Cultivation and production potential evaluation of Cyperus esculentus L. in marginal land of Inner Mongolia

Abstract: Marginal lands can greatly contribute to fully meeting the ever-increasing demands for cultivated resources in recent years. In general, the available marginal land refers to the new reclamation lands that converted from grassland, wetland or other lands in the past 25 years. Among them, there are serious land desertification and low productivity in Inner Mongolia of northwestern China, where the marginal land is widely distributed so far. Alternatively, Cyperus esculentus L. has been one of the most important crops to ensure the safety of grain and oil in China, due mainly to the high yield and oil content. Therefore, it is a new idea to promote the cultivation of Cyperus esculentus L. on a large number of marginal lands under a rapid development of mechanized agriculture. In this study, a multi-factor comprehensive evaluation was made to determine the cultivation and production potential of Cyperus esculentus L. in the marginal land of Inner Mongolia, further to predict the energy and economic benefits from the new oil crop. The results show that there was a total of 125 000 km2 of marginal land in the study area, of which the area of first-class marginal land was 26 000 km2, mainly distributed in the central and eastern Bayannur, Baotou, Xilinhot, and Tongliao counties. The types of land cover were the sparse vegetation, farmland and mixed vegetation. The area of second-class marginal land was 64 000 km2, particularly distributed in Huolin Gol, and Wuhai City, where there were the vegetation-based farmland and vegetation mixed areas. The area of third-class marginal land was 35 000 km2, mainly distributed in the desert edge areas of the western Alxa League. It was difficult to reclaim in some complex restricted areas with harsh climate conditions, due to the low rainfall and transportation. As such, approximately 15.9 million tons of edible oil was produced per year, when planting the Cyperus esculentus L. on these marginal lands. Otherwise, 1.87×1012 MJ of biomass energy was obtained, corresponding to the 44.7 million tons of fuel oil. On the whole, Cyperus esculentus L. presented great potential in the production of edible oil and biodiesel. Correspondingly, the marginal land can be widely expected to alleviate the shortage of edible oil, as well as the energy crisis in the realization of carbon neutral goals. The marginal land can also be fully utilized to alleviate the increasingly tense human-land contradiction for a higher land productivity. Since the industrial chain of Cyperus esculentus L. has not yet been fully mature, the accuracy of the estimation can increase with the promotion of plantation and industry, when evaluating the potential of planting, oil yield, and biomass energy production on marginal lands. The finding can also provide a scientific data support to the marginal land use, as well as the cultivation and promotion of Cyperus esculentus L. in the sandy areas of northwestern China, so as to alleviate the shortages of regional grain, oil and energy resources.