Why does Slovakia have a more vibrant agricultural sector than the neighboring
Czech Republic?

Because of the fertile plains of the Danube River.

Explanation:

Slovakia and Czechia (formerly the Czech Republic) despite being part of a single country until three decades ago, and being neighbors with very close ties, have developed differently and their economies have a lot of differences. One of the biggest differences is that Slovakia has a highly developed agricultural sector while Czechia's is very small and doesn't contribute much to the economy.

s The reason for this difference is geography. Slovakia has a relatively large and very fertile plain, with the Danube River being a big plus in it. This provides Slovakia with enough area and very good conditions so that it can have a prosperous agricultural sector. Czechia, on the other hand, is almost entirely covered with mountains and hills, and the little area of the handfull of valleys is mostly urbanized, thus the country doesn't have what it needs to develop the agricultural sector.