It has been observed that the inclusion of morphosyntactic information in dependency treebanks is crucial to obtain high results in dependency parsing for some languages. In this paper we explore in depth to what extent it is useful to include morphological features, and the impact of diverse morphosyntactic annotations on statistical dependency parsing of Spanish. For this, we give a detailed analysis of the results of over 80 experiments performed with MaltParser through the application of MaltOptimizer. Our goal is to isolate configurations of morphosyntactic features which would allow for optimizing the parsing of Spanish texts, and to evaluate the impact that each feature has, independently and in combination with others. 1