Sutra će vlasnik doći traktorom i donijeti sijeno do štale.

Sutra is an adverb meaning tomorrow. Croatian often uses time words like danas (today), sutra (tomorrow), and jučer (yesterday) on their own, without any preposition.

So Sutra će vlasnik doći... is simply Tomorrow the owner will come...

The future is formed with the auxiliary će plus an infinitive.

• će doći = will come
• će donijeti = will bring

In this sentence, one će covers both verbs:

Sutra će vlasnik doći i donijeti...
= Tomorrow the owner will come and bring...

Će is a clitic, and clitics in Croatian usually go in the second position in the clause.

So if the sentence starts with Sutra, the clitic normally comes right after it:

Sutra će vlasnik doći...

That does not mean će belongs especially to sutra. It is just following the usual clitic placement rule.

A different word order is also possible:

Vlasnik će sutra doći...

Because both infinitives can share the same future auxiliary.

So:

će doći i donijeti
means
will come and bring

Croatian does not need to repeat će before the second infinitive unless the speaker wants special emphasis or a different rhythm.

Traktorom is the instrumental singular of traktor.

Here the instrumental expresses the means of transport or the vehicle used:

• doći traktorom = to come by tractor
• literally, to come using a tractor

This is a very common use of the instrumental in Croatian.

In this sentence, the most natural meaning is by tractor or using a tractor.

English can express this in several ways depending on context:

• come by tractor
• come on a tractor
• sometimes come with the tractor, if the context makes that natural

But grammatically, Croatian is mainly marking the means/instrument with the instrumental case.

Sijeno is a neuter singular noun, and here it is the direct object of donijeti, so it is in the accusative.

But for many neuter inanimate nouns in Croatian, the nominative and accusative forms are identical.

So:

• nominative: sijeno
• accusative: sijeno

That is why the form does not change.

Because do and u mean different things.

• do štale = to the barn, up to the barn, as far as the barn
• u štalu = into the barn

Also, do takes the genitive, so štala becomes štale.

So:

• štala = base form
• do štale = to/up to the barn

The sentence as written does not necessarily say the hay is brought inside the barn, only to it.

Vlasnik means owner.

Croatian has no articles, so there is no separate word for the or a/an. Whether vlasnik means the owner or an owner depends on context.

In a sentence like this, English would usually say the owner, because it sounds like a specific owner is already known.

Croatian often leaves out subject pronouns when they are not needed. This is called a pro-drop language.

Here, the subject is already clearly stated as vlasnik, so adding on would usually be unnecessary.

• Sutra će vlasnik doći... = normal
• Sutra će on, vlasnik, doći... = much more marked, with extra emphasis

Yes. Both are perfective verbs:

• doći = to come / arrive as a completed event
• donijeti = to bring as a completed event

This fits the sentence well, because it describes two whole future actions:

1. the owner will arrive
2. he will bring the hay

If you used imperfective verbs such as dolaziti or donositi, the meaning would usually shift toward repeated, ongoing, or less bounded action.

Yes. Croatian word order is fairly flexible.

For example, these are all possible:

• Sutra će vlasnik doći traktorom i donijeti sijeno do štale.
• Vlasnik će sutra doći traktorom i donijeti sijeno do štale.
• Sutra će doći vlasnik traktorom i donijeti sijeno do štale.

The basic meaning stays the same, but the emphasis changes.

Starting with Sutra highlights the time: tomorrow.