Robusta genotypes cultivated in the Brazilian Amazon

The root system distribution of coffee, especially Coffea canephora cv. Robusta, remains poorly characterized. The aim of this study were: (i) to analyze the distribution of the root system in various genotypes of C. canephora cv. Robusta cultivated in the Amazon region; (ii) to evaluate genetic variability based on root traits; and (iii) to test the correlation between root traits, aboveground part, and production capacity. Roots were collected up to a depth of 60 cm and 30 cm away from the stems. The roots were washed, scanned, and processed to quantify root volume (mm3 cm−3), surface area (mm2 cm−3), diameter (mm), and length (mm cm−3). The variations in root systems reveled phenotypic variability among different genotypes of C. canephora cv. Robusta. Most roots were concentrated in the surface layer of the soil (0–30 cm), with LB015 standing out. At a depth of 50–60 cm, AS10, AS4, A106, and GJ08 had more roots than other genotypes, suggesting a promising capacity to avoid drought. There were significant negative correlations between root traits, aboveground part, and production capacity. This study provides valuable information for the selection of genotypes with desirable root traits for different environmental conditions, contributing to the improvement of management practices and breeding programs for Robusta coffee.

Changes in the Root Architecture of Oil Palm Seedlings in Response to Nitrogen Starvation

Oil palm (Elaeis guineensis) is a widely cultivated crop known for its high oil yield. It is cultivated extensively across tropical regions, notably in Southeast Asia, Africa, and Latin America. It plays a vital role in global vegetable oil supply, meeting approximately 35% of the world’s demand. However, the expansion of oil palm plantations often involves the utilization of degraded soils where nutrient availability, particularly nitrogen, is limited, posing challenges to plant growth and productivity. Roots are crucial in responding to nitrogen deficiency by adjusting their growth and distribution; however, research on root system distribution patterns in oil palm still needs to be completed. This study analyzes the root system architecture using RhizoVision Explorer, a 2D root image processing software while assessing its relationship with nitrogen availability across two commercial cultivars: Deli × La Mé of African oil palm (Elaeis guineensis) and the interspecific hybrid O×G Coari × La Mé. Our findings reveal significant associations between eight root traits in oil palm seedlings and treatments with and without nitrogen availability. Notably, total root morphology (length, surface area, and volume), rotation angle, solidity, and hole characteristics decreased under nitrogen deprivation, whereas surface angle frequency increased. We highlight the variability of these traits across cultivars, suggesting genetic dependence and potential utility in breeding programs. Moreover, interactions observed in primary root morphology and hole size indicate greater differences between control and nitrogen-treated groups in C × LM than in D × LM cultivars. On the other hand, cultivar differences, regardless of nitrogen availability, influenced lateral root morphology, while nitrogen availability, irrespective of cultivar, affected inclined angle frequency. Significant differences were observed in growth and development parameters such as root and shoot biomass, root-to-shoot ratio, and leaf emission numbers between nitrogen-optimal and nitrogen-starved conditions. Nitrogen significantly affects root architecture and plant growth in oil palm, particularly in the C × LM cultivar during the nursery stage.

Vine spacing of <i>Vitis vinifera</i> cv. Shiraz/101-14 Mgt. I. root growth and physiological activity

Knowledge of vine reaction to plant spacing under relatively high potential soil conditions is limited. This study comprised effects of vine spacing (with fixed row spacing) of Shiraz (clone SH 9C)/101-14 Mgt on a high potential soil in the Breede River Valley, Robertson, South Africa, on soil conditions, root system distribution, and vine physiological reaction. The vineyard was planted in 2008 to a VSP trellis, with a fixed row spacing of 2.2 m and a row orientation of approximately NNE–SSW (30°). In-row vine spacing changed from 0.3–4.5 m with increments of 30 cm (from 15151–1010 vines/ha), totalling 15 treatments. After the completion of cordon development, results were generated over six seasons. Soil conditions seemed generally uniform and showed no obvious characteristics that could have affected treatments differentially. An increase in density occurred in fine, extension and permanent root categories with closer spacing, increasing the total number of roots/ha. Roots penetrated deeper with closer vine spacing. Vine spacing impacted physiological parameters and revealed a complex interplay between root distribution, vine structure expansion, canopy microclimate, water relations, photosynthetic output, berry temperature, carbon distribution, and day/night recovery that would affect grape composition and wine quality. Optimum vine spacing appeared to be 1.8 m, both closer and wider spacing leading to limitations in physiological activity. Interactions amongst below- and aboveground growth and physiological parameters are comprehensively discussed with a focus on sustainability.

Contribution of tree and crop roots to soil carbon stocks in a Sub-Sahelian agroforestry parkland in Senegal

In the Sub-Sahelian region (Senegal), Faidherbia albida trees have been maintained for years in agroforestry parklands for their numerous services offered to people and to crops. The aerial crop biomass and yield are notably greater under the tree crown, but most of this biomass is exported and does not contribute to soil carbon (C) inputs. Belowground litter inputs are crucial, but little is known about the root system distribution, productivity and contribution to soil C inputs. This study aims to assess the field heterogeneity of F. albida and crop root systems along the soil profile based on the distance to the tree to evaluate the root contribution to soil C stocks.During two successive rotations of pearl millet in 2020 and groundnut in 2021, soils and roots were sampled from two locations (Under and Far from the tree), in 5 soil layers to a depth of 150 cm and with three tree replicates. The aerial biomass was also sampled. The annual relative contribution of roots to soil C stocks was estimated as the ratio between root litter-derived C inputs (considering hypothetical root turnover only for trees and the whole root biomass for crops) and soil C stocks.We found a similar crop root biomass density Under and Far from the tree, but the higher root:shoot ratio Far from than Under the tree confirmed the beneficial effect of trees on the aerial crop biomass. Unexpectedly, the tree root biomass density was higher at + 30 m from the trunk than Under the tree in the 30–100 cm soil layer, suggesting a long-distance soil exploration by the trees. Down to 150 cm of depth, the tree root litter contribution to soil C stocks represented 6.1 % and 7.1 % of the total root litter-derived C inputs (Under and Far from the tree, respectively). In this type of Sub-Sahelian parklands with low soil C stocks, increasing the tree density or selecting deep and highly rooted crop varieties should be favoured.

Spatial and Texture Analysis of Root System distribution with Earth mover’s Distance (STARSEED)

PurposeRoot system architectures are complex and challenging to characterize effectively for agronomic and ecological discovery.MethodsWe propose a new method, Spatial and Texture Analysis of Root SystEm distribution with Earth mover’s Distance (STARSEED), for comparing root system distributions that incorporates spatial information through a novel application of the Earth Mover’s Distance (EMD).ResultsWe illustrate that the approach captures the response of sesame root systems for different genotypes and soil moisture levels. STARSEED provides quantitative and visual insights into changes that occur in root architectures across experimental treatments.ConclusionSTARSEED can be generalized to other plants and provides insight into root system architecture development and response to varying growth conditions not captured by existing root architecture metrics and models. The code and data for our experiments are publicly available: https://github.com/GatorSense/STARSEED.

桢楠幼苗适应喀斯特岩溶裂隙生境及降雨时间格局变化的方式

PDF HTML阅读 XML下载 导出引用 引用提醒 桢楠幼苗适应喀斯特岩溶裂隙生境及降雨时间格局变化的方式 DOI: 10.5846/stxb202112183590 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市自然科学基金面上项目（cstc2020jcyj-msxmX0244）；中央高校基本科研业务费专项（XDJK2020B037）；国家自然科学基金项目（31500399） Phoebe zhennan S. Lee seedlings adjust the biomass allocation and root distribution to adapt to the karst fissure habitat and rainfall temporal pattern Author: Affiliation: Fund Project: General Project of Chongqing Natural Science Foundation(cstc2020jcyj-msxmX0244);Special Funds for Fundamental Scientific Research Operation of Central Universities(XDJK2020B037);National Natural Science Foundation of China(31500399) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:喀斯特生态系统是全球陆地生态系统的重要组成部分，生态环境极为脆弱。由于碳酸盐岩长期强烈的化学溶蚀作用，其基本特征体现为地表土壤和地下岩溶裂隙及洞穴的二元结构。近年来，在全球气候变化下，我国西南地区降雨格局呈现降雨频次减少且单次降雨量增加的趋势。因此，岩溶裂隙和区域降雨时间格局改变将对喀斯特地区的植物生长产生重要影响。通过模拟不同岩溶裂隙生境（S0：24 cm土壤；S1/2：12 cm土壤层+12 cm裂隙层；S3/4：6 cm土壤层+18 cm裂隙层）和不同降雨时间格局（I2d：2 d降雨间隔；I19d：19 d降雨间隔），探究二年生桢楠（Phoebe zhennan S.Lee）幼苗是否通过生物量分配及根系分布的调整来适应变化环境。结果显示：（1）短时间降雨格局下，相比全土生境，少量岩溶裂隙存在并不影响桢楠幼苗生物量的积累，然而随着岩溶裂隙层进一步增厚和降雨时间间隔延长，桢楠降低了总生物量，减少了茎且增大了根和叶的生物量分配。（2）桢楠幼苗的根系垂直分布随着深度增加而下降，且无论在何种降雨时间格局下，两种岩溶裂隙生境下桢楠均增加了岩溶裂隙之上土壤层的根系生物量分配比例。研究表明：赋存有土壤的岩溶裂隙能成为植物幼苗赖以生存的生境，但这种提供生境的能力随岩溶裂隙层增厚以及降雨时间间隔延长而减弱。桢楠幼苗以牺牲对茎生物量的分配投资为代价，提高对根系或者叶片的生物量投资，同时增大界面土层中的根系分布，来保证最大化地利用有限的土壤资源，从而适应喀斯特的岩溶裂隙（及干旱）生境。 Abstract:Karst is one of the most important fragile ecological environments in globally terrestrial ecosystems. It is basically characterized by the dual structure of surface soil and underground karst fissures and caves, due to the long-term strong chemical dissolution of carbonate rocks. In recent years, under global climate change, the rainfall pattern in southwestern China has shown a trend of decreasing rainfall frequency and greater sub-rainfall. The karst region in southwestern China, which belongs to the subtropical monsoon climate, often suffers from more obvious alternating wet and dry conditions. The underground karst fissures and variation in the temporal pattern of regional rainfall will have a significant impact on plant growth and development in this region. In this study, in order to explore whether the seedlings of Phoebe zhennan S. Lee adjust biomass allocation and root distribution to adapt to the changing environment, we simulated different karst fissure habitats (S0:24 cm soil; S1/2:12 cm soil layer+12 cm karst fractured layer; S3/4:6 cm soil layer+18 cm karst fractured layer) and different rainfall temporal patterns (I2d:rainfall interval of 2 days; I19d:rainfall interval of 19 days), and checked the plants biomass accumulation and allocation, root vertical distribution. The results showed that:(1) under the short-term rainfall pattern, compared with the whole soil habitat, the habitat with a small proportion of karst fissures did not affect the biomass accumulation of P. zhennan seedlings. With the thickening of karst fractured layer and the extension of the rainfall interval, P. zhennan reduced the total biomass, allocating less biomass to stems and more to roots and leaves. (2) The vertical distribution of root system of P. zhennan seedlings decreased with the deepen of soil layer, but increased the root biomass allocation ratio in the soil layer above the karst fissures, regardless of the rainfall temporal pattern. The results show that the fissures hosted soil can be a certain habitat for plants. However, with the thickening of fractured layer and extension of the rainfall interval, the fissures weaken the ability of the habitat. P. zhennan seedlings increase investment to root and leaf at the expense of stem biomass, and increase the root distribution in the interface soil layer above the fissures to ensure the maximum use of limited soil resources so as to adapt to the fissure (and arid) habitat in karst. 参考文献 相似文献 引证文献

Genotypic variation in rice root system distribution and activity in response to short-term soil drought

Genotypic variation in rice root system distribution and activity in response to short-term soil drought

Influence of Root Volume, Plant Spacing, and Planting Pattern of Tap-like Tree Root System on Slope Protection Effect

Vegetation slope protection has been widely utilized as an eco-friendly approach for slope stability. Up to now, research on the slope protection effect of shrubs and herbaceous vegetation is more than those of trees, which can be attributed to the challenge of evaluating the slope protection effect of tree root systems that can be influenced by many factors, such as root morphology, root volume, plant spacing, and planting patterns. Therefore, this study takes tap-like tree root systems as the research object, constructs the corresponding root-soil composite model by using 3D printing technology, and carries out a series of physical model experiments on slopes supported by tap-like tree root systems, examining the anti-sliding force, slope surface displacement, sliding range, and slope cracks throughout the entire process of deformation and the damage to shallow slopes, to finally evaluate the effectiveness in the slope protection effect of tree root systems from multiple perspectives. The results indicate that: (1) the peak anti-sliding force of the slope supported by tree root systems correlates positively with the root volume and negatively with plant spacing generally, and the influence of tree plant spacing on the peak anti-sliding force is weaker than that of the root volume; (2) the displacement of slopes supported by tree root systems in the square planting pattern is generally less than that in the staggered planting pattern, and the displacement of slopes has a negative correlation with the root volume and a positive correlation with the plant spacing; (3) the sliding range of the slope supported by tree root systems is significantly reduced compared with that of the unsupported slope, and the tree root system can prevent the occurrence of slope surface cracks to a certain extent, which makes the sliding-body show better integrity. The above understanding enriches the study on the slope protection effect of the tree root system, reveals the influence of the tree root volume, plant spacing, and planting pattern (square distribution and staggered distribution) of the tap-like tree root system, and offers some guidance for the engineering application of tree slope protection in practice.

Three- dimensional modeling and visualization of rice root system based on the improved dual-scale automaton and L-system

• The 3D Visualization growth modeling of rice roots was proposed. • The improved dual-scale automaton described the root growth process. • The growth model and morphological structure model were transformed into L-system. • Ten phenotypic traits were quantified. • The relationship between root structure and functional traits was aided analyzed. In agronomy sciences and researches, root system architecture (RSA) of Oryza sativa L. (rice) is often used to reflect the spatial configuration of rice roots. But, because soil has its own opacity, the cognition and expression of the spatial morphology and structure of rice roots have become the bottleneck in the in-depth study. The three-dimensional (3D) modeling and visualization can be used to help further study and recognize the morphological, structural and functional traits of rice roots. To clarify the rules governing the structure and distribution of the rice root system, and so to understand the relationship between RSA and the functionality of rice roots, a method combined the improved dual-scale automaton with Lindenmayer-system (L-system) for the three-dimensional modeling and visualization of the rice root system is hereby proposed. The basic parameters of the rice root growth were firstly measured by the destructive detection, and various appropriate growth functions were selected according to the rice root growth rule and development so as to control the rice root growth rate in the modeling. In the dual-scale automaton modeling, the identifiers of micro-states and macro-states were redefined with numbers and characters, and hence the improved dual-scale automaton model was used to describe the growth process of rice roots, which was then combined with L-system grammar. According to the morphological structure characteristics of the rice root growth, the direction and radius of the rice root growth were constrained, and a single three-dimensional morphological model was thus constructed. Then, the visualization of the rice root growth was realized by MATLAB. By calculating the total rice root length, total rice root surface area, total rice root volume, maximum rice root width, maximum rice root depth and other indicators of the model, as well as analyzing and comparing the experimental measurement data, it was finally found that the average accuracy of the simulation of the total rice root length, total rice root surface area and total rice root volume was 94.27%, 93.68% and 92.35%, respectively. Besides, the maximum rice root width and maximum rice root depth had strong correlation with the corresponding measured data. So, the results showed that the model had good simulation effects on the rice morphological structure. Again, based on this, the relationship between the rice root structure and its functions was further analyzed by quantifying the structural parameters such as the rice root length fraction, solidity, convex hull volume, rice root volume density and rice root surface area density, etc. This model laid a foundation for the coupling of both the morphological structure model of the rice root growth as well as the model of physiological and ecological factors of next stage, hoping to provide a reference for the 3D modeling and visualization research of the root growth of other crops.

Installation and imaging of thousands of minirhizotrons to phenotype root systems of field-grown plants

BackgroundRoots are vital to plant performance because they acquire resources from the soil and provide anchorage. However, it remains difficult to assess root system size and distribution because roots are inaccessible in the soil. Existing methods to phenotype entire root systems range from slow, often destructive, methods applied to relatively small numbers of plants in the field to rapid methods that can be applied to large numbers of plants in controlled environment conditions. Much has been learned recently by extensive sampling of the root crown portion of field-grown plants. But, information on large-scale genetic and environmental variation in the size and distribution of root systems in the field remains a key knowledge gap. Minirhizotrons are the only established, non-destructive technology that can address this need in a standard field trial. Prior experiments have used only modest numbers of minirhizotrons, which has limited testing to small numbers of genotypes or environmental conditions. This study addressed the need for methods to install and collect images from thousands of minirhizotrons and thereby help break the phenotyping bottleneck in the field.ResultsOver three growing seasons, methods were developed and refined to install and collect images from up to 3038 minirhizotrons per experiment. Modifications were made to four tractors and hydraulic soil corers mounted to them. High quality installation was achieved at an average rate of up to 84.4 minirhizotron tubes per tractor per day. A set of four commercially available minirhizotron camera systems were each transported by wheelbarrow to allow collection of images of mature maize root systems at an average rate of up to 65.3 tubes per day per camera. This resulted in over 300,000 images being collected in as little as 11 days for a single experiment.ConclusionThe scale of minirhizotron installation was increased by two orders of magnitude by simultaneously using four tractor-mounted, hydraulic soil corers with modifications to ensure high quality, rapid operation. Image collection can be achieved at the corresponding scale using commercially available minirhizotron camera systems. Along with recent advances in image analysis, these advances will allow use of minirhizotrons at unprecedented scale to address key knowledge gaps regarding genetic and environmental effects on root system size and distribution in the field.

Variability of Root System Size and Distribution among Coffea canephora Genotypes

This work aimed to evaluate the variability in the distribution of the root system among genotypes of C. canephora cv. Conilon and indicate management strategies for a more efficient mineral fertilization. Root distribution was evaluated in six genotypes. The experimental design was in randomized blocks with three replications. Soil monoliths measuring about 27 cm3 were collected at six different soil depths, at three row distances and nine distances of inter-row planting. The collections were carried out in one plant of each repetition. In total, 1296 samples were evaluated. The roots were washed, digitized and processed to quantify length density, volume, surface area and diameter. The distribution of the root system was characterized using semivariograms. It was observed that the highest concentration of roots occurred in the distances close to the irrigation drippers. There was variation in the distribution of the root system among the genotypes. However, in general, the root system is concentrated at a depth of 0 to 20 cm in the soil, at distances up to 50 cm in the planting row and up to 60 cm in inter-rows. Therefore, the greatest efficiency in nutritional management can be achieved by applying fertilizers within a radius of 50 cm around the plant.

Impact on the soil and the infiltration as a consequence of oil palm cultivation (Elaeis guineensis jacq) in Tabasco

Objective: To evaluate the possible negative impacts on soil fertility, as a result of the soil use change from the grassland to oil palm. Design/methodology/approach: The following variables were evaluated: soil organic matter (SOM), bulk density (BD), mechanical penetration resistance (MPR), root system distribution, and infiltration in 5-, 11- and 25-year-old oil palm plantations, as well as in an adjoining grassland —whose land use had not changed to oil palm cultivation. Results: During the first years of cultivation, the substitution of the grassland for oil palm caused SOM losses, increased BD and MPR, and reduced infiltration levels. After 11 years, these effects became stable and were reversed. Therefore, in mature plantations of >25 years, the soil and infiltration conditions improved, even surpassing the grassland. These changes occur at a depth of 40 cm and are attributable to the SOM provided by the root system; consequently, root distribution does not block infiltration, becoming a beneficial factor, particularly in mature plantations. Study limitations/implications: The research must be replicated under other soil conditions, in order to observe the fertility behavior. Findings/conclusions: After the grassland is replaced by oil palm, soil fertility deteriorates during the first years; fertility becomes stable and recovers after 11 years. Meanwhile, the effect reverses and surpasses grassland fertility levels after 25 years.

ПРАКТИЧЕСКИЕ АСПЕКТЫ ПРИМЕНЕНИЯ БИОУДОБРЕНИЯ «ВЕСНА» КАК ФАКТОР ЗАЩИТЫ ПОЧВЕННОГО ПЛОДОРОДИЯ

The article is devoted to the study of the effect of biofertilizers on the number of different groups of soil microarthropods of chernozem of ordinary agrocenosis of perennial grasses in the condi-tions of the Lower Don. Most groups of mites and collembolus on the agrocenosis of perennial grasses, being saprophages by the nature of nutrition, undoubtedly play an important role in the circulation of substances, indirectly affecting the productivity of the agrocenosis. It was found that when applying the biofertilizer "Vesna", the number of all groups of microarthropods at the exper-imental site exceeded the control indicators by 1.5 times. All groups of ticks showed a large num-ber, gamase and shell ticks prevailed. The number of leg-tails was less than the number of ticks in the experimental area, but it turned out to be higher than the number of leg-tails in the control ar-ea. The vertical distribution of microarthropods in the horizon of 0-20 cm of the chernozem of the ordinary agrocenosis of perennial grasses was characterized by an uneven distribution: basically all groups of ticks and longtails are concentrated in the horizon of 0-10 cm, which is determined by the gradient of hydrothermal conditions and the distribution of root systems of plants of agro-cenosis.

Semantic segmentation model of cotton roots in-situ image based on attention mechanism

The growth and distribution of root system in the soil has an important influence on the growth of plants and is one of the important factors affecting crop production. However, the root system of plants is located in the dark and closed soil. Even if we can obtain high-definition root image from the complex soils, the interference of the soil particles on root system and the small difference of color between them will pose challenges for further root segmentation. In this experiment, the cotton mature root system is used as the research object. Based on the introduction of sub-pixel convolution DeepLabv3+ semantic segmentation model, we further added the attention mechanism to the model, assigning more weight to the pixel points of fine roots and their root hairs, and designed a semantic segmentation model of cotton roots in-situ image based on the attention mechanism. The experimental results show that the model has higher segmentation accuracy and operational efficiency than only introduces sub-pixel convolution DeepLabv3+ model, U-Net model and SegNet model. The precision value, recall value and F1-score are 0.9971, 0.9984 and 0.9937 respectively, and the IoU value of 161 untrained root image segmentation tasks was 0.9875. At the same time, we also performed segmentation experiments on the early cotton root images. The results show that the DeepLabv3+ model which only introduces sub-pixel convolution, U-Net model and SegNet model have poor segmentation effects. The semantic segmentation model based on attention mechanism proposed in this paper can be segmented accurately. The above results show that the proposed model can distinguish the cotton root system from the complex soil background accurately and has good segmentation effect. It can realize the accurate segmentation of root image in early and mature period in the process of cotton root growth, and provide important theoretical value and practical application reference for deep learning in plant root segmentation.

Root System Distribution of Sweet Cherry Trees Grafted on Vigorous Rootstock in Molic Eutricambosoil in Northern Transylvania

The type of the root system development of different species and cultivars gives valuable information for choosing of proper rootstock/scion combinations in different soils and soil horizons, the establishment of active rhizosphere where the input nutrition can give maximum results. Researches showed that cherry grafted on a vigorous rootstock in molic eutricambosoil develops a root system which is mainly horizontally spread (88-90°), in some rare cases with angles of 45°, with 5-7 strong V order roots (>80 mm) which provides good anchorage for trees. To the periphery the roots reached up to 6.5-8.5 m in the old trees and 3.5 m in the young trees. The depth of the root system achieved 2.0-2.5 m in the old trees and 1.0-1.5 m in the young trees. The highest quantity of roots were observed between 18-60 cm depth in both young and old trees.

Long-Term Growth of Alfalfa Increased Soil Organic Matter Accumulation and Nutrient Mineralization in a Semi-Arid Environment

Land use patterns and vegetation coverage in semi-arid areas of the Loess Plateau have undergone great changes due to the implementation of the “Grain for Green” project. The introduction of legume pasture species, such as alfalfa (Medicago sativa L.) and sweet clover (Melilotus officinalis L.), is one of the most efficient methods of vegetation restoration and reconstruction in this region. However, there is a need for an effective assessment of the root system distribution and its interaction with soil after long-term introduction. An experiment involving the introduction of alfalfa and sweet clover on abandoned farmlands was initiated in 2003 to assess the long-term effects. After 17 years, root and soil samples at depths of 0–20 and 20–60 cm were collected to characterize the root biomass, root carbon (C), nitrogen (N), and phosphorus (P), soil microbial biomass carbon (MBC) and nitrogen (MBN), soil organic carbon (SOC), and soil N and P. The results showed that the root biomass density of alfalfa in the 0–20 and 20–60 cm layers (63.72 and 12.27 kg m–3, respectively) were significantly higher than for sweet clover (37.43 and 8.97 kg m–3, respectively) and under natural abandonment (38.92 and 9.73 kg m–3, respectively). The SOC, total nitrogen (TN), total phosphorus (TP), available phosphorus (AP), nitrate-nitrogen (NO3–-N), MBC and MBN in the 0–20 and 20–60 cm layers were higher after alfalfa introduction compared with sweet clover introduction and natural abandonment, although the ammonia-nitrogen (NH4+-N) concentration in the 0–20 cm layer was lower. There were significantly positive correlations between root biomass density and both soil nutrients and microbial biomass, while there was a negative correlation between the soil NH4+-N and root biomass density. These results indicate that alfalfa root growth improved soil organic matter accumulation and nutrient mineralization. The accumulation and mineralization of soil nutrients also guaranteed root and microorganism growth. Therefore, it was concluded that alfalfa introduction will promote soil nutrients immobilization and mineralization and may enable sustainable land use in the semi-arid region of the Loess Plateau, China.

GPR-Based Automatic Identification of Root Zones of Influence Using HDBSCAN

The belowground root zone of influence (ZOI) is fundamental to the study of the root–root and root–soil interaction mechanisms of plants and is vital for understanding changes in plant community compositions and ecosystem processes. However, traditional root research methods have a limited capacity to measure the actual ZOIs within plant communities without destroying them in the process. This study has developed a new approach to determining the ZOIs within natural plant communities. First, ground-penetrating radar (GPR), a non-invasive near-surface geophysical tool, was used to obtain a dataset of the actual spatial distribution of the coarse root system in a shrub quadrat. Second, the root dataset was automatically clustered and analyzed using the hierarchical density-based spatial clustering of applications with noise (HDBSCAN) algorithm to determine the ZOIs of different plants. Finally, the shape, size, and other characteristics of each ZOI were extracted based on the clustering results. The proposed method was validated using GPR-obtained root data collected in two field shrub plots and one simulation on a dataset from existing literature. The results show that the shrubs within the studied community exhibited either segregated and aggregated ZOIs, and the two types of ZOIs were distinctly in terms of shape and size, demonstrating the complexity of root growth in response to changes in the surrounding environment. The ZOIs extracted based on GPR survey data were highly consistent with the actual growth pattern of shrub roots and can thus be used to reveal the spatial competition strategies of plant roots responding to changes in the soil environment and the influence of neighboring plants.

Relationships between mangrove root system and benthic macrofauna distribution

Despite the ability of mangrove trees to allocate a large proportion of the total biomass to the underground roots, little is known about the benthic macrofauna–root system relationships. We evaluated the above- and belowground structures of plants, soil properties, algal cover and their relationship with macrofauna as a function of soil strata (0–2.5, 2.5–5 and 5–10 cm) and distance (0–0.30 and 3–3.5 m) from trunks in three mangrove sites in southern Brazil. Coarse root biomass was higher near the trunks and in shallower layers, while fine root biomass predominated far from trunks and indifferent to the soil stratum. The macrofauna was more associated with changes in the root systems than with other soil properties. Most of the benthic taxa occurred in the upper layers of the soil (0–2.5 cm) and near trunks (< 0.30 m), where there was a lower proportion of fine roots. Fine root entanglement inhibited the presence of organisms with more complex body plans, which may hamper their locomotion and feeding activities. Therefore, the structure and function of macrofauna varied according to the depth stratum and distance from the trunks.

Species-Specific Responses of Root Morphology of Three Co-existing Tree Species to Nutrient Patches Reflect Their Root Foraging Strategies.

Root foraging strategies of plants may be critical to the competition for nutrient resources in the nutrient patches, but little is known about these of co-existing tree species in subtropical regions. This study aimed to elucidate root foraging strategies of three co-existing tree species in nutrient heterogeneous soils by exploring their root distribution, root morphology, photosynthates allocation and nutrient accumulation. Seedlings of the three tree species [moso bamboo (Phyllostachys edulis), Chinese fir (Cunninghamia lanceolata), and masson pine (Pinus massoniana)] were grown for 8months under one homogeneous soil [uniform nitrogen (N) plus phosphorus (P)] and three heterogeneous soils (localized N supply, localized P supply, or localized N plus P supply). The biomass, root morphological parameters (i.e., root length and root surface area), specific root length (SRL), non-structural carbohydrates (NSCs, i.e., mobile sugar and starch) in roots, total N and total P of plants were measured. The plasticity and distribution of root system were analyzed by calculating the root response ratio (RRR) and root foraging precision (FP), respectively. The results are as follows (i) Chinese fir tended to forage more N by promoting root proliferation in the N-rich patch, while root proliferation of bamboo and pine did not change. For P, bamboo absorbed more P by promoting root proliferation in the P-rich patch. The total P content of Pine and Chinese fir under localized P supply treatment remain the same despite the fact that the root length in the P-rich patch and the FP increased. (ii) Chinese fir foraged more N by increasing root length and decreasing SRL in the NP-rich patch; bamboo foraged more N and P by increasing root length and SRL in the NP-rich patch. The FP and foraging scale (FS) of both bamboo and Chinese fir were significantly improved under localized N plus P treatment. (iii) The concentrations of NSC were positively correlated with root morphological plasticity for moso bamboo and Chinese fir. Our results indicated that higher morphological plasticity is exhibited in moso bamboo and Chinese fir than masson pine in nutrient heterogeneous soils, allowing them to successfully forage for more nutrients.

Improving Water Use Efficiency by Optimizing the Root Distribution Patterns under Varying Drip Emitter Density and Drought Stress for Cherry Tomato

The spatial distribution of root systems in the soil has major impacts on soil water and nutrient uptake and ultimately crop yield. This research aimed to optimize the root distribution patterns, growth, and yield of cherry tomato by using a number of emitters per plant. A randomized complete block design technique was adopted by selecting eight treatments with two irrigation regimes and four levels of emitters under greenhouse conditions. The experiment results showed that the root distribution extended over the entire pot horizontally and shifted vertically upwards with increased emitter density. The deficit irrigation resulted in reduced horizontal root extension and shifted the root concentrations deeper. Notably, tomato plants with two emitters per plant and deficit irrigation treatment showed an optimal root distribution compared to the other treatments, showing wider and deeper dispersion measurements and higher root length density and root weight density through the soil with the highest benefit–cost ratio (1.3 and 1.1 cm cm−3, 89.8 and 77.7 µg cm−3, and 4.20 and 4.24 during spring–summer and fall-winter cropping seasons, respectively). The increases in yield and water use efficiency (due to increased yield) were 19% and 18.8%, respectively, for spring–summer cropping season and 11.5% and 11.8%, respectively, for fall–winter cropping season, with two emitters per plant over a single emitter. The decrease in yield was 5.3% and 4%, and increase in water use efficiency (due to deficit irrigation) was 26.2% and 27.9% for spring-summer and fall-winter cropping seasons, respectively, by deficit irrigation over full irrigation. Moreover, it was observed that two, three, and four emitters per plant had no significant effects on yield and water use efficiency. Thus, it was concluded that two emitters per plant with deficit irrigation is optimum under greenhouse conditions for the cultivation of potted cherry tomatoes, considering the root morphology, root distribution, dry matter production, yield, water use efficiency, and economic analysis.