Increased Root Mass Research Articles

Can silvopasture with arboreal legumes increase root mass at deeper soil layers and improve soil aggregation?

AbstractSilvopastoral system (SPS) is a multifunctional agroforestry practice. This study evaluate soil properties and root biomass under SPS in Pernambuco, Brazil. The experiment was established in 2011. The treatments were (1) monoculture signalgrass (MS) [Urochloa decumbens (Stapf.) R. D. Webster], (2) intercropped pasture of signalgrass with legume Gliricidia (SG) [Gliricidia sepium (Jacq.) Steud.], and (3) intercropped pasture of signalgrass with legume sabiá (SS) (Mimosa caesalpiniifolia Benth). Treatments were allocated in randomized complete block design with three replications. Samples were collected at 0‐ to 10‐, 10‐ to 20‐, 20‐ to 40‐, 40‐ to 60‐, 60‐ to 80‐, 80‐ to 100‐, and 100‐ to 120‐cm soil depths. Soil samples were also taken from the native forest (NF) considered as a reference at the same Experimental Station. Legume SPS (SG and SS) presented greater root biomass per unit area compared to MS at 60‐ to 80‐cm depth (p < 0.05); however, MS had greater root biomass per hectare at the top layers. The average values of the weighted mean diameter of soil aggregates were 3.20, 3.19, 3.07, and 3.27 mm in MS, SG, SS, and NF, respectively, at 0‐ to 120‐cm depths. The SPS increased soil cation exchange capacity in deeper layers, indicating greater biological activity at greater depth. Grasslands and SPS store 235 Mg C ha−1 with 71% of that found in deeper layers (20–120 cm). SPS with signalgrass intercropped with arboreal legumes has potential to improve deep soil C storage and resilience of livestock systems in tropical regions.

Time-Dependent and Coating Modulation of Tomato Response upon Sulfur Nanoparticle Internalization and Assimilation: An Orthogonal Mechanistic Investigation.

Nanoenabled strategies have recently attracted attention as a sustainable platform for agricultural applications. Here, we present a mechanistic understanding of nanobiointeraction through an orthogonal investigation. Pristine (nS) and stearic acid surface-modified (cS) sulfur nanoparticles (NPs) as a multifunctional nanofertilizer were applied to tomato (Solanum lycopersicumL.) through soil. Both nS and cS increased root mass by 73% and 81% and increased shoot weight by 35% and 50%, respectively, compared to the untreated controls. Bulk sulfur (bS) and ionic sulfate (iS) had no such stimulatory effect. Notably, surface modification of S NPs had a positive impact, as cS yielded 38% and 51% greater shoot weight compared to nS at 100 and 200 mg/L, respectively. Moreover, nS and cS significantly improved leaf photosynthesis by promoting the linear electron flow, quantum yield of photosystem II, and relative chlorophyll content. The time-dependent gene expression related to two S bioassimilation and signaling pathways showed a specific role of NP surface physicochemical properties. Additionally, a time-dependent Global Test and machine learning strategy applied to understand the NP surface modification domain metabolomic profiling showed that cS increased the contents of IA, tryptophan, tomatidine, and scopoletin in plant leaves compared to the other treatments. These findings provide critical mechanistic insights into the use of nanoscale sulfur as a multifunctional soil amendment to enhance plant performance as part of nanoenabled agriculture.

Seed priming attenuates the impact of salt stress and enhances lettuce yields

Salt stress is a major factor that contributes to reduced lettuce productivity. Seed priming has emerged as a promising technique to improve crop stress tolerance. In this study, Romaine lettuce seeds were primed with calcium chloride (CaCl2), distilled water (hydro), and potassium nitrate (KNO3) to test their effectiveness in improving salt stress tolerance. Lettuce seeds treated with hydro, 50 mM CaCl2, and 0.5% KNO3 were exposed to 0 or 100 mM sodium chloride (NaCl). Priming treatments significantly increased lettuce's fresh mass by 22%–61% under salt stress. Hydro-primed lettuce showed the most significant increase in root mass (109%), a 38% higher root length, a 35% increase in surface area, and a 25%–40% increase in volume, tips, forks, and crossings of roots. The hydro-primed lettuce had higher gas exchange rates than the non-primed control, followed by the KNO3- and the CaCl2-primed lettuce. Furthermore, hydro-primed seedlings exhibited the highest proline accumulation (105%) under salt stress. The accumulation of sugars (up to 50%) in hydro- and CaCl2-primed lettuce led to a 56% decrease in electrolyte leakage and membrane damage. The correlation network analysis of the traits revealed that hydro-primed seedlings exhibited a higher + ve/-ve edge ratio, which indicates their greater resilience to salt stress than other priming techniques. Priming of seeds before planting offers the potential for improving resilience to stress.

Inundation impacts on diversified pasture biomass allocation and soil particulate organic matter stocks

AbstractNatural soil inundation caused by frequent and intense precipitation affects carbon allocation in grassland biomass, ultimately leading to changes in soil carbon storage. Increasing forage diversity could provide resiliency to inundation of grassland. The objective was to evaluate forage and root biomass and C and N stocks in the soil particulate organic matter (POM) from pastures under recurring short‐term inundation. Three forage species combinations were evaluated in an inundated (typically lasting for a few days after heavy rain events) and a non‐inundated pasture: (1) predominantly tall‐fescue (Festuca arundinacea Schreb.); (2) mixture of cool‐season perennials composed of tall‐fescue, orchardgrass (Dactylis glomerata L.), bluegrass (Poa pratensis L.) and white (Trifolium repens L.) and red clover (Trifolium pratense L.); (3) and cool‐season mixture of perennials overseeded with oats (Avena strigosa Schreb.) and rye (Secale cereale L.). Roots and forage biomass were sampled during the growing seasons of 2021 and 2022. Soil POM was evaluated 2.5 years after establishment. Inundation reduced forage and root biomass mainly during periods of higher inundation frequency, leading to lower C‐POM stocks (p < .05). Inundation caused a shift in the forage botanical composition, that is, higher occurrence of weeds and less productive grass species with shallow roots. The perennial cool‐season mixture did not increase forage yield compared with tall fescue only but did increase root mass. This occurred mainly at deeper layers and, consequently, increased C‐POM stocks (p < .05). Overseeding of winter annuals reduced overall forage production, despite increasing spring biomass when inundated in the first year, but reduced C and N‐POM stocks (p < .05). Perennial cool‐season forage mixtures can increase the resilience of pastures to inundation events and contribute to increased carbon sequestration in grasslands where inundation is prevalent.

Vineyard soil texture and pH effects on Meloidogyne hapla and Mesocriconema xenoplax

AbstractNorthern root‐knot nematode (Meloidogyne hapla) and ring nematode (Mesocriconema xenoplax) are the most prevalent plant‐parasitic nematodes of wine grapes in the Pacific Northwest, but M. hapla is most important in eastern Washington and M. xenoplax in western Oregon. These regions differ edaphically where Washington soils are minimally weathered and alkaline while Oregon soils are highly weathered and acidic. To examine the effect of soil texture and pH on nematode reproduction, an alkaline, sandy loam soil (pH 7.9) from Washington and an acidic loam soil from Oregon (pH 5.4) were modified to the other pH extreme, and to a middle pH of 6.9. Tomatoes were planted into each soil/pH combination, and either 500 M. hapla second‐stage juveniles or M. xenoplax individuals were added to each pot. After 7 weeks, plants were harvested, three roots collected for analysis, remaining roots and leaves dried and weighed, and nematode population densities determined as eggs on roots (M. hapla) and nematodes in soil (M. xenoplax). Soil texture (sandy loam or loam) had no effect on either nematode, but M. hapla reproduction was greater in the lowest pH soil while M. xenoplax was unaffected by soil pH. Mesocriconema xenoplax parasitism reduced root length and root tip number, whereas M. hapla increased root mass in the highest pH Washington soil. Under these experimental conditions, it appears vineyard soil texture in the Pacific Northwest is not a determining factor in population growth of these nematodes, but M. hapla performed better at low pH.

Influence of a Hydrocarbon Biodestructor on the Growth and Content of Phytohormones in Secale cereale L. Plants under Petroleum Pollution of the Soil

The phytoremediation of soil contaminated with petroleum depends on the association of plants with rhizosphere bacteria capable of promoting plant growth and destroying petroleum hydrocarbonates. In the present work, we studied the effects of “Lenoil” biological product containing bacteria Pseudomonas turukhanskensis IB 1.1, capable of destroying petroleum hydrocarbons on Secale cereale L plants, which previously proved to be resistant to the weak oil pollution of gray forest soil and to the composition of microorganisms in their rhizosphere. The composition of microorganisms in the rhizosphere of rye roots was studied, morphometric parameters of shoots and roots of rye plants were estimated, and hormone concentration was immunoassayed under conditions of 4% petroleum pollution of the soil. Addition of petroleum to the soil increased the content of oligonitrophilic (by 24%) and hydrocarbon-oxidizing (by 33%) microorganisms; however, the content of cellulolytic (by 12.5 times) microorganisms in the rhizosphere decreased. The use of Lenoil led to a further increase in the number of cellulolytic (by 5.6 times) and hydrocarbon-oxidizing (by 3.8 times) microorganisms and a decrease in the number of oligonitrophilic (by 22.7%) microorganisms in the rhizosphere. Under petroleum pollution, the content of auxins (IAA), zeatin riboside, zeatin nucleotide, and zeatin decreased, while the content of abscisic acid (ABA) increased in the shoots of rye plants. Lenoil treatment led to an eight-fold increase in the IAA content in the roots and a decrease in the ABA content in the aerial part and in the roots. It was shown for the first time that the treatment of petroleum-contaminated soil with “Lenoil” increased root mass due to the development of lateral roots, concurrent with high root IAA content. Petroleum pollution increased the deposition of lignin and suberin in the roots, which strengthened the apoplastic barrier and, thus, reduced the infiltration of toxic components. The deposition of suberin and lignin decreased under ”Lenoil” treatment, indicating a decrease in the concentration of toxic petroleum components in the soil degraded by the bacteria. Thus, the biological preparation reduced the growth-inhibiting effect of petroleum on rye plants by increasing the content of growth-stimulating phytohormones (IAA and cytokinins) and reducing the content of ABA, justifying the importance of further study of relevant hormones for the improvement of phytoremediation.

Crop responses to application of optimum nitrogen fertilizers on soils of various fertilities formed from long-term fertilization regimes

How crops uptake synthetic nitrogen (N) applied to soils of differing fertilities formed from long-term fertilization regimes is a noteworthy scientific question that remains unclear. This is important for understanding nitrogen use efficiency (NUE) and N losses of synthetic N input to soils of different quality. Here, we investigated crop biomass, N uptake, root growth, and NUE in response to three synthetic N rates (including no N fertilizer, No-N; optimum N, Opt.-N; original N, Ori.-N) in long-term plots (since 2006), with various background fertilities induced by long-term fertilization regimes (nil N, optimum synthetic N, conventional synthetic N, and balanced synthetic N and manure) in a cropping system of winter wheat–summer maize rotation. When Opt.-N was applied, no significant differences in crop biomass between soils. However, N uptake by the crops on nil N soils was lower than that on N-fertilized soils. Crop biomass and N uptake in the nil N soils were significantly lower than those in the N-fertilized soils under No-N and Ori.-N supply, and no significant differences were observed between the N-fertilized soils. When Opt.-N was supplied to the nil N soils, grain yield and N uptake increased by 126–191% and 138–148%, respectively, compared with No-N. This change was associated with a large increase in root mass and root length density in the soils. In optimum synthetic N soils, the crop maintained a high yield (7.0–8.2 Mg ha−1) and N uptake (136–228 kg N ha−1) when they received continuous Opt.-N rate. Crop yield and N uptake significantly decreased when N fertilizer supply was ceased, indicating a low legacy effect; however, the long-term straw return alleviated the above decline. Conventional synthetic N soils with long-term excessive N application continued to maintain a comparable high yield (6.1–7.0 Mg ha−1) and N uptake (128–206 kg N ha−1) even after N fertilizer supply was stopped, indicating a high legacy effect. This effect could be applied with less N fertilizer to reduce N losses. Balanced synthetic N and manure could provide resistance to N fertilizer reduction and maintain high yield and soil fertility even after N fertilizer supply is ceased. Our results highlight the strong resilience of soils to crop productivity when resupplying N fertilizer to long-term nil N soils and the different legacy effects from historic fertilization regimes, while emphasizing that balanced synthetic N and manure is an ideal measure for sustainable N management.

Effects of bacterization on the development of Zea mays during droughts in the conditions of a vegetation experiment

Sustainable agriculture is a concept developed in the late 20th century to promote the production of crops using the biological capabilities of cultivated organisms while minimizing the human impact on agrocenoses. In recent years, the discovery of new types of bacteria that positively impact plant growth has opened up opportunities for the development of effective microbiological preparations and they offer promising prospects for adaptive crop production, enabling farmers to adjust to changing environmental conditions while reducing reliance on anthropogenic inputs. Corn, as the third most important grain crop after wheat and rice, is sensitive to a lack of moisture. Therefore, understanding the mechanisms of adaptation and resistance of this plant to drought remains an urgent task. The aim of the work was to determine the effect of bacterization of Zea mays ("Early gourmet 121") seeds by strains of rhizobacteria on the development of corn under conditions of artificial drought in a vegetation experiment. Strains of bacteria with known properties useful for plant growth and development were used – Bacillus cereus, Pseudomonas putida, Azospirillum brasilense and Azotobacter chroococcum. The study investigated the indicators of seedlings and the content of mono-, oligo-, and soluble sugars in the leaves and the activity of polyphenol oxidase in the roots. The results showed that bacterization of seeds with suspensions of P. putida led to an increase in the length of roots in plants grown under moisture deficit conditions and significantly affected the above-ground parts. Positive effects on the mass of the above-ground parts were observed when seeds were bacterized with suspensions of P. putida, A. chroococcum and a mixture of bacterial suspensions and grown under sufficient irrigation. A similar positive effect occurred when seeds were bacterized only with a mixture of suspensions of the tested bacteria under drought conditions. Bacterization of corn seeds with P. putida or A. brasilense resulted in increased root mass and sugar accumulation in leaves when growing seedlings under conditions of moisture deficit. Additionally, inoculation of P. putida or A. chroococcum seeds increased the activity of polyphenol oxidase enzyme in seedling roots. While the bacteria showed a positive impact on corn development under some conditions, this effect was not observed when there was sufficient moisture. Therefore, we believe that a more promising approach for developing biological preparations based on beneficial microorganisms is to explore combinations of multiple soil bacteria strains. By identifying a mix of bacteria that can effectively stimulate plant growth in both stressed and favourable conditions, we can maximize the potential benefits for crop production. Such combinations of bacteria may enhance plant growth and yield not only during drought stress but also under optimal conditions, providing a more robust and reliable solution for crop management.

Establishment of alfalfa interseeded into corn in response to one cycle of selection and hybridization

AbstractIntercropping alfalfa (Medicago sativa L.) in corn (Zea mays L.) can improve forage production, but wet growing conditions and high corn yields adversely impact alfalfa establishment. Therefore, we evaluated breeding alfalfa specifically for intercropping by selecting surviving plants from previous alfalfa varietal evaluations under corn and assigning them to five polycrosses to form cycle‐1 synthetics. Pollen from four polycrosses was also used to generate hybrid seed using a male‐sterility system. Corn was planted in May, intensively managed, and harvested for silage during September at Arlington and Prairie du Sac Wisconsin during 2019. Parental, polycross, and hybrid alfalfa entries were interseeded as swards between corn rows. Two subplots within each whole plot were treated with prohexadione, fungicide, and insecticide (PFI) or left as nontreated controls. Competition from high yielding corn combined with 43% above average precipitation during the growing season contributed to complete stand failure of nontreated alfalfa. Application of PFI improved foliar health, increased root mass, and enabled alfalfa establishment. Following corn silage harvest average stand density of PFI‐treated polycross entries was 35% greater than parental entries (105 vs. 78 plants m−2); broad‐sense heritability was 0.54. Overall, PFI‐treated polycross and hybrid entries had similar stand densities after corn, but posthoc comparisons indicated two hybrids had twofold greater stand density than parental entries. These results indicate plant selection can be highly effective for developing polycross and hybrid germplasm with improved survival under corn. Our findings should stimulate further breeding work to improve alfalfa and other forages for use in intercropping systems.

Natural selection under conventional and organic cropping systems affect root architecture in spring barley

A beneficial root system is crucial for efficient nutrient uptake and stress tolerance. Therefore, evaluating the root system variation for breeding crop plants towards stress adaptation is critically important. Here, we phenotyped root architectural traits of naturally adapted populations from organic and conventional cropping systems under hydroponic and field trails. Long-term natural selection under these two cropping systems resulted in a microevolution of root morphological and anatomical traits. Barley lines developed under an organic system possessed longer roots with narrow root angle, larger surface area, increased root mass density, and a thinner root diameter with an increased number of metaxylem vessels. In contrast, lines adapted to the conventional system tend to have a shorter and wider root system with a larger root volume with a thicker diameter but fewer metaxylem vessels. Allometry analysis established a relationship between root traits and plant size among barley genotypes, which specifies that root angle could be a good candidate among studied root traits to determine root-borne shoot architecture. Further, multivariate analyses showed a strong tendency towards increased variability of the organically adapted population's root morphological and anatomical traits. The genotyping of ancestor populations validated the observations made in these experiments. Collectively, this results indicate significant differences in root phenotypes between conventional and organic populations, which could be useful in comparative genomics and breeding.

ESTIMATION OF YIELD OF TABLE BEET FOR USE OF BIOLOGICAL PREPARATIONS IN THE CONDITIONS OF THE FOREST-STEPPE OF THE RIGHT BANK OF UKRAINE

The results of researches of influence of biological preparations on biometric parameters of plants and productivity of table beet are resulted. The influence of biological preparations on the phases of growth and development of table beet plants, its yield and biometric parameters of products is established. Treatment of plants with the biological complex Organic Balance + Azotophyte + Liposomes accelerated the phenological phases of growth and development of table beet plants. As a result of measuring the height of plants, an increase in control over the treatment of plants with biological products was detected, in particular in the variety Red Ball Organic Balance + Azotophyte + Liposam provided an increase of 1.0 cm relative to control. The increase in plant height in the Pablo F1 hybrid was 2.2 cm with the use of Organic Balance + Azotophyte + Liposam. The largest number of leaves was observed for the treatment of plants Organic Balance + Nitrogen + Liposomes: in the variety Red Ball growth relative to the variant without treatment was 2.3 pcs / plant, in the hybrid Pablo F1 - 2.8 pcs / plant. Treatment of plants Organic Balance + Azotophyte + Liposam contributed to an increase in leaf area by 0.09 dm2 / plant in the variety Red Ball, 0.22 dm2 / plant in the hybrid Pablo F1. The use of Humifrend + Azotofit + Liposam also contributed to the increase of this indicator with an increase relative to the controls of 0.06 and 0.15 dm2 / plant, respectively. The influence of biological preparations on the biometric parameters of plants was established in the phase of intensive root growth. The largest biometric parameters in the phase of intensive root growth were recorded during the treatment of plants Organic Balance + Azotophyte + Liposam. In particular, the height of plants treated with Organic Balance + Azotophyte + Liposam increased by 2.2 and 3.1 cm compared to the untreated options. A slightly smaller increase in this indicator was recorded for treatments of plants Humifrend + Azotofit + Liposam - 0.8 and 1.0 cm, respectively. The number of leaves also increased during the treatment of plants with biological products. In the Pablo F1 hybrid, this figure was higher than the Red Ball variety - 16.0 - 18.7 units / plant. The use of Organic Balance + Azotophyte + Liposam provided an increase in the number of leaves by 2.8 pcs / plant relative to control, for the treatment of plants Humifrend + Azotophyte + Liposam increase was 1.8 pcs / plant. The positive effect of the use of biologicals was observed taking into account the area of leaves. With the use of Organic Balance + Azotophyte + Liposam, this figure in the studied varieties and hybrids increased by 0.8-1.3 thousand m2 / ha, respectively, compared with the control. Slightly less growth of this indicator was observed for the treatment of plants Humifrend + Azotofit + Liposam 0.3-0.7 thousand m2 / ha, respectively. The highest indicators of biometric parameters of plants were observed in the hybrid Pablo F1 for plant treatment Organic Balance + Azotophyte + Liposam, where the increase in plant height was 0.7-1.2 cm, the number of leaves - 1.8-2.1 pcs / plant, leaf area - 0.8-1.1 thousand m2 / ha, respectively. The highest yields were recorded with the application of Organic Balance + Nitrogen + Liposomes: in the Red Ball variety the increase was 7.1 t / ha, in the Pablo F1 hybrid - 10.3 t / ha relative to control. A positive effect was also obtained with the application of Humifrend + Azotofit + Liposam, where the increase was 4.9 and 8.4 t / ha, respectively. Treatment of plants with a complex of biological preparations Organic Balance + Azotophyte + Liposam provided an increase in root mass in the variety Red Ball - 45 g, in the hybrid Pablo F1 - 30 g, respectively. During the treatment of plants Humifrend + Azotofit + Liposam the increase was 30 g - variety Red Ball and 25 g - hybrid Pablo F1. Indicators, the diameter of the root crop was in the range of 8.4 and 9.0 cm. 5 cm. The increase in root diameter with the use of Humifrend + Azotofit + Liposam was slightly smaller and amounted to 0.1-0.3 cm. plants Humifrend + Azotofit + Liposam contributed to an increase in this indicator relative to control by 0.3-0.2 cm

Improving yield and health of legume crops via co-inoculation with rhizobia and Trichoderma: A global meta-analysis

Trichoderma is a genus of fungi used for biocontrol and plant growth promotion; however, effects of co-inoculation with rhizobia in legumes still require detailed analysis. This study conducted a global meta-analysis of 59 published studies (1992–2021) on co-inoculation of legumes with rhizobia and Trichoderma spp. to assess factors affecting the efficiency of plant growth compared to inoculation exclusively with rhizobia. Co-inoculation favored plants by reducing disease incidence (−44%) and increasing root mass (+17%), nodule number (+32%), nodule mass (+37%), nodule nitrogenase activity (+35%), shoot nitrogen content (+8%), and grain yield (+14%). Co-inoculation of legumes can decrease root diseases caused by Fusarium spp., Rhizoctonia spp., Macrophomina phaseolina, Pythium debaryanum and Sclerotium rolfsii and also has potential as a plant growth promoter regardless of plant health. Positive effects of co-inoculation on grain yield and root mass were observed under the majority of the factors evaluated (e.g., legume species, microorganisms, co-inoculation methods, experimental conditions, plant health status, and edaphic factors). Co-inoculation with rhizobia and Trichoderma spp. may contribute to sustainable intensification of legume production systems due to multiple plant benefits under a wide range of conditions.

Bacillusvelezensis Strains for Protecting Cucumber Plants from Root-Knot Nematode Meloidogyne incognita in a Greenhouse.

Meloidogyne incognita Kofoid et White is one of the most dangerous root-knot nematodes in greenhouses. In this study, we evaluated two Bacillus strains (Bacillus velezensis BZR 86 and Bacillus velezensis BZR 277) as promising microbiological agents for protecting cucumber plants from the root-knot nematode M. incognita Kof. The morphological and cultural characteristics and enzymatic activity of the strains have been studied and the optimal conditions for its cultivation have been developed. We have shown the nematicidal activity of these strains against M. incognita. Experiments with the cucumber variety Courage were conducted under greenhouse conditions in 2016–2018. We determined the effect of plant damage with M. incognita to plants on the biometric parameters of underground and aboveground parts of cucumber plants, as well as on the gall formation index and yield. It was found that the treatment of plants with Bacillus strains contributed to an increase in the height of cucumber plants by 7.4–43.1%, an increase in leaf area by 2.7–17.8%, and an increase in root mass by 3.2–16.1% compared with the control plants without treatment. The application of these strains was proved to contribute to an increase in yield by 4.6–45.8% compared to control. Our experiments suggest that the treatment of cucumber plants with two Bacillus strains improved plant health and crop productivity in the greenhouse. B. velezensis BZR 86 and B. velezensis BZR 277 may form the basis for bionematicides to protect cucumber plants from the root-knot nematode M. incognita.

ADAPTABILITY OF BEETROOT VARIETIES IN CONDITIONS OF CLIMATE CHANGE

According to the results of the research, the influence of water-retaining granules on the biometric parameters of beetroot plants was revealed, in particular, an increase in the assimilation surface area was noted. The highest height of beetroot plants was observed in the Bordo Kharkivskiy variety for the application of water-retaining granules – 33.4 cm, which is 4.9 cm more than in the variant without granules. A positive effect of the use of water-retaining granules was also observed in the Opolskiy variety, where the increase was 3.7 cm compared to the variant without granules. The lowest figure was in the variety Opolskiy without pellets – 22.1 cm. An important indicator in the biometric evaluation of beet varieties is the weight of the root crop. It was the largest in the options for the introduction of water-retaining granules: in the Bordo Kharkivskiy variety growth relative to control was – 6.5 g, in the Opolskiy variety – 7.6 g. Biometric measurements also showed an increase in the mass of the aboveground part of the plants with the introduction of water-retaining granules by 5.4 and 4.9 g, respectively. A higher percentage of the mass of the root in relation to the total mass of the beetroot plant in phase 5 of a pair of true leaves was obtained in the variety Opolskiy – 57.6 – 58.6 %. In the phase of intensive root formation, the highest plant height was recorded in Bordo Kharkivskiy varieties and Opolskiy with the use of water-retaining granules, where the increase was 3.2 cm relative to the control. The same pattern was observed when determining the number of leaves on the plant, where the increase was – 3.5 – 3.2 pieces / plant. An increase in root mass was observed with the introduction of water-retaining granules by 3.3 and 4.0 g, respectively. In the Bordo Kharkivskiy variety the weight of the aboveground part was higher compared to the weight of the root crop, while in the Opolskiy variety the opposite weight of the root crop was observed, the indicator of which was 55.3 – 56. % of the total weight of the plant. Measurements of the area of beet leaves showed that this figure depended on the variety and use of water-retaining granules. In the phase of root moult, the larger leaf area was with the use of water-retaining granules 1.3 – 1.6 thousand m2 / ha, which is more than the control options by 0.3 – 0.4 thousand m2 / ha. The largest leaf area was recorded in the phase of intensive root formation in all studied variants. In the variants where water-retaining granules were used, the increase was 0.5 thousand m2 / ha in the Bordo Kharkivskiy variety, 0.3 thousand m2 / ha in the Opolskiy variety. In the phase of technical maturity of beetroot plants, a decrease in leaf area relative to the phase of intensive root formation was observed. However, the highest figure was in the options with the introduction of water-retaining granules. The use of water-retaining granules provided an increase in yield by 23.0 – 17.5 t / ha relative to controls. The Bordo Kharkivskiy variety was characterized by a larger diameter of the root crop – 7.5 – 8.4 cm, which is 2.9 – 2.6 cm larger than the Opolskiy variety, respectively. However, the plants of the Opolskiy variety showed a longer root length relative to the Bordo Kharkivskiy variety by 4.8 – 6.0 cm, respectively. Water-retaining granules contributed to the increase in root mass, where the increase was in the variety Bordo Kharkivskiy – 83.0 g, in the variety Opolskiy – 63.0 g

Siliceous and non‐nutritious: Nitrogen limitation increases anti‐herbivore silicon defences in a model grass

Abstract Silicon (Si) accumulation alleviates a diverse array of environmental stresses in many plants, including conferring physical resistance against insect herbivores. It has been hypothesised that grasses, in particular, utilise ‘low metabolic cost’ Si for structural and defensive roles under nutrient limitation. While carbon (C) concentrations often negatively correlate with Si concentrations, the relationship between nitrogen (N) status and Si is more variable. Moreover, the impacts of N limitation on constitutive physical Si defences (e.g. silica and prickle cells) against herbivores are unknown. We determined how N limitation affected Si deposition in the model grass Brachypodium distachyon and how changes in these constitutive defences impacted insect herbivore Helicoverpa armigera growth rates. We used scanning electron microscopy (SEM) and energy dispersive X‐ray spectrometry in conjunction with X‐ray mapping (XRM) to quantify physical structures on leaves and determine Si deposition patterns. We also determined how N limitation and Si supply impacted the jasmonic acid (JA) pathway, the master regulator of induced defences against arthropod herbivores. N limitation reduced shoot growth by over 40%, but increased root mass (+21%), leaf Si concentrations (+50%) and the density of silica (+28%) and flattened prickle (+76%) cells. Energy‐dispersive X‐ray spectroscopy and XRM established that Si was being deposited in these structures, together with hooked prickle cells and macro‐hairs. Herbivore relative growth rates (RGR) were more than 115% lower in Si‐supplied plants compared to plants without Si supply and negatively correlated with leaf Si concentration and silica cell density. RGR was further reduced by N limitation and positively correlated with leaf N concentrations. Increases in JA concentrations following induction of the JA pathway were at least doubled by N limitation. Synthesis. Si accumulation and deposition were highly regulated by N availability, with N limitation promoting both constitutive Si physical defences and induction of the JA defensive pathway, in line with the resource availability hypothesis. These results indicate that grasses use ‘low‐cost Si’ when resources are limited and suggest that plant productivity may benefit from optimising conventional fertilisers and Si fertilisation.

Microorganisms in the biological control of root-knot nematode: A metanalytical study

Nematodes can cause annual losses in the order of 100 billion dollars in crops worldwide. Its control using chemical nematicides proves to be quite aggressive to the environment. For this reason, the management of microorganisms has been promising. However, it is essential to know the control potential of each organism. Thus, the objective of this study was to verify the efficiency of different microorganisms in the biological control of Meloidogyne sp. A systematic review of the literature was carried out from 2000 to 2020 with the keywords “Meloidogyne and biology control", resulting in 659 articles, of which 51 were pre-selected and, after the more detailed evaluation, was selected ten published articles. These ten articles generated a total of 83 studies for meta-analyses. Each study included a treatment group using some microorganisms (bacteria, fungus, actinomycetes) for nematode biocontrol, a control group without using biocontrol agents. From this meta-analysis, we can observe that the use of microorganisms decreased the number of galls (42.05%), the number of eggs (57.77%), the gall index (28.58%) and the eggs mass (53.48%). The use of microorganisms was also positive in increasing root mass (832.89%). We can conclude that the use of microorganisms proved to be efficient in controlling nematodes M. javanica and M. incognita. The fungi Pleurotus ostreatus and Phanerochaete chrysosporium have more significant potential for biocontrol for these species.

Meta-analysis reveals benefits of co-inoculation of soybean with Azospirillum brasilense and Bradyrhizobium spp. in Brazil

Co-inoculation of soybean with Azospirillum brasilense and Bradyrhizobium spp. is an increasing practice in Brazil, but little is known about the conditions that maximize crop efficiency. In this study, data from field experiments run between 2009 and 2020 in Brazil were gathered to evaluate which environmental and agronomic conditions affect the response of soybean to bacterial co-inoculation. Results showed that co-inoculation of soybean increased root mass in 11%, nodule number in 5.4%, nodule mass in 10.6%, N concentration in shoots in 2.8%, grain yield and N concentration in grains in 3.2% and 3.6% respectively compared to the conventional single inoculation with Bradyrhizobium spp. Grain yield was used to discriminate co-inoculation efficiency, and soybean was more responsive to the simultaneous inoculation with B. japonicum and B. diazoefficiens in sandy soils, non-tillage system, tropical climate, soybean cultivars with determinate growth habit, and grain yield class lower than 3500 kg ha−1. Co-inoculation can also be important to mitigate the effects of water stress on plants. Co-inoculation of soybean with A. brasilense and Bradyrhizobium spp. demonstrated to be an efficient technology that contributes to the sustainability of soybean production.

Biochar co-applied with organic amendments increased soil-plant potassium and root biomass but not crop yield

Purpose: Biochar can improve soil nutrient retention and alleviate salinity; however, use is not widespread due to cost. Biochar is usually co-applied with a full-rate of supplementary fertiliser before planting. This study investigated co-application of bamboo biochar with organic fertiliser and amendments on nutrient cycling, plant growth, yield and commercial value of ginger. Methods: Four treatments were applied including no amendment, organic amendments and organic amendments co-applied with biochar at two applications rates of 10 t ha−1 and 30 t ha−1. Plant growth, biomass, foliar nutrient and water-extractable soil nutrients were examined. Results: Co-applied high rate biochar increased available soil potassium (K) concentration (+ 89%) over 22 weeks and led to increased foliar K concentration (+ 25%) at harvest and after 30 weeks compared with organic amendments alone. Biochar high rate decreased soil sodium concentration (− 22%) over 22 weeks. Biochar high rate increased root mass fraction and plant height but decreased the number of stems, and therefore, did not increase aboveground biomass compared with all other treatments. In contrast, ginger rhizome yield, grade and commercial value were not affected by biochar treatments. Conclusion: Added biochar provided additional net K that improved foliar concentration late in the growing season following dissolution. The additional K supply then stimulated root growth and biomass re-allocation despite daily irrigation throughout the growing season. Therefore, we suggest biochar as a useful amendment to prevent nutrient loss and alleviate salinity for organic crops.

Cotton/halophytes intercropping decreases salt accumulation and improves soil physicochemical properties and crop productivity in saline-alkali soils under mulched drip irrigation: A three-year field experiment

Abstract Soil salinization has become a severe threat deteriorating soil quality and restricting sustainable agricultural development in arid and semi-arid areas. The objective of this study was therefore to propose a new cotton/halophytes intercropping system [such as cotton/Suaeda salsa intercropping (CSSI) and cotton/alfalfa intercropping (CAI) systems] to improve soil salinization and crop production based on the traditional monoculture cotton (MC). A three-year field experiment was conducted to explore the effects of the MC, CSSI, and CAI systems on soil salt accumulation, salt removal, soil physicochemical properties, root mass density, aboveground biomass, seed cotton yield, and irrigation water productivity (IWP). Experiment treatments consisted of three cropping systems: MC, CSSI, and CAI systems, respectively. All treatments were designed using a randomized complete block with three replications. The result indicated that the CSSI and CAI systems could decrease soil EC1:5, salt accumulation, bulk density, Na+ content, and pH in no mulch strips and increase salt removal, soil porosity, and organic carbon content compared with the MC system. Compared with the MC system, the CSSI system increased root mass density in 0−20 cm soil depth. No significant differences in seed cotton yield and IWP were found among the MC, CSSI, and CAI systems in 2014. However, total aboveground biomass, seed cotton yield, and IWP were significantly higher in the CSSI and CAI systems than that of the MC system in 2015 and 2016. This study suggested that the cotton/halophytes intercropping system showed greater salt removal and crop productivity than the MC system. Therefore, the CSSI and CAI systems should be recommended as a long-term agronomic remediation method for improving soil salinization and increasing cotton yield in the arid area of northwest China.

THE EFFECTS OF WATERING RATES USING THE DRIP IRRIGATION METHOD ON THE ROOT MASS GROWTH OF BIRD’S NEST FERNS

The increasing demands of gardeners have made peat moss a popular option as a planting material. However, the price of peat moss has increased recently. Therefore, alternative substances for use as a planting material need to be studied. The root of the bird’s nest fern offers a cheaper, easier to produce and more readily available source for a planting material than peat moss. The objective of this research was to increase root mass growth by using drip irrigation. With an experimental design using CRD, two-year old bird’s nest ferns with root mass sizes of 5 inches were watered by means of a drip irrigation method at rates of 200, 400, 600, 800 and 1,000 ml every 3 days. The data measured were root mass height, root mass diameter, leaf length, leaf width and canopy width. The data were analyzed by ANOVA and the differences between the means of treatment were compared by DMRT. The research found that the ferns which received water at a rate of 800 ml produced a root mass height of 11.06 cm and a root mass diameter of 11.93 cm. They were significantly different (p<0.05). The ferns which received water at a rate of 200 ml produced a leaf length of 29.52cm and a leaf width of 9.55 cm. The amount of water causes fern growth to significantly different (p<0.01). The 800 ml rate of drip irrigation also produced the largest canopy width of 48.12 cm.