In one field trial comparing no-till and conventional tillage, soil samples taken after 15 years without liming revealed that the pH of the upper 15 cm was lower on the no-till plot than on the conventional plot. Which of the following most likely accounts for this difference?
A) earthworms were more active in the no-till plot
B) acidifying effects of nitrogen-containing fertilizers
C) organic decomposition produced more organic acids in the no-till plot
D) plowing mixes the surface soil more thoroughly
E) Al3+ ions are tied up by the organic matter thereby releasing H+ ions
B
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A sexually mature female animal produces eggs or ova cells in the ____________________
Fill in the blank(s) with the appropriate word(s).
Used typically for symmetrical objects; the cutting-plane line actually cuts through one quarter of the part. The sectional view shows half of the interior and half of the exterior at the same time.
A. Full section B. Half section C. Broken out section D. Removed section E. none of the above
What is the difference between a load and a control?
A) Controls use power. Loads either let power pass or they do not let it pass. B) There is no difference. They are two words for the same thing. C) Loads are the power, as in L1 and L2. Controls use the power. D) Loads use power. Controls either let power pass or they do not let it pass.
When editing a text file with vi, if you want to save your changes and exit right away, you can use ____ or ZZ from command mode.
A. :wq B. :q! C. :se D. :sq