Dry applied fertilizers are easily incorporated prior to planting. They are also side-dressed to the crop during early stages of development, prior to the canopy closure. However, within most soils there can be considerable lock-up of some nutrients and so high fertilizer rates are usually needed to cover losses.
Volatilization can also be significant when urea is applied onto trash. Management needs to take this into account. Fertilizer prills or granules can be applied into furrows cut into the trash and soil alongside the stools of the ratoon sugarcane crop. This improves fertilizer efficiency and usually provides a higher sugarcane yield response.
Fertilizer can be applied in solution at planting by spraying the nutrients directly onto the plant sett. This can be a useful way of applying nutrients that are needed for early growth, especially phosphorus, boron and zinc.
Foliar application is used to address an immediate nutritional need or where soil conditions restrict availability of specific nutrients. Properly formulated products are increasingly important ensuring balanced sugarcane crop nutrition, particularly in ratoon crops.
For plant crops, direct application to the setts or close to the setts seems to be the most efficient way of micronutrient application.
Fertigation, providing nutrients through the irrigation system, the fertilizer is delivered directly to the plant. Drip systems provide a limited zone of moisture where roots can thrive and this is a particularly effective production system to improve moisture use in dry regions. Fertigation also ensures better application uniformity for every stool, by providing the correct amount of nutrient at the optimum growth stage. Under a fertigation system it is important to maintain correct nutrient ratios to ensure a plant’s needs are properly met throughout the production period.
While only around 1% of the cane crop is currently fertigated worldwide, this practice offers great potential to maximize sugarcane yields and crop margins. Compared to rain-fed or other forms of irrigation, fertigation of sugarcane has a marked effect on sugarcane yield (Figure 9). It is often a more efficient means of applying fertilizer than solid application.