Effects of soil carbon, nitrogen, and phosphorus contents and microbial characteristics on the quality of Datong daylily and hyperspectral diagnosis

Clarifying the relationship between the formation of edible quality of daylily and soil nutritional status is an important prerequisite for producing high-quality daylily. Based on Datong daylily, this study analysed the relationships between soil and quality parameters in daylily. Then we constructed hyperspectral monitoring models for soil parameters and relationship models between soil and quality parameters, to clarify the effects of relevant soil parameters on quality parameters and achieve hyperspectral monitoring of soil parameters and prediction of quality parameters. The main results were as follows: Nitrate nitrogen (NO 3 - -N), ammonium nitrogen (NH 4 + -N), alkali hydrolysable nitrogen (AN-N), available phosphorus (AP), and protease activity (Pro-act) played important roles in the growth of daylily. Path analysis revealed that the protein content of daylily was mainly affected by soil organic carbon (SOC), Pro-act, and phosphatase activity (Pho-act), the soluble sugar content was mainly affected by NO 3 - -N, AN-N, invertase activity (Inv-act), and microbial biomass carbon (MBC), the total flavonoids content was mainly affected by SOC, total nitrogen (TN), and Pro-act, and the total phenols content was mainly affected by SOC, TN, total phosphorus (TP), and Inv-act. Only hyperspectral estimation of SOC, TN, NH 4 + -N, and Pho-act could be realized in all soil parameters. By obtaining these four soil parameters on May 15, the quality of daylily could be predicted. This study can provide a theoretical basis and technical support for improving the edible value of daylily.