301 22 Alternative Soil Amendments for Organic Cultivation System B.B. Basak, Ajoy Saha, and Binoy Sarkar 22.1 INTRODUCTION Soil degradation is an age old issue as the process of agricultural practices itself. But the impact of soil degradation on food production and environment is becoming more alarming than ever before due to its horizontal and vertical expansion (Durán Zuazo and Rodríguez Pleguezuelo 2008). Indiscriminate use of agro-chemicals and synthetic fertilizers is one of the responsible factors for deterioration of soil quality under modern intensive agricultural practices. In this context, adoption of agricultural practices which can support present and future food and feed demand without hampering ecosystem services is highly needed. Sustainability of a production system implies optimum yields that can be maintained with minimum or acceptable environmental consequence through sustainable manage- ment tools (Tilman et al. 2002). It is quite relevant to mention here that an organic farming practice is the only sustainable farming practice legally accepted in many countries (Diacono and Montemurro 2010). Maintenance of soil fertility and supply of plant nutrition in organic agriculture is a more com- plex long-term integrated approach rather than a short-term conventional one. Shifting from ‘conventional’ to ‘organic’ agriculture is not only just a replacement of syn- thetic chemicals with organics; rather, it also requires a greater level of management efforts and skills (Hue and Silva 2000). Organic inputs, particularly the nutrient sources, are very important and only approved sources of nutrients are allowed in the organic production system. Organic and inorganic wastes generated from farming as well industrial activities, low-grade mineral resources, sea weeds and microbes have potential to supply plant nutrients, correct soil problems and maintain soil health (Nick and Bradley 1994). The only concern regarding the use of these materials is that they need to be approved by the international regulation and certifcation bodies. Here the scope of alternative sources of amendments, which are approved in the organic produc- tion system, will be discussed with their nutrient supplying capacities. This is not only a way to CONTENTS 22.1 Introduction ......................................................................................................................... 301 22.2 Organic Production System................................................................................................. 302 22.3 Certifcation and Regulations .............................................................................................. 302 22.4 Soil Amendments ................................................................................................................ 302 22.4.1 Plant and Animal By-Products ............................................................................... 302 22.4.2 Aerobically and Anaerobically Digested Products ................................................ 303 22.4.3 Rock and Mineral Powders .................................................................................... 305 22.4.4 Seaweed and Algal Products................................................................................... 306 22.4.5 Microbial Inoculants .............................................................................................. 307 22.4.6 Soil Conditioners .................................................................................................... 308 22.5 Quality Evaluation .............................................................................................................. 309 22.6 Conclusions ......................................................................................................................... 310 Acknowledgments.......................................................................................................................... 310 References ...................................................................................................................................... 310