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Salinity is a paramount factor that poses challenges to agricultural productivity and sustainability. At the same time, fenugreek is valued as a forage crop for its medicinal properties in addition to its extensive edible use. The objective of this study is to explore how fertilization and salinity impact soil physical properties and root system development in fenugreek cultivation. A field experiment was established at the Agricultural University of Athens during growing seasons 2019-2020 (1st GS) and 2020-2021 (2nd GS) in a split-splot design with the 2 main salinity treatments (High salinity; HS & Conventional salinity; CS) and 5 fertilization treatments (biocyclic-vegan (BHS), manure (FYM), compost (COMP), inorganic fertilization (11-15-15) and the control (C). Soil porosity was statistically significantly affected by both salinity (p<=0.05) and fertilization (p<=0.001). Also, organic matter was significantly affected by fertilization (p<=0.001). HS (59.78±2.65) resulted in 20.02% fewer nodules on plant roots compared to CS treatments (71.75±2.65). The maximum number of nodules was recorded in the FYM treatment (68.93±0.77). In addition, mean root diameter was affected by fertilization (p<=0.01) COMP (2.92±0.31 mm) and NPK treatments (2.83±0.31 mm) resulted in 19.52% and 23.32% smaller root diameter respectively compared to BHS, while FYM (2.68±0.31 mm) resulted in a 30.22% smaller diameter. A significant increase of seed yield was noticed under organic fertilization where the highest yield of 2.1 t ha-1 was recorded in BHS (2nd GS). Although fenugreek was affected by high salinity, it demonstrated considerable resistance and maintained its yields, rendering it a crop suitable for challenging soils. [ABSTRACT FROM AUTHOR]

The present study focuses on the effect of root density on gas permeability and water retention in biochar‐amended soil used as a cover material in landfills. Biochar amendment of soil is important measurement in landfill cover, while vegetation is an important for ecological restoration. Despite its importance, little attention has been given to the adaptation of vegetated biochar‐amended soil in landfill cover. The interactions between the biochar, vegetation, and soil concerning the gas permeability remain unknown, which may lead to unexpectedly increased waste gas emissions in landfill covers. To enhance the utilization efficiency of biochar amendment and vegetation techniques in landfill covers, further investigation of their coupled effects on gas permeability and water retention is necessary. Four different treatments were applied to manufacture series of soil columns: bare soil (BS), biochar‐soil composite (BSC), vegetated biochar‐soil composite with low planting density (VBSCL) and high planting density (VBSCH). The soil water characteristic curve and gas permeability were observed under natural wetting and drying cycles. The results showed that VBSCL increased gas permeability by 142% as compared to BSC. VBSCH enhanced gas permeability by 168% as compared to BSC. This was due to the spreading and decaying root systems forming preferential pathways for gas transfer. Additionally, VBSCL and VBSCH made around a 10% increase in volume water content at the whole suction range, while BSC just enhanced around 20% water content at the low suction range (less than 10 kPa). The combination of roots and biochar have significantly enhanced water retention during entire suction range due to capillarity. [ABSTRACT FROM AUTHOR]

Salinity is a paramount factor that poses challenges to agricultural productivity and sustainability. At the same time, fenugreek is valued as a forage crop for its medicinal properties in addition to its extensive edible use. The objective of this study is to explore how fertilization and salinity impact soil physical properties and root system development in fenugreek cultivation. A field experiment was established at the Agricultural University of Athens during growing seasons 2019-2020 (1st GS) and 2020-2021 (2nd GS) in a split-splot design with the 2 main salinity treatments (High salinity; HS & Conventional salinity; CS) and 5 fertilization treatments (biocyclic-vegan (BHS), manure (FYM), compost (COMP), inorganic fertilization (11-15-15) and the control (C). Soil porosity was statistically significantly affected by both salinity (p

In this work, we evaluated the influence of root structure on shallow landslide distribution. Root density measurements were acquired in the field and the corresponding root cohesion was estimated. Data were acquired from 150 hillslope deposit trenches dug in areas either devoid or affected by shallow landslides within the Garfagnana Valley (northern Tuscany, Italy). Results highlighted a correlation between the root reinforcement and the location of measurement sites. Namely, lower root density was detected within shallow landslides, with respect to neighboring areas. Root area ratio (RAR) data allowed us to estimate root cohesion by the application of the revised version of the Wu and Waldron Model. Then, we propose a new method for the assimilation of the lateral root reinforcement into the infinite slope model and the limit equilibrium approach by introducing the equivalent root cohesion parameter. The results fall within the range of root cohesion values adopted in most of the physically based shallow landslide susceptibility models known in the literature (mean values ranging between ca. 2 and 3 kPa). Moreover, the results are in line with the scientific literature that has demonstrated the link between root mechanical properties, spatial variability of root reinforcement, and shallow landslide locations. [ABSTRACT FROM AUTHOR]

Planting spacing plays a key role in the root system architecture of the cotton group under local irrigation. This study used the Cellular Automata (CA) theory to establish a root visualization model for the cotton group at two different planting spacing (30 and 15 cm) within a leaching-pond. At a planting spacing of 30 cm, the lateral roots grew almost horizontally toward the irrigation point, and a logarithmic relationship was observed between root length density and soil water suction. However, at a planting spacing of 15 cm, the lateral roots exhibited overlapping growth and mainly competed for resources, and a power function relationship was observed between root length density and soil water suction. The main parameters of the visualization model for each treatment were essentially consistent with the experimental observations, with respective simulation errors were 6.03 and 15.04%. The findings suggest that the correlation between root length density and soil water suction in the cotton plants is a crucial driving force for the model, leading to a more accurate replication of the root structure development pathway. In conclusion, the root system exhibits a certain degree of self-similarity, which extends into the soil. [ABSTRACT FROM AUTHOR]

In order to understand the ecophysiology of sub-Sahelian tree species and to optimize their use in agroforestry, studies on tree root distribution are essential. The aim of this study was to investigate the root distribution of three sub-Sahelian tree species, Adansonia digitata, Faidherbia albida and Borassus akeassii, in three sites along a precipitation and soil gradient in Senegal. Root density maps observed on trench walls and soil-coring methods were used to characterize variations in root density of mature trees. Coarse and fine root distribution was strongly influenced by the site conditions, with root density being highest in the humid site for all tree species. B. akeassii had the highest root density compared to the other two species. Fine root biomass was concentrated in the 0–30 cm soil layer for A. digitata and from 30 to 60 cm for B. akeassii and F. albida. Laterally, the fine root biomass decreased substantially with increasing distance from the trees. Understanding the root distribution of sub-Sahelian tree species across climatic conditions could help to reduce competition between crops and perennials in agroforestry parklands. [ABSTRACT FROM AUTHOR]

During the restoration of degraded vegetation, the mutual matching of underground root systems is crucial for the formation and effective function of the future plant community. In this study, the Amoeba graphic method was integrated to comprehensively establish a root framework index (RFI), based on the three dimensions of root morphology, as well as quantitative and spatial connection characteristics, to quantify the root system architecture. The root development characteristics of alfalfa (T-type), switchgrass (F-type), and mixed planting with alfalfa and switchgrass (T+F-type) were monitored at the test positions. The RFI parameters comprise the acting coefficient of the root framework, root density, root framework degree, and soil bulk density. The RFI values of T-, F-, and T + F-type were 0.38, 0.86, and 1.68, respectively, and were found to provide a well representation of the root structure characteristics. The findings obtained in this study provide scientific support for the ecological construction and evaluation of degraded vegetation.

In a three-year experiment (2019–2021), the roots of 7-year-old apple trees (Malus domestica cv. 'Red Jonaprince') grown under drip irrigation were studied. The aim of the study was to determine the effect of irrigation on root density at different depths and distances from the trunk. The working hypothesis assumed that irrigation significantly affects the total length of apple roots. The irrigation treatments corresponding to the calculated water evapotranspiration (ET100), 50% of the calculated ET (ET50), a control (ET0, no irrigation, under rainfed conditions), and a treatment using double-drip lines (2Drops) were monitored. Soil cores were collected in spring and autumn. The total length of the roots (TRLt) and the length of new vital roots (TRLv) to a depth of 80 cm were evaluated. The effects of treatments were mostly insignificant for the TRLt; only in the dry season in 2019 were the TRLt values of the irrigated treatments (ET50 and ET100) significantly higher, 18.67 km·m−2 and 17.45 km·m−2, in comparison to 11.16 km·m−2 for the ET0, at a 10 cm distance from the tree trunk. The irrigation treatments had a statistically significant effect on the TRLv values near the trunk in 2019 and 2020, while in autumn 2020 and 2021, irrigation significantly affected the TRLv at greater distances from the tree trunk. In summary, the irrigation treatments mostly had no significant effect on the total root length. However, an effect of irrigation on the root length of new vital roots was observed at certain sampling dates and distances from the trunk. [ABSTRACT FROM AUTHOR]

The use of rootstocks tolerant to water stress in pepper crops is a complementary technique for saving irrigation water without affecting yields by means of particular rootstock physiological traits, which changes the scion's perception stress. The present study aimed to analyze the morphological and physiological adaptation of the 'Cuerno' pepper cultivar grafted onto tolerant rootstock NIBER® subjected to capacitance sensor-based deficit irrigation. The stomatal conductance, relative water content and leaf water potential parameters were used to confirm the degree of crop stress. Leaf dry weight and root volume were higher in the grafted plants under the control irrigation and stress treatment conditions. Total fresh root biomass and root volume percentage of grafted plants under water stress were 24% and 33% higher, respectively, than the ungrafted plants. The grafted plants subjected to both water stress and control conditions had a higher marketable production than the ungrafted plants. The higher yields obtained using tolerant rootstocks were explained by the reduced blossom-end rot incidence. [ABSTRACT FROM AUTHOR]

This paper examines the root density dynamics in gramineous–leguminous grass stands in various landscape conditions at different agrocoenosis development stages. Field studies were conducted in Tver oblast on an agroecological transect: a field that intersects the main landscape positions of a finite moraine hill. One hundred twenty sampling points were established on the transect 10 m from each other. The density of roots was measured in 2019–2021 under grasses at the first to third year of life. Effects exercised by environmental landscape factors on the root density were determined using various statistical analysis techniques. The studied parameter depends on both internal (biogeocoenotic) and external (landscape) factors. Internal factors result in a fivefold increase in root density in the period from the first to the first year of life. As the grass stand gets older, the root development intensity goes down. In the first year of life, root development is determined by the state of legumes, soil fertility elements, and terrain altitude; that in the second year is by interspecific competition in the agrocoenosis, granulometric and mineralogical composition of soils, and locality altitude; and that in the third year is by specifics of the soil pore space. Microlandscape conditions determine 21.5% of the total variability in root density growth under grasses only in the first year of use. If grasses are used not only for forage purposes but also for landscape reclamation, it can be recommended to cultivate old grass stands on light skeletal soils, while it is reasonable to exploit grasses only in the first year of use in areas where moraine occurs at shallow depths. [ABSTRACT FROM AUTHOR]

In this work, we evaluated the influence of root structure on shallow landslide distribution. Root density measurements were acquired in the field and the corresponding root cohesion was estimated. Data were acquired from 150 hillslope deposit trenches dug in areas either devoid or affected by shallow landslides within the Garfagnana Valley (northern Tuscany, Italy). Results highlighted a correlation between the root reinforcement and the location of measurement sites. Namely, lower root density was detected within shallow landslides, with respect to neighboring areas. Root area ratio (RAR) data allowed us to estimate root cohesion by the application of the revised version of the Wu and Waldron Model. Then, we propose a new method for the assimilation of the lateral root reinforcement into the infinite slope model and the limit equilibrium approach by introducing the equivalent root cohesion parameter. The results fall within the range of root cohesion values adopted in most of the physically based shallow landslide susceptibility models known in the literature (mean values ranging between ca. 2 and 3 kPa). Moreover, the results are in line with the scientific literature that has demonstrated the link between root mechanical properties, spatial variability of root reinforcement, and shallow landslide locations.

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To evaluate the effects of herbaceous plants' roots density on soil structure and slope stability in a shallow landslide-affected area, we determined the mechanical characteristics of roots of four herbs (Cynodon dactylon, Artemisia sacrorum, Digitaria sanguinalis, and Clematis florida) growing on slopes prone to landslides and analyzed their effects on soil physicochemical properties. Root tensile strength and shear strength of root–soil composites were determined at different root densities. The slope safety factor was simulated using the strength reduction method. Compared with bare land soil, rhizosphere soils were characterized by higher bulk density, porosity, nutrient content, aggregate content, and greater stability (p < 0.01). Among the four plant species studied, C. florida improved soil structure and soil nutrient contents most effectively. The roots of A. sacrorum displayed the highest tensile strength, reaching up to 248 Mpa. The root–soil complexes of A. sacrorum displayed the highest cohesion and cohesion growth rate compared to bare land. The roots of A.sacrrorum can therefore provide additional cohesion, while the cohesion increase rate of soil without roots varies from 83.30 to 195.94%. The cohesion and safety factor of root–soil complexes of C. dactylon decreased with increasing root density, while those of D. sanguinalis increased with increasing root density. Thus, herbs stabilize slopes by improving soil structure and the mechanical properties of their roots. [ABSTRACT FROM AUTHOR]

The use of rootstocks tolerant to water stress in pepper crops is a complementary technique for saving irrigation water without affecting yields by means of particular rootstock physiological traits, which changes the scion’s perception stress. The present study aimed to analyze the morphological and physiological adaptation of the ‘Cuerno’ pepper cultivar grafted onto tolerant rootstock NIBER® subjected to capacitance sensor-based deficit irrigation. The stomatal conductance, relative water content and leaf water potential parameters were used to confirm the degree of crop stress. Leaf dry weight and root volume were higher in the grafted plants under the control irrigation and stress treatment conditions. Total fresh root biomass and root volume percentage of grafted plants under water stress were 24% and 33% higher, respectively, than the ungrafted plants. The grafted plants subjected to both water stress and control conditions had a higher marketable production than the ungrafted plants. The higher yields obtained using tolerant rootstocks were explained by the reduced blossom-end rot incidence.

In a three-year experiment (2019–2021), the roots of 7-year-old apple trees (Malus domestica cv. ‘Red Jonaprince’) grown under drip irrigation were studied. The aim of the study was to determine the effect of irrigation on root density at different depths and distances from the trunk. The working hypothesis assumed that irrigation significantly affects the total length of apple roots. The irrigation treatments corresponding to the calculated water evapotranspiration (ET100), 50% of the calculated ET (ET50), a control (ET0, no irrigation, under rainfed conditions), and a treatment using double-drip lines (2Drops) were monitored. Soil cores were collected in spring and autumn. The total length of the roots (TRLt) and the length of new vital roots (TRLv) to a depth of 80 cm were evaluated. The effects of treatments were mostly insignificant for the TRLt; only in the dry season in 2019 were the TRLt values of the irrigated treatments (ET50 and ET100) significantly higher, 18.67 km·m−2 and 17.45 km·m−2, in comparison to 11.16 km·m−2 for the ET0, at a 10 cm distance from the tree trunk. The irrigation treatments had a statistically significant effect on the TRLv values near the trunk in 2019 and 2020, while in autumn 2020 and 2021, irrigation significantly affected the TRLv at greater distances from the tree trunk. In summary, the irrigation treatments mostly had no significant effect on the total root length. However, an effect of irrigation on the root length of new vital roots was observed at certain sampling dates and distances from the trunk.

Aims: The stability of hillslopes is an essential ecosystem service, especially in alpine regions with soils prone to erosion. One key variable controlling hillslope stability is soil aggregate stability. We aimed at identifying dominant controls of vegetation parameters on aggregate stability and analysed their importance for soil aggregate stability during landscape development. Methods: We quantified the aggregate stability coefficient (ASC) and measured plant cover, diversity, root mass and root length, density (RMD, RLD) along two chronosequences with contrasting bedrocks (siliceous, calcareous) in the Swiss Alps. Results: We found that ASC developed slower along the calcareous chronosequence. Furthermore, we observed a significant positive effect of vegetation cover and diversity on ASC that was mediated via root density. These relationships developed in a time-depended manner: At young terrain ages, vegetation parameters had a strong effect on aggregate stability compared to older stages. Moreover, RLD was the most powerful predictor of ASC on young terrain, whereas on older moraines RMD became more important. Conclusions: We highlight that root density plays a major role in governing ASC for soils differing in moraine ages. The changing importances of RLD and RMD for ASC development suggest different mechanistic linkages between vegetation and hillsope stability during landscape development. [ABSTRACT FROM AUTHOR]

A field experiment was conducted during rabi 2016-17 and 2017-18 to evaluate the influence of different residue and nitrogen management practices on soil physico-chemical properties, root density, weed growth and grain yield of happy seeder sown wheat. Experiment was conducted in randomized block design consisting of eleven residue and nitrogen management treatments in four replications. The results inferred that weed biomass was significantly less in chopped straw treatments (C) as compared to unchopped treatments (NC). Treatments receiving 150 kg N/ha had higher root density than 125 kg N/ha treatments at all soil depths during both years. Soil physical and chemical properties were not significantly affected but there was improvement in these properties after two years of residue retention. Grain yield (5.42 and 5.36 t/ha) was maximum in treatment where 150 kg N (30 kg at chopping of straw and 120 kg as per recommendation) was applied along with 5 t/ha FYM (C+N30+120+FYM5), which was significantly better than NC + N125, C + N125, C + FYM5 + N125 and C + N20+105 treatments but statistically at par with rest of the treatments.

Protective roles of shade trees for climate-resilient cacao appear to depend on tree-site matching. Agroforestry practices involve a wide range of context-specific management options, which can be complex and pose challenges due to tradeoffs. To assess the benefits and drawbacks, across a range of contexts, of various cacao-based land use systems on multifunctionality and economic performance. We used the process-based Water, Nutrient and Light Capture in agroforestry systems (WaNuLCAS) model to assess the performance of five cacao-based land use systems (cacao monoculture, cacao + annual crops, cacao + fruit tree, cacao + fast-growing tree, and cacao + slow-growing tree), in three climate regimes (tropical rainforest, monsoon, and savannah), two soil textures, and two sources of data for cacao root length density (W Africa and Indonesia, respectively). Several metrics quantified the performance of each land use system, including the Land Equivalent Ratio for production (LER P),multifunctionality (LER M), Net Present Value (NPV), Return to Labour (RtL), and Benefit-Cost Ratio (BCR). Simulated cacao production per tree, positively or negatively influenced by intercrops, responded to the number of days cacao grew under water-limited conditions. High cacao root density supported higher LER P values (an average of 1.15 versus 0.95 in other cases). In the savanna, the LER P difference between cacao with high root density and those with low root density became 0.27. Among agroforestry systems, cacao + annual crops had the highest LER P of 1.13, followed by cacao + slow-growing trees (1.09), while the lowest outcome (0.98) was for cacao + fruit trees. These values were higher in rainforest climates, and lowest for savanna. Soil texture had no effect on the average LER P across other main factors. Tree-based agroforestry had a higher time-averaged carbon stock than monocultures or systems with annual crops. However, their effects on other environmental performance aspects, averaged over a 20-year life cycle, were modest, and variation in LER M was small. Economic performance indicators diverged, with the highest NPV were for cacao + annual crops or cacao + fruit trees, the highest BCR was for cacao + fruit trees, and the highest RtL was for cacao + fruit trees followed by cacao + slow-growing trees. Our study highlights that the potential benefits of cacao-based agroforestry practices depend on strong root development by the cacao trees. In selecting for high yields in monocultures, the benefits of intercropping may be forfeited, especially in drier climates with the lower values for root length density measured in W Africa. [Display omitted] • Cacao can have annual food crops, fruit trees, slow- or fast-growing timber trees as companion plants. • Cacao agroforestry options depend on rainfall, soils and cacao root development. • A calibrated WaNuLCAS model estimated multifunctionality and economic performance. • Integrating cacao with fruit trees achieves best economic performances. • Selection for high-yielding cacao with low belowground C investment, forfeits intercropping options. [ABSTRACT FROM AUTHOR]

The effect of root reinforcement depends on the biotechnical characteristics of the root system including the tensile strength of individual roots, the root density and the distribution of the root system in the soil. This research was conducted in the Hyrcanian forest in Iran, where shallow landslides are frequent due to road construction. The effect of the root biotechnical characteristics of Alnus subcordata, Paulownia fortunei and Populus deltoides each one in 2-, 10- and 15-year-old plantations was assessed. The profile trenching method was used in this study to obtain the root area ratio of individual species by counting the number of roots and measuring the root diameter. For each species, single root specimens were sampled and tested for tensile tests in the laboratory using the standard Instron apparatus. The natural moisture content (two weeks after rainfall), Atterberg limits, shear strength of the soil were determined for plantations, stable and unstable sites. Results of this study indicated that plastic index and internal friction angle decreased with increasing root diameter rate. Moreover, internal friction angle and cohesion increased with increasing root area ratio and root diameter and density index. Tensile strength of roots decreased with increasing stand age. The highest and the lowest tensile strengths among species were observed for Paulownia fortunei and Populus deltoides, respectively. The findings of this research contribute to expanding the knowledge of root biotechnical properties of some tree species and to the choice of the most appropriate species for improving plastic index and shear strength in landslide prone areas.

Previous studies have proved that root distribution along gully headwalls greatly alters soil properties and further affects the soil erodibility of gully heads. However, it is not clear whether the gully headcut migration is affected by root distribution and soil properties. Five representative gullies developed in different land uses were selected to clarify the variations of root distribution and soil properties and their effects on headcut migration in the rainy season (May to October 2021) in the Mollisols region of northeast China. Results showed that the 68.4%–93.3% of root mass density and 65.6–88.5% of root length density were concentrated in 0–30 cm soil layer of gully heads, and the roots of 85%. The gullies developed in farmlands had relatively higher soil compactness, shear strength and aggregate stability, but lower organic matter (OMC), disintegration capacity and soil permeability than those developed in woodlands, unpaved roads in farmland and stable gully-beds. Changes in soil properties of gully heads were closely related to root density. The linear, areal, and volumetric migration rate of gully heads varied greatly and were 1.07–35.11 m yr−1, 28.95–562.46 m2 yr−1 and 56.82–6626.37 m3 yr−1, respectively, with the average of 9.07 m yr−1, 156.92 m2 yr−1 and 1503.02 m3 yr−1, respectively. The change in headcut migration rate was significantly affected by root density, soil properties and drainage area, of which soil texture, OMC, soil aggregate structure, and the drainage area were the critical factors influencing headcut migration in the Mollisols region of northeast China.

Alternating degradation and restoration phases of soil quality, as is common in crop-fallow systems, can be avoided if the restorative elements of trees and forests can be integrated into productive agroforestry systems. However, evidence for the hypothesis of 'internal restoration' in agroforestry is patchy and the effectiveness may depend on local context. We investigated to what extent cocoa (Theobroma cacao, L.) agroforestry can recover soil structure and infiltration in comparison to monoculture systems across the Konaweha Watershed, Southeast Sulawesi. We compared soil organic carbon, fine root length and weight, soil aggregate stability, macroporosity and infiltration from three soil layers at five land use systems: i.e. degraded forests, 9–14 years old of complex-cocoa agroforestry, simple-cocoa agroforestry, monoculture cocoa and 1–4 years old annual food crops, all with three replications. In general, roots were concentrated in the upper 40 cm of soil depth, contained of 70% and 86% of total fine root length and weight. Compared to simple agroforestry and cocoa monoculture, complex agroforestry had greater root length and weight in the topsoil, even though it attained only half the values found in degraded forests. Higher root density was positively correlated to soil organic carbon. In upper soil layers, complex agroforestry had slightly higher soil aggregate stability compared to other agricultural systems. However, no significant difference was found in deeper layers. Complex agroforestry had higher soil macroporosity than other agricultural systems, but not sufficient to mimic forests. Degraded forests had two times faster steady-state soil infiltration than agricultural systems tested (13.2 cm h−1 and 6 cm h−1, respectively), relevant during peak rainfall events. Compared to other agricultural systems, complex agroforestry improves soil structure of degraded soil resulting from forest conversion. However, a considerable gap remains with forest soil conditions. [ABSTRACT FROM AUTHOR]

Grain legumes known as “Pulse crops” are economically and nutritionally one of the most important crop families after cereals. Climate change and abiotic stress factors are limiting yield potential in these crops. Root system architecture, a neglected field, is promising for improved environmental adaptability and higher growth potential. Genotypes with deep and dense root system may cope better with water and nutrient limitations. This study aimed to evaluate 12 common cultivars from six different legume species. Root system architectures were evaluated under controlled conditions in a plexiglass system at the early vegetative stage. Roots were divided into four depth zones (0, 5, 10, 15> cm), and inter and intra species diversity were analysed. Significant diversity was obtained within and between the species. Bean, chickpea, and broad bean constituted deeper and dense root systems while lentil, soybean, and pea formed non-dense and shallower root systems. There was a significant correlation between earliness and early vegetative root vigour. The results of the study may provide a better understanding of the root system architectures of each species-genera. The results presented here may shed light on the selection of root traits in legume breeding programs. [ABSTRACT FROM AUTHOR]

Iran has been faced to drought during last decades, and one way to overcome this phenomenon is to improve the water productivity by introducing new crops tolerant to water stresses such as quinoa. Two‐year field experiment was performed to find out the response of quinoa (cv. Titicaca) to deficit irrigation imposed at different growing stages. Hence, the effect of full irrigation (100% irrigation water requirement) and deficit irrigation (50% full irrigation) on physiological parameters, yield, irrigation water productivity and root density of quinoa was investigated during 2016 and 2017 growing seasons. The result showed that there was a significant difference between all variables in two years. Higher average air temperature in 2017 (2.0°C) resulted in a reduction of seed yield and water productivity (55% and 40% of that obtained in 2016, respectively). Application of deficit irrigation during different growing stages reduced crop height, stomatal conductance and seed yield, while it increased the root length density in both years. In conclusion, flowering stage of quinoa was very sensitive to deficit irrigation, and irrigation at grain filling stage would not help to recover the seed yield. Furthermore, the seed yield was lower than that obtained in other studies performed in other countries using same quinoa cultivar, which could be due to higher amount of applied irrigation water and different phenology under different climatic conditions. A decision on cultivating this crop under semi‐arid conditions has to be made considering limited water resources. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Aims: Generally, grapevine roots have been less studied than the above‐ground parts of the plant. Here we analyse scion–rootstock interactions in mature vines growing in a heavy clay soil in a climate characterised by severe summer drought to investigate the effect of the scion–rootstock interaction in a suboptimal soil. Methods and Results: The rootstocks, 34 Ecole de Montpellier, 140 Ruggeri and 1103 Paulsen, were grafted onto Nerello Mascalese and Nero d'Avola scions and assessed along with self‐rooted vines. Root distribution and root architecture were analysed using the profile wall method at 0, 60 and 120 cm from the row midline. Root density was greatest at a depth between 21 and 60 cm. The cumulative root fraction for root density registered a β value, a numerical quantity that summarises depth distribution, ranging between 0.932 and 0.962. Root number and density were significantly lower for the self‐rooted vines compared to that of the grafted vines. Conclusions: The scion genotypes affected most developmental parameters, including the diameter of the root system, the root density at 21–80 cm depth and the ratio of fine roots to coarse roots. Significance of the Study: The scion plays an important role in grapevine root growth, development and distribution in a heavy clay soil, although the mechanism remains unclear. [ABSTRACT FROM AUTHOR]

Revegetation represents an effective measure for preventing soil erosion on the Loess Plateau. However, the effects of revegetation‐induced changes in soil and root properties on soil resistance to concentrated flow erosion (SRC) remain unclear. This study sampled soils and roots across a 25‐year chronosequence from farmland to grasslands of different ages (3, 7, 10, 18, and 25 years) to quantify variations in soil and root properties (soil bulk density, SBD; soil disintegration rate, SDR; saturated hydraulic conductivity, SHC; organic matter content, OMC; water‐stable aggregate, WSA; mean weight diameter, MWD; root mass density, RMD; root length density, RLD; and root surface area density, RSAD) and their effects on SRC. Farmland and grassland SRCs were obtained using a hydraulic flume. Soil properties and root density gradually improved with restoration time. In terms of the comprehensive soil property index calculated via principal component analysis, grassland values were 0.66 to 1.94 times greater than farmland values. Grassland SRCs increased and gradually stabilized (>18 years) over time and were 1.60 to 8.26 times greater than farmland SRC. SRC improvement was significantly related to increases in OMC, SHC, WSA, and MWD and decreases in SBD and SDR over time. SRC was effectively simulated by the Hill curve of RMD, RLD, and RSAD. SDR, SHC, and RMD (0.5–1.0 mm) affected SRC the most. This study scientifically describes how revegetation improves soil quality and soil resistance to flow erosion, and suggests that vegetations rich in 0.5–1.0 mm roots should be preferred during revegetation. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work was to evaluate the variations in root dry matter mass (RDM) and the percentage distribution (PD) of the root density of Florico grass (Cynodon nlemfuensis) in the 0-40-cm soil layer, when managed under different grazing strategies. Two defoliation frequencies (90 and 95% light interception, as the criterion for allowing animals in the paddock) and two defoliation severities (post-grazing heights of 20 or 30 cm) were assessed. Four seasonal evaluations of the root system were performed between the winter of 2012 and the autumn of 2013, using the monolith and trench excavation technique, collecting 1-dm3 samples from soil surface down to a depth of 40 cm, in four sequential extracts of 10 cm each. Lower RDM values (0.69 g dm-3) were obtained in winter, with the four grazing strategies, whereas higher values were observed in spring (1.64 g dm-3), for the 30-cm post-grazing residue, and in autumn (1.63 g dm-3) for the 20 cm post-grazing residue, regardless of the light interception value. Between 52 and 66% of the RDM density was observed in the 10-cm layer, for all four grazing strategies, in all seasons.

Recent studies in salt marshes have demonstrated the role of plant roots in sediment stabilisation, and hence the importance of marshes in providing coastal protection. However, the relative role of root traits and environmental factors in controlling sediment stability, and how intraspecific variability of root traits vary within and among marshes, remain poorly understood. In this study, we investigated which root trait(s) drive sediment stability (resistance to lateral erosion) in two marsh species with an important role in coastal protection (Spartina anglica and Atriplex portulacoides) and how the environment affects the expression of these traits. We sampled three marshes along salinity gradients in each of two estuaries in Wales (UK), establishing replicate plots in the respective dominant zones of each species. In all plots we sampled abiotic variables (sand, redox potential, pH, salinity) and root traits (root density, specific root density, root volume, root length density); in a subset of these plots (three per species in each marsh) we extracted soil-plant cores and assessed their erosion resistance in a flume. Sediment stability was enhanced by increases in root density and reductions in sand content. Abiotic variables affected root density in different ways depending on species: in S. anglica, redox was the only significant factor, with a positive, linear effect on root density; in A. portulacoides, redox had a non-linear (U-shaped) effect on root density, while sand had a negative effect. Collectively, these results show that (i) intraspecific variability in root density can influence sediment stability in salt marshes, and (ii) sediment properties not only influence sediment stability directly, but also indirectly via root density. These results shed light on spatial variability in the stability of salt marshes to lateral erosion and suggest that root density should be incorporated into coastal vegetation monitoring programs as an easy-to-measure root trait that links the environment to sediment stability and hence to the function and services provided by marshes.

Edaphic arthropod communities provide valuable information about the prevailing status of soil quality to improve the functionality and long-term sustainability of soil management. The study aimed at evaluating the effect of plant and grass cover on the functional biodiversity and soil characteristics in a mature olive orchard (Olea europaea L.) managed for ten years by two conservation soil managements: natural grass cover (NC) and conservation tillage (CT). The trees under CT grew and yielded more than those under NC during the period of increasing yields (years 4–7) but not when they reached full production. Soil management did not affect the tree root density. Collecting samples underneath the canopy (UC) and in the inter-row space (IR), the edaphic environment was characterized by soil structure, hydrological properties, the concentration and storage of soil organic carbon pools and the distribution of microarthropod communities. The soil organic carbon pools (total and humified) were negatively affected by minimum tillage in IR, but not UC, without a loss in fruit and oil yield. The assemblages of microarthropods benefited, firstly, from the grass cover, secondly, from the canopy effect, and thirdly, from a soil structure ensuring a high air capacity and water storage. Feeding functional groups—hemiedaphic macrosaprophages, polyphages and predators—resulted in selecting the ecotonal microenvironment between the surface and edaphic habitat.

(1) Background: Root traits play important roles in acclimating to water and phosphorus (P) shortages. However, the relative importance of root size and efficiency under these conditions is unknown. (2) Methods: This study investigated the role of root size and efficiency in acclimating to water- and P-limited environments. Three soybean genotypes with contrasting root sizes were grown in tall cylindrical pots to compare grain yield, root density, and water- and nutrient-uptake efficiencies under two water (well-watered and water-stressed) and three P levels (0 (P0), 60 (P60), and 120 (P120) mg P kg−1 dry soil). (3) Results: Water or P deficit, and combined water and P deficit significantly decreased grain yield, which was associated with greater P uptake per unit root dry weight (DW) under water stress. The genotype Zhonghuang 30 (ZH) with the greatest water, nitrogen, and P uptakes per unit root DW had the highest grain yield at P60 and P120 under water stress and P0 under well-watered conditions, but ZH had the lowest grain yield at P60 and P120 under well-watered conditions, due to its small root size. (4) Conclusions: High root efficiency—which was correlated with high root density—improved grain yield under P- and water-limited conditions, but restricted yield potential when P and water were not limited.

Vegetation plays an important role in gully headcut erosion in China's Loess Plateau, but little is known about the effects of root density on gully headcut erosion. This study attempted to investigate the effects of grass root density on gully headcut erosion and morphological development of the gully head using plots with different grass root densities (with bare land as the control). The experiment was performed on plots with different grass root densities, and the rainfall intensity and inflow discharge increased throughout the experiment. The results showed that headcut migration in bare land was mainly activated by upstream flow incision, headwall erosion, and plunge pool erosion, whereas headcut migration in grassland was driven by soil‐root matrix collapse at the headcut, headwall erosion, and plunge pool erosion. The soil loss rate (SLR), gully headcut retreat distance (GRD), gully area (GA), and upstream soil loss volume (SLVU) in grassland plots with different root densities were 45.64–68.45%, 66.97–85.38%, 69.26–78.18%, and 67.89–87.02% less than those in the bare land plots, respectively. However, as root density increased, the gully depth in the grassland plots increased from 19% to 59%, and the proportion of gully head soil loss volume (SLVGH) to the total soil loss volume increased from 63.37% to 88.37%. The SLR, GRD, GA, and SLVGH showed decreasing trends as the root density increased, as described by a Hill curve. Moreover, roots with diameters of 0–0.5 mm had greater effects on soil loss and morphological evolution than roots with larger diameters. Our results provide a reference for the reasonable selection of grass root density for controlling gully headcut erosion in China's Loess Plateau. [ABSTRACT FROM AUTHOR]

• Controlled traffic farming (CTF) increased crop yield on sandy loam soil. • Root growth was improved in permanent crop beds of the CTF system. • Beetroot roots exceeded 1.5 m depth on coarse sandy soil independent of traffic system. • CTF maintained or increased soil mineral nitrogen supply in permanent crop beds. Increased farm machinery weight in agricultural production results in soil compaction. Controlled traffic farming (CTF) restricts traffic to permanent lanes, thereby creating traffic free beds for crop production. Field experiments were conducted at two organic vegetable farms in Denmark, on a sandy loam (2013–2016) and on coarse sand (2013–2015) to investigate CTF effects compared with random traffic farming (RTF) on vegetable yield, root growth, and soil mineral nitrogen (N). Root growth was measured using minirhizotrons. White cabbage, potato, and beetroot yield increased by 27%, 70% and 42%, respectively, in CTF compared with RTF in 2015 and winter squash indicated a yield increase of 43% on sandy loam in 2016. White cabbage (2015) and potato, beetroot and winter squash (2016) grew 2–25 times more roots and beetroot grew deeper roots under CTF compared with RTF on sandy loam in 2016. On coarse sandy soil, beetroot root frequency was 1.4 times greater under CTF than under RTF and beetroot roots grew deeper than 1.5 m under both treatments in 2015. Soil mineral N and potential net N mineralization were equal between treatments or higher in CTF by 2–41 kg ha−1 and 11 mg kg−1 35 days−1, respectively, indicating N supply was maintained or increased in this system. Despite the variability in crop and root growth responses to traffic between years and crops, the effects were always equal or positive for CTF following treatment implementation. Therefore, our results encourage the use of CTF for organic vegetable production under temperate conditions. [ABSTRACT FROM AUTHOR]

The effect of root reinforcement depends on the biotechnical characteristics of the root system including the tensile strength of individual roots, the root density and the distribution of the root system in the soil. This research was conducted in the Hyrcanian forest in Iran, where shallow landslides are frequent due to road construction. The effect of the root biotechnical characteristics of Alnus subcordata, Paulownia fortunei and Populus deltoides each one in 2-, 10- and 15-year-old plantations was assessed. The profile trenching method was used in this study to obtain the root area ratio of individual species by counting the number of roots and measuring the root diameter. For each species, single root specimens were sampled and tested for tensile tests in the laboratory using the standard Instron apparatus. The natural moisture content (two weeks after rainfall), Atterberg limits, shear strength of the soil were determined for plantations, stable and unstable sites. Results of this study indicated that plastic index and internal friction angle decreased with increasing root diameter rate. Moreover, internal friction angle and cohesion increased with increasing root area ratio and root diameter and density index. Tensile strength of roots decreased with increasing stand age. The highest and the lowest tensile strengths among species were observed for Paulownia fortunei and Populus deltoides, respectively. The findings of this research contribute to expanding the knowledge of root biotechnical properties of some tree species and to the choice of the most appropriate species for improving plastic index and shear strength in landslide prone areas. [ABSTRACT FROM AUTHOR]

Highlights • The response of double subsurface drip irrigation system having 30 x 30 cm drippers spacing at 30 cm depth is better than double surface online laterals with four drippers drip irrigation system. • Soil moisture withholding was higher in the sub-surface drip irrigation (30 x 30 cm) with double inline laterals compared to double surface online laterals with four drippers drip irrigation system. • The total average quantities of water used ranged from 2520.20 to 8340.60 Lbahar−1t−1 and WUE was found to be a ranged from 1.98 to 4.01 kgm−3 in micro-irrigation systems. • The results showed that 30 x 30 cm dripper spacing of inline double laterals buried at 30 cm depth enhanced the water use efficiency of pomegranate. Abstract The effects of various micro-irrigation systems on some parameters of Pomegranate (Punica granatum L. cv. Bhagwa) i.e. physiological, yield, fruit qualities, root density, water use and water use efficiency parameters studied in the field experiments. Six types of micro-irrigation treatments with four replications were applied: 4-subsurface and 2-surface micro-irrigation were presented along with the 1-inline lateral at dripper spacing 30 cm, 2-inline laterals at drippers spacing 30 x 30 cm, 2-inline laterals at drippers spacing 40 x 40 cm; 2-inline laterals at drippers spacing 50 x 50 cm; 1-online lateral with 2-drippers (2D) and 2-online laterals with 4-drippers (4D), respectively. Maximum plant height, steam diameter, leaf area index, flowers, nutrient status and yield was recorded in subsurface drip irrigation system (SDI) with 2-inline laterals (30 x 30 cm) followed by (40 x 40 cm), (50 x 50 cm), surface drip irrigation (DI) with 2-laterals and 4drippers, 1-inline lateral at dripper spacing 30 cm and 1-online lateral with 2drippers. Soil moisture withholding was also higher in the SDI with double inline laterals (30 x 30 cm). The total average quantities of water used ranged from 2520.20 to 8340.60 Lbahar−1 t−1 and water use efficiency was found to be ranged from 1.98 to 4.01 kg m-3 in micro-irrigation systems. The biophysical advantages are low canopy humidity and fewer diseases and weeds. The results showed that 30 x 30 cm inline double lateral enhanced the flowering intensity, yield, root density and water use efficiency of pomegranate. [ABSTRACT FROM AUTHOR]

As in any other plant, the grapevine roots play a vital role in terms of anchorage, uptake of water and nutrients, as well as storage and production of chemicals. Their behaviour and development depend on various factors, namely rootstock genetics, soil physical and chemical features, and field agronomic practices. Canopy management, involving techniques such as defoliation and pruning, could greatly influence root growth. To date, most of the studies on grapevine winter pruning have focused on the effects on yield and quality of the grapes achievable through different pruning systems and techniques, while knowledge regarding root distribution, development, and growth in relation to winter pruning is still not completely understood. In this context, the purpose of our study was to investigate the effect of winter pruning on the root system of field-grown Vitis vinifera cv. Pinot Gris grafted onto rootstock SO4. We compared two pruning treatments (pruned-P and no pruned-NP) and analysed the effect on root distribution and density, the root index, and the root sugar reserve. Root data were analysed in relation to canopy growth and yield, to elucidate the effect of winter pruning on the root/yield ratio. Our data indicated that: (1) winter pruning stimulated the root growth and distribution; (2) canopy development was not negatively affected by this technique; (3) no pruned treatment produced less growth of the roots but a larger canopy. Information regarding both root growth and root canopy ratio is important as it gives us an understanding of the relationship between the aerial and subterranean parts of the plant, how they compete, and finally, offers us the possibility to ponder on the cultural practices.

Pasture-based livestock production is impacted by management and weather. In pastures, there is conflict between leaf retention for plant growth and leaf harvest for animal nutrition. Defoliated pastures with low light interception (LI) may have a low forage growth rate (FGR), while excessive growth shades leaves, reducing FGR and resulting in an S-shaped regrowth curve. To optimize production, it is best to keep FGR linear. Three studies were conducted to evaluate the impact of management and weather on FGR. Replicated pastures were used to measure FGR when grazed from 25 to 10 cm and allowed to regrow. The impact of alternative defoliation timings and intensities on FGR were studied using clipped treatments at three recovery intervals and two stubble heights. Variability in FGR was studied using a field validated plant growth model. Of the 24 growth periods studied, two displayed exponential, 12 linear and 10 linear-plateau growth. There was no effect of FM on growth curve form. In May and June, LI increased with canopy height, up to 0.93. Stubble height and days of growth impacted FGR with an interaction. There was no treatment impact on root density. Weather caused variation in FGR. A low FGR risk occurs at high elevations; greater risk occurs east of the plateau.

The paper deals with the spatial distribution of root density in highbush blueberry plantations of various ages for a proper planting distance recommendation and a better irrigation and fertilization management. The environmental conditions consist of sandy-loamy soils and a continental temperate climate. Two highbush blueberry cultivars were studied, ‘Bluecrop’ and ‘Blueray’. Root density (RD) and density of root cross-sectional area (RCSA) were investigated for various root diameters. It was found that the prevalent type of roots in highbush blueberry crops is the hair type, with root diameters less than 0.1 mm. Both RD and RCSA decreased with distance from plant and with soil depth; the 38-year-old crop showed a more developed root system versus the 8‑year-old crop. In both cases the roots did not grow more than 0.6 m laterally and more than 0.7 m deep. According to these results, the planting distances in highbush blueberry could be reduced to substantially increase the number of plants/ha and fruit yield. Irrigation application should be carried out to wet a proper soil volume, about 0.6-0.7 m deep for older crops, and about 0.5 m deep for younger crops. [ABSTRACT FROM AUTHOR]

In Mexico, rice (Oriza sativa L.) is cultivated under irrigation and rainfed conditions with moisture restrictions and frequent periods of drought during the growing season. Grain yield (GY) is reduced severely when drought coincides with flowering and the grain-filling period. The objective of this study was to evaluate the GY and its components, and the root density (RD) in eight F6 lines of rice and one control (the national variety El Silverio), under irrigation (I) and rainfed (R) conditions in Zacatepec, Morelos, Mexico. The lines come from the nurseries of the Latin American Fund for Irrigation Rice (FLAR, for its acronym in Spanish; Santa Rosa, Cali, Colombia). The experiment was sown on June 10, 2013, with a seeding rate of 100 kg ha-1 and a fertilization rate of 180- 40-40 of N-P-K. GY and the number of grains m-2 (G M-2) were the characteristics most affected by the water deficit in R. The RD in I (74 %) and R (72 %) was higher in the stratum of 0-30 cm; the RD in R (0.45, 0.26, 0.18 and 0.10 cm cm-3) was higher than in I (0.26, 0.16, 0.10 and 0.05 cm cm-3) in every stratum of the soil. Lines 2 and 7 were the most productive in I and R, and showed high aerial biomass (BM), harvest index (HI) and G M-2. Line 2; in addition, showed higher RD than the other lines in the strata of 15-30, 30-50 and 50-70 cm in I and R. The control showed lower GY and its components, and RD than the other genotypes. GY was positively related to its components in average of I and R. The most productive lines could be used commercially and as parents in a rice breeding program for irrigation and rainfed areas. [ABSTRACT FROM AUTHOR]

Abstract: Agricultural soil landscapes of hummocky ground moraines are characterized by 3D spatial patterns of soil types that result from profile modifications due to the combined effect of water and tillage erosion. We hypothesize that crops reflect such soil landscape patterns by increased or reduced plant and root growth. Root development may depend on the thickness and vertical sequence of soil horizons as well as on the structural development state of these horizons at different landscape positions. The hypotheses were tested using field data of the root density (RD) and the root lengths (RL) of winter wheat using the minirhizotron technique. We compared data from plots at the CarboZALF‐D site (NE Germany) that are representing a non‐eroded reference soil profile (Albic Luvisol) at a plateau position, a strongly eroded profile at steep slope (Calcaric Regosol), and a depositional profile at the footslope (Anocolluvic Regosol). At each of these plots, three Plexiglas access tubes were installed down to approx. 1.5 m soil depth. Root measurements were carried out during the growing season of winter wheat (September 2014–August 2015) on six dates. The root length density (RLD) and the root biomass density were derived from RD values assuming a mean specific root length of 100 m g−1. Values of RD and RLD were highest for the Anocolluvic Regosol and lowest for the Calcaric Regosol. The maximum root penetration depth was lower in the Anocolluvic Regosol because of a relatively high and fluctuating water table at this landscape position. Results revealed positive relations between below‐ground (root) and above‐ground crop parameters (i.e., leaf area index, plant height, biomass, and yield) for the three soil types. Observed root densities and root lengths in soils at the three landscape positions corroborated the hypothesis that the root system was reflecting erosion‐induced soil profile modifications. Soil landscape position dependent root growth should be considered when attempting to quantify landscape scale water and element balances as well as agricultural productivity. [ABSTRACT FROM AUTHOR]

Due to water shortages and the increasing need for food in recent years, the optimization of water consumption parameters, fertilizers, and food production are essential and a priority. The aim of this study is to investigate the effect of partial root-zone irrigation (PRI) methods on corn plant characteristics. The study also tried to measure the water use efficiency (WUE) of corn in pot cultivation and provide the best method of management in the fields of irrigation and fertigation. For this purpose, three irrigation methods, including alternate partial root-zone irrigation (APRI), fixed partial root-zone irrigation (FPRI), and conventional irrigation (CI) were studied in pots, and completely randomized blocks with eight replications were carried out. Each pot was evenly separated with plastic sheets into two sub-parts of equal volume, between which no water exchange occurred. The water content of the field capacity was calculated by the weighting method. The water requirement was provided daily, equal to 95% of the field capacity water content. Parameters including shoot and root dry weight, nitrate (N) uptake, the remaining nitrate in the soil, leaf area index, and WUE during the growing season were measured and compared. According to the results, the amount of saved water using the FPRI and APRI methods compared to the CI method were 28% and 32%, respectively. The highest and lowest WUE were observed as equal to 4.88 and 3.82 g/L using the APRI and CI methods, respectively, among which the CI method had the highest yield according to the amount of utilized water. Given the statistical examinations, there was no significant difference in the nitrate level of plants between CI and APRI, and the lowest uptake was observed in FPRI. Finally, considering indicators of yield production and WUE simultaneously, the APRI method was selected as the best method of management. [ABSTRACT FROM AUTHOR]