All agri worlds are of similar size, located in similar orbital zones within their void systems and subject to specific exposure to a prescribed spectrum of solar radiation. Their soils have to be within a tight compositional range, and they have to be close to major supply worlds.
The Imperium is not a gentle custodian of such places. After discovery of a candidate planet, the first fifty years are spent in terraforming according to well-worn Martian procedures. All pre-existing life is scrubbed from the rocks, either by the application of controlled virus-chewers or by timed flame-drops. The atmosphere is regulated, first through the actions of gigantic macro-processors and thereafter by a land-based network of control units, more commonly referred to as command nodes. Weather, as least as generally understood, disappears. Rainfall becomes a matter of controlled timing, governed by satellites in low orbit and kept in line by fleets of dirigibles. The empty landscape is divided up into colossal production zones, each patrolled by crawlers and pest-thopters. Millions of base-level servitors are imported, kept at the very lowest level of cognitive function but bulked up by a ruthless level of muscle-binders.
Soon after this process completes, every agri world looks exactly the same – a flat, wind-rummaged plain of high-yield crops swaying towards the empty horizon. A person could walk for days and never see a distinctive feature. Not that anyone sane would choose to walk in such places – the industrial fertiliser dumps are so powerful that they turn the air orange and make it impossible to breathe unfiltered. A single growing season exhausts the soil completely, requiring continual delivery of more sprays of nitrates and phosphates, all delivered from the grimy berths of hovering despatch flyers. The entire world is given over to a remorseless monoculture, with orthogonal drainage channels burning with chem-residue and topsoil continually degrading into flimsier and flimsier dust.
But that doesn’t matter. A planet can be driven like this for thousands of years before it eventually keels over and becomes a death world. The quality of the crops gets steadily worse, but the quantity can be sustained almost indefinitely, assuming that supply lines are maintained and imports remain consistent. At the end of every season, the great harvester leviathans are stoked up and dragged from their pens and let loose on the grey fields, smokestacks belching and tracked undercarriages sinking deep. These massive creatures of high-sided metal and intricate pipework, the smallest of which are a hundred metres long, crawl across the blasted prairies, sucking up every last speck of pallid grain and piping it directly to antiseptic internal hoppers. Feed-landers come down from high flight, dock with the still-trundling leviathans and extract the raw material, from where it is taken into the city-sized processor vats, blasted with antibiotics, smashed, burned, crushed, then stamped and packaged. Once ready for transport, containers are dragged up into orbit aboard swell-bellied landers, ready for transfer to the void-bound mass conveyers, which deliver the refined product to every starving hive world and forge world in their long circuits.
There is a quaint tradition in the various propaganda departmentos of the Administratum of marketing agri worlds as quasi-paradises, free of the squalor and overcrowding of a standard urban station, and full of bucolic ease. Vid-cards are dropped into communal hab-warrens, extolling the virtues of a life lived outdoors with the sun on your back and a ruddy-faced boy or girl – subject to preference – by your side. In reality, life on an agri world is as unrelenting, back-breaking and monotonous as the vast majority of other Imperial vocations. There are no trees laden with glossy fruit, only kilometre after kilometre of hissing corn.
There are no gentle strolls under the warming sun, only punishing work details in rad-suits, leaning into the dust-laden winds that howl around the equator with nothing to halt their rampage. Once the new arrivals have made planetfall and found this out, it is too late. Crew transports arrive on agri worlds full and leave empty. There is a saying among the indentured workers – you come for the soil, you end up part of it.