The Morphological and Phenological Development of Timothy as Affected by Weather, and Its Relation to Nutritional Value

Abstract

Results from a series of harvest time experiments were used, together with meteorological data, to express the relationship between development and weather and between development and nutritional value of timothy. Development was estimated in three different ways: as phenological stage, leaf proportion and plant height. Various methods were tested to predict the development of the phenological stage and nutritional value. Increased temperature accelerated the rate of development, especially the change in leaf proportion and phenological development. Water deficiency tended to increase the rate of phenological development, but also the rate of decline in leaf proportion in the first crop. The effects of day length on development varied between crops. Developmental variables could not replace the weather variables in explaining the decline in nutritional value, but sometimes explained a little more when used together with the weather variables. The accuracy in predicting crude protein was better when this was done late in the season, but the converse was true for digestibility.

Key Words:

• protein
• digestibility
• leaf proportion
• plant height
• prediction