Environmental Analysis Leaf Organisms


This test determines the micro bial colonisation on the leaf surface. This is particularly useful for comparing before and after compost tea applications. Adequate cov erage of leaf surfaces by beneficial micro-organisms can help reduce pests and diseases.


In order to effectively measure and differentiate between these organisms, both differential interference contrast (DIC) and fluo rescence microscopy techniques are undertaken using Olympus BX51 microscopes. DIC offers a means of swiftly assessing total


Figure 4: Example of active fungi and bacteria stained using FDA fluorescent dye, viewed under epi-fluorescence microscope (200x microscope)


bacteria and fungi within a sample, whereas fluorescence microscopy utilising FITC and FDA staining enables active bacteria and fungi to be directly counted (Figure 4).


Interpreting the Soil Foodweb test


Any field, forest, pasture or even golf course has a unique soil food web with a particular proportion of bacteria, fungi and other groups, in addition to a certain level of complexity within each group of organisms in terms of numbers of species. These differences are due to soil, vegetation and climate factors, as well as land management practices.


A Soil Foodweb test enables a snapshot assessment to be made of the complexity of the ‘structure’ of a particular food web with regards to its composition and relative numbers of organisms in each group. For example, the ratio of fungi to bacteria is characteristic to the type of soil ecosystem. Grasslands and agricultural soils usually have bacterial- dominated foodwebs. Highly productive agricultural soils tend to have ratios of fungal to bacterial biomass of around 1:1 or less. However, forests tend to have fungal-dominated food webs where the ratio of fungal to bacterial biomass may be 5:1 to 10:1 in a deciduous forest; and 100:1 to 1000:1 in a coniferous forest.2


Having established the particular foodweb structure via the test, by then consulting the globally derived Soil Foodweb database, the laboratory can ascertain what remedial actions are required to optimise the structure for a particular location and crop type. Depending on the required land use, there are various ‘natural’ actions that can be undertaken to enhance the structure and complexity of a particular soil foodweb. These include altering land management practices, such as


crop rotation and reduction in tillage, and application of composts.


For example, a field with a 4-year crop rotation, when compared to one with a 2-year rotation, may have a greater variety of food sources (ie roots and surface residue), and therefore is more likely to have a greater variety of bacteria, fungi and other organisms. Furthermore, in reduced tillage agricultural systems, the ratio of fungi to bacteria increases over time, and earthworms and arthropods become more plentiful.


Compost and compost teas of varying microbial compositions can be applied depending on the required soil foodweb structure and land use. The composition of the compost or compost tea, and hence the soil that it is applied to, can be altered simply by adding an inoculum of the preferred food of the microorganism that needs to be boosted. For example, bacterial foods are green, high in easy-to-use sugar and nitrogen (eg grass clippings and cover crops, such as legumes and molasses), whereas, fungal foods are brown plant materials high in cellulose, lignin and tannin (eg woody fibrous materials, such as straw and sawdust). By following a step-wise approach to repairing and developing a specific soil foodweb with the correct balance and biomass of beneficial microorganisms which ultimately enables the presence of earthworms and/or microarthropods, then plant health can be assured.3


Conclusion


Utilising the Soil Foodweb test to assess soil health and subsequent natural remediation activities (eg altering land management practices and application of compost and compost teas), is helping agronomists to reduce their dependency on synthetic fertilisers and other chemical inputs such as insecticides, many of which are now subject to stringent EU regulations. In the long term, this is not only financially beneficial, but also extremely advantageous to the environment and general population as a whole.


References: 1


2 AUTHOR DETAILS


Dr Vinodh Krishnamurthy Soil Foodweb Lab Services and Research,


Laverstoke Park Farm


Sue Wilson, Head of Microscopy, Olympus Medical


What is compost tea? Available: www.laverstokepark.co.uk/compost-tea-explained [March 2010]


Elaine R. Ingham. Soil Biology Primer [online]. Available: http://soils.usda.gov/sqi/concepts/soil_biology/biology.html [March 2010].


3


The Soil Foodweb Approach. Available: www.soilfoodweb.com/sfi_approach1.html [March 2010]


Contact: Esther Ahrent Department Manager Marketing Communications Olympus Europa Holding GMBH Email: esther.ahrent@ olympus-europa.com Web:


www.microscopy.olympus.eu


9


Soil Moisture Plus Temperature Sensor


The SM300 from Delta T-Devices (UK) measures soil moisture and temperature with research grade accuracy: Soil moisture and temperature; Dependable accuracy ± 2.5%; Good temperature and salinity stability and Easy data logger connection (0-1V).


The SM300 offers outstanding performance in mineral, organic and saline soil conditions, and it is stable across wide ranges of temperature and salinity. The SM300’s construction uses industrial grade connectors and high specification materials throughout to produce a soil moisture sensor of outstanding quality. The built-in temperature sensor simplifies soil temperature measurement and achieves 0.5°C accuracy.


The SM300 minimises soil disturbance, preserving the original soil structure around the measurement rods. It is easy to insert and install whether at the soil surface or at depth. The SM300’s circular shape facilitates installation in augered holes – extension tubes are available. The SM300 is a dual-purpose probe – it can be used both with the Delta-T HH2 hand-held Moisture Meter for instant moisture readings, or left in situ for data logging of moisture and temperature. The SM300 is compatible with all Delta-T data loggers; they provide cost effective solutions for recording up to 60 sensors. In fact the SM300 can be connected to most types of data logger (simple 0 to 1V DC output for water content).


Reader Reply Card no 25


New Updated Mass Spectrometry Applications Guide


Dionex (USA) is pleased to announce the release of the updated mass spectrometry (MS) applications guide. The new applications presented in the MS Applications Guide offer excellent analytical choices for separation scientists in the fields of water testing, health and safety, chemicals, and food and beverages. The update provides 12 new environmental and industrial applications, including urea in ultrapure water, carbamates in water, alkylphenol ethoxylates, phenolic acids, FA and TFA, nicotine and metabolites, glyphosates, perchlorate in baby formula and milk, melamine and cyanuric acid, and ionic liquids by IC-MS and LC-MS. For instance, perchlorate contamination of milk and milk products has sparked concern given its adverse effects on infant health. The MS Applications Guide presents an IC-MS/MS method for the ultratrace-level perchlorate analysis in both liquid and powdered baby formula.


The methodology presented in the guide highlights the interface of liquid chromatography techniques, such as high performance liquid chromatography (HPLC or LC) or ion chromatography (IC) and mass spectrometry as powerful analytical tools for the detection and characterisation of compounds. By the release of this update, Dionex continues to provide innovative solutions for the analysis of compounds that are of growing concern in the life sciences, environmental, chemical, and food and beverage industries.


Reader Reply Card no 26


ACE


Automated soil CO2 exchange system Designed for superior soil flux experimentation CO2 analyser in chamber


ADC BioScientific Ltd. 1st Floor Charles House Furlong Way Great Amwell Hertfordshire SG12 9TA UK


Tel: +44 (0)1920 487901 Fax: +44 (0)1920 466289 E-mail: sales@adc.co.uk www.adc.co.uk


ADC: Network up to 30 ACE Stations


analysing the carbon cycle


Reader Reply Card no 27


May/June 2010


IET


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