The point to understand, when considering crop production in terms of chlorophyll management, is that any chlorosis – any loss of green for any reason – will result in less production of glucose and lower yields. This is why we are so insistent upon the value of leaf analyses during the crop cycle to ensure that the ‘chlorophyll builders’, and their subcontractors, are always at optimum levels in the leaf. For example, we always insist on maintaining luxury levels of ‘The Big Four’ in the leaf. ‘The Big Four’ – calcium, phosphorus, magnesium and boron – are needed at good levels throughout the season. Why is this? Well, as explained, calcium is an important subcontractor ensuring the delivery of the builders to their chloroplast workplace. Boron is a calcium synergist – the steering wheel behind the trucker. Magnesium, as the cornerstone molecule in the chloroplast, may be the centrepiece for the sugar factory, but what about phosphorus? The fact is that phosphorus is the banker that funds the entire building project. The injection of funds in this context relates to a series of phosphate-based compounds, which provide the energy needed for every plant process. The most important of these compounds is adenosine-triphosphate (ATP), but there are no fewer than six phosphate compounds involved in the initial creation of glucose. You can supply all of the nitrogen, magnesium, sulphur and trace elements in the world, and the calcium to ensure their supply, but without phosphorus there is no sugar production and there is no conversion of simple sugars into the compounds like proteins, oils and starch, which provide the basis of the farmer’s income.