Mario Tenuta

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Viewing 15 posts - 1 through 15 (of 28 total)
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  • in reply to: Lecture Questions #4471
    Mario Tenuta
    Keymaster

    Hello Jennifer. There is no purpose to the priming effect. It does have an effect though. An increase in microbial activity with addition of labile material results in release of extracellular enzymes by soil bacteria and fungi. These enzymes are released by microbes to depolymerize the labile carbon. However, the enzymes also encounter humus and work to depolymerize the humus. This is the priming effect, an increase in degradation of stabilized carbon as a result of addition of labile carbon materials to soil. I hope this helps understand the priming effect better. take care, Mario

    in reply to: Participation Marks #4470
    Mario Tenuta
    Keymaster

    Hi. I will start compiling those marks starting this Sunday.

    in reply to: A Question About the Final Exam Procedure #4469
    Mario Tenuta
    Keymaster

    Hi All. I keep to the same instructions about the exam as given in lectures. It will be emailed and posted online to the course homepage at the start of the exam period (1:30pm). It is open book and needs to be emailed back by 4:30pm. Exceptions being students registered with student support services that have time considerations to beyond 4:30pm. take care, Mario

    in reply to: Lab 7 Question #4468
    Mario Tenuta
    Keymaster

    yes, it is.

    in reply to: Horizon designation for organic soils #4467
    Mario Tenuta
    Keymaster

    Hi Victoria. Of is the best designation. This way the horizon is not confused with the LFH surface layer of forest or shrub land.

    in reply to: Lab 4 #4390
    Mario Tenuta
    Keymaster

    Hi. Please see Lecture 5 slide 11. It shows the diagnostic horizon for each of the soil orders. A diagnostic horizon is what is key to placing a soil in a particular Order. You will see that the diagnostic horizons are not shared between Orders. Take care, Mario

    in reply to: Lab 4 #4389
    Mario Tenuta
    Keymaster

    yes for those who have the Monday session.

    in reply to: Great groups and subgroups #4316
    Mario Tenuta
    Keymaster

    Hello, yes I made a mistake, it should be Great Groups. Page 23 of Soil Classification System of Canada linked on our website gives the Great Groups for all soil orders in Canada.

    in reply to: Lecture Questions #4311
    Mario Tenuta
    Keymaster

    Hello All. I sorting out with the TA the marking of labs and their return to you. They will be emailed back to you so you can see how you did. take care, Mario

    in reply to: Exam external resources #4310
    Mario Tenuta
    Keymaster

    Hello All. As this is an open book exam you can and are encouraged to consult materials external to lectures and powerpoints. take care, Mario

    in reply to: Lab 1 marks #4302
    Mario Tenuta
    Keymaster

    Hi. We went over this in class. I was confused and thought this week was a break week. I said last week it was due next week because of the break. No one said “what do you mean, a break”. Recognizing the mistake I said you can send the assignment in before your session next week. take care, Mario

    in reply to: Impact of Perennial Crops on Aggregate Size #4298
    Mario Tenuta
    Keymaster

    Hello. For starters, perennial vegetation such as forages and grasses are not disturbed by tillage. So larger aggregates can form without being broken by the impact of cultivation equipment in breaking them apart. However, we have cropped soils that are not tilled but don’t build as good soil structure as under perennials. Perennials invest more energy and resources into building root systems than annual crops. Perennials rely on roots to store energy and nutrients for growth in spring. Many perennials can grow sooner than annual in spring and continue to grow in the fall. Thus perennials for the most part, grow for a longer portion of the year than annual crops in our climate. This all results in more carbon input into soil with perennial via the root system. Further perennial roots are growing and dieing constantly, this adds carbon to soil and feeds microbes. The roots also encourage micorrhizal association (roots with a fungus, we will learn more on this later). The mycorrhizae have thin threads or filaments of cells. These excrete sticky glycoproteins to bind soil together. They also physically make a mesh around aggregates. Roots also can bind microaggregates together to make larger aggregates, partly because of excretion of sticky carbon substances and also because they push and pack soil as they grow and expand in pores. So you see its about carbon input for a longer period of time, roots, feeding soil microbes and lack of disturbance. Sorry for the long answer.

    in reply to: Role of Microaggregates #4297
    Mario Tenuta
    Keymaster

    Hello Victoria. Good question. It should read

    contains pores that are very narrow that allow for water storage and retention in soil

    take care,
    Mario

    in reply to: Lab 2 #4289
    Mario Tenuta
    Keymaster

    Yes, applies to both lab sections. Happy Thanks Giving, Mario

    in reply to: Lab 2 #4287
    Mario Tenuta
    Keymaster

    Lab 2 lab is due before your lab section time the week we come back from the break. take care, Mario

Viewing 15 posts - 1 through 15 (of 28 total)

Welcome to the Applied Soil Ecology Lab at the University of Manitoba