Economics of fertilizer use has always been of high concern. “In times like the present, when farming conditions and produce markets become difficult, some advise farmers that the best way to weather the storm is to cut costs: savings can be made on the outlay on fertilizers. They say that yield increases over the years have not matched the increase in fertilizer use; that yield targets have been set too high; that, when produce prices fall, lower yields are acceptable especially as higher yields will lower prices; that it is not necessary to build up soil fertility and that advice to do so leads to over-use of fertilizers…as far as maize growing in South Africa is concerned, these ideas are false.” Although this sentiment is familiar to us today, this statement from South Africa is taken from IPI’s Potash Review report dating back to 1980 and much is still relevant today.
“There is no doubt of the great importance of the prices in shaping the use of fertilizers. However, of even greater importance is the dissemination of technical knowledge. The better the command of the farmers of the technique of manuring, the higher the level to which they lift the limiting-yield curve”. This is also relevant, yet is a quote from IPI’s Potash Review published in 1956 - now over 50 years ago.
Clearly the question of the benefit-to-cost ratio of fertilization has always been an issue, and more so during times of high fertilizer price and economic constraint. Uncertainty of the benefit from fertilization may always exist (and even just because climate is so unpredictable), so knowing more about efficient fertilizer use is crucial.
As always, reducing fertilizer rates will impact on yield. But these days, farmers can employ better tools to make fertilizer use more efficient, including using more efficient delivery systems, monitoring nutrients in soil and plant, and using remote sensing images-and decision support systems. Using these will increase the benefit-to-cost ratio of fertilizer application. And so we reach the same conclusion as in 1956 stated above: the more knowledge, the higher the limiting-yield curve can be lifted.
