Passage Summary: Growing crops with seawater near the coast is cheaper than other irrigation because you don't have to pump the water very far, and pumping is the most expensive part of the whole process.

Conclusion: Farming crops with seawater near the ocean would be less expensive than most other forms of irrigated agriculture.

Reasoning: The primary cost of irrigation is pumping water, and since seawater wouldn't need to be moved far if the farm is near the coast, those costs would be minimized.

Analysis: The claim about pumping being the 'greatest expense' serves as a premise. It provides the necessary link to explain why the distance the water travels is the deciding factor for the total cost. By establishing that pumping is the biggest financial burden, the author can then conclude that minimizing that specific burden (by being near the ocean) makes the whole operation cheaper. This is a classic building-block premise that supports an intermediate step in the logic.