Plant biostimulants are diverse substances and microorganisms used to enhance plant growth. The global market for biostimulants is projected to increase 12 % per year and reach over $2,200 million by 2018. Despite the growing use of biostimulants in agriculture, many in the scientific community consider biostimulants to be lacking peer-reviewed scientific evaluation. This article describes the emerging definitions of biostimulants and reviews the literature on five categories of biostimulants: i. microbial inoculants, ii. humic acids, iii. fulvic acids, iv. protein hydrolysates and amino acids, and v. seaweed extracts. The large number of publications cited for each category of biostimulants demonstrates that there is growing scientific evidence supporting the use of biostimulants as agricultural inputs on diverse plant species. The cited literature also reveals some commonalities in plant responses to different biostimulants, such as increased root growth, enhanced nutrient uptake, and stress tolerance.

/pdf/agricultural-uses-of-plant-biostimulants-spbkauhybj.pdf

Agricultural uses of plant biostimulants

Humic acids: Structural properties and multiple functionalities for novel technological developments

Phosphorus activators contribute to legacy phosphorus availability in agricultural soils: A review

Interaction among plant nutrients can yield antagonistic or synergistic outcomes that influence nutrient use efficiency. To provide insight on this phenomenon, peer-reviewed articles were selected ...

https://www.tandfonline.com/doi/pdf/10.1080/00103624.2017.1407429

Effects of Nutrient Antagonism and Synergism on Yield and Fertilizer Use Efficiency

No-till practices have the potential to increase soil organic C, but little about known about the relative contribution of surface residue and roots to soil organic C accumulation. In a simulated no-till experiment, we studied the fate of (14)C-labeled surface residue and in situ roots during a 1-yr incubation. Soil samples collected during the incubation were chemically dispersed and separated into five particle size and density fractions. The organic C, (14)C, and total N content of each fraction was determined. Alkali traps were used to measure (14)C losses due to respiration. After 360 d, 66% of the (14)C contained in the surface residue on Day 0 had been respired as (14)CO2, 11% remained in residue on the soil surface, and 16% was in the soil. In comparison, 56% of the root-derived (14)C in the soil was evolved as (14)CO2 and 42% remained in the soil. The large (500-2000 micrometer) and small (53-500 micrometer) particulate organic matter (POM) fractions together contained 11 to 16% of the initial root derived (14)C in the soil. In contrast, POM contained only 1 to 3% of the initial surface residue-derived (14)C. These data show clear differences in the partitioning of surface residue- and root-derived C during decomposition and imply that the beneficial effects of no-till on soil organic C accrual are primarily due to the increased retention of root-derived C in the soil.

/pdf/carbon-dynamics-of-surface-residue-and-root-derived-organic-569eufbr4y.pdf

Carbon dynamics of surface residue- and root-derived organic matter under simulated no-till. [Erratum: Nov/Dec 2002, v. 66 (6), p. 2040.]

Fertilization, either in the form of organic or inorganic, always affects plant growth, yield, and nutritional quality of fruit crops. Further, the efficacy of fertilizers depends on various factors, including the area, climatic conditions, and cultivars. Rawalakot has ideal climatic conditions for growing strawberries. However, no studies related to the impact of different soil amendments on the growth habit and fruit quality of strawberries have been conducted so far. Therefore, in this study, different combinations of organic (farmyard manure (FYM) and poultry manure (PM)) and inorganic (urea) (N 150 kg/ha) fertilizers were used for comparison of growth pattern and postharvest quality of strawberry cv. Chandler. The organic and inorganic fertilizer regimes showed comparatively better results in terms of all the parameters studied. However, plants grown on soils amended with FYM equivalent to 75 kg N per ha + PM equivalent to 75 kg N per ha and FYM equivalent to 50 kg N per ha + PM equivalent to 50 kg N per ha + urea 50 kg N per ha showed 41% and 28% more survival percentage compared to control. Furthermore, the number of leaves, number of flowers, number of fruits, and yield were significantly high in plants grown on amended soil. Moreover, a significantly high amount of total soluble solids (10.0°Brix), titratable acidity (1.18%), ash (0.84%), fiber (3.03%), total phenols (7.61 μg gallic acid/g fresh weight), total flavonoids (7.93 mmol quercetin/100 g fresh weight), and total antioxidants (0.60 activity of FeSO4 mg/g fresh weight) was noted in comparison with control. Similarly, a combined treatment of FYM, PM, and urea also showed good results in terms of all the growth and fruit quality parameters as compared with other fertilizer regimes as well as control. However, the overall results of this study revealed that strawberries grown on soil amended with a combined dose of FYM equivalent to 75 kg N per ha + PM equivalent to 75 kg N per ha could be a potential dose for maximum yield and better quality fruits of strawberry.

/pdf/influence-of-organic-and-inorganic-fertilizer-regimes-on-3j0y52w3.pdf

Influence of Organic and Inorganic Fertilizer Regimes on Growth Patterns and Antioxidants Capacity of Strawberry (Fragaria × Ananassa Duch.) cv. Chandler

Background: Poor utilization of urea fertilizer and N losses from agriculture lands demands alternate fertilization practices to reduce N losses and improve utilization, i.e., application of nitrification inhibitors. Aims: This study was aimed to evaluate and compare the influence of dicyandiamide (DCD) and selected medicinal plant materials and on N transformations, nitrification inhibition and recovery of applied N. Methods: Treatments included: urea nitrogen (UN), UN + DCD, UN + Gingiber officinale, UN + Viola odorata, UN + Sewertia chirata, UN + Azadirachta indica, UN + Sphaenathus indicus, UN + Allium sativus, UN + Artemisia absenthium, UN + Fumaria indicus, UN + Caesalpinea bondusella, UN + Barberis lyceum, and an un‐amended control. Urea was applied at 200 mg N kg⁻¹ soil, while DCD and medicinal plant materials were applied at of 1% and 20% of applied urea, respectively. Results: Medicinal plant materials inhibited nitrification of urea‐derived NH4+-N. On an average of medicinal plant materials treatments, 51% of NH4+-N was still present in soil compared to 17% NH4+-N in UN treatment without medicinal plant materials after 28 days. Similarly, NO3--N was 76.54 mg kg⁻¹ in UN treatment compared to 34.40 mg kg⁻¹ in UN + medicinal plant materials treatments, indicating 55% reduction in nitrification. Apparent nitrogen recovery (ANR) in UN treatment was 65% compared to 74% in UN + DCD treatment. ANR in treatments, where UN was amended with medicinal plant materials, varied between 58 to 70%. Conclusions: The use of DCD and medicinal plant materials with UN significantly reduced NH4+-N oxidation and nitrification (NO3--N). In general, medicinal plant materials were more effective in regulating N transformations and, thus, offer a suitable alternate fertilization practice to reduce N losses and improve fertilizer utilization.

Evaluation of selected medicinal plant materials and dicyandiamide on nitrification of urea-derived ammonium under laboratory conditions

The present study was conducted to evaluate and characteriseRhizobium leguminosarum bv.trifolii nodulating rhizobia isolated from root nodules of indigenous and exotic ecotypes of white clover (Trifolium repens L.) in the mountain region of the State of Azad Jammu and Kashmir Pakistan. Isolates from indigenous ecotypes were collected from three different locations i.e. Tollipir, Banjosa, and Rawalakot while exotic ecotypes i.e. Irrigation and NuSiral were collected from Australia. Preliminary characterisation of isolates was carried-out on the basis of colony characteristics, phosphorus solubilisation, osmotic potential, relative absorbance, indole acetic acid spot test, mean doubling time and C-source utilisation.Rhizobium population in the respective soils was also estimated by using most probable number (MPN). The maximumRhizobium population of 5.8 × 106 g−1 soil was recorded in Tollipir soil compared with population of 3.1. × 105 g−1 soil in Rawalakot soil. All strains showed homology to a typicalRhizobium strain and identified asRhizobium on the basis of growth pattern and other testing parameters. The isolates were Gram negative, small rods and acid producing fast growers with a mean generation time in between 2.7 to 3.4 h. All isolates except isolates from Tollipir showed resistant against four antibiotics except tetracycline. Isolates from Banjosa, Tollipir and Rawalakot (indigenous) had larger surface charge than isolates from Irrigation and NuSiral (exotic). Highest osmotic potential of −31.02 bar was recorded in the isolates from Banjosa while isolates from Tollipir and Rawalakot had an osmotic potential of −22 bar. Field evaluation of isolated isolates showed significant increase in plant growth and root nodulation. The study will be useful for identifying the isolates under laboratory conditions and developing successful inoculation strategy for the production of white clover in the mountain region of Azad Jammu and Kashmir.

Characterisation and evaluation ofRhizobium leguminosarum bv.trifolii nodulating rhizobia isolated from white clover native to Azad Jammu and Kashmir, Pakistan

Functional analysis of mitogen-activated protein kinases (MAPKs) in potato under biotic and abiotic stress

Drought stress is a significant abiotic factor influencing maize growth and development. Understanding the molecular mechanism of drought tolerance is critical to develop the drought tolerant genotype. The identification of the stress responsive gene is the first step to developing a drought tolerant genotype. The aim of the current research was to pinpoint the genes that are essential for conserved samples in maize drought tolerance. In the current study, inbred lines of maize, 478 and H21, a drought-tolerant and susceptible line, were cultivated in the field and various treatments were applied. The circumstances during the vegetative stage (severe drought, moderate drought and well-watered environments) and RNA sequencing were used to look into their origins. In 478, 68%, 48% and 32% of drought-responsive genes (DRGs) were found, with 63% of DRGs in moderate drought and severe drought conditions in H21, respectively. Gene ontology (GO) keywords were explicitly enriched in the DRGs of H21, which were considerably over-represented in the two lines. According to the results of the GSEA, “phenylpropanoid biosynthesis” was exclusively enriched in H21, but “starch and sucrose metabolism” and “plant hormone signal transduction” were enhanced in both of the two lines. Further investigation found that the various expression patterns of genes linked to the trehalose biosynthesis pathway, reactive oxygen scavenging, and transcription factors, may have a role in maize’s ability to withstand drought. Our findings illuminate the molecular ways that respond to lack and offer gene resources for maize drought resistance. Similarly, SNP and correlation analysis gave us noticeable results that urged us to do the same kind of analysis on other crops. Additionally, we isolated particular transcription factors that could control the expression of genes associated to photosynthesis and leaf senescence. According to our findings, a key factor in tolerance is the equilibrium between the induction of leaf senescence and the preservation of photosynthesis under drought.

https://www.mdpi.com/2073-4425/14/1/31/pdf?version=1672378845

Majid Mahmood Tahir

Papers

Influence of Organic and Inorganic Fertilizer Regimes on Growth Patterns and Antioxidants Capacity of Strawberry (Fragaria × Ananassa Duch.) cv. Chandler

Evaluation of selected medicinal plant materials and dicyandiamide on nitrification of urea-derived ammonium under laboratory conditions

Characterisation and evaluation ofRhizobium leguminosarum bv.trifolii nodulating rhizobia isolated from white clover native to Azad Jammu and Kashmir, Pakistan

Functional analysis of mitogen-activated protein kinases (MAPKs) in potato under biotic and abiotic stress

Comparative Gene Enrichment Analysis for Drought Tolerance in Contrasting Maize Genotype