Soil amendment with biochar is evaluated globally as a means to improve soil fertility and to mitigate climate change. However, the effects of biochar on soil biota have received much less attention than its effects on soil chemical properties. A review of the literature reveals a significant number of early studies on biochar-type materials as soil amendments either for managing pathogens, as inoculant carriers or for manipulative experiments to sorb signaling compounds or toxins. However, no studies exist in the soil biologyliterature that recognize the observed largevariations ofbiochar physico-chemical properties. This shortcoming has hampered insight into mechanisms by which biochar influences soil microorganisms, fauna and plant roots. Additional factors limiting meaningful interpretation of many datasets are the clearly demonstrated sorption properties that interfere with standard extraction procedures for soil microbial biomass or enzyme assays, and the confounding effects of varying amounts of minerals. In most studies, microbial biomass has been found to increase as a result of biochar additions, with significant changes in microbial community composition and enzyme activities that may explain biogeochemical effects of biochar on element cycles, plant pathogens, and crop growth. Yet, very little is known about the mechanisms through which biochar affects microbial abundance and community composition. The effects of biochar on soil fauna are even less understood than its effects on microorganisms, apart from several notable studies on earthworms. It is clear, however, that sorption phenomena, pH and physical properties of biochars such as pore structure, surface area and mineral matter play important roles in determining how different biochars affect soil biota. Observations on microbial dynamics lead to the conclusion of a possible improved resource use due to co-location of various resources in and around biochars. Sorption and therebyinactivation of growth-inhibiting substances likelyplaysa rolefor increased abundance of soil biota. No evidence exists so far for direct negative effects of biochars on plant roots. Occasionally observed decreases in abundance of mycorrhizal fungi are likely caused by concomitant increases in nutrient availability,reducing theneedfor symbionts.Inthe shortterm,therelease ofavarietyoforganic molecules from fresh biochar may in some cases be responsible for increases or decreases in abundance and activity of soil biota. A road map for future biochar research must include a systematic appreciation of different biochar-types and basic manipulative experiments that unambiguously identify the interactions between biochar and soil biota.

http://www.css.cornell.edu/faculty/lehmann/pictures/publ/SoilBiolBiochem%2043,%201812–1836,%202011%20Lehmann.pdf

Biochar effects on soil biota – A review

Biochar is a carbon-rich coproduct resulting from pyrolyzing biomass. When applied to the soil it resists decomposition, effectively sequestering the applied carbon and mitigating anthropogenic CO2 emissions. Other promoted benefits of biochar application to soil include increased plant productivity and reduced nutrient leaching. However, the effects of biochar are variable and it remains unclear if recent enthusiasm can be justified. We evaluate ecosystem responses to biochar application with a meta-analysis of 371 independent studies culled from 114 published manuscripts. We find that despite variability introduced by soil and climate, the addition of biochar to soils resulted, on average, in increased aboveground productivity, crop yield, soil microbial biomass, rhizobia nodulation, plant K tissue concentration, soil phosphorus (P), soil potassium (K), total soil nitrogen (N), and total soil carbon (C) compared with control conditions. Soil pH also tended to increase, becoming less acidic, following the addition of biochar. Variables that showed no significant mean response to biochar included belowground productivity, the ratio of aboveground : belowground biomass, mycorrhizal colonization of roots, plant tissue N, and soil P concentration, and soil inorganic N. Additional analyses found no detectable relationship between the amount of biochar added and aboveground productivity. Our results provide the first quantitative review of the effects of biochar on multiple ecosystem functions and the central tendencies suggest that biochar holds promise in being a win-win-win solution to energy, carbon storage, and ecosystem function. However, biochar's impacts on a fourth component, the downstream nontarget environments, remain unknown and present a critical research gap.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1111/gcbb.12037

Biochar and its effects on plant productivity and nutrient cycling: a meta‐analysis

Soil microbial populations are immersed in a framework of interactions known to affect plant fitness and soil quality. They are involved in fundamental activities that ensure the stability and productivity of both agricultural systems and natural ecosystems. Strategic and applied research has demonstrated that certain co-operative microbial activities can be exploited, as a low-input biotechnology, to help sustainable, environmentally-friendly, agro-technological practices. Much research is addressed at improving understanding of the diversity, dynamics, and significance of rhizosphere microbial populations and their cooperative activities. An analysis of the co-operative microbial activities known to affect plant development is the general aim of this review. In particular, this article summarizes and discusses significant aspects of this general topic, including (i) the analysis of the key activities carried out by the diverse trophic and functional groups of micro-organisms involved in cooperative rhizosphere interactions; (ii) a critical discussion of the direct microbe–microbe interactions which results in processes benefiting sustainable agroecosystem development; and (iii) beneficial microbial interactions involving arbuscular mycorrhiza, the omnipresent fungus–plant beneficial symbiosis. The trends of this thematic area will be outlined, from molecular biology and ecophysiological issues to the biotechnological developments for integrated management, to indicate where research is needed in the future.

http://www.dzumenvis.nic.in/Microbes%20and%20Plants%20Growth/pdf/Microbial%20co-operation%20in%20the%20rhizosphere.pdf

Microbial co-operation in the rhizosphere

Recently, iron oxide nanoparticles (NPs) have attracted much consideration due to their unique properties, such as superparamagnetism, surface-to-volume ratio, greater surface area, and easy separation methodology. Various physical, chemical, and biological methods have been adopted to synthesize magnetic NPs with suitable surface chemistry. This review summarizes the methods for the preparation of iron oxide NPs, size and morphology control, and magnetic properties with recent bioengineering, commercial, and industrial applications. Iron oxides exhibit great potential in the fields of life sciences such as biomedicine, agriculture, and environment. Nontoxic conduct and biocompatible applications of magnetic NPs can be enriched further by special surface coating with organic or inorganic molecules, including surfactants, drugs, proteins, starches, enzymes, antibodies, nucleotides, nonionic detergents, and polyelectrolytes. Magnetic NPs can also be directed to an organ, tissue, or tumor using an external magnetic field for hyperthermic treatment of patients. Keeping in mind the current interest in iron NPs, this review is designed to report recent information from synthesis to characterization, and applications of iron NPs.

/pdf/synthesis-characterization-applications-and-challenges-of-2ixwf29t2j.pdf

Synthesis, characterization, applications, and challenges of iron oxide nanoparticles

Chitosan as a potential natural compound to control pre and postharvest diseases of horticultural commodities

Isolates of Fusarium moniliforme (Sheld.) emend. Snyd. & Hans., F. oxysporum (Schlecht) emend. Snyd. & Hans., and F. solani (Mart.) Appel & Wollenw. emend. Snyd. & Hans. were recovered from three 5-year-old field grown asparagus (Asparagus officinalis L. cv. Mary Washington) by isolating from symptomatic and asymptomatic feeder roots, storage roots, crown and basal stem segments. Fusarium moniliforme was more virulent than F. oxysporum on asparagus seedlings and F. solani was considered nonpathogenic. Isolates of F. moniliforme and F. oxysporum were placed into vegetative compatibility groups (VCGs) by demonstrating heterokaryosis with complementation tests using nitrate-nonutilizing (nit) mutants (pairing nitM and nit1 mutants). Ninety-seven of 135 isolates of F. moniliforme were placed in 13 vegetative compatibility groups. The remaining 38 isolates were not classified by vegetative compatibility because of poor nit mutant recovery. Eight of 18 isolates of F. oxysporum were unique and classed as single ...

http://www.researchgate.net/profile/James_Lamondia/publication/237163992_Pathogenicity_and_vegetative_compatibility_among_isolates_of_Fusarium_oxysporum_and_F._moniliforme_colonizing_asparagus_tissues/links/553019c70cf27acb0de85384.pdf

Pathogenicity and vegetative compatibility among isolates of Fusarium oxysporum and F. moniliforme colonizing asparagus tissues

Micronutrient deficiencies in global food chains are a significant cause of ill health around the world, particularly in developing countries. Agriculture is the primary source of nutrients required for sound health, and as the population has continued to grow, the agricultural sector has come under pressure to improve crop production, in terms of both quantity and quality, to meet the global demands for food security. The use of engineered nanomaterial (ENM) has emerged as a promising technology to sustainably improve the efficiency of current agricultural practices as well as overall crop productivity. One promising approach that has begun to receive attention is to use ENM as seed treatments to biofortify agricultural crop production and quality. This review highlights the current state of the science for this approach as well as critical knowledge gaps and research needs that must be overcome to optimize the sustainable application of nano-enabled seed fortification approaches.

Seed Biofortification by Engineered Nanomaterials: A Pathway To Alleviate Malnutrition?

Salt marshes rank as the most productive ecosystems on the planet. Biomass production can be greater than 3 kg dry matter/m2/year, which is 40% more biomass than tropical rainforests produce. Salt marshes provide multiple benefits to mankind. For example, coastal communities receive protection from storm surges and wave erosion. Salt marshes absorb excess nitrogen and phosphorus from sewage and fertilizer run-off into rivers, which, in turn, prevents algal blooms and hypoxia in coastal waters. In addition, these unique ecosystems provide habitat and shelter for many hundreds of species of shellfish, finfish, migratory and sedentary birds, and other marine animals. Despite the richness in animal species, the intertidal marshes of the salt marsh ecosystem are dominated by only a few plant species. Of these, the most prevalent plant species in a marsh are the tall and short forms of smooth cordgrass (Spartina alterniflora). The first recorded account of a dieback in a U.S. salt marsh was in the earl...

https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS-09-12-0871-FE

Sudden Vegetation Dieback in Atlantic and Gulf Coast Salt Marshes.

Replanted asparagus fields commonly fail to produce a profitable stand due to alleopathic residues left behind from the previous asparagus crop, elevated densities of pathogenic Fusarium spp., and low densities of vesicular arbuscular mycorrhizae (VAM). Formononetin, a plant isoflavone that stimulates VAM spores to germinate, and sodium chloride (NaCl), a disease-suppressing amendment, were evaluated alone and in combination for their effect on reestablishing asparagus at two locations in abandoned asparagus fields. Greenhouse studies also were conducted with naturally and artificially infested soils. Formononetin was applied as a crown soak or soil drench, and NaCl was applied as a granular treatment. Feeder roots from soil cores sampled from field plots and from greenhouse transplants were assayed for colonization by VAM and for lesions caused by Fusarium oxysporum and F. proliferatum. Formononetin increased the number of VAM vesicles in roots from the field and greenhouse studies and reduced the percent root lesions caused by Fusarium spp. when compared with the nontreated controls. NaCl was more effective than formononetin in reducing the percentage of root lesions in both field and greenhouse experiment when compared with untreated plants but had no effect on VAM colonization. However, there was evidence that NaCl negated the effect of formononentin on VAM colonization. The NaCl treatment increased the May 2001 spear number by 15% and marketable spear weight by 23%. At one site, treatment with formononetin increased mean number of stalks per plant by 29% in 2000 and 14% in 2001. Both formononetin and NaCl improve growth and reduce disease of asparagus in replanted asparagus and may be useful in reestablishing asparagus in abandoned asparagus field.

https://apsjournals.apsnet.org/doi/pdfplus/10.1094/PDIS.2002.86.12.1318

Influence of Formononetin and NaCl on Mycorrhizal Colonization and Fusarium Crown and Root Rot of Asparagus

The application of sodium chloride on asparagus beds, an old practice that has been abandoned, suppressed Fusarium crown and root rot caused by Fusarium oxysporum and F. proliferatum. Spring applications of NaCl (560-1, 120 kg/ha) suppressed the disease under various field conditions and were superior to KCl, KNO 3 , NH 4 NO 3 , or Ca(NO 3 ) 2 in retarding asparagus decline and increasing marketable yields (...)

Wade H. Elmer

Papers

Pathogenicity and vegetative compatibility among isolates of Fusarium oxysporum and F. moniliforme colonizing asparagus tissues

Seed Biofortification by Engineered Nanomaterials: A Pathway To Alleviate Malnutrition?

Sudden Vegetation Dieback in Atlantic and Gulf Coast Salt Marshes.

Influence of Formononetin and NaCl on Mycorrhizal Colonization and Fusarium Crown and Root Rot of Asparagus

Suppression of fusarium crown and root rot of asparagus with sodium chloride