Maize stover as substrate for anaerobic digestion: collection efficiency, silage quality, and removal of P and C

Bart Vandecasteele, Alex De Vliegher, Chris Van Waes, Andy Peene, Jan Smis, Johan Van Waes

    Research output: Chapter in Book/Report/Conference proceedingC3: Conference Abstract

    Abstract

    After harvest of corn maize, the residual aboveground plant can be collected to be used as substrate for anaerobic digestion. The removal of corn stover as feedstock for bioenergy purposes may, however, adversely impact soil quality as its use may affect the C and P balance of agricultural fields. The overall goal of this research was to provide an understanding of the relationship between stover management practices and resulting impacts on soil and silage quality. Indices for total nutrient (nitrogen and phosphorus) removal were calculated for a range of maize varieties.

    The potential residual plant fraction of maize was measured for 20 different corn maize varieties tested on 4 locations from the Variety Research Network. The C, N and P content was measured for a selection of corn maize varieties on 4 locations, i.e. 20 varieties in 1 location, and 8 varieties in 4 locations. In this way the effect of variety or soil type on maize stover biomass, P and N content was assessed.

    The efficiency of collection of residual plant parts was assessed on 2 locations. Both locations were on sandy soil. As the applied equipment resulted in equal spreading of the crop residues over the soil during corn harvest, the stover collection suffered from low efficiency and the collected material had high soil particle load.

    The collected plant material was stored in wrapped square bales, and several silage additives were tested. During storage of the bales, pH was monitored at two sampling events, and silage quality was measured twice, i.e. after 3 and 12 months of storage. The dry matter content of the collected stover resulted in low concentrations of the fermentation products, at least for the sampling after 3 months of storage.

    One of the aims of this study was to assess the removal of N, C and P from agricultural fields in northern Belgium when corn stover was removed. Results indicate that potentially 20 kg P2O5/ha, 71 kg N/ha and 8800 kg OM/ha will be removed with the stover. The potential effective soil organic carbon removal is 900 kg C/ha when a humification coefficient of 0.30 is applied. However, due to incomplete collection of the stover, the actual removal is 7-14 kg P2O5/ha, 23-50 kg N/ha and 2900-6200 kg OM/ha.

    The use of rye as catch crop after corn maize cultivation and source of C was tested on 2 locations for two years. The contribution of the catch crop to the effective soil organic C varied between 190 and 680 kg C/ha, and was strongly related to the sowing time.

    The effect of crop residue removal in combination with catch crops, crop rotation or application of external sources of C on soil organic carbon levels was simulated. External sources of C (e.g. compost) or crop rotations with grassland are important measures to maintain the soil organic carbon content in case of maize stover removal.
    Original languageEnglish
    Title of host publicationBook of Abstracts of the International Conference ORBIT2012
    Number of pages4
    Publication date2012
    Pages187
    ISBN (Print)ISBN/AEN 3-935974-35-3
    Publication statusPublished - 2012
    EventORBIT2012 - Rennes, France
    Duration: 12-Jun-201214-Jun-2012

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