Potential grain output and technology approaches in the plain around the Bohai Sea in Shandong Province

It is a big challenge to promote grain production in China under the background of limited arable lands and increasing grain demand due to an enormous population. In order to provide scientific basis for national policy decision-making on increasing grain production capacity, planning and distributing, potential grain outputs of 30 counties in the area around the Bohai Sea in Shandong Province were estimated by using current data about arable lands, cropping systems and land productivity in recent years. The results show that the potential increase in grain output was likely to reach 4.034 1 × 10⁹ kg, which could be achieved by expanding planting area of grain crops and enhancing grain yield per unit area. There were two approaches to enlarge the area of grain crops. Firstly, about 50% of the current areas of cotton of single cropping per year system change into wheat/corn double cropping system by enriching soil fertility and adopting special varieties. This approach may increase grain production by 2.364 7 × 10⁹ kg. Secondly, some of the current uncultivated lands with severe saline-alkali develop for planting grain crops after taking comprehensive measures to increase grain output to 7.755 5 × 10⁸ kg. Furthermore, the promotion of wheat and corn grain yield under current cultivated farmlands will further increase grain output by 8.938 5 × 10⁸ kg. Counties with greater potential for grain output increase by either expanding planting area or enhancing grain yield are in the Delta area and along the banks of the Yellow River. The main technology approaches include: 1) leaching and discharge of salt ions from saline-alkali soils by intense freshwater watering and drainage, which will as well reduce salt accumulation in surface soils; 2) enriching soil fertility and increasing land productivity by using soil improvement measures such as application of organic manure, utilization of microbial remediation agents and management of crop residues; 3) optimizing farming systems by screening and applying crop cultivars with high salt-tolerance. Furthermore, it was essential to conduct demonstration of standard technologies at farmland scale.