Assessing the effects of Azolla and compost on soil fertility and paddy yield under farmers’ field conditions in Kerala, India

Abstract

Rice (Oryza sativa L.) is one of the most important cereal crops and is the staple food for more than half of the population in Asia. Excessive use of chemical fertilizer degraded the soil profile and led to environmental issues, highlighting the need for alternative, sustainable options. While organic farming practices improve soil health, limited studies have evaluated the combined effects of multiple organic amendments under field conditions. The present study aims to assess the combined effects of Azolla and compost on soil fertility and paddy yield under farmers’ field conditions in Kerala, India. Five nutrient management treatments were evaluated viz., P1- Application of basal nutrients only (Farm yard manures (FYMs)); P2- Application of compost with basal nutrients and P3- Application of Azolla with basal nutrients, P4- Application of both compost and Azolla with basal nutrients; and C- Farmer’s traditional organic management practices as control. Results demonstrated that the rice variety Karuna, under P4, exhibited a 50% increase in growth and yield parameters compared to C. Post-harvest soil analysis confirmed enhanced nutrient retention and microbial activity in organic amendments treatments. The present study demonstrated that integrated organic amendments, i.e., the combined application of Azolla and compost, significantly enhance paddy yield and soil nutrient status as compared to conventional organic farming. However, the results are location and season-specific, and further long-term multi-location studies are required to evaluate the broader agronomic, ecological, and economic implications of such integrated approaches. The study highlights the potential of integrated nutrient management strategies for reducing excessive dependence on chemical fertilizers while supporting sustainable rice production systems.