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Managing annual row crops on marginally productive croplands can be environmentally unsustainable and result in variable economic returns. Incorporating perennial bioenergy feedstocks into marginally productive cropland can engender ecosystem services and enhance climate resiliency while also diversifying farm incomes. We use one of the oldest bioenergy-specific field experiments in North America to evaluate economically and environmentally sustainable management practices for growing perennial grasses on marginal cropland. This long-term field trial called 9804 was established in 1998 in eastern Nebraska and compared the productivity and sustainability of corn (Zea mays L.) --both corn grain and corn stover--and switchgrass (Panicum virgatum L.) bioenergy systems under different harvest strategies and nitrogen (N) fertilizer rates. This experiment demonstrated that switchgrass, compared to corn, is a reliable and sustainable bioenergy feedstock. This experiment has been a catalyst for other bioenergy projects which have also expanded our understanding of growing and managing bioenergy feedstocks on marginal cropland. We (1) synthesize research from this long-term experiment and (2) provide perspective concerning both the knowledge gained from this experiment and knowledge gaps and how to fill them as well as the role switchgrass will play in the future of bioenergy. [ABSTRACT FROM AUTHOR]

Corn residue grazing is an economical winter feed resource for cows in the Midwest. However, questions about changes in the feeding value have been raised. A 2-yr experiment was conducted to evaluate the effects of corn grain yield on the quantity and quality of corn residue. In yr 1, 32 hybrids were evaluated from four locations in Nebraska. In yr 2, 31 hybrids were evaluated from three locations in Nebraska. Each hybrid was harvested from four replicate plots. Three of the locations were irrigated and four were rainfed. Observed grain yields ranged from 1,416 to 22,318 kg/ha (23 to 355 bushels/acre) with a mean of 12,704 kg/ ha (202 bushels/acre). As corn yield increased, the amount of grain relative to whole plant biomass (harvest index) increased (P < 0.01). Harvest index ranged from 48.4% to 67.6% and averaged 59.3%. The increase in harvest index indicates there was less residue produced per kilogram of corn grain produced in greater yielding corn. However, as expected, total amount of residue (kg/ha) still increased (P < 0.01) as grain yield (kg/ha) increased. Within the residue, the proportions of leaf and husk increased (P < 0.01) slightly, stalk decreased (P < 0.01) slightly, while the proportion of cob did not change (P = 0.62) as grain yield increased. On average, the observed plant proportions in this experiment were 15.8% husk, 18.6% leaf, 50.5% stalk and 15.1% cob (DM basis). As grain yield increased, the proportion of husk within residue increased from 14 to 21% and leaf increased from 17 to 24%. In contrast, the proportion of stalk within residue decreased from 53 to 41%. Cattle primarily consume leaf and husk when grazing corn residue, thus the availability and digestibility of those plant parts could be a key factor that affects diet quality of grazing cattle. Both the digestible organic matter (DOM, % of DM) in leaf and husk and the kilograms of DOM from leaf plus husk per 25.4 kilograms of grain declined (P < 0.01) as grain yield increased. On average, the DOM (% of DM) for husk was 69.3% but declined from 83.6 to 56.4% with increasing in grain yield. The average DOM (% of DM) for leaf was 55.6% and declined from 65.3 to 41.6% as grain yield increased. The average amount of DOM from leaf plus husk was 3.6 kg/25.4 kg of grain (8 lb/bushel) and declined from 5.8 to 2.5 kg/25.4 kg of grain (12.8 to 5.5 lb/ bushel) as grain yield increased. Thus, the concentration of nutrients in corn residue declined as grain yield increased, meaning greater yielding corn had reduced quality residue. The impacts of this decline in diet quality on cow performance should be further evaluated. [ABSTRACT FROM AUTHOR]

Soybean harvest leaves little residue, potentially subjecting the soil to negative environmental impacts. Additionally, integrated livestock producers with crops and cattle identified a need to fill early spring forage deficiencies. Planting winter-hardy cereal cover crops after soybean harvest provides ground cover until the next cash crop is planted and has potential for early spring grazing before perennial pastures are ready. A 3-year study was conducted near Mead, Nebraska to evaluate the grazing potential of winter wheat, winter triticale, and cereal rye when planted after soybean harvest. A 7.3-ha field was split into nine 0.81-h paddocks and paddocks were then randomly assigned to a small cereal species (n = 3 paddocks per treatment), then divided further into 2, 0.4 ha paddocks to allow for rotational grazing within the assigned paddock. Growing steers were stratified by body weight (BW) and randomly assigned to paddock with 6 steers per paddock in years 1 and 2, and 5 steers per paddock in year 3. Steers were limit-fed at 2% of BW to equalize gut fill and weighed before and at the conclusion of grazing. Grazing was initiated when a paddock reached 13 cm. The initial BW did not differ among treatments (P > 0.05) with steers weighing 303, 335, and 372 kg in years 1 through 3, respectively. The final BW did not differ among treatments (P > 0.05). There was a treatment by year interaction (P = 0.01) for average daily gain (ADG). There were no differences (P > 0.05) in ADG among treatments in year 1 (1.9 kg/d) or year 3 (1.3 kg/d). However, in year 2, steers grazing rye gained more (P < 0.01) at 1.4 kg than wheat (0.83 kg) and triticale (0.67 kg), which did not differ (P > 0.05). There were no differences (P > 0.05) among treatments for animal unit months (AUM) per hectare. Year 1 provided the most (P < 0.01) grazing at 5.1 AUM/ha, year 2 provided the least (P < 0.01) at 2.4 AUM/ha, and year 3 was intermediate at 3.1 AUM/ha. For gain per hectare (GPH), there were no differences (P > 0.05) among treatments. Steers in year 1 had greater (P < 0.01) GPH (390 kg/ha) than subsequent years, with year 2 (93 kg/ha) being less (P < 0.01) than year 3 (151 kg/ha). For all 3 years, there were no differences among treatments in pre-graze (P > 0.05) or postgraze biomass (P > 0.05). These data suggest that during early spring there are no major differences in the grazing potential and growing cattle performance for wheat, rye, or triticale in eastern Nebraska. [ABSTRACT FROM AUTHOR]

Winter-hardy small grains offer an opportunity to improve soil health as a cover crop, and they can also be used as a forage source for cattle. Winterhardy small grains differ in the time needed to reach various maturity stages. Species selection may also impact yield and nutritive value. A two-year study was conducted in eastern Nebraska to determine the effect of species and maturity on yield and nutritive value of winter-hardy small grains used for silage. Three species were evaluated; cereal rye, winter wheat, and winter triticale at four stages of maturity: boot, anthesis, milk, and soft dough. The experimental design was a randomized complete block design with four blocks per year. Small grain species were considered whole plots with maturity at harvest considered sub-plot. Each year, the small grain species were randomly assigned within each block. Within each plot, maturity was randomly assigned to one quarter of each plot. Dry matter (DM) forage yield, crude protein (CP), digestible organic matter (DOM), and nutrient yield per hectare were measured and analyzed using the mixed procedure of SAS. Forage yield increased for all species (P < 0.01) with maturity, except for wheat, where there was a decrease at soft dough. Forage yield of cereal rye and triticale did not differ (P>0.05), except at soft dough where triticale was greater (P < 0.01) than cereal rye. Forage yield of triticale and cereal rye yield was greater (P£0.05) than wheat at anthesis and soft dough. Crude protein (% DM) decreased (P < 0.01) with maturity across all species. Among species, CP for cereal rye was greater (P£0.01) than triticale at boot, anthesis, and soft dough, but not different (P³0.10) from wheat at boot, milk, and soft dough. At boot, anthesis, and milk stages, CP of triticale was not different (P³0.07) than wheat, but triticale was lower than wheat (P < 0.01) at soft dough. The DOM (% DM) decreased (P < 0.01) with maturity, except at soft dough. The DOM of cereal rye and wheat did not differ (P > 0.05), but both were greater (P < 0.01) than triticale. Cereal rye and triticale had greater (P £ 0.05) nutrient yields than wheat in terms of energy (DOM) and CP. There was no difference for CP yield across stages (P = 0.10), but there was an effect of maturity on DOM yield. The DOM yield increased from boot to anthesis, (P = 0.05), anthesis and milk did not differ (P = 0.08) and increased (P < 0.01) again at soft dough. This suggests that planting either cereal rye or triticale resulted in the greatest nutrient yield per acre. Harvest at anthesis had increased yield compared to boot with minimal loss in nutritive value; for maximizing energy yield per acre, harvesting at soft dough was the best option. [ABSTRACT FROM AUTHOR]