Location: Soil and Water Management ResearchTitle: Living mulch management spatially localizes nutrient cycling in organic corn production
|GINAKES, PEYTON - University Of Minnesota|
|GROSSMAN, JULIE - University Of Minnesota|
|SOOKSA-NGUAN, THANWALEE - University Of Minnesota|
Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2020
Publication Date: 6/23/2020
Citation: Ginakes, P., Grossman, J., Baker, J.M., Sooksa-Nguan, T. 2020. Living mulch management spatially localizes nutrient cycling in organic corn production. Agriculture. https://doi.org/10.3390/agriculture10060243.
Interpretive Summary: Kura clover (Trifolium ambiguum), a perennial legume, has been used in recent years as a perennial living mulch in corn and soybean row crop production, with the goal of providing the benefits of annual cover crops but without the need for annual replanting. In this system, zone tillage is used each spring to clear a row for planting the annual cash crop. During the remainder of the year, the kura clover gradually spreads by rhizomes back into the row, necessitating the next round of zone tillage the following spring. The effect of tilling in the clover regrowth each spring on soil organic matter is not well-known. This research was conducted to determine those impacts on three reactive carbon pools: particulate organic matter (POM), permanganate oxidizable carbon (POXC), and microbial biomass. Soil samples were taken both in the row and between the rows at three time points in each of two years: before spring tillage, approximately 10 days after zone tillage, and at corn harvest. Both POM and POXC decreased within the row during the growing season, suggesting that zone tillage stimulated microbial decomposition of soil organic matter to focus nutrient recycling within the row, compared to between-row regions. The results provide further indication that the kura clover perennial living mulch system may improve synchrony in nutrient recycling.
Technical Abstract: Kura clover (Trifolium ambiguum) is a perennial living mulch species that can be used in conjunction with zone tillage to reduce nitrogen pollution, maintain ground cover, and provide nitrogen to crops. In such systems, kura clover is maintained between crop rows by limiting tillage only to within-row areas. However, the effect of zone-tilled living mulches on soil quality and nutrient cycling in these distinct regions is relatively unexplored. We examined three pools of labile soil organic matter (SOM): microbial biomass, particulate organic matter (POM), and permanganate oxidizable carbon (POXC). Soil samples were collected from both within-row and between-row locations of a zone-tilled kura clover living mulch at three time points per year: before spring zone tillage, approximately 10 days after spring zone tillage and corn (Zea mays) planting, and at corn harvest in 2015 and 2016. In 2016, POM and POXC decreased within rows relative to between-row regions after tillage, suggesting that zone till management stimulated decomposition of readily available SOM to effectively localize nutrient cycling in this region and slow mineralization between rows where living kura clover remained. This work shows that zone-tilled living mulches may be a promising avenue for enhancing the synchrony of nutrient mineralization specifically within crop rows, while maintaining year-round ground cover between rows.