Cultivator

I was really surprised to hear that this cultivator cost as much as 1 million yen.

Source: tatoeba (1994536)

Near-synonyms: scarifier, scuffler (not always precisely differentiated; dialectal usage has varied)

Source: wiktionary

As the crop gets bigger, the shank spacing on the cultivator will need to be adjusted accordingly.

Source: wiktionary

The Cultivator, or Horse Hoe.—This is an instrument not as much known and used as it deserves and ought to be. It is adapted for operations between the plough and harrow, and at certain times is much better than either. It is half a plough, half harrow, and half hoe, and does all these operations conjointly. […] Now this is the time to use the cultivator. It ought, after a few days, to follow the harrow, and is much more useful than the plough, as well as a great saving of labour. It cuts as deep and pulverizes the soil as well. It tears up and brings to the surface the roots of grass which the plough only covers, and by adapting the width of the cultivator to the space between the rows of corn, it half hoes the corn at the same time, and does the whole work most admirably. When there is much grass growing with the corn, it is an extremely useful instrument, as it pulls it up by the roots and in a great measure destroys it. For the Fiorin or Quack roots, with which our soil too much abounds, it will be of great service, and it appears to me it will be the most effectual remedy for it of any instrument we have yet tried. Corn is much sooner dressed with the hand-hoe, by the half ploughing, half hoeing operation of the cultivator. The cultivator is likewise very useful for the raising of potatoes, and for stirring the ground between the rows of turnips; and where a clover lay has been turned over to put down to wheat, when the plough cannot be again resorted to for fear of disturbing the sod, this instrument may be used for a shallow ploughing, which it will do much better than can by any other mode be effected. Corn is now raised with much less labour than formerly. It was the custom to hand-hoe a crop two, and often three times, and this was always an expensive and tedious process. Hoeing is now often omitted entirely, and is seldom done more than once; and still there are heavier crops of corn raised now than formerly. […] -Dr. Beekman.

Source: wiktionary