Abstract
Organic rice farming has increasingly gained attention for its potential to enhance biodiversity compared to conventional agricultural methods. In this study, we examined the abundance of plant species groups of conservation interest in rice fields in Hungary, located at the northern periphery of rice cultivation. We compared organically and conventionally managed rice fields to determine their impact on plant biodiversity. Our results indicated that organic fields generally support a greater abundance of non-harmful macrophytes, charophytes, and red-listed species. However, these differences were less pronounced in fields considered less ecologically valuable, irrespective of management types. Our analysis revealed that water conductivity had a more significant impact than farming type. Lower conductivity correlated with weed communities of higher conservation values, particularly in organically managed fields. This effect was significant compared with conventional fields but was only evident in areas with relatively low conductivity, likely reflecting low nutrient levels in the water. These findings suggest that to maximize biodiversity benefits, organic agriculture should be practiced alongside the judicious use of low amounts of organic manure or nutrients. Such practices could enhance species-rich macrophyte communities, contributing to the preservation of the unique biodiversity found in this historic rice cultivation region.