The use of winter cover crops (WCC) such as hairy vetch (Vicia villosa Roth) and cereal rye (Secale cereale L.), in a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation provides long‐term benefits that are generally overlooked. There is a particular lack of information regarding the effects of WCC on soil physical and chemical properties. The objective of this study was to assess the effects of four crop sequences (C/S, corn‐fallow/soybean‐fallow; C‐R/S‐R, corn‐rye/soybean‐rye; C‐R/S‐V, corn‐rye/soybean‐vetch; and C‐R/S‐VR, corn‐rye/soybean‐vetch and rye) under no‐till on several soil physical and chemical properties. Soil chemical properties included soil organic matter (SOM), pH, total nitrogen (TN), nitrates (NO3–N), and available phosphorus (P). The analyzed soil physical properties analyzed were: water‐aggregate stability (WAS), bulk density (Db), penetration resistance (PR), total porosity (TP), pore‐size distribution, water retention properties, and saturated hydraulic conductivity (Ksat). The experimental design was a split‐split‐plot where whole‐plot treatments (sampling period) had a Latin square design and subplot treatments (crop sequences) were arranged in a randomized complete block design with four replications. Compared with winter fallow, crop sequences that included WCC provided substantial benefits from the soil productivity standpoint. Specifically, the use of the C‐R/S‐V or C‐R/S‐VR increased SOM down to 30 cm. All WCC sequences improved WAS with increases of 9, 13, and 17% for C‐R/S‐R, C‐R/S‐V, and C‐R/S‐VR, respectively. Winter cover crop sequences reduced Db and PR of the soil surface and increased total and storage porosity along with plant available water. While the C‐R/S‐V sequence was the most effective in reducing soil NO3–N, the C‐R/S‐R sequence was the most effective in fixing soil P.

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Among several candidate perennial taxa, Miscanthus  giganteus has been evaluated and promoted as a promising bioenergy crop. Owing to several limitations, however, of the sterile hybrid, both at the taxon and agronomic production levels, other options need to be explored to not only improve M.  giganteus, which was originally collected in Japan, but to also consider the development of other members of its genus, including Miscanthus sinensis, as bioenergy crops. Indeed, there is likely much to be learned and applied to Miscanthus as a bioenergy crop from the long history of intensive interaction between humans and M. sinensis in Japan, which in some regions of the country spans several thousand years. Combined with its high amount of genetic variation, stress tolerance, biotic interactions with fauna, and function as a keystone species in diverse grasslands and other ecosystems within its native range, the unique and extensive management of M. sinensis in Japan as a forage grass and building material provides agronomists, agroecologists, and plant breeders with the capability of better understanding this species in terms of potential contribution to bioenergy crop development. Moreover, the studies described in this review may serve as a platform for future research of Miscanthus as a bioenergy crop in other parts of the world.

yield of the following crop (Wagger and Mengel, 1993). Winter cover crop residues can affect soil water dynam-Extensive research on the use of winter cover crops (WCC) under ics by reducing runoff, increasing infiltration, and reducdifferent agricultural practices in the USA and Canada has shown both negative and positive effects on subsequent corn (Zea mays L.)ing evaporation, all of which may ultimately benefit crop yield. These contrasting results determine the need for a comprehen-yield (Unger and Vigil, 1998). Conversely, WCC can also sive quantitative review. The objective of this study was to use metacompete with the crop by using soil water during active analytic methods to summarize and quantitatively describe the effects growth (Munawar et al., 1990). of WCC on corn yield based on peer-reviewed published research. Legumes and grasses have been used extensively asThirty-six studies were included in the analysis representing different WCC (Frye et al., 1988;Smith et al., 1987; Wagger and regions of the USA and Canada under different agricultural practices Mengel, 1993). In general, at the time of killing, legume (i.e., species, fertilization, kill date, tillage, etc.). The effect-size used WCC provide less biomass with narrower carbon to to compare studies was the response ratio, calculated as yield of corn nitrogen (C/N) ratios than grass WCC (Doran and following WCC over yield of corn following no cover. Biculture WCC Smith, 1991) at the time of WCC killing. Because of their increased corn yield by 21%, but there is greater variation due to the small number of studies in this group. Overall, grass WCC neither narrow C/N ratio, legume residues usually decompose increased nor decreased corn yields and this response was not depen-faster, releasing inorganic N into the soil that becomes dent on the use of N fertilizer. Legume WCC increased corn yield available for the following crop (Varco et al., 1989; Wagby 37% when no nitrogen (N) fertilizer was applied and this benefit ger, 1989). Lal et al. (1991) recognized that weather condecreased with application of N fertilizer.