Why is the land that Wylie and Van Pelt inherited unsuitable for farming?

The terrain is bad and the land is overwhelmingly thin. They were forced to grow wheat on it, which made it even thinner.
So what was Patrick's plan?

"What's this?
Wiley asks Patrick, looking at a small seed.
'They're buckwheat seeds.

'Buckwheat?

'It's what's called a cereal, but it can grow in thin soil and it's edible, so it's good. I'll tell you how to eat it!

'Huh?

'Then raise chickens. Raise chickens!
'I'll give it a try under your orders, but what about immediate funds and food?
'We'll lend you money. No interest.'
'Thank you, sir!

'So, Van Pelt's land has a lot of rocky mountains, so there's not much area to plant. So, raise goats!　Goats can eat meat and make cheese from their milk. Cheese is good!　And grow potatoes and sweet potatoes!　We'll buy them and turn them into alcohol!
'I understand alcohol, but goats?
'Oh, yeah, you want to do sheep?　Wool is good for money too!

'Huh,'

'What I'm saying, both of you, is that if farming is too difficult, you should take up animal husbandry!　Meat is more profitable!　The food is grass, and it grows everywhere!　Well, not just grass, but other stuff, too!　We'll support Van Pelt's place, too!　It's a lot of work to keep the animals from running away and to protect them from the goblins, but if we can do that, we'll have a good income!　Listen up, you two!　First, rebuild the economy of the territory!　Then we'll dominate the surrounding nobles with our economy. We'll make it impossible for the Snakes to run the territory without them. Our booze!　We'll make it a specialty at Wylie's and Van Pelt's. We'll sell it!　And we'll paint the west as Snakeskin!　We'll crush any nobleman who stands in the way of our faction!

What⁉︎''