First, this isn’t designed for food crops.

Through the periodic removal of mature macrophytes from the floating plant mat, we prevent the accumulated nutrients from re-entering the aquatic ecosystem at senescence. Those plants are then composted at an upland location, allowing bacterial decomposition to release some of the organic phosphorus so it can be recycled and used as a fertilizer ingredient for growing soil mixtures. The foam and nylon parts of the floating plant mats are re-used to start a new cycle of plant growth and nutrient uptake.

If a similar approach was used for crops, they could be pulled to shore or accessed with boats. In either case, they could be formed as long narrow strips instead of circles or squares to easily access the crop portion.