Influence of Fertility Levels on the Varietal Response of Sugarcane

Abstract

There are many as yet unanswered questions concerning the relationship between sugarcane varieties and soil fertility. Important among them are the following: 1. Are the results of sugarcane-variety field trials valid for different fertility levels when performed at but one fertility level? 2. Is it necessary to run fertilizer field trials on new varieties? 3. Should certain sugarcane varieties be recommended for soils of low fertility and different varieties for soils of medium or higher fertility? Statistical examination of the data from eight variety-fertilizer experiments carried on in different parts of Puerto Rico: Humid, semihumid, arid-irrigated, and arid-nonirrigated, and also on different soil types, revealed the following answers to these questions concerning differences in varietal response to different fertility or fertilizer levels, using nitrogen, phosphorus, and potassium: 1. Certain varieties did not consistently yield best at all fertility levels. 2. Some varieties appeared to do better at higher fertility levels than at low ones; others performed better at low fertility levels. 3. Inasmuch as varietal response is different at various fertility levels, caution is recommended in evaluating new variety trials at only one fertility level. 4. Not all varieties responded similarly to fertilizer applications, and it would be misleading to define fertilizer requirements or the fertility level on the basis of the performance of one cane variety only, if other varieties are to be grown in that area. 5. A discussion of the interaction of varieties and fertilizers is presented in which it is suggested that some cane varieties developed in one geographic area do better there than elsewhere, while other varieties grow well over wide areas.