Effects of demand-driven fertilization on growth, appearance, and nitrogen use efficiency of turfgrass

Summary

Grass growth in a Scandinavian climate is primarily controlled by temperature and light. In spring, temperature constitutes the major growth limiting factor while in the autumn short days and a low solar angle means that the lack of light is the greatest obstacle to growth. It follows from this that grass growth on golf courses is low in spring and autumn and peaks in the middle of the summer. A consequence of this natural behaviour of plants is that nutrient demands throughout the growing season also follow this pattern. However, there is no consensus today concerning the way fertilizers are applied on golf courses. The largest amounts of nutrients are often applied early and late in the season and the composition of the fertilizer varies greatly. As a consequence, the nutrient use efficiency is generally low.

The objective of this project was to evaluate the effects of demand-driven fertilization on growth, appearance and nitrogen use efficiency on creeping bentgrass, ‘Penn A4’. Demand-driven fertilization implies that fertilizers are applied frequently (once per week) and in doses adjusted to the growth climate and the desired growth rate of the grass species in question. An ideal fertilizer should contain all essential nutrients and the proportions between the nutrients should remain fixed during the whole growing season. Thus, no extra P or K should be given during spring and autumn respectively.

Our results clearly show that demand-driven fertilization offers great advantages compared to present techniques. The fertilizer rate can be substantially reduced with no negative effects on the appearance of the grass. A high playing quality can be maintained during the whole season and no extra precautions with regard to fertilization are required in association with major playing events. Root development and the carbohydrate status of the grass are favoured when nutrients are given in growth-limiting amounts during the growing season. The fertilizer use efficiency is greatly improved when the fertilizer doses are adjusted to season and the desired growth rate of the grass. No extra K is required during autumn in order to improve frost tolerance. No extra P is required during spring in order to overcome the low mobility of this element when the soil temperature is low. A complete fertilizer is strongly advocated on USGA greens in order to avoid serious nutrient deficiencies and the need for repeated soil analyses. More information concerning the nitrogen growth relationship of the most common grass species is needed in order to fully implement this concept and to identify the lowest possible fertilizer rates that also maintain playing quality.

Fundings (kSEK)