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Experiments were established in a controlled-growth chamber and in the field to evaluate the effect of the length of time intervals between winter rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DBP) to 2 days after planting (DAP) corn in the field and from 21 DBP to 1 DAP in controlled studies. Results were similar in both environments. In general, shorter intervals increased seedling disease and reduced corn emergence, shoot growth, and grain yield of corn following winter rye compared with corn planted 10 or more days after rye termination or without rye. Incidence of Pythium spp. increased with shorter intervals (less than 8 DBP); incidence of Fusarium spp. was not consistent between runs and experiments. In 2014, in the 1-DAP treatment, number of ears and grain yield were reduced (P = 0.05 and 0.02, respectively). In 2015, all termination intervals reduced plant population, number of ears, and yield (P = 0.01), with the 2-DBP treatment causing the biggest decrease. A 10-to 14-day interval between rye termination and corn planting should be followed to improve corn yield following a rye cover crop. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. AbstractExperiments were established in a controlled-growth chamber and in the field to evaluate the effect of the length of time intervals between winter rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DBP) to 2 days after planting (DAP) corn in the field and from 21 DBP to 1 DAP in controlled studies. Results were similar in both environments. In general, shorter intervals increased seedling disease and reduced corn emergence, shoot growth, and grain yield of corn following winter rye compared with corn planted

A gronomy J our n al • Volume 101, I s sue 2 • 2 0 0 9 ABSTRACT Novel management practices are needed to improve the declining dryland crop yields and soil organic matter contents using conventional farming practices in the northern Great Plains. We evaluated the 21-yr eff ect of tillage and cropping sequence on dryland grain and biomass (stems + leaves) yields of spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and pea (Pisum sativum L.) and soil organic matter at the 0-to 20-cm depth in eastern Montana, USA. Treatments were no-tilled continuous spring wheat (NTCW), spring-tilled continuous spring wheat (STCW), fall-and spring-tilled continuous spring wheat (FSTCW), fall-and spring-tilled spring wheat-barley (1984-1999) followed by spring wheat-pea (2000-2004) (FSTW-B/P), and the conventional spring-tilled spring wheat-fallow (STW-F). Spring wheat grain and biomass yields increased with crop growing season precipitation (GSP) and were greater in STW-F than in FSTCW and FSTW-B/P when GSP was <250 mm. Although mean grain and biomass yields were greater, annualized yields were lower in STW-F than in other treatments. In FSTW-B/P, barley and pea grain and biomass yields also increased with increased GSP. Soil organic C and total N were lower in STW-F than in other treatments and linearly related (R 2 = 0.64 to 0.78) with total annualized biomass residue returned to the soil from 1984 to 2004. Alternate-year summer fallowing increased spring wheat grain and biomass yields compared with annual cropping but reduced annualized yields and soil organic matter. For sustaining dryland crop yields and soil organic matter, no-tillage with annual cropping system can be adopted in the northern Great Plains.

The limited time available for cover crop establishment after maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] harvest is one of the main reasons for low cover crop adoption in the upper Midwest. Therefore, a 2-yr multilocation study was conducted to evaluate winter annual cover crops establishment, their effect on main crop grain yields, and soil water content when interseeded into standing maize and soybean. Treatments were three interseeding dates (broadcasting at R4, R5, and R6 growth stages for maize, and R6, R7, and R8 for soybean) and three cover crops (win-winter rye [Secale cereale L.] plus a no cover crop control). Cover crop establishment and growth varied with interseeding date across locations and seasons for both maize and soybean systems. Averaged over the years, rye produced more green cover and biomass than the oilseeds in spring. However, at the northern-most site, the greatest (40%) green cover was recorded from pennycress and indicates its potential as a cover crop. Seeding date and cover crops did not negatively affect maize or soybean grain yields or soil water content. Generally, cover crop establishment and growth were better in the soybean system than maize due to better light penetration. Further research is needed to develop better suited cultivars and/or agronomic management practices for interseeding into maize. The results of this study indicate that producers could integrate these covers to diversify and add ecosystem services to soybean production practices.Abbreviations: PAR, photosynthetic active radiation; PC, pennycress; PLS, pure live seeds; PPD, plant population density; WC, winter camelina.

Development of compatible, persistent, wann-season f:rass-legume mixtuns could increase forage yield and quality during summer months. We established a trial to detennine forage yield, quality, species compatibility, and persistence of binary mixtures of wann·st·ason grasses with selected legumes, five of which are native to the ~:entral USA. Grass entries were switchgrass (Panicum virgaJum L.), sideoats grama (Bouleloua curtipendula Michx.), and indiangrass [Sorghastrum nutans (L.) Nash]. Legume entries were purple prairieclover [Dalea purpurea Vent.; syn. Petalostemon purpureum (Vent.) Rydb.], roundhead lespedeza (Lespedeza capitata Michx.), leadplant fAmorplra canescens Pursh), Ulinois bundleOower [Desmanthus illinoensis (Mich{.) MacMill., B. Robins. & Fern.), catclaw sensitive brier [Schrankia nuttaUii (DC.) Standi.), and cicer milkvetch (Astragalus cicer L.), a cool-season species. Unfertilized grass plots without legumes also were included. The experiment was on a Haynie very fine sandy loam soil (coarse-silty, mixed, calcareous, mesic Typic Udifluvents). All mixtures containing purple prairieclover, roundhead lespedeza, Illinois bunolleflower, or catclaw sensitive brier yielded more forage than did g1·asses grown alone or with leadplant, except for pure switchgrass in 1986. All legumes increased the crude protein concentration of fora:~e compared to that of grass-alone plots, except for leadplant with switchgrass in 1986. Inclusion of catclaw sensitive brier and cicer milkvetch with grasses consistently improved in vitro digestible dry mutter concentration (IVDDM), while inclusion of roundhead lespedeza, leadplant, and Illinois bundleflower generally resulted in decreased IVDDM concentration of forage. Purple prairieclover generally did :mot influence JVDMD of mixtures. Persistence of all legumes was good. Cicer milkvetch was not compatible with these grasses because it developed a thick, dense canopy prior to initiation of growth by these grasses.T HE ADVANTAGES OF COOL-SEASON LEGUMES in coolseason pasture and hayland plantings :have been well documented (Burns and Standaert, 1985;Wagner, 1954). Including adapted legumes with grasses in a mixture has consistently increased forage yield and quality compared to unfertilized grasses. Rumbaugh et al. (1982) reported that interplanting alfalfa (Medicago sativa L.) or cicer milkvetch into a stand of crested wheatgrass [Agropyron desertorum (Fisch.) Schult.] significantly increased forage yield, as well as protein concentration and yield of the grass. Broadcast-seeding of biennial sweetclover [Melilotus officina/is (L.) Desr.] into native range increased yield and protein concentration of western wheatgrass [Pascopyron smithii (Rydb.) A. LOve] (Nichols and Johnson, 1969).Cool-season legumes may not be satisfactory companion species in warm-season grass pastun!s. Differences in seedling vigor, optimum time of establishment,