Úroda je dobrý výsledek.

Because dobrý belongs to výsledek, not to úroda.

• úroda = a feminine noun
• výsledek = a masculine noun
• dobrý výsledek = good result

So the structure is:

• Úroda = subject
• je = is
• dobrý výsledek = predicate noun phrase

The adjective must agree with the noun it modifies, so we get dobrý výsledek, not dobrá výsledek.

If you wanted the adjective to describe úroda, you would say Úroda je dobrá.

Je is the 3rd person singular present form of být = to be.

So:

• já jsem = I am
• ty jsi = you are
• on/ona/ono je = he/she/it is

In this sentence, úroda is singular, so je is the correct form.

In this sentence, both nouns are in the nominative singular.

• úroda = nominative singular
• výsledek = nominative singular
• dobrý agrees with výsledek, so it is also nominative singular masculine

That is why the sentence looks like a straightforward X is Y structure.

This is a very common learner question.

After být (to be), Czech can use a predicate noun in the nominative or sometimes in the instrumental.

Here, dobrý výsledek is in the nominative, which works well for a simple identification or statement.

So:

• Úroda je dobrý výsledek. = nominative predicate
• Úroda je dobrým výsledkem. = instrumental predicate, also possible in some contexts

Very roughly:

• nominative often sounds like a direct equation or label
• instrumental can sound a bit more like a role, function, or stylistic alternative

For a beginner, the most important thing is: the sentence as given is grammatically normal.

A good clue is the ending -a.

Many Czech nouns ending in -a are feminine, especially in the nominative singular.

So:

• úroda is feminine
• that is why, if you described it directly with good, you would say dobrá úroda

Of course, there are exceptions in Czech, but -a = often feminine is a very useful beginner pattern.

Because Czech does not have articles like English.

So úroda can mean:

• a harvest
• the harvest

And dobrý výsledek can mean:

• a good result
• the good result

Context tells you which one is meant.

This is one of the big differences between English and Czech: Czech usually leaves definiteness unstated unless the context makes it clear.

The given word order is the most neutral one:

• Úroda je dobrý výsledek.

Czech word order is more flexible than English, because case endings help show grammatical relationships.

You can change the order for emphasis, for example:

• Dobrý výsledek je úroda.

But that changes the focus or emphasis, not the basic meaning.

For learners, the safest default is:

subject + je + complement

A few useful points:

• Czech stress is usually on the first syllable of each word
• ú and ý are long vowels

So approximately:

• Úroda → Ú-ro-da
• dobrý → DO-bree
• výsledek → VÝ-sle-dek

A few pronunciation notes:

• ú is a long oo
• ý is a long ee sound in modern Czech pronunciation
• je sounds roughly like ye

So a rough English-friendly guide would be:

OO-ro-da ye DO-bree VEE-sle-dek

Not perfect, but close enough for a beginner.

Both ú and ů represent the same long u sound in modern Czech.

The difference is mostly spelling.

A useful rule:

• ú is usually written at the beginning of a word
• ů is usually written inside a word

So:

• Úroda starts with ú because it is at the beginning

This is mainly an orthography rule, not a pronunciation difference.

Yes, but it means something different.

• Úroda je dobrý výsledek. = The harvest is a good result
• Úroda je dobrá. = The harvest is good

In Úroda je dobrá, the adjective dobrá agrees with úroda:

• úroda = feminine singular
• so dobrá = feminine singular

So both sentences are grammatical, but they are not the same sentence.