Conservation tillage systems are said to have all of the following advantages but one over conventional tillage systems.
A) it involves the use of less toxic weed control practices
B) it reduces soil erosion
C) it encourages higher microbial population numbers in the soil
D) it increases the hydraulic conductivity of the soil
E) its labor and energy requirements are lower
Question 2
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
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