Mutual feedback mechanisms between functional traits and soil nutrients drive adaptive potential of tiger nuts (Cyperus esculentus L.) in marginal land.

Purposes: Developing the cultivation and utilization of tiger nuts on marginal land is an effective approach to tackle the shortage of arable land in northern China. However, key information on their growth is unclear. This study aims to reveal the adaption potential of tiger nuts to on marginal land to help improve and adjust management practices. Methods: Three treatments were arranged to plant tiger nut in marginal land: no fertilization (N:P = 0:0), traditional fertilization (N:P = 15:15), and additional nitrogen fertilizer (N:P = 60:15). Functional traits of tiger nut and soil nutrients over three growth periods were investigated. Results: Under no fertilization, tiger nuts extended roots and toughened leaves to maximize nutrient absorption, and then quickly transported those nutrients to tubers. However, the lack of available phosphorus in the soil prevented the expansion of tubers. With the addition of fertilizers, tiger nuts produced more individuals, and their abundant belowground tissues resulted in soil organic matter increase. Under traditional fertilization, the tuber remains the main reproductive organ for tiger nuts, and phosphorus has a significant effect on the expansion of tubers. But under additional nitrogen fertilizer, the main reproductive organ changed to the stolon, nitrogen and phosphorus acted on stolons to promote their extension. Conclusion: Tiger nuts outstandingly adapt to marginal land environments and adjust their adaptation strategies according to varying soil nutrient conditions, Best tuber production will be achieved in soils with higher phosphorus availability, and a significant nitrogen proportion increase in fertilizers is necessary for enhancing aboveground production. [ABSTRACT FROM AUTHOR]