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Corn (Zea mays L.) stover has been identified as an important feedstock for biofuel production but its removal will likely increase soil erosion. To address this issue 35 species of grasses and legumes were evaluated as potential perennial ground covers (PGCs) in corn. Selection of species encompassed both C3 and C4 species with a wide range of developmental and morphological features. The objectives were to (i) identify species that could support a high level of corn production while requiring minimal management and (ii) identify morphological traits and growth habits of suitable entries as PGC. Over the 3-yr study period species with slow growing and spreading habits were more conducive to corn production, even though these PGCs still caused an average 23% reduction in corn grain yield. Meadow fescue (Festuca pratensis Huds.), sheep fescue (Festuca ovina L.), Canada bluegrass (Poa compressa L.), fowl bluegrass (Poa palustris L.), and colonial bentgrass (Agrostis capillaris L.) were identified as suitable PGC species. These species were generally shorter and slower to spread into the corn rows compared with other, more aggressive species. Based on these observations an ideotype for future PGC species should be low growing, clump forming, and shade tolerant and have delayed green-up in the spring. [ABSTRACT FROM AUTHOR]

Constraints to maize (Zea mays L.) stover biomass harvest may be mitigated by using a living mulch (LM) to offset C exports and control soil erosion. Living mulches can compete with the main crop for resources, particularly water. The objectives of this research were to quantify soil water dynamics and maize water use in continuous maize with stover removal. Continuous soil water content (SWC) and reproductive whole-plant water use were measured in no-till maize growing in LMs of creeping red fescue (CF) (Festuca rubra L.), Kentucky bluegrass (KB) (Poa pratensis L.), and a no-LM control between 2008 and 2010 near Ames, IA. In 2 yr with excessive rainfall (2008 and 2010), LMs increased SWC compared to the control at 15 cm. No-till LM treatments lowered grain yield in 2008 and 2010 compared to the control, although a KB fall strip-till treatment, which was part of the larger research study, produced yields that were not different than the control all 3 yr. Reproductive water use efficiency for no-till KB in 2008 and 2009 (51 and 42 g grain per cm water) was 21 and 14% greater than the control (42 and 37) but 24% lower in 2010 (41 vs. 51). Maize water use in the control exhibited a bimodal response averaged across the 3 yr with peak water use occurring at the R1 through R2 period (0.58 cm d-1) and declining to 0.26 cm d-1 during R5 through R6. In contrast, no-till KB exhibited a simple negative linear relationship with water use rates declining from a high of 0.47 cm d-1 during the R1 through R2 period to 0.22 cm d-1 during R5 through R6. These results indicate LMs may increase SWC and utilize water more effectively, particularly when combining strip-till and herbicide management. [ABSTRACT FROM AUTHOR]