PSS 021 Lecture Notes - Lecture 7: Nitrogen Fixation, Nitrite, Food Web
21 Sep 2017
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Document Summary
Soul contains four important parts: mineral solids (45%) , water (25%), air (25%), and organic matter (5%) Good tilth (the structure of the soil and how well it responds to any manipulation) Low populations of plant disease and parasitic organisms. How soils become degraded : a synergistic reaction. Less water storage in soil, lowers diversity, decreases soil nutrients. Organic matter (keep it alive and spongy) The half life of organic matter is very. Fractions of som: particulate organic matter, simple compounds (sugars, starches, proteins, half-life of days to months. Stable humus: complex compounds (ex: humic acids, half-life of years to decades. Soil organic carbon: refers only to the carbon component of a compound. About 58% of the mass of organic matter exists as carbon. If we know the carbon content, we can estimate the amount of som: som (%) = soc (%) x 1. 72. Nutrients are converted into forms that plants can use directly.
