A rice variety with a high straw biomass retained nitrogen and phosphorus without affecting soil bacterial species

Abstract

It is well documented that rice paddy fields act as agricultural wetlands that remove or retain nutrients; however, their associated effects on soil microbial communities are rarely reported. The present study evaluates the impact of rice variety on nutrient removal via plant uptake, nutrient retention in the soil, and bacterial associations in rice paddy fields, using a network analysis that compares the soil bacterial communities of two rice varieties. We found that the high-straw rice variety (YD-1) allows uptake of a high amount of nitrogen (N) and phosphorus (P) from paddy rice fields via harvesting, but causes less residual total N and P to remain in the soil. However, both rice varieties (YD-1 and XS-134 (Xiushui-134)) had non-significant effects on the dominant bacterial taxa. The short-term response of bacterial community diversity to rice variety is found to be mainly due to less frequently recovered species. A network analysis that incorporates soil nutrients as nodes, along with bacterial taxa, found that only one node representing the total P related to the non-dominant species had an indirect association with the rice straw biomass. The observed short-term impact of the two rice varieties (XS-134 and YD-1) on soil bacterial diversity and nutrient surplus in these agricultural wetlands is limited under a high level of fertilization.