The risk in throwing out a low-ball offer in any negotiation is that it may indicate that you aren't serious / aren't aware of the true value of what you're trying to buy.
If you went into a car dealership and saw a car with a $15k sticker price, and offered $5k, the salesperson might view you as a waste of time, and not properly engage. On the other hand, if you truly know the value of the car is $11k, and you offer a price of $10,500, the salesperson might see that your offer price is close to what the dealership wants, and could work to get you the rest of the way there.
In real estate, the additional complication is that, depending on jurisdictional regulations, often multiple offers are given privately to the real estate agent, who passes the information on to the buyer. If you could see that it was a slow day at the car dealership and made a low offer, the above salesperson might still entertain you because you're the best shot of a sale they have at the moment. In a real estate transaction however, you might not even know how many real offers are happening at the same time. Instead of counter-offering, the land owner might just ignore your bid entirely.
So the question is: would your offer be so low that the seller would just ignore you? And as a follow-up, how much would you actually be willing to pay, if you were forced to go that high?
Ultimately the price of anything is what the purchaser pays for it. If there are a lot of comparables for that thing, then you can easily determine what the price 'should' be. But real estate is not fungible; there may be close comparables, but no exact matches. This means that it can be very difficult to determine the value of property, and the value to you might not be the same as the value to the seller. For example - does the acreage have good public access to nearby grazing properties? If so, it has increased value for someone who keeps sheep [or who plans to sell to sheep herders in the future], but no increased value for your personal use.
So, if the value of the property to you for your use is only 70k [perhaps you'd go as high as 75k, but you want to leave yourself some negotiating room], and if you wouldn't ever go as high as 150k, then having the seller walk away means nothing to you. But if you would otherwise go as high as 140k because that's what the property is worth to you, then you may lose your shot by starting so low.
Can the land have increased in value so much over a year? Maybe, particularly if improvements were made, or if access to the land changed in the interim. Maybe the last seller was very motivated to sell, and couldn't wait for a proper offer. But ultimately the price 1 year ago doesn't impact the value today, except as a possible indicator of a near-comparable property. The real question is how much you're willing to pay for it, based on current comparable properties today.