This book contains basic, theoretical and practical information on the use of wastewater treated by a natural stabilisation pond system in the irrigation of sunflower crops for silage and ruminant feed. The work focuses on the microbiological analysis of the crop. As it has an interdisciplinary approach, it is intended for undergraduate and postgraduate courses in various areas of knowledge in order to gain an understanding of the technique used, and the work can also be used as a basis by researchers who want to expand their knowledge and/or continue their studies in the area of reusing domestic effluents in agriculture.