drivers of soil respiration of root and microbial ... - Unitus DSpace
drivers of soil respiration of root and microbial ... - Unitus DSpace
drivers of soil respiration of root and microbial ... - Unitus DSpace
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1.5. Objectives <strong>of</strong> the study<br />
22<br />
The general aim <strong>of</strong> the study was to advance the underst<strong>and</strong>ing <strong>of</strong> the processes <strong>and</strong> factors<br />
controlling the behaviour <strong>of</strong> different <strong>soil</strong> <strong>respiration</strong> sources in grassl<strong>and</strong> ecosystems. The work is<br />
subdivided into different topics, according to the following specific objectives <strong>and</strong> various<br />
methodological approaches used to attain them:<br />
• To found out how <strong>root</strong>- <strong>and</strong> <strong>microbial</strong>-derived <strong>respiration</strong> respond to changes in biotic <strong>and</strong><br />
abiotic factors on different time scales: from daily to interannual (Chapter 2).<br />
• To found out the delay in the response <strong>of</strong> <strong>root</strong> <strong>respiration</strong> to photosynthetic C supply from<br />
aboveground <strong>and</strong> to calculate to what grade these processes are coupled (Chapter 3)<br />
• To verify how the plant species, plant growing stage <strong>and</strong> nutrient supply influence the magnitude <strong>of</strong><br />
autotrophic component <strong>of</strong> <strong>soil</strong> <strong>respiration</strong> <strong>and</strong> the speed <strong>of</strong> cycling <strong>of</strong> C through the plant<br />
community (Chapter 5).<br />
• To assess the response <strong>of</strong> <strong>root</strong>-derived <strong>respiration</strong> <strong>and</strong> <strong>soil</strong> <strong>microbial</strong> activity to management<br />
based on defoliation practices (mowing <strong>and</strong> grazing) (Chapter 4).<br />
• To quantify the contribution <strong>of</strong> individual <strong>soil</strong> <strong>respiration</strong> sources to total CO2 efflux from<br />
grassl<strong>and</strong> ecosystems by different in situ partitioning techniques. To verify the comparability <strong>of</strong><br />
the obtained results <strong>and</strong> discuss the methodological shortcoming <strong>of</strong> each method (Chapter 6).<br />
The objectives <strong>of</strong> this study required both in situ measurements <strong>of</strong> <strong>soil</strong> <strong>respiration</strong> fluxes <strong>and</strong><br />
different environmental variables influencing them at the selected grassl<strong>and</strong> site as well as laboratory<br />
cultivation <strong>and</strong> experiments with a single plant species <strong>and</strong> following analyses <strong>of</strong> <strong>soil</strong> <strong>and</strong> plant material.<br />
Details <strong>of</strong> methodological approaches will be discussed in the chapters.<br />
1.6. Study approach <strong>and</strong> summary <strong>of</strong> main findings<br />
Drivers <strong>of</strong> <strong>soil</strong> <strong>respiration</strong> <strong>of</strong> various origin (Chapter 2)<br />
Partitioning <strong>of</strong> <strong>soil</strong> <strong>respiration</strong> into <strong>root</strong>- <strong>and</strong> <strong>microbial</strong>-derived components <strong>and</strong> bimonthly<br />
measurements <strong>of</strong> all <strong>respiration</strong> fluxes were performed in Amplero, a Mediterranean grassl<strong>and</strong> site<br />
located in central Italy (AQ). Amplero is one <strong>of</strong> the main sites <strong>of</strong> CarboEurope Integrated Project<br />
<strong>and</strong> is equipped with eddy covariance tower for determining CO2 exchange between the vegetation<br />
<strong>and</strong> the atmosphere (Fig.7).
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