Soil function-included simulation on energy development potential of corn stover

Abstract: The residue of traditional crop, corn stover, has many advantages for biomass energy such as a larger yield, lower cost, easier heaviest, etc. Currently, it has become a major resource of biomass energy. With the increasing demand of biomass energy on corn stover, the excessive harvesting could damage the sustainability of agriculture and environment in the future. To acquire the sustainable energy potential of corn stover, considering the demand of soil on corn stover is very critical in order to assess the total harvestable stover amount of corn stover in China. To maintain the function of soil, it is necessary to consider the demand of soil on corn stover. First, the corn yield per hectare was projected in 2020, 2030, and 2050 based on the corn yield from 1978 to 2011 in China. Then, the corn stover yield in every province was projected based on the relational expression between corn and corn stover. On the other hand, the research results in relative papers were collected for various types of soils. The maximum, medium, and minimum values of the demand of various types of soils on corn stover in these papers were used to calculate the harvest potential of corn stover in every province of China. To maintain the function of soil, three scenarios (higher reservation, moderate reservation, and lower reservation) were designed according to the reservation value of corn stover in various types of soils. For various scenarios, ① the minimum reservation amount (maximum, medium, and minimum value) was calculated based on soil type (clay soil, loam soil, sandy soil) and the soil area used for corn in every province. ② Other factors such as the harvesting of corn stover and the scale of corn stover used for burning and feedstuff were also considered when the corn stover potential used for biomass energy is being calculated. ③ Considering the alternative of corn stover used for burning by coal or natural gas in the future and the calorific value of corn stover, the biomass energy potential was calculated in a different alternative scale. Research results are given in the paper by using the above method. Assuming that the corn stover used for burning is not replaced by coal or gas in the future, the research results in three scenarios are given. In the lower reservation scenario, the corn stover potential in 2020, 2030, and 2050 will be 0.213, 0.216, and 0.303 billion tons. In the moderate reservation scenario, the corn stover Potential in 2020, 2030, and 2050 will be 0.139, 0.142, and 0.229 billion tons. In the higher reservation scenario, the corn stover potential in 2020, 2030, and 2050 will be 0.042, 0.045, and 0.129 billion tons. Assuming that the corn stover used for burning is completely replaced by coal or gas in the future, the research results will increase. In the lower reservation scenario, the corn stover potential in 2020, 2030, and 2050 will be 0.279, 0.282, and 0.396 billion tons. In the moderate reservation scenario, the corn stover Potential in 2020, 2030, and 2050 will be 0.182, 0.185, and 0.299 billion tons. In the higher reservation scenario, the corn stover potential in 2020, 2030, and 2050 will be 0.056, 0.058, and 0.169 billion tons. In China, the biomass energy potential of corn stover in 2020, 2030, and 2050 will be 4.33×1015, 4.37×1015, and 6.15×1015 kJ, respectively in the lower reservation scenario when the corn stover used for burning is replaced by gas or coal. In the higher reservation scenario and no corn stover used for burning is replaced by gas or coal, the biomass energy potential of corn stover in 2020, 2030, and 2050 will be 0.64×1015, 0.70×1015, and 1.99×1015 kJ. The biomass energy potential of corn stover is less than other research results considering the demand of soil on corn stover. The research result will also be affected by the per unit yield of corn. Although the biomass energy potential of corn stover is less than other research results, it benefits the sustainable development for agriculture and biomass energy. It does this by protecting the soil, controlling erosion from water and wind, retaining soil moisture, increasing or maintaining soil organic matter, adding to the available pool of soil nutrients, increasing biological activity, improving soil structure, and improving crop yields. However, as more corn stover is left in the land, more biomass energy is wasted and CH4 is generated by waste corn stover. The result of this study provides a reference for decision-making on the corn stover development.