On average, plowed land erodes away at slightly more than 1

Question

On average, plowed land erodes away at slightly more than 1 millimeter per year, while new soil builds up at about 0.2 millimeters per year. As a result, continually cultivated soil will become exhausted in the space of several hundred years, 
unless no-till agriculture is practiced. No-till agriculture is a method in which crop stubble remains in place and a special drill inserts the seeds into the soil. However, only about 16 percent of cultivated areas in the United States use this method.

Which of the following is best supported by the information above?

(A) Although the advance of farming technology has made no-till agriculture available to wealthy farmers, such methods are financially impractical for many American farmers. 
(B) If the United States does not utilize means that replenish or reuse exhausted soil, it must eventually find other ways of getting agricultural products. 
(C) Agricultural industries that do not require plowing - such as dairy or chicken farms - are not affected by topsoil erosion. 
(D) If 5 out of 6 of all American farms were to practice no-till agriculture, the United States would produce enough agricultural products to meet domestic demand for several hundred years. 
(E) Hydroponic farming (farming without soil) would solve the United States’ land erosion problem.

DexDee · Answer

I vote for B.

Everything else seems to be largely out of scope. Only B seems to form some logical line of reasoning, although not the most convincing sort.

vgmats · Answer

I don't like B very much. 
According to B: if US  "does not utilize means that replenish or reuse exhausted soil"  then it must eventually find other ways of getting agricultural products

However, the stimulus says:
As a result, continually cultivated soil will become exhausted in the space of several hundred years, unless no-till agriculture is practiced.
I interpret this statement to mean - 
US can practice 'No-Till' agriculture and solve the solve the soil erosion problem. And 'No Till' agriculture doesn't replinish or reuse exhausted soil. Therefore, we can use 'no-till' agriculture (without the need to replinish/reuse exhausted soil) and NEVER need to find other ways of getting agricultural products (eg: importing agri products from other countries)

DexDee · Answer

^ You are right in stating that the US  can  use No-till agriculture to negate the impending doom, but  wrong  to assume that they will do just that! From what we know, "only 16 percent of cultivated areas in the United States use this (No-till) method". There is no indication from the premise that US is considering to promote this technology to larger areas. So the way things are right now, soil erosion seems to be an inevitability. And that only means... B!

vgmats · Answer

Yes, i agree with you that there is no indication that US WILL use no-till farming. But, the fact that US CAN use no-till farming is enough to eliminate B.

If US can use no-farming then it is not true that " it must eventually find other ways of getting agricultural products." 
It CAN use 'no-till faming' OR 'find other ways of getting agri products'
Therefore, saying that US MUST find other ways is wrong (IMHO)

donkadsw · Answer

I'm after D.

If 5 out of 6 farms practice no-till agriculture, the erosion would be one-sixth of 1mm ~ .167 mm/year but new soil builds up at 0.2 mm/year. So there is really no risk of erosion.

DexDee · Answer

^ Without soil to work with, will no-till farming work? Unless you assume that US will use no-till farming at some point BEFORE soil erosion reaches critical ( unsustainable ) levels, no-till farming is not going to save the day. 
 Besides, the other options seem to be out of scope?

DexDee · Answer

This logic works only if you assume that all farms are of equal size. At the least, 5 farms together must be greater than the size of the sixth farm. I had discounted D because we are required to make such an assumption.

vgmats · Answer

Continuing on Option B:

Lets call:
A = No-Till Farming by US
B = US adopts methods to replinish and reuse exhausted soil
C = Land Erosion Reaches Critical Levels
D = US needs to resort to alternative ways to get agri products (eg export them)

According to the Stimulus:
A CAN Prevent B

Common Sense:
If B happens we can prevent C
If C Happens then D MUST Happen

According to the 2nd Option
If B does not happen then D MUST happen
But Actually from above: If A AND B do not happen then D must happen

Nothing Says A does NOT Happen...therefore it is wrong to say C (and consequently D) will happen.

akkifreaky · Answer

I also think it should be D.

Options B seems to suggest something which is not mentioned in the stimulus.

But option D certainly points out that No Till agriculture should be followed as given in the stimulus.

Hope I am correct. Please post the OA now.

DeeptiM · Answer

Narrowed down to B & D..chose B...

reatsaint · Answer

I vote for B as well, with the choice between B and D.

vgmats · Answer

OA is  B

I'm not convinced with the OA, but seems like the best option.

Anyone else feels that this is not a very GMAT-like question?

bluemints · Answer

I agree with you that this is unlike an official question, which has a unambiguous answer.
But the other options are out of scope or assume a lot of information, making B the most appealing choice

dentobizz · Answer

Agree with you'll on this.
The official Inference/Must be true questions have options that are pretty straight forward and many a times are paraphrases or extended inferences of the conclusion.
No extra or outside information besides the question stem is included in the options. 
But the option B stands out since all the rest are pretty bad/easy to eliminate.

kanigmat011 · Answer

I have one doubt here
while going through concepts of must be true questions, its necessary that info in the correct answer needs to be validated by the info in the stimulus.
But here no where its present in Stimulus about the other ways etc.
And this observation is not just for this particular question, i have seen this in almost every question i have gone through.

Experts kindly let us know if the above approach is incorrect,and suggest what needs to be done in order to crack these questions

dp14695 · Answer

This is Find conclusion Or Must be true type of question.

(A) Although the advance of farming technology has made no-till agriculture available to wealthy farmers, such methods are financially impractical for many American farmers. -  Out Of Scope. No mention of Rich farmer here or there is no differentiation provided for rich and poor farmers

(B)If the United States does not utilize means that replenish or reuse exhausted soil, it must eventually find other ways of getting agricultural products. -  After long time continually cultivated soil will become exhausted as Most of USA land is eroding away at slightly more than 1 millimeter per year so there will be no soil for agriculture activity.

(C) Agricultural industries that do not require plowing - such as dairy or chicken farms - are not affected by topsoil erosion.  - completely out of scope

(D) If 5 out of 6 of all American farms were to practice no-till agriculture, the United States would produce enough agricultural products to meet domestic demand for several hundred years. -  We don't know production capacity of today and of future. We can not make prediction as such.

(E) Hydroponic farming (farming without soil) would solve the United States’ land erosion problem.  - completely out of scope

tittoo · Answer

For inference/must be true questions, is it okay to make predictions of what will happen in the future? 
On many other questions of this type, I have seen this as a trend on wrong answers.

Any thoughts or insights from experts?

dp14695 · Answer

You can not make predictions inference/must be true questions. Must Be True questions require you to select an
answer choice that is proven by the information presented in the stimulus.
You cannot bring in information from outside the stimulus to answer the questions; all of the information necessary to answer the question resides in the stimulus.

Could Be True answers are attractive because they can possibly occur, but they are incorrect because they do not have to be true.

Exaggerated answers take information from the stimulus and then stretch that information to make a broader statement that is not supported by the stimulus.

tittoo · Answer

Thanks! Doesn't answer choices B and D both make predictions about the future?
So the correct answer choice is making a prediction here.

On average, plowed land erodes away at slightly more than 1

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On average, plowed land erodes away at slightly more than 1

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