。
The neighbor's land yields better crops than mine.
Literal
Next [of-の] person [of-の] land [topic-は] own [of-の] land [than-より] better crops [object-を] produces.
~より優れた + noun ('better X than Y') is a standard comparative-as-modifier construction. 穀物 ('grains, cereals, crops'). 産出する ('to produce, yield') is the formal Sino-Japanese verb for agricultural or industrial output. The sentence has a 'grass is greener' feel.