Precision irrigation valves must open per-zone in real-time but rural farms have no WiFi

Soil moisture sensors across a 500-acre farm detect that Zone 14 is at wilting point and needs water within the hour, but the farm's field zones are 2+ miles from the nearest WiFi router and have spotty cellular at best -- a cloud API call to classify soil conditions and decide irrigation timing either fails entirely or takes 30+ seconds during peak tower congestion. Over-irrigating by even 15% wastes $8,000-$12,000 per season in water costs for a mid-size farm, and under-irrigating at a critical growth stage permanently reduces yield by 20-30%. Cloud models cannot solve this because the connectivity gap is geographic and permanent -- rural cell towers are oversubscribed and fiber will never reach mid-field sensor stations. A Gemma E2B model running on each irrigation controller node classifies soil moisture, weather forecast data cached daily, and crop growth stage to make per-zone open/close decisions autonomously, even when fully disconnected for days.