4. Fertilizing Corn – Except in no-till farming, the growing of corn generally involves soil cultivation and the making of linear furrows. It is in the furrow that basal fertilizers are applied and seeds of corn are sown.
Application of nutrient supplements to corn, termed fertilization, usually starts just before sowing of seeds (called basal application) and another application, called sidedressing, at 28-32 days after planting (DAP). Called two split application, the common practice is to apply one-half of the recommended nitrogen and all of the phosphorus and potassium as basal while the remaining one-half nitrogen is applied as sidedress.
By way of example, assume that the recommended rate of fertilization in a one-hectare land is 2 bags of complete fertilizer (Triple 14 or 14-14-14) and 3 bags of urea (46-0-0). This assumption is still reasonable, at least to poor farmers and in some lands which are still relatively fertile. These 5 bags of fertilizer have a total content of 83 kg nitrogen, 69 kg phosphorus, and 69 kg of potassium, equivalent to a rate of application of 83-69-69 kg/ha N-P2O5-K2O.
Assuming on the other hand that the recommended rate in fertilizing corn is 83-69-69 kg/ha N-P2O5-K2O, two-split application means that 41.5 kg N (1/2 of 83 kg N),
69 kg P, and 69 kg K (41.5-69-69 kg/ha N-P2O5-K2O) will be applied as basal and
the remaining 41.5 kg N will be applied as sidedress. This converts roughly to
2 bags of Triple 14 and 1 bag of urea for basal application and 2 bags of urea
for sidedress application.
Relying on human labor, the common practice in applying basal fertilizer is to drill small amounts of the fertilizer mixture (2 bags Triple 14 + 1 bag urea) at the bottom of the furrow. To save time and labor, a farmer fastens to his hip a “tail” with an uprooted tuft of grass at the tip. As the farmer walks forward, the grass is dragged. It scratches the bottom and sides of the furrow causing some soil to cover the fertilizer. Sowing of seeds at the bottom of the furrow immediately follows.
As to the remaining fertilizer (2 bags urea), it is sidedressed usually at 28-32 days after planting. Immediately after sidedressing, a furrower (double-bladed moldboard plow) is made to pass at the center of each row. This cultural practice is called hilling-up in which furrow slices move towards both sides and elevate the bases of corn plants. The furrow slices also cover the applied fertilizers.
Traditional corn farmers have long ago practiced no-till farming in hilly areas. However, the growing of glyphosate-resistant corn and the use of herbicides are quite recent. Nevertheless, they are quick to adapt and apply modified corn farming technology.
They still apply fertilizers twice - where fertilizers are sufficiently available considering that marginal farmers are always cash stripped. They’ve been practicing this even with the traditional no-till farming technology which uses indigenous or improved non-GMO varieties of corn. However, zero tillage has made basal application of fertilizer impractical. Without furrow, planting is by manual dibbling and dropping of fertilizer into the holes immediately before seed sowing would be an impossible task.
A family of marginal farmers in fact revealed that they had tried fertilizing corn by applying the dibble method of planting. But they resisted the suggestion of adopting the method, laughing that it will take plenty of time to fertilize a hectare of land. More so, it is physically punishing.
Instead, they fertilize corn at 15 and 30 days after planting. Never mind the right definition of basal, these farmers call this first application of fertilizer as “basal” application. And so when you tell them to apply basal fertilizer, they do it at 15 days after planting or close to it.
And so for the above 5 bags of fertilizers, they apply 3 bags (2 bags Triple 14 + 1 bag urea) at 15 DAP and the remaining 2 bags of urea at 30 DAP. In sloping land they drop a small amount of fertilizer (or fertilizer mixture) close to the base of eacn plant at the more elevated side.
That’s it. They do not cover the fertilizers with soil by hoeing or with any tool. For them it is not necessary, for them doing it will just be wasted labor. They are without doubt that it does not matter in order that the applied fertilizer will become useful to the plants and convert to a successful harvest. What matters is that the ground can be rendered weed free by herbicide spray and so eliminate the need to do hand weeding and interrow tillage, and that the soil is moist when fertilizer is applied or, hopefully, rain will immediately pour from heaven to dissolve the fertilizer.