Forage Nutritive Value Research Articles

Stem and leaf forage nutritive value and morphology of reduced lignin alfalfa

AbstractReduced lignin alfalfa (Medicago sativa L.) has the potential to improve alfalfa forage quality, yet forage morphology, biomass allocation, and stem and leaf forage nutritive value remains undetermined. The objectives of this study were to characterize changes in morphological development and forage nutritive value within stem and leaf fractions for reduced lignin alfalfa. Reduced lignin (‘54HVX41’) and reference (‘DKA43‐22RR’) alfalfa cultivars were sampled weekly from the mid‐vegetative stage through full flower during the seeding (2015) and first production (2016) year at two locations in Minnesota. Samples were staged to determine maturity, divided into stem and leaf fractions, weighed, and analyzed for forage nutritive value. Alfalfa cultivars were similar in stem and leaf yield, leaf to stem ratio (L/S), stem crude protein (CP), stem neutral detergent fiber (NDF), leaf CP, leaf NDF, leaf acid detergent lignin (ADL), and leaf NDF digestibility (NDFD). On average, reduced lignin alfalfa showed a 14% decrease in stem ADL and a 12% increase in stem NDFD compared to reference alfalfa. For both cultivars, increases in forage maturity increased stem and leaf yields and decreased L/S. Forage maturity also affected stem and leaf forage nutritive values; as maturity increased, NDF and ADL increased while CP and NDFD decreased. These results indicate that changes in forage nutritive value for reduced lignin alfalfa are largely a result of changes in ADL and NDFD within the stem fraction, and confirm that alfalfa forage nutritive value is negatively affected by forage maturity, particularly within the stem portion of the plant.

Herbage mass, botanical composition, forage nutritive value, and preference of grass–legume pastures under horse grazing

AbstractCool‐season perennial grasses are the foundation of productive horse pastures in the north‐central United States. The addition of legumes in pastures can increase forage mass and digestible energy content, yet little research has investigated grass–legume pastures under horse grazing. The objectives of this research were to evaluate herbage mass, botanical composition, forage nutritive value, and preference of grass–legume pastures under horse grazing. Plots consisting of orchardgrass (Dactylis glomerata L.), Kentucky bluegrass (Poa pratensis L.), and meadow fescue (Festuca pratensis Huds.) were planted in monoculture and in binary mixtures with alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.) and grazed by horses in Minnesota during the 2013, 2014, and 2015 grazing seasons. Herbage mass, weed mass, and forage nutritive values were determined prior to grazing, and horse preference was evaluated following grazing. When evaluating herbage mass, the inclusion of alfalfa resulted in a consistently higher mass than grass monoculture. Kentucky bluegrass mixtures resulted in a decreased mass of non‐sown (weed) species and an increase in horse preference. Improved forage nutritive values were also observed with the inclusion of legumes regardless of grass species, including higher crude protein and neutral detergent fiber digestibility at 48 h and lower neutral detergent fiber. As a result, using grass–legume mixtures in pastures can provide benefits for grazing horses and pasture productivity.

Forage nutritive value of modern alfalfa cultivars

AbstractGenetically engineered, reduced lignin (RL) alfalfa (Medicago sativa L.) cultivars have been developed for enhanced forage nutritive value. Research is needed to quantify the differences in forage nutritive value among conventionally bred cultivars marketed as high in nutritive value (HNV) and RL cultivars. The objective was to evaluate forage nutritive value and yield differences in HNV and RL cultivar groups compared with control cultivars. Research was conducted in the seeding and following years in New York and Minnesota, with sampling over multiple days within three harvest seasons. Annual yield was similar among control, HNV, and RL cultivars. Relative to the control and HNV cultivars, lignin was 12.5% lower and neutral detergent fiber digestibility (NDFD) was 5% higher for RL cultivars. Reduced lignin cultivars had higher relative forage quality (RFQ) than control and HNV cultivars for five of six site/season combinations. Within harvest seasons, lignin, acid detergent fiber (ADF), and neutral detergent fiber (NDF) increased, whereas crude protein (CP), NDFD, RFQ, and milk production decreased with increasing growing degree‐days. Growing degree‐day responses were similar across cultivar market groups, with the exception of ADF, NDF, RFQ, and milk during the establishment year in Minnesota, where the rates of decrease in RFQ through time were lower for RL than for control and HNV. Overall, RL cultivars had improved forage nutritive value that persisted with maturity within cutting seasons. Control and HNV cultivars did not consistently differ in nutritive value. Growers can select cultivars for improved nutritive value without concern about compromising forage yield.

Overseeding cool‐season forages on rhizoma peanut fields

AbstractRhizoma peanut (Arachis glabrata Benth.) is an important hay crop in the southern United States. Since rhizoma peanut is a warm‐season perennial legume, it remains dormant during the cool season. Overseeding rhizoma peanut during the cool season could optimize land productivity per unit area throughout the year. However, the effect of overseeding on rhizoma peanut performance in the following growing season is unknown. This study evaluated different combinations of rye (Secale cereale L. ‘FL401’) and/or ryegrass (Lolium multiflorum Lam. ‘Prine’) mixed or not with clovers (Trifolium spp.) overseeded on dormant ‘Florigraze’ rhizoma peanut. Rye–clover mixtures resulted in greater herbage accumulation (6,040 lb ac−1 yr−1) than grass monocultures, clovers, and rye–ryegrass mixtures. However, rye–clover mixtures had similar herbage accumulation to rye–ryegrass–clovers (5,640 lb ac−1 yr−1) and ryegrass–clovers (4,560 lb ac−1 yr−1). Crude protein (CP) concentration in grass was greater for rye and rye–ryegrass (9.8%, for both) than in ryegrass monoculture (8.2%), nonetheless, it was similar to other treatments (9.1%, on average). Ryegrass and ryegrass–clovers resulted in the greater in vitro digestible organic matter (IVDOM) for the grasses (81%, on average) than all other treatments (70%, on average). Overseeding rhizoma peanut did not affect its herbage responses. On average, herbage accumulation, CP, and IVDOM for Florigraze rhizoma peanut in the first harvest following the overseeding treatments were 3,845 lb ac−1, 14.2%, and 75.7%, respectively. Results indicate that overseeding cool‐season grass–legume mixtures would optimize forage production per unit area and improve forage nutritive value without compromising rhizoma peanut herbage responses in the growing season.

Forage potential of corn intercrops for beef cattle diets in northwestern Alberta

AbstractIntercropping systems involving cereals with legumes provide several advantages such as elevated forage yield and improved forage nutritive value. This study was designed to assess viability of corn (Zea mays L.) intercrops to improve the forage crude protein (CP) of corn forage for beef cattle production. A corn monocrop (C‐M) was compared with seven corn intercrops (five annual legumes, a non‐legume crop (radish (Raphanus sativus L.), C‐RA) and an annual crop mixture (ACM)). The corn forage dry matter (DM) yield was significantly improved (P < .05) for C‐M than all intercrops. Of the seven intercrops, only corn‐radish intercrop (C‐RA) produced significantly lower total forage DM yield (corn + companion) than C‐M. Of the seven corn intercrops, only corn‐hairy vetch (Vicia villosa Roth) (C‐HV) and corn–annual crop mixture (C‐ACM) had significantly (P < .05) improved forage CP and digestible CP than C‐M. Both C‐HV and C‐ACM exceeded the CP recommendations for mature beef cattle and also had adequate CP for young (growing and finishing calves) beef cattle, thereby eliminating the need for protein supplementation during the feeding of either C‐HV or C‐ACM beef cattle. Forage minerals were not significantly affected (P > .05) by corn intercrops. Forage total digestible nutrients (TDN) was significantly (P < .05) influenced by intercrops and varied from 65.9‐71.2%. Results indicate that selected corn intercrops can improve nutritive value of forage for beef cattle production.

Browse potential of bristly locust, smooth sumac, and sericea lespedeza for small ruminants

Temperate grass and legume yield and quality are markedly reduced during hot, dry summer months in the southern USA; therefore, browse species could add feed options for small ruminants during this season. Our objective was to compare total biomass yield and forage nutritive value of two browse species, leguminous bristly locust (Robinia hispida) and smooth sumac (Rhus glabra), as well as a leguminous shrub known as sericea lespedeza (Lespedeza cuneate), during summer months (June, July, August and September). Plants were sampled monthly during growing-seasons in 2012 and 2013 to determine biomass yield (foliar, shoot, and total above ground) and foliar nutritive value [crude protein (CP), acid detergent fiber (ADF), acid detergent lignin (ADL), and condensed tannins (CT)]. There was a species × harvest time interaction for foliar biomass yield (P = 0.0125). This interaction was likely due to low yield in June for bristly locust compared with sericea lespedeza and smooth sumac, but in all other months (July, August, and September) yields were similar for each species. Bristly locust had the highest CP (16.9%), followed by sericea lespedeza (14.8%), and smooth sumac (12.3%). Acid detergent fiber and ADL were similar between bristly locust (ADF 38.5%; ADL 24.1%) and sericea lespedeza (ADF 38.4%; ADL 23.1%), but was lower for smooth sumac (ADF 22.1%, ADL 6.3%; P < 0.05). Condensed tannins, an anti-nutritive yet anti-parasitic phenolic compounds, were highest in smooth sumac, intermediate in bristly locust, and lowest in sericea lespedeza. Plant foliar percentage (ratio of foliar to shoot mass), was highest in smooth sumac (55.1%), followed by sericea lespedeza (47.7%), and bristly locust (42.6%). Overall, smooth sumac had the highest foliar biomass and lowest ADF and ADL; however, this species had the lowest CP and highest CT. Consequently, average foliar biomass yield of all three browse species in our study far exceeded forage yield from dominant forage species [tall fescue (Schedonorus arundinaceus) and bermudagrass (Cyanodon dactylon)] in this region and may provide high-yielding, low input, anti-parasitic fodder for small ruminants during this period in the Southeastern U.S.

Allometries in Plants as Drivers of Forage Nutritive Value: A Review

The nutritive value of forage for herbivores has been for a long time determined by the concentration in protein and, hence in nitrogen (N), the concentration in different minerals (P, K, Ca, Mg, and oligo-elements), and the in vivo dry matter (DM) digestibility. Forage DM digestibility, the proportion of ingested DM being metabolized by ruminant animals has been related to different components of plant tissue composition such as Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF); the NDF concentration represents an estimate of cell wall content while the ADF concentration is an estimate of the more lignified cell wall content. Forage nutritive value is generally analyzed by relating the attributes of nutritive value to plant phenology, in order to predict the decline of these attributes with plant age. A more functional approach, initially developed for the analysis of N concentration dynamic analysis (Lemaire et al. 2008 and Lemaire et al. 2019), and extended for digestibility for this review, is based on the assumption that above-ground plant mass (W) is composed of two compartments: (i) the metabolic compartment (Wm), associated with plant growth process scaling with leaf area, having a high N concentration (%N), and a high Digestibility (%D); (ii) the structural compartment (Ws) associated with architectural plant development, scaling with plant height and thickness and having low %N and %D. With the postulate that Wm is allometrically related to W (Wm = c × Wα with α &lt; 1), the ontogenetic decline of both %N and %D as the plant gets bigger and forage mass increases can be explained, and the purely empirical statistical approach of forage quality based on plant phenology can be replaced by a more mechanistic and comprehensive analysis linking forage production and forage quality dynamics within the same functional approach for a better understanding of genotype-environment-management interactions.

Nitrogen fertilization in tall fescue: Productivity, agronomic efficiency and relative profitability

AbstractTall fescue (Schedonorus arundinaceus [Schreb.] Dumort.) is a perennial forage grass with good nutritive value and has the potential to be grown in many parts of the world. Field experiments were conducted over a 3‐year period (2010–2012) at two locations [University of Wyoming Powell Research and Extension Center (PREC) and a producer field (Stroh farm) in Powell, Wyoming] to evaluate forage accumulation, forage nutritive value, agronomic efficiency (AE) and relative profitability (RP) of using different cultivars or lines and nitrogen (N) rates in tall fescue production systems. The study design was factorially arranged in a randomized complete block with four replications at PREC and three replications at Stroh farm. Treatments comprised seven tall fescue cultivars ('97TF584,' 'Cowgirl,' 'Fawn,' 'Kentucky‐31,' 'Maximize,' 'Soft,' and 'Texoma') and three N rates (0, 56 and 112 kg/ha). There was a linear response (p = .02) of annual forage accumulation to year × N. Crude protein, in vitro dry matter (DM) digestibility, acid detergent fiber and neutral detergent fiber ranged from 90 to 102, 704–719, 360–383 and 555–581 g/kg, respectively. There were main effects (p &lt; .01) of year, cultivar and N rate on AE and RP. Kentucky‐31 had the highest AE (53 kg DM/kg N), and AE was greater in the 56 kg N/ha (48 kg DM/kg N) compared to the 112 kg N/ha (39 kg DM/kg N). However, RP (where RP greater than 1 means revenue from N application is greater than the 0 kg N/ha treatment) was greater in the 112 kg N/ha (2.44) compared to the 56 kg N/ha (1.93). Among the cultivars, Kentucky‐31 had the highest RP of 2.56. Overall, all cultivars were responsive to added N and showed potential to be profitable under grass hay production systems.

What is the maximum nitrogen in marandu palisadegrass fertilization?

AbstractThe absence of nutrient replacement, especially nitrogen (N), is one of the main causes of grazing system underutilization and tropical climate pasture degradation. Therefore, N is a very important nutrient in the pasture maintenance; however, it is necessary to know the maximum limit to be used of this nutrient, since fertilization increases production cost. Thus, the objective of this study was to identify the N dose that provides the highest production of marandu palisadegrass (Brachiaria brizantha cv. Marandu), and the fertilization effect on pasture degradation process and forage nutritive value. Treatments consisted in the application of : 0 (control), 25, 50, 75 and 100 kg N ha−1 cycle−1 of regrowth. The evaluations were carried out during the summers (November to April) of 2015/2016 and 2016/2017. The highest dry matter yield (DMY) and forage accumulation rate (FAR) occurred between doses of 50 and 75 kg ha−1 cycle−1, with no change in productive potential at higher doses. The reduction in mineral content and the increase in crude protein (CP) are the main changes in the nutritional value of marandu palisadegrass, with no pronounced effect on in vitro dry matter digestibility (IVDMD), indigestible neutral detergent fiber (iNDF) and potentially digestible dry matter proportions of CP in the cell wall (CPCW) and in cellular content (CPCC).The productive effect of nitrogen fertilization under marandu palisadegrass is the increase in DMY and FAR. Thus, the use of nitrogen fertilizers in pasture systems with marandu palisadegrass has a greater impact on the area gain than the individual gain, assuming these systems, the use of nitrogen doses of 50 to 75 kg ha−1 cycle−1.

Potassium Fertilization Affects Alfalfa Forage Yield, Nutritive Value, Root Traits, and Persistence

Potassium (K) is a critical macronutrient for alfalfa growth; however, reports of the effects of K fertilization on alfalfa yield, quality, and persistence have been inconsistent. Five K fertilizer rates ranging from 0 to 403 kg K ha−1 were applied to eight alfalfa cultivars during the establishment year (2011) and three subsequent production years (2012–2014) at three locations varying in baseline soil test potassium (STK) levels. Alfalfa yield, nutritive value, and STK were measured annually. During the final year, stem density and belowground traits were quantified. Forage yield, nutritive value, and root traits varied by cultivar, but there were no interactions between cultivar and K rate. Crown rot varied by cultivar but was not affected by K rate. Averaged across cultivars, the effect of K on yield varied by location and stand age. At the site with the lowest baseline STK values, K fertilizer had a positive quadratic effect on yield, which plateaued at a K rate of 296 kg K ha−1. There was no effect of K on yield at the site with the greatest baseline STK. Potassium fertilizer reduced forage nutritive value and increased forage K concentration. Aboveground and belowground biomass K concentration increased with K fertilizer at rates beyond those that maximized yield, indicating luxury consumption of K. However, mineralization of soil K resulted in a net increase in STK after accounting for K removal during harvest. Potassium removal rates that resulted in maintained STK were 167, 227, and 268 kg K ha−1 yr−1 at three locations.Core Ideas A positive effect of K fertilizer on alfalfa yield was consistent across cultivars. K fertilization reduced alfalfa nutritive value. K fertilization increased root biomass but did not affect root diameter or crown rot. Alfalfa demonstrated luxury consumption of K. Soil test K increased after accounting for K removal during harvest.

Predicting Pre‐harvest Forage Nutritive Value of Spring and Summer Growth of Alfalfa–Grass Mixtures

Currently available regression equations developed to predict pre‐harvest nutritive attributes from simple field measurements taken in alfalfa (Medicago sativa L.)–grass mixtures can help producers determine when to best harvest their forages but they are applicable to only spring growth. Our objective was to develop and validate predictive equations of pre‐harvest forage nutritive attributes of mixed alfalfa–grass stands for the spring and first summer growth cycles. Forage samples (n = 1856) were collected in 2015 and 2016 from three research sites in Quebec, Canada, and used to develop predictive equations that were then validated using samples (n = 315) collected on commercial farms across Quebec and compared to equations previously developed in New York State for use during spring growth. For newly developed equations with two to four field measurements, R2 ranged from 0.70 to 0.84. The best equation developed to estimate a neutral detergent fiber assayed with a heat stable α‐amylase and corrected for the ash content of the residue (aNDFom) had an R2 of 0.82 and a root mean square error (RMSE) of 29.3 g kg−1 dry matter (DM). Some equations can be used to predict aNDFom concentration and the relative feed value of samples from commercial farms, but only if alfalfa proportion can be precisely determined. Locally developed equations resulted in better predictions than equations developed only for spring growth in New York State. Forage producers now have access to a tool to predict the pre‐harvest nutritive value of their forages for two growth cycles.Core Ideas Predictive equations can help producers determine when to harvest their forage fields. Equations developed can predict nutritive value of alfalfa‐grass stands for the spring and first summer growth cycles. Alfalfa proportion must be precisely determined for equations to yield reliable results.

Improvement of alfalfa forage quality and management through the down-regulation of MsFTa1.

SummaryAlfalfa (Medicago sativa L.) is one of the most important forage crops worldwide. As a perennial, alfalfa is cut several times each year. Farmers face a dilemma: if cut earlier, forage nutritive value is much higher but regrowth is affected and the longevity of the stand is severely compromised. On the other hand, if alfalfa is cut later at full flower, stands persist longer and more biomass may be harvested, but the nutritive value diminishes. Alfalfa is a strict long‐day plant. We reasoned that by manipulating the response to photoperiod, we could delay flowering to improve forage quality and widen each harvesting window, facilitating management. With this aim, we functionally characterized the FLOWERING LOCUS T family of genes, represented by five members: MsFTa1, MsFTa2, MsFTb1, MsFTb2 and MsFTc. The expression of MsFTa1 correlated with photoperiodic flowering and its down‐regulation led to severe delayed flowering. Altogether, with late flowering, low expression of MsFTa1 led to changes in plant architecture resulting in increased leaf to stem biomass ratios and forage digestibility. By manipulating photoperiodic flowering, we were able to improve the quality of alfalfa forage and management, which may allow farmers to cut alfalfa of high nutritive value without compromising stand persistence.

Seasonal changes in forage nutritive value of common weeds encountered in Missouri pastures

AbstractDuring the 2015, 2016, and 2017 growing seasons, weed and weed-free mixed tall fescue and legume forage samples were harvested from 29 pastures throughout Missouri for investigation of the nutritive value of 20 common pasture weed species throughout the season. At certain times during the growing season, many broadleaf weed species had greater nutritive values for a given quality parameter as compared with the available weed-free, mixed tall fescue and legume forage harvested from the same location. There were no significant differences in crude protein concentration between the weed-free forage and many weeds throughout the growing season. However, crude protein content of common burdock, common cocklebur, common ragweed, dandelion, horsenettle, and lanceleaf ragweed was greater than that of the corresponding forage sample at multiple collection periods. The digestible neutral detergent fiber (dNDF) content of all broadleaf weeds except lanceleaf ragweed was significantly lower than that of the weed-free forage at all collection periods. Conversely, large crabgrass had significantly greater digestible neutral detergent fiber levels than did the mixed tall fescue forage at all sampling dates. Dandelion and spiny amaranth had greater in vitro true digestibility (IVTD) content than did the forage for the entire growing season. Three perennial weeds—horsenettle, vervains, and late boneset—did not differ in IVTD levels as compared with the mixed tall fescue and legume forage at any collection date. For most summer annual weeds, the trend was toward greater digestibility earlier in the season, with a gradual decline and often lower IVTD by the late summer or early fall. The results of this study will enable producers to make more informed management decisions about the potential benefit or detriment a weed may provide to the overall nutritive value of the pasture system.

Intercropping winter cereals in Kura clover for spring forage production

Intercropping winter cereals into Kura clover (Trifolium ambiguum M. Bieb.) has the potential to improve forage nutritive value without reducing yields. The objective of this research was to compare forage yield and nutritive value of cereal–legume mixtures to cereals or Kura clover grown in monoculture and harvested at two different maturity stages in spring. Winter rye (Secale cereale L.), winter wheat (Triticum aestivum L.), and winter triticale (×Triticosecale Wittmack) were sown in autumn at two locations as monocultures and into herbicide suppressed and non-suppressed Kura clover and harvested for forage the following spring. Harvested at the cereal crop boot stage at Arlington, forage yields averaged 4.7, 4.8, 5.3, and 1.7 Mg ha−1and 3.5, 3.7, 4.1, and 2.6 Mg ha−1at Lancaster for mixtures with non-suppressed Kura clover, suppressed Kura clover, monoculture cereals, and monoculture clover, respectively. At the milk stage, yields across all mixture treatments increased by 46% to 115% compared to the boot stage at Arlington and by 88% to 101% at Lancaster. Kura clover in mixtures increased crude protein by 34% to 46% and in vitro true digestibility by 3% to 6%, neutral detergent fiber digestibility by 0% to 6%, and reduced neutral detergent fiber concentration by 8% to 18% relative to cereal monocultures. The nutritive value of mixtures and monoculture Kura clover was always greater than that of monoculture cereals. Winter cereals can be successfully managed with Kura clover for forage production by maximizing nutritive value with boot stage harvests or achieving higher yields by harvesting at the milk stage.

Quantitative Trait Loci (QTL) for Forage Traits in Intermediate Wheatgrass When Grown as Spaced-Plants versus Monoculture and Polyculture Swards

It has been hypothesized that the genetic control of forage traits, especially biomass, for grass plants growing as spaced-plants versus swards is different. Likewise, the genetic control of compatibility in grass–legume polyculture mixtures is assumed to be different than for forage production in a grass monoculture. However, these hypotheses are largely unvalidated, especially at the DNA level. This study used an intermediate wheatgrass mapping population to examine the effect of three competition environments (spaced-plants, polyculture, and monoculture) on classical quantitative genetic parameters and quantitative trait loci (QTL) identification for biomass, morphology, and forage nutritive value. Moderate to high heritable variation was observed for biomass, morphological traits, and nutritive value within all three environments (H ranged from 0.50 to 0.87). Genetic correlations (rG) among environments for morphology and nutritive value were predominantly high, however, were moderately-low (0.30 to 0.48) for biomass. Six biomass QTL were identified, including three on linkage groups (LG) 1, 6, and 15 that were only expressed in the monoculture environment. Moreover, three biomass QTL on LG 10, 14, and 15 exhibited significant QTL by environment interactions. This study verified that the genetic control of grass biomass in a monoculture versus a grass–legume mixture is only partially the same, with additional genes expressed in monoculture, and that biomass in widely spaced-plants versus swards is predominantly under different genetic control. These results indicate that selection for improved grass biomass will be most successful when conducted within the targeted monoculture or polyculture sward environment per se.

Forage nutritive value and predicted fiber digestibility of Kernza intermediate wheatgrass in monoculture and in mixture with red clover during the first production year

Kernza intermediate wheatgrass is the first perennial grain crop in the world and has been developed with conventional breeding to increase seed yield of forage intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey). When managed for dual-use (grain and forage), Kernza intermediate wheatgrass can produce grain, crop residue (straw) in the summer, and green forage in the spring and fall. Mixtures of this grass with legumes could increase forage yield and nutritive value and provide other environmental and economic benefits. Despite the growing interest in these dual-use production systems, forage nutritive value of Kernza intermediate wheatgrass forage in a dual-use system in the Upper Midwest is unknown. A replicated field experiment was established in two locations in southern Wisconsin (Arlington and Lancaster) with two treatments: Kernza intermediate wheatgrass grown in monoculture and mixture with red clover (Trifolium pratense L.). Forage samples were collected at late vegetative stage in the spring, at grain harvest in the summer, and at the end of the regrowth period in the fall. Forage nutritive value of the monoculture was greatest in the spring with 456, 249 and 225 g kg−1 for neutral detergent fiber (NDF), acid detergent fiber (ADF) and crude protein (CP), respectively; lowest in the summer with 702, 427 and 51 g kg−1 NDF, ADF and CP, respectively, and intermediate in the fall with 590, 337 and 119 g kg−1 NDF, ADF and CP, respectively. Predicted total-tract neutral detergent fiber digestibility (ttNDFD) was 0.53 for the spring forage and averaged 0.37 for the summer and fall forage, with no differences between the mixture and monoculture. The relative forage quality (RFQ) for the monoculture was 175 for the spring forage, 65 for the summer residue, and 116 for the fall. Intercropping red clover with Kernza intermediate wheatgrass increased CP of the summer crop residue by 69%, and increased CP and RFQ of the fall forage by 49% and 11%, respectively, while reducing NDF and ADF of the fall forage by 25% and 18%, respectively. Therefore, Kernza intermediate wheatgrass forage is suitable for lactating beef cows, dairy cows, and growing heifers when harvested in the spring and fall, and it offers high potential for dual-use grain and forage systems.

Farmer perspectives and experiences introducing the novel perennial grain Kernza intermediate wheatgrass in the US Midwest

AbstractKernza® intermediate wheatgrass (Thinopyrum intermedium) is a novel perennial grain and forage crop with the potential to provide multiple ecosystem services, which recently became commercially available to farmers in the USA. The viability and further expansion of this promising crop require understanding how it may fit the needs of farmers’ livelihoods and the structure of their farming systems. However, no prior research has studied the perceptions and experiences of Kernza growers. The goals of this research were to understand why farmers grow Kernza, how Kernza fits into their systems and identify challenges for future research. We conducted in-depth interviews with ten growers in the North Central USA during the summer of 2017, who accounted for a third of the Kernza farmers in the USA at the time. All farmers had a positive attitude toward experimentation and trying new practices, and they were interested in Kernza for its simultaneous ecological and economic benefits. Kernza was marginal in terms of area, quality of fields and resources allocated in the farm systems, which also meant that farmers maintained low costs and risks. Growers utilized and valued Kernza as a dual-use crop (grain and forage), sometimes not harvesting grain but almost always grazing or harvesting hay and straw for bedding. Weeds were perceived as a challenge in some cases, but Kernza was valued as a highly weed-suppressive crop in others. Farmers requested information on optimal establishment practices, assessment of forage nutritive value, how to maintain grain yields over years, weed management, markets and economic assessment of Kernza systems. These results agree with other cases on sustainable practices adoption showing that engaging farmers in the research process from the beginning, identifying knowledge gaps and testing management alternatives are critical for the success and expansion of novel agricultural technologies.

Facilitating Crop–Livestock Reintegration in the Northern Great Plains

Integrated crop–livestock systems (ICLSs) can help increase food production while benefiting soils and the environment. This review summarizes recent impacts of ICLSs on crop and livestock production and rural economics and discusses lessons learned in the northern Great Plains (NGP). Research on ICLS conducted in the NGP indicates that the crop residue grazing, swath grazing, and annual forage grazing can positively influence crop production; whereas, livestock performance varies with season, forage nutritive value, and grazing management. Furthermore, ICLSs can reduce the costs and risks of agricultural production. The success of ICLSs in NGP region depends on trade‐offs, planning, economic benefits, policies, regulations, community acceptance, and management skills. The ICLSs could play a strategic role in future agricultural production. The lessons learned from adopting ICLSs in the NGP include the lack of available land for fertilizer (manure) management, that to implement ICLS practices skills and knowledge must be maintained, and ICLS provides an entry point for young farmers and ranchers however capital is needed. These experiences and lessons could be valuable references for producers to adopt ICLSs in the NGP or other regions.Core IdeasIntegrated crop–livestock systems positively affect crop production by improving soil health.Common integrated crop–livestock system management techniques can enhance the northern Great Plains crop production.Integrated crop–livestock system livestock performance is impacted by season, forage selection, and management.Integrated crop–livestock systems can increase economic benefits and reduce economic risks.Experiences and lessons in the northern Great Plains could be valuable for other regions to adopt integrated crop–livestock systems.

Nitrogen Delivery Method and Monensin Effects on Productivity, Nutritive Value, and Botanical Composition of Grazed Annual Ryegrass Pasture

Nitrogen fertilization is a major input cost of forage production, and alternatives that maintain yield and nutritive value would be advantageous. A 3‐yr study was conducted to evaluate forage nutritive value and clover proportion when N fertilizer was replaced partially with interseeded clovers (Trifolium spp.) or protein supplements for stocker cattle grazing annual ryegrass (Lolium multiflorum Lam.). Nitrogen delivery methods with or without monensin included annual ryegrass fertilized with 112 kg N ha−1 in split application (NFERT), and other methods that received 56 kg N ha−1, including annual ryegrass interseeded with crimson clover (CC, Trifolium incarnatum L.) or arrowleaf clover (AC, Trifolium vesiculosum Savi), or grazing cattle supplemented with distillers dried grains plus solubles at a rate of 0.65% body weight daily (DDGS) or whole cottonseed (Gossypium hirsutum L.) at the rate of 0.65% body weight daily (WCS). Clover proportion was greater (P = 0.003) for CC than AC across all 3 yr of the study, and CC was more (P = 0.003) abundant when monensin was fed. Year affected forage in vitro true digestibility (IVTD, P &lt; 0.001) and crude protein (CP, P &lt; 0.001) concentration such that IVTD and CP were greatest in Year 3, intermediate in Year 2, and least in Year 1. Forage degradable intake protein (DIP) concentration was affected by N delivery method (P &lt; 0.001) and year (P &lt; 0.001) such that CC was less than NFERT, DDGS, WCS, and AC, and Year 1 was greatest, Year 2 was intermediate, and Year 3 was the least. Results are interpreted to mean that year affected forage nutritive value more than did N delivery method.

Establishment and Stand Development of Alfalfa Interseeded into Native Grass Mixture: Cultivar and Row Spacing Effects

Interseeding alfalfa (Medicago sativa L.) into native grasslands can enrich forage nutritive value, but successful establishment in semiarid regions is limited by chronic water deficit. The objective was to evaluate establishment and stand development of two upright‐type alfalfa cultivars, ‘WL 440HQ’ (WL), ‘NuMex Bill Melton’ (NM), and prostrate‐type ‘Falcata’–‘Rhizoma’ blend (FR), interseeded into mixtures of four native grass species at 36‐ or 71‐cm row spacing near Lubbock, TX. Average emergence was 265, 216, and 175 seedlings m−2 for WL, NM, and FR, respectively; however, the WL stand declined faster than the FR and NM stands during seedling and crown development stages (P &lt; 0.01). The upright‐type cultivars maintained a greater crown density and ground cover compared with FR at both row spacings (P &lt; 0.05). Alfalfa seedling or crown density fitted against time (d) with exponential models revealed an initial sharp decline followed by a slow rate of decline after establishment. At the end of 3 yr, row‐spacing results converged to similar levels for plant density (6.5 crowns m−2) and alfalfa cover (23.5%). This indicates significant seed cost savings with the wider row spacing at that level of stand establishment. Interseeding adapted, upright‐type cultivars at wide row spacing can produce a desirable level of alfalfa establishment in a semiarid grassland of the southern Great Plains.