Bean Shoot Research Articles

Species interactions and bacterial inoculation enhance plant growth and shape rhizosphere bacterial community structure in faba bean – wheat intercropping under water and P limitations

Grain legumes / cereals intercropping systems with microbial inoculants, hold promise for improving crop productivity under stressful conditions. However, the tripartite interaction involving intercropping system, associated microbiota and stress combining water deficit and low phosphorus (P) availability remains understudied. This study evaluated the impact of three bacterial consortia (C4, C6, and Cref containing Rhizobium and PSB strains) including single Rhizobium (Rhizobium laguerreae) on the agro-physiological performance of wheat (Triticum durum) and faba bean (Vicia faba) grown as intercrops or sole-crops under P and water deficient conditions. Inoculation, especially with C6, significantly improved shoot and root biomasses of both wheat (up to 66 and 81 %) and faba bean (up to 54 and 266 %) intercrops compared to single Rhizobium inoculation and control treatments. Intercropping generally outperformed sole-cropping in above-ground physiology, root morphological traits, shoot and root P content, with a notable effect in response to C6 exhibiting low microbial biomass P. Changes in bacterial community structure were primarily driven by cropping pattern and water regime rather than bacterial inoculation. Intercropping maintained bacterial diversity but shifted community structure, favoring Proteobacteria. Overall, inoculating intercropped wheat and faba bean with Rhizobium-containing consortia induced beneficial below-ground interspecies interactions under water and P-limiting conditions.

Biochar addition and reduced irrigation modulates leaf morpho-physiology and biological nitrogen fixation in faba bean-ryegrass intercropping

Intercropping legume with grass has potential to increase biomass and protein yield via biological N2-fixation (BNF) benefits, whereas the joint effects of biochar (BC) coupled with deficit irrigation on intercropping systems remain elusive. A 15N isotope-labelled experiment was implemented to investigate morpho-physiological responses of faba bean-ryegrass intercrops on low- (550 °C, LTBC) or high-temperature BC (800 °C, HTBC) amended sandy-loam soil under full (FI), deficit (DI) and partial root-zone drying irrigation (PRD). LTBC and HTBC significantly reduced intrinsic water-use efficiency (WUE) by 12 and 14 %, and instantaneous WUE by 8 and 16 %, respectively, in faba bean leaves, despite improved photosynthetic (An) and transpiration rate (Tr), and stomatal conductance (gs). Compared to FI, DI and PRD lowered faba bean An, gs and Tr, but enhanced leaf-scale and time-integrated WUE as proxied by the diminished shoots Δ13C. PRD enhanced WUE as lower gs, Tr and guard cell length than DI-plants. Despite higher carbon ([C]) and N concentration ([N]) in faba bean shoots amended by BC, the aboveground C- and N-pool of faba bean were reduced, while these pools increased for ryegrass. The N-use efficiency (NUE) in faba bean shoots was reduced by 9 and 14 % for LTBC and HTBC, respectively, but not for ryegrass. Interestingly, ryegrass shoots had 52 % higher NUE than faba bean shoots. The N derived from atmosphere (% Ndfa) was increased by 2 and 9 % under LTBC and HTBC, respectively, while it decreased slightly by reduced irrigation. Quantity of BNF in faba bean aboveground biomass decreased with HTBC coupled with reduced irrigation, mainly towards decreased biomass and soil N uptake by faba bean. Therefore, HTBC might not be a feasible option to improve WUE and BNF in faba bean-ryegrass intercropping, but PRD is permissible as the clear trade-off between BC and PRD.

A new functional food product – microgreen vegetable beans – feature and nutritional properties

Microgreens are valued for their freshness and refined taste, and by adherents of a healthy diet – for their saturation with vitamins, trace elements, antioxidants, enzymes and valuable protein. The product enjoys steadily growing demand not only in the production segment (restaurants, cafes, supermarkets), but also in home cultivation – «vegetable garden on the window». Among vegetable crops, vegetable pea micro-greens are very popular, especially varieties with a mustachioed leaf type. It is this product that helps culinary masters to give products bright visual and taste accents. Few people know that among legumes, in addition to vegetable peas, there is an excellent alternative with no less nutritional value. This is a micro-green of vegetable beans. Bean shoots are more fleshy and juicy, crispy, sweet with a nutty taste, and most importantly, absolutely everyone can grow them. Obtaining microgreens from vegetable bean culture is a promising direction, since its nutritional value and biochemical composition are comparable to the microgreens of vegetable peas. The content of the main nutrients on average for the studied varieties of breeding of the Federal State Budgetary Scientific Institution Federal Scientific Vegetable Center (FSBSI FSVC) is: protein – 20-35% (dry weight), ascorbic acid – 0,51 mg/g, carotenoids – 0,48 mg/g, monosaccharide – 1,15%, dry matter – 10,62%. However, vegetable beans have an undeniable advantage in cultivation – it is the possibility of using up to two or three cuts from one crop, due to the ability to form additional shoots when using the method of cutting under the «root». The yield from the container when sowing 100 seeds obtained in two cuts ranged from 320 g to 400 g, depending on the variety and method of cutting. The highest yield was obtained from the cv. Velena, which forms about 200 g of fresh shoots both in the first and second cut. According to the results of our research, it is recommended to use two cuts for the cv. Belorusskie and cv. Russkie chernye, while the cv. Velena is able to give a full-fledged microgreen even with the third cut.

Shoot and Root Responses of Mung Bean (Vigna radiata L.) to Phosphorus Fertilizer Placement with Different Potassium Sources

ABSTRACT Mung bean (Vigna radiata L.) is a major pulse crop in many parts of the world, but its yields are generally lower than other pulse crops due to biotic and abiotic stresses, including nutrition. An experiment was conducted to examine the effects of localized application of phosphorus (P) (32P labeled P fertilizer) and different sources of potassium (K) (KNO3, KCl, K2SO4 and KH2PO4) on shoot and root growth of mung bean, nutrient uptake and applied P and K recovery on a sandy loam Yellow Chromosol soil with low P and K status. Among the K sources highest shoot and root yield was obtained with K2SO4. Similarly, total plant P and the percentage of total P content obtained from the fertilizer (Pdff) was highest in this treatment. P application resulted in an increase in root length/soil mass, root mass density both inside and outside the band and in the percentage of roots in the fertilizer band. Each of the above parameters was numerically highest in the P+K2SO4 surface applied treatment. Root growth in the banded P resulted in better mung bean growth and nutrient uptake which was associated with stimulated root growth in the band and/or through increased uptake of P per unit root length. Co-application of K with P did not stimulate P uptake. Since co-application of P and K did not result in a synergistic response to either nutrient separation of these nutrients can be practiced.

Inhibitory Effect of Cadmium on the Growth of Mung Bean (Vigna radiata (L.) R. Wilczek) and the Removal by Chelating Agent

This research studied the effect of cadmium (Cd) on the growth of mung bean (Vigna radiata (L.) R. Wilczek). The mung bean was cultured in a Hoagland solution containing different concentrations of Cd (0, 0.1, 0.3 and 0.5 mg/L) for 5 days. The result showed a significant decrease in the lengths of the roots and shoots of mung bean that was grown in cadmium solution. This effect was proportional to the concentrations of Cd. To assess cell death in the root of mung bean, Evan’ s blue staining technique was used in this study. The results showed that the concentrations of Evan's blue dye taken up by Cd-exposed mung beans at 0.1, 0.3, and 0.5 mg/L were 1.5612 ± 0.5417, 6.8641 ± 1.7447, and 8.0850 ± 2.6336 mg/L, respectively. A concentration-dependent increase of dead cellswas found in the Cd-treated group, mostly at the root cap zone. With respect to this result, the level of dead cells that was stained with Evan’s blue dye could be used as a biomarker to indicate cadmium contamination in water. Furthermore, the effects of chelating agents (EDTA) on cadmium removal were also studied. The results showed the possibility of using EDTA as a cadmium treatment agent and promoted plant growth in cadmium contamination areas.

Selenium nanoparticles reduce Ce accumulation in grains and ameliorate yield attributes in mung bean (Vigna radiata) exposed to CeO2

Exposure of crops to CeO2 nanoparticles (nCeO2) in agricultural environments impact crop quality and human health. In this regard, the effects of selenium nanoparticles (nSe) on the yield and quality of Vigna radiata (L.) exposed to nCeO2 were investigated. The experiment was carried out as a factorial with two factors: NPs (nCeO2, and nSe) as factor one and concentrations as factor two [(0, 250, 500 and 1000 mg/L nCeO2; 0, 25, 50 and 75 mg/L nSe)]. Nanoparticles were foliar applied to 45-day old mung bean shoot in two steps and one-week interval. At 250–1000 mg/L, nCeO2 increased P, protein and Ce accumulation in grain. Additionally, at 1000 mg/L, the nCeO2, significantly decreased seed number, yield, Fe, and Zn storage in seeds. Conversely, at 25 and 50 mg/L, nSe stimulated the growth and yield of mung bean, and significantly increased P, Fe, Zn, and Se in seeds, but reduced the protein content in seeds. The Se25+Ce250 and Se50+Ce250 significantly increased pod number, seed number, grain weight, yield, Fe, Zn and Se storage in grains. In contrast, the Ce accumulation in seeds decreased in all combination treatments (nCeO2 + nSe) compared to their respective single nCeO2 treatments. Moreover, in the plants exposed to high nCeO2 concentrations, nSe application resulted in undamaged vacuoles, less starch granules' accumulation, significant yield improvement, and elevated Fe, Se, and Zn in seeds. Data suggest that selenium nanoparticles prevent nCeO2 stress in mung bean and improve grain production and quality.

EFFECT OF INOCULATING Bradyrhizobium liaoningense ON GROWTH, CHLOROPHYLL CONCENTRATION, NODULATION AND YIELD OF SOYA BEANS

Soya bean is important staple food crops in Western Kenya. Legumes play a significant role in agriculture by fixing nitrogen. Currently Kenya is experiencing low yield of soya beans. Approximately 0.8 t/ha is under production and this is due to low soil fertility. This has posed a threat to agricultural productivity. Symbiotic rhizobia inoculation increases crop yields through biological nitrogen fixation. However, the potential of Bradyrhizobium liaoningense in improving yield and productivity of soya beans has not been documented. Rhizobia bacteria are known to improve growth and yield of several other crops but the effect of inoculating soya beans with B. liaoningense on growth, chlorophyll concentration, nodulation and yields has not been determined. This study was conducted at Maseno University under greenhouse conditions. Previously purified local isolates of B. liaoningense (S3) from wild soya beans plants were used to inoculate the soya bean seeds. 4.5 litre plastic pots were filled with 7kg of top soil. Ten seeds of Soya beans coated with Bradyrhizobium liaoningense inoculants were sown in each pot except the control. The seeds were treated with the isolates inoculants as: un-inoculated (control), 1.07x107 cfu/ml, 1.19x107 cfu/ml, 1.31x107 cfu/ml and 2.67x107 cfu/ml inoculation of B. liaoningense. The experiment was laid out as Completely Randomised Design (CRD). The treatments were replicated three times. After two weeks of germination, the seedlings were thinned to three plants per pot. Watering was done daily with 200 ml of water per pot up to the end of the experiment. Data on plant height, number of leaves, leaf area, shoot and root fresh weight and dry weight, chlorophyll concentration, number of nodules and number of pods were determined. Data was subjected to Analysis of Variance (ANOVA). Treatments means were separated using Fisher’s Least Significant Difference at (P = 0.05). Soya bean growth, chlorophyll concentration, number of nodules and number of pods after inoculation treatments were significantly different among the treatments (P ≤ 0.05). Plant height, number of leaves and leaf area were highest in 2.67 x 107 cfu/ml of B. liaoningense inoculation followed by 1.31x 107 cfu/ml inoculation, 1.19x107 cfu/ml, 1.07x107 cfu/ml and lowest in un-inoculated. Inoculation at 2.67 x 107 cfu/ml significantly increased soya bean root and shoot fresh weight and dry weights. Chlorophyll concentration was found to be highest in 2.67 x 107 cfu/ml treatment and lowest in un-inoculated control treatment. Inoculation at 2.67 x 107 cfu/ml increased the number of nodules of soya beans. Number of pod per plant were highest at 2.67 x 107 cfu/ml treatment and lowest in un-inoculated (control treatment). These findings showed that B. liaoningense inoculation was effective in enhancing growth, chlorophyll synthesis, formation of root nodules and pods in soya beans. From the study it can be recommended that B. liaoningense from wild soya bean may be used as a biofertiliser to improve productivity of soya beans by smallholder farmers in Kenya.

Nutritional and biological value of natural-bio shoots mung bean “Mungoltin”. Food and biological values

Based on the results of our own research, examination of scientific dossier materials and reference literature data, it was established that dry powder Mungoltin made from the shoots of mung beans produced by Oriona-Scorpion LLC (Uzbekistan) contains a sufficient amount of protein, minerals, vitamins and dietary fiber, does not have a negative impact on the health status of experimental animals and does not result in functional and material cumulation. Acute systemic toxicity testing with intragastric administration of Mungoltin was carried out in 18 adult white male rats. Animals were divided into 4 groups. The animals of the first group received a nutrition dose of 5000 mg/ kg; the white rats of the second group were administered with a dose of 7500 mg/kg, and the rodents in the third group were given a dose of 10000 mg/kg, respectively. The animals in group 4 (the reference group) received distilled water. Upon a prolonged intragastric exposure to Mungoltin, no changes in biochemical parameters were detected. The activity indicators of alkaline phosphatase, trans-aminase enzymes and total protein in the blood serum did not differ significantly from those found in the reference group. Therefore, using Mungoltin will not cause a cytotoxic effect in relation to normal highly proliferating cells in an organism. The results of histomorphological studies of tissues of internal organs upon intragastric administration of Mungoltin within 30 days confirm the absence of toxic effects. According to toxicity parameters under the conditions of the above acute experiments, Mungoltin can be attributed to class 5 practically as a non-toxic substance.

Faba Bean Variety Mixture Can Modulate Faba Bean–Wheat Intercrop Performance Under Water Limitation

Commercial legume varieties vary in terms of their drought tolerance when grown as sole crops, though relatively little is known about how legume variety selection affects cereal–legume intercrop performance under drought conditions. This study aims to test the hypothesis that positive rhizosphere interactions in faba bean–wheat intercrops will confer a “buffering capacity” on faba bean and wheat performance under water stress and that this effect will (i) depend on faba bean varietal selection and (ii) be enhanced with increasing faba bean varietal diversity. In a greenhouse experiment, three commercial faba bean (Vicia faba L.) varieties [Gloria (G), Alexia (A), Julia (J)] were grown in sole crop or intercropped with spring wheat (Triticum aestivum L.) under well-watered or water-stress conditions. Under intercropping, either one, two, or all three faba bean varieties were grown together with wheat to test the effect of intraspecific diversity on a cereal–legume intercrop performance. Consistent with the proposed hypothesis, we found that, under well-watered and water-stress conditions, wheat and faba bean shoot biomass production and nitrogen (N) acquisition improved with intercropping and that faba bean variety and variety mixture strongly modulated the intercropping effect. Interestingly, in both well-watered and water-stress conditions, wheat dry biomass and N accumulation were greatest in intercrops containing Gloria, while nodule number, nodule weight, and N accumulation in faba bean were greatest for intercrops containing Alexia and Julia (AJ). The effect of varietal diversity was inconsistent. Intercrops with two faba bean varieties tended to have positive or neutral effects on measured wheat and faba bean variables. However, overall performance under intercropping was generally reduced when all three faba bean varieties were planted with wheat. The effect of faba bean species diversity can buffer faba bean–wheat intercrop performance against water stress, and intercropping tended to have positive or neutral effects on the measured wheat and faba bean variables, notably with two-varietal faba bean mixtures.

Coupling effects of phosphorus fertilization source and rate on growth and ion accumulation of common bean under salinity stress.

Many agricultural regions in arid and semiarid climate zone need to deal with increased soil salinity. Legumes are classified as salt-sensitive crops. A field experiment was performed to examine the application of phosphorus (P) fertilizer source and rate on growth, chlorophylls and carotenoid content, DNA and RNA content and ion accumulation in common bean (Phaseolus vulgaris L.) cultivated under salinity stress. An experimental design was split-plot with three replicates. The main plots included two P sources, namely single superphosphate (SP) and urea phosphate (UP). The sub-plots covered four P rates, i.e., 0.0, 17.5, 35.0, and 52.5 kg P ha–1. All applied P fertilization rates, in both forms, increased plant height, leaf area, dry weight of shoots and roots per plant, and total dry weight (TDW) in t ha−1. The highest accumulation of N, P, K+, Mg2+, Mn2+, Zn2+, and Cu2+ was determined in the shoot and root of common bean, while 35 kg of P per ha−1 was used compared to the other levels of P fertilizer. The highest P rate (52.5 kg ha−1) resulted in a significant reduction in Na+ in shoot and root of common bean. The response curve of TDW (t ha–1) to different rates of P (kg ha–1) proved that the quadratic model fit better than the linear model for both P sources. Under SP, the expected TDW was 1.675 t ha–1 if P was applied at 51.5 kg ha–1, while under UP, the maximum expected TDW was 1.875 t ha–1 if P was supplied at 42.5 kg ha–1. In conclusion, the 35.0 kg P ha–1 could be considered the best effective P level imposed. The application of P fertilizer as urea phosphate is generally more effective than single superphosphate in enhancing plant growth and alleviating common bean plants against salinity stress.

Root Traits Related with Drought and Phosphorus Tolerance in Common Bean (Phaseolus vulgaris L.)

Roots are key organs for water and nutrient acquisition and transport. Therefore, root phenes that are associated with adaptation to low phosphorus (P) environments could enhance top-soil exploration, while deeper allocation is important for acquiring water and mobile nutrients. The understanding of interactions among root phenes can help in the development of common bean (Phaseolus vulgaris L.) genotypes adapted to drought and low fertility through genetic improvement. Two experiments (pot and field) were conducted at the Agricultural Research Institute of Mozambique to assess the contribution of root phenes to common bean shoot biomass and grain yield under combined stress (drought and low P). The pot study assessed eight genotypes, with four treatments combining water regimes (drought and non-stress) and phosphorus levels (200 and 25) mg P kg−1 soil. In the field study, 24 common bean genotypes were also grown in high and low phosphorus (40 kg P ha−1 and without P application) under irrigation and limited water. The grain yield from fields under drought and P stress were correlated with the pot data on root traits. The response of root phenes to drought and phosphorus stress appeared to be related to the deep and shallow root systems, respectively. Deep rooted genotypes produced more total root biomass and high taproot lateral branching density, which resulted in high total root length under drought and low P stress, while shallow rooted genotypes had low total root biomass and less taproot lateral branching. Increased shoot biomass and grain yield under drought and low P was associated with higher mean values of taproot lateral branching density and total taproot length. Genotypes SER 125, BFS 81, FBN12111-66 and MER 22 11-28 showed a greater score of tap root branching density in the pot study with the highest grain yield in the field under low P and drought stress. Therefore, these can be recommended for use in low phosphorus and drought stress environment or serve as parents for improving phosphorus use efficiency and drought tolerance in common bean.

Legume-rhizobium specificity effect on nodulation, biomass production and partitioning of faba bean (Vicia faba L.)

Greenhouse and multi-location experiments were conducted for two consecutive years to investigate the effects of rhizobium on nodulation, biomass production and partitioning of faba bean. Split-plot in randomized complete block design was used for field experiments. Treatments consisted of six rhizobium strains and three faba bean varieties. Peat carrier-based inoculant of each strain was applied at the rate of 10 g kg−1 seed. Non-inoculated plants without N fertilizer and with N fertilizer served as –N and + N controls, respectively. Data on nodulation, shoot dry weight and root dry weight were collected and analyzed. Inoculation of rhizobium significantly increased nodulation of faba bean under greenhouse and field conditions. Location x strain x variety interaction had significant effects on nodulation, dry matter production and partitioning. Rhizobium inoculation increased nodulation, shoot and root dry weights of faba bean across locations. For example, inoculation with rhizobium strains NSFBR-15 and NSFBR-12 to variety Moti resulted in 206.9 and 99.3% shoot dry weight increase at Abala Gase and Hankomolicha, respectively and 133.3 and 70.7% root dry weight increase on the same variety at the same sites, respectively. Nodulation and biomass production depend on the compatibility between faba bean genotype and rhizobium strain and its interaction with soil bio-physical conditions.

Seaweed liquid extracts induce hormetic growth responses in mung bean plants

Hormesis is a dose–response phenomenon that is characterized by stimulation at low doses and inhibition at high doses. Extensive evidence has accumulated showing the occurrence of hormesis in numerous plant species independent of physicochemical agents, and this phenomenon has become a target for achieving greater crop productivity. Biostimulants (i.e., elicitors) are agents that activate adaptive responses, moderately stimulate biological performance and aid plants in tolerating stress when applied at low doses that fall within the stimulatory zone of a dose–response curve. Biostimulants based on seaweed liquid extracts (SLEs) are widely known to exert great benefits in plants at very low doses. However, the consequences to plants when SLEs are applied at high doses remain underexplored. A dose–response study was performed on mung bean (Vigna radiata) seedlings by applying a wide range of SLE doses to evaluate growth stimulation patterns. While the application of SLEs at high concentrations mostly caused a decrease in various morphological parameters, the application of SLEs at low concentrations stimulated some of these. Nevertheless, common features of SLE stimulation were present. Mung bean shoot length, root length, and dry weight responded to the SLE concentrations in a hormetic manner. A biphasic dose–response confirmed the relationships between SLE dose and mung bean plant growth parameters, which were due to the properties of the constituents of the SLE of each seaweed species. The SLE growth stimulation pattern found in this study will contribute to the establishment of safe application doses. This paper provides a strong foundation for enhancing the research protocols of studies on the effects of SLEs on plant growth and supports incorporating hormesis into risk assessment practices in agriculture.

The dynamics of plant nutation

In this article we advance a cutting-edge methodology for the study of the dynamics of plant movements of nutation. Our approach, unlike customary kinematic analyses of shape, period, or amplitude, is based on three typical signatures of adaptively controlled processes and motions, as reported in the biological and behavioral dynamics literature: harmonicity, predictability, and complexity. We illustrate the application of a dynamical methodology to the bending movements of shoots of common beans (Phaseolus vulgaris L.) in two conditions: with and without a support to climb onto. The results herewith reported support the hypothesis that patterns of nutation are influenced by the presence of a support to climb in their vicinity. The methodology is in principle applicable to a whole range of plant movements.

Identification, Characterization and Evaluation of Multifaceted Traits of Plant Growth Promoting Rhizobacteria from Soil for Sustainable Approach to Agriculture.

This study assessed potential of plant growth promoting rhizobacteria (PGPR) found in 34 soil samples collected from Sirmaur, Himachal Pradesh. Out of 238 rhizobacterial isolates, 48 rhizobacterial isolates exhibited multiple PGP (plant growth promoting) traits. Out of the 48 isolates, nine isolates exhibiting most promising PGP traits were evaluated. CSRS12 isolate showed maximum solubilization of phosphate and potassium up to 530.71 and 30.44mg l-1, respectively. Maximum zinc solubilizing efficiency (ZSE) was also observed in case of isolate CSRS12. The maximum IAA production was observed by isolate PPRS17 with 37.34mg l-1 followed by PCRS24 with 34.44mg l-1 after 120h. Maximum siderophore unit production was observed upto 92.29% by isolate CSRS12 followed by 65.54% with isolate TA1PS. The selected PGPR isolates were identified through 16S rDNA sequencing. The identified PGPRs were Burkholderia arboris (isolate CSRS12), Pseudomonas aeruginosa (isolate PPRS17) and Acinetobacter baumannii (isolate TA1PS). B. arboris CSRS12 isolate showed multiple PGP traits as mineral solubilization of phosphate, potassium and zinc, production of siderophore and ammonia. Among all three PGPR treatment, B. arboris CSRS12 isolate showed significant increment in lateral root number, root and shoot length, fresh and dry weight of root and shoot of mung bean (Vigna radiata) in pot experiments. The results showed that CSRS12 isolate could be used for exploitation as bio-inoculant, which can facilitate better productivity and ecological dynamics for both domesticated crops as well as wild varieties.

Mung bean shoot and root growth under wood ash as a soil acidity neutralizer and fertilizer

ABSTRACT Eucalyptus wood ash can be a bio-rationale, economically viable, source of fertilizer, to neutralize soil acidy, and contribute to minimizing costs for small farmers who produce mung beans [Vigna radiata (L.) Wilczek] which has a considerable cost of production. The objective was to evaluate the wood ash amendment to the soil and its effects on changing pH and as a fertilizer for mung beans. Amounts of wood ash were 0, 9, 18, 27, 36 or 45 g∙dm−3 in the Oxisol. Wood ash can be used as neutralizer and fertilizer, improving the growth of shoots and roots with doses between 21 and 27 g∙dm−3.

Plant residues differing in C/N ratio in mulch and soil — the effect of the mulch on nutrient availability and microbial biomass is more pronounced with higher leaching amount

This study investigated the effect of C/N ratio, placement of plant residues, and leaching amounts on soil respiration, microbial biomass, and nutrient availability within four weeks after amendment. Young faba bean shoots (FB, C/N 7) and mature wheat straw (WH, C/N 80) were used as low and high C/N residue, respectively. Soil was unamended, mulched with FB or WH only, or mulched with one residue and mixed with the other residue. Leaching with 5 or 25 mL water was carried out on days 4, 12, and 20. Cumulative respiration and microbial biomass N were higher with 25 than 5 mL only in treatments with two residues. WH under FB mulch reduced N availability compared to FB mulch alone, whereas FB under WH increased N availability compared to WH mulch alone. When soils were leached with 25 mL water, available N in FB mulch over WH was lower on day 12, but higher later, compared to WH mulch over FB. In contrast, in WH mulch over FB microbial biomass N increased over time whereas available N decreased. In conclusion, the effect of C/N ratio of the mulch on soil available and microbial biomass N was greater with the higher leaching amount.

Presence of wheat straw in soil influences nutrient availability and leaching in soil mulched with high or low C/N organic materials

ABSTRACT The study aimed to determine nutrient availability in soil mulched with organic materials and how this is influenced by the presence of high C/N residue in the soil. Three organic materials were used: mature wheat straw (W, C/N 81), young faba bean shoots (FB, C/N 7) and sheep manure (SM, C/N 8). There were eight treatments: unamended control, soil containing W, soil containing W and mulched with W, FB or SM and soil only with W, FB or SM mulch. Soils were leached on days 4, 12, 20 and 28 and sampled 8 days after each leaching. Cumulative respiration over 36 days was influenced by mulch type: FB > W > SM and higher in soil mixed with W and mulched than in soil with only mulch. Microbial biomass N was two-fold higher in soil mixed with wheat and mulched than in soil with only mulch. Available N was between 0.2 and two-fold higher in soil with only mulch than soil with mulch and mixed with W. Available N increased over time with FB mulch but changed little with SM or W mulch. In conclusion, W in the soil can enhance N immobilisation and thus reduce N leaching from FB mulch.

EFFECT OF PRESOWING SEED PROCESSING OF SEEDS ON THE FIELD CAPACITY AND RESIDENCE OF PLANTS OF COMMON BEANS IN THE CONDITIONS OF THE RIGHT-BANK FOREST-STEPPE OF UKRAINE

The results of three-year studies of the effect of presowing seed treatment on field germination and plant survival of common bean plants in the conditions of the Right-Bank Forest-Steppe of Ukraine are presented. The study determined the patterns of the effect of presowing seed treatment on the change in these indicators in 2014-2016. It was established that the field germination of seeds and the survival rate of the studied varieties of common beans depending on the presowing treatment with different nitrogen-fixing strains of Rhizobium phaseoli microorganisms together with the biological preparations Regoplant and EPAA were slightly different. To a certain extent, the variability of indicators of field germination and survival of common bean plants was influenced by weather conditions. The best conditions for obtaining friendly shoots of common bean are the highest field germination established in the variant Rhizobium phaseoli (F-16) + Regoplant + EPAA and amounted to 95,2% for the Galactica variety, 97,3% for the Slavia variety, respectively. The lowest rates were observed in the variant without seed treatment, in the Galactica variety – 89,4%, and in the Slavia variety – 91,5%. The survival of common bean plants also depended on the presowing treatment of seeds and was high in the Galactica variety in the Rhizobium phaseoli (657a) variants – 90,5%, and Rhizobium phaseoli (657a) + Regoplant + EPAA – 90,2%. In the Slavia variety, in the variant with presowing seed treatment of Rhizobium phaseoli (F-16) + Regoplant + EPAA – 83,1%. The results of analysis of variance of the data obtained confirm that, to the greatest extent, field germination, over the years of research, was influenced by presowing treatment of seeds (B) - 70% and variety (A) - 25%. The interaction of factors (AB) - 1% and other factors - 4%, practically did not affect the change in field germination.

Influence of mulch C/N ratio and decomposition stage on plant N uptake and N availability in soil with or without wheat straw

AbstractMulches can improve soil properties, but little is known about nutrient availability in mulched soil that contains plant residues and the effect of mulching with manures. The aim of this study was to determine the effects of mulching with high or low C/N organic materials, in which low C/N materials differed in decomposability, and the presence of wheat straw in the soil on plant growth and N uptake, soil N availability and microbial biomass N within about four months after mulching. Three organic materials were used: mature wheat straw (W, C/N 80), young faba bean shoots (FB, C/N 7), and sheep manure (SM, C/N 8). There were eight treatments differing in amendment methods (mulching or mixing with W or both) and mulching materials (W, FB or SM). Treatments that were only mulched with W, FB or SM are referred to as m‐treatments. In m/s‐treatments, after W was mixed into the soil, W, FB or SM were placed on the soil surface as mulch. Two other treatments included an unamended control and soil mixed with W. Wheat was planted 0, 35 or 70 days after mulching (referred to as 0, 35, and 70 DAM) and grown for 35 days. Faba bean mulch increased shoot dry weight, shoot N uptake and available N compared to wheat or sheep manure mulch, particularly in the m‐treatments. Shoot dry weight was higher in m‐treatments than corresponding m/s‐treatments with the same mulch type. Shoot N uptake was higher in 70 DAM than in 0 DAM in all treatments and 0.3 to three‐fold higher in m‐treatments than the corresponding m/s‐treatments. Microbial biomass N was higher in 0 DAM than in 35 and 70 DAM in most treatments and up to two‐fold higher in m/s‐treatments than the corresponding m‐treatments. Available N in m/s‐treatments was two to six‐fold higher than m‐treatments in 0 DAM, but differed little in older mulch ages of W and SM. It can be concluded that compared to soil with only mulch, mixing of wheat straw into soil reduced plant growth and N uptake, particularly in the early stages of mulching (0 and 35 DAM). However, the presence of wheat in mulched soil may provide a longer lasting source of N for plants and reduce the risk of N leaching from rapidly decomposing low C/N mulch due to greater microbial biomass N uptake than only soil with mulch.