  Improving the efficiency of agriculture is a growing priority due to food
security issues, environmental concerns, and economics. Precision agriculture
and variable rate application technology could enable increases in yield while
maintaining or reducing fertiliser use. However, this requires the development
of control algorithms which are suitable for the challenges of agriculture. In
this paper, we propose a new mechanistic open model of lettuce growth for use
in control of precision agriculture. We demonstrate that our model is
cooperative and fits well to experimental data. We use the model to show, via
simulations, that a simple proportional distributed control law increases crop
uniformity and yield without increasing nitrogen use, even in the presence of
sparse actuation and noisy observations.
