Chlorophyll In Practice- an Example

Essentially, yield building is about capturing and converting more sunlight and carbon dioxide into sugar. A lack of sugar can limit yield dramatically. Terminal dominance, for example, is a function of sugar rationing. Terminal dominance is about the top bud having more importance than the buds below. When a plant senses a chlorophyll shortage, it will favour the top bud.

The importance of maintaining maximum chloroplast counts cannot be overemphasised. Many plant species make decisions about the amount of seed or fruit they will attempt to produce early in the crop cycle. Reproduction is the plant’s sole purpose in life, and all decisions are based on seed viability in prevailing conditions. The corn plant is a perfect example of this phenomenon. At five weeks after spiking, the corn plant conducts a chlorophyll inventory. At this precise point, the number of chloroplasts present will determine the exact number of kernel rows that the plant will produce. The number of rows will always be even, so an increase of two rows can significantly increase yields. Nine weeks after spiking (emergence), the corn plant performs another chloroplast count. This time, the number of cobs per plant will be decided along with the length of those cobs. The plant is essentially making a reproductive decision based on the likelihood of good sugar supply, which is critical for fruit and seed development.

If we can ensure maximum chloroplast counts immediately, prior to week five or week nine, then we have every possibility of achieving excellent yields. A soil test or a timely leaf analysis will determine the exact composition of an appropriate foliar spray, but often (especially in broadacre situations) it will be nitrogen that will be most deficient (particularly in a nitrogen-hungry plant like corn).

In the case of the corn plant, nitrogen is often the key contributor to chlorosis. The game plan is to provide nitrogen and everything else that will ensure the maximum number of chloroplasts before the yield-determining chlorophyll audit. At four and a half weeks, nitrogen, humic acid and a blanket-coverage, total nutrient foliar can be applied to boost chlorophyll, to beat the chloroplast count and set the stage for good results. If we repeat this exercise again at eight and a half weeks, before the second audit, our rich-green chlorophyll complement would convince the plant to push for two ears of maximum length instead of a single ear (terminal dominance does not occur in the presence of adequate sugar).