Growth analyses of prairie and corn biomass cropping systems

Background/Question/Methods

Corn is currently used as the primary biofuel feedstock in the United States, but prairies could be used as a biofuel feedstock that produce substantial amounts of biomass in addition to providing numerous ecosystem services such as increasing soil organic matter concentrations, decreasing erosion rates, reducing nutrient pollution into water bodies, and increasing landscape diversity. Our objective was to determine whether the light interception and biomass production differed between prairie and corn cropping systems. Light interception and biomass accumulation were measured biweekly and end-of-season biomass was measured in October in four systems: unfertilized prairie, fertilized prairie, continuous corn, and continuous corn with a rye cover crop.

Results/Conclusions

The prairie systems began growing earlier in the year than the corn systems, but the corn systems had higher maximum growth rates. Tradeoffs between early-spring growth and high maximum growth rates resulted in equal biomass area durations for the fertilized prairie and corn systems. The unfertilized prairie had lower biomass area duration than the other systems. The duration of light interception was greatest in the fertilized prairie, intermediate in the unfertilized prairie, and lowest in the corn systems. The corn systems, however, produced more end-of-season biomass than the prairie systems, and between the prairie systems, the fertilized prairie produced more biomass than the unfertilized prairie. Although only the characteristics of aboveground biomass production were assessed in this study, total biomass (i.e. above- and belowground) production and duration are also likely to differ between prairie and corn systems. Cropping systems such as prairies that have active plant growth early in the growing season when soil erosion and water pollution rates are highest should be considered for use as biofuel feedstocks because of their concomitant production of ecosystem services and biomass.