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Forage availability in summer is critical for sustaining high stocking densities of herbivores on pasture in the eastern U.S. The objective of this study was to determine forage productivity and quality of switchgrass (Panicum virgarumL.) and bluestems [Andropogon gerardiiVitman, Schizachyrium scoparium(Michx.) Nash, and Bothriochloa caucasica(Trin.) C.E. Hubb.] in summer. The experimental site was located in southwestern Pennsylvania on Guernsey silt loam (fine, mixed, mesic Aquic Hapludalf) soil. Two replicates, each containing eight warm‐season grasses with different proportions of volunteer cool‐season grasses and overseeded legumes were grazed from 1975 to 1977 and then harvested for hay in 1978 and 1979. Pastures were grazed each year in mid‐May, late July or early August, and early October. Nitrogen at 0, 45, and 90 kg ha−1and P at 0, 20,40 kg ha−1were applied to subplots. ‘Blackwell’ switchgrass and ‘Kaw’ big bluestem from the Great Plains readily established stands but did not persist as well as cultivars from the eastern USA. Total annual production from switchgrass‐dominated pastures was about 8.0 Mg ha−1and that from ‘NY 1145’ big bluestem was 6.0 Mg ha−1, Over a 4‐yr period, NY 1145 produced about 70% more forage in late July than did Kaw big bluestem. Mean yield distribution of the switchgrass and bluestem pastures was approximately 15% in May, 55% in July‐August, and 30% in October. July yield increased about 11 kg kg−1of N applied. Mean in vitro dry matter disappearance (IVDMD) values for switchgrass and bluestem ranged from 470 to 570 g kg−1,, but it was determined that IVDMD under‐estimated in vivo digestibility by 100 to 200 g kg −1, Crude protein concentration ranged from 70 to 120 g kg−1, Mean crude protein concentration of grass fertilized with 45 and 90 kg N ha−1over a 3‐yr period was 10 and 26% higher, respectively, than that for unfertilized grass. Overseeded legumes, especially red clover (Trifolium pratenseL.), established good stands in warm‐season grasses with < 75% stands. Mixed stands of warm‐ and cool‐season grasses and legumes can be maintained under grazing or hay production, with a substantial shift in seasonal yield distribution that can be very beneficial to beef (Bos taurus) producers.

Production of cool‐season (C3) herbage generally is low in summer and fall in the humid eastern USA. This study was conducted to determine the yields and pest problems of spring‐sown turnip, Brassica rapaL.; swede, B. napusL.; rape, B. napusL.; interspecific crosses between Chinese cabbage, B. campestris sensufaioL., and turnip or rape; or kale, B. oleraceaL., that were stockpiled. The crops were no‐till seeded (turnip and swede at 1.4 kg ha−1, rape, the hybrids, and kale at 4.2 kg ha−1) into mature alfalfa (Medicago sativaL.)‐grass stands. Prior to seeding, the sod was treated with isopropylamine salt of N‐(phosphonomethyl) glycine at 1.1 kg a.i. ha−1. The study was made in central Pennsylvania on Hagerstown silt loam (fine, mixed, mesic Typic Hapludalfs) soil in 1979 and 1980 and on Hublersburg silt loam (clayey, illitic, mesic Typic Hapludults) soil in 1981. Dry matter yield determinations were made sequentially at 30‐day intervals from 60 to 150 days post‐seeding. Fertilizer (P and K) was applied according to soil test results and 80 kg N ha−1was applied at seeding and 70 kg N ha−1between the 60‐ and 90‐day sampling dates. Three‐year mean dry matter yields for 13 of 19 cultivars exceeded 7.0 Mg ha−190 days post‐seeding. Yields plateaued from 80 to 160 days depending on plant species, cultivar, and year. Cultivar (across species) ✕ sampling date, turnip cultivar ✕ year, and swede, rape, and kale sampling date ✕ year interactions were significant for yield. Incidence of plant diseases was positively related to slowing of growth at physiological maturity. Some New Zealand turnip and rape cultivars were more resistant to flea beetle [Phyllotreta cruciferaeGoeze and P. striolata(Fab.)] than cultivars of European origin. Crude protein concentration of turnip and Chinese cabbage hybrid tops was higher at 120 than 90 days, but it was not for other species. Crude protein concentration ranged from 110 g kg−1in roots of certain cultivars to 270 g kg−1in turnip tops. Species ✕ sampling date and year ✕ sampling date interactions were significant for crude protein concentration and in vitro dry matter disappearance (IVDMD). The IVDMD values ranged from 800 to 930 g kg−1Kale had the lowest mean IVDMD, 840 g kg−1.

Native perennial warm‐season grasses are established and used in the northeastern United States for beef cattle (Bos taurus) production, wildlife habitat, and soil conservation. This research was conducted in Pennsylvania to study select plant growth responses and forage quality of switchgrass (SWG), Panicum virgatumL., and big bluestem (BBS), Andropogon gerardiiVitman, to dolomitic lime, and P and N fertilizers on strongly acid, fine‐loamy, mixed, mesic, Typic Fragiaqualfs. The soil amendments were applied after the first growing season. Growth of SWG and BBS was markedly improved by topdressings of lime and N fertilizer. In 1981 and 1982, untreated warm‐season grass yielded approximately 50%, and grass receiving the low rate of applied nutrients yielded 90%, of that with the high lime and fertilizer rate (8.76 Mg ha−1). Nitrogen fertilizer increased production of stems and leaf sheaths more than leaf laminae. Crude protein concentration (CPC) of both species generally was low, but N fertilizer increased CPC from 52 to 77 g kg−1. In vitro dry matter disappearance values were low, but significant species X N, lime X N, species X lime X N, and N X year interactions occurred. Lime effects were significant for concentrations of Ca, Mg, and Mn; P fertilizer for Ca, Mg, and P; and N fertilizer for Ca, Mg, P, and Mn. Aluminum concentrations in forage were low even with an exchangeable soil Al of 100 kg ha−1. Approximately 80% of the root mass of each species was within the top 10 cm of soil, but roots were observed growing along prism faces of the fragipan at 60 cm. The warm‐season grasses were productive on strongly acid (31 Mg lime ha−1needed for neutralization), infertile soil, with low inputs of lime (4.5 Mg ha−1) and fertilizer.