quick explain to me TxT

I think this answer can only help you grasp the crop rotation farm. If you want the answer to your last question, skip all these and go to the very last sentence.

The crop rotation farm allows the soil to rest and have the necessary nutrients and microorganisms, which in turn allows plants to grow.

Barley and wheat, these two are the main crops that feed the nation and also suck the soil dry.

Beans (clover as substitute in some Manga I read), allows the soil to rest (which the prince assumes) . The beans will be the food of the livestock such as pigs and cock, I mean chicken, and in return they will excrete waste (poop, stool, feces) which give life to the soil (take note that a fertilizer provides nutrients to the plant). Thus, the beans help barley and wheat to grow indirectly. (the prince assumes)

Crop rotation - they have 3 different lands which allows the three plants to be planted distinctive to each land
land 1 - wheat, land 2 - barley, land 3 - beans, then rotate after harvest:
land 1 - barley, land 2 - beans, 3- wheat, then rotate again after harvest and so on and on.

I think the problem here is that the prince did not take consideration on research. There are many kinds of wheat, barley, and beans, in which why there are some called winter barley and spring barley (no sh1t).

1. Research, there should have some research about this crop rotation on smaller lands in order to check if the labor, cost, and time will back the use of the said method. We have control group (the current method they have) and the experiment group (the method they are introducing, a.k.a the crop rotation method)
2. They did not consider the date that barley, wheat, and beans should be planted. There are some called spring barley and winter barley but the problem is the date which corresponds to the temperature in spring, fall, autumn, and winter (I dunno if that's the correct order) when the plants should be sowed(planted). Though assuming we have the same climate on those months.
3. Composite (a.k.a. The magical compost of the princess (MC) - I think this would be the viable answer for why the princess' crop rotation is better. The answer:

"Compost nourishes the soil, while fertilizers provide nutrients for the plants."

Note: this might not be the answer, but only assuming from my knowledge. I'm no expert nor study agriculture and I only share some assuming knowledge as a wannabe knowledgeable person. ヾ(❀╹◡╹)ﾉ~

It also depends on the plants you use!

The overall premise is that the next plant you plant should add the nutrients that the previous plant took.

So if you planted something that *took* all the nitrogen from the soil then the next thing you need to plant needs to *add* nitrogen to the soil.

But if you don't take that into consideration and plant something that also needs to take a look of nitrogen to grow then it won't grow well at all and the soil will be worse off.

The FL is explaining exactly what to do and how to do it where ass all were told from the "star maiden" is simply "rotate the crops" without any direction. So I feel like the probably planted random stuff and it didn't take.

The almighty spoken!