Grass Monocultures Research Articles

The longevity of cultivation in decreasing the potential for phosphorus loss in runoff

Phosphorus (P) loss from highly fertilised grazed pastures can impair surface water quality. High P concentrations in grazed pastures are maintained to boost legume production, but systems that use monocultures of grass and clover can be more profitable and decrease P losses by lowering soil P in grassed areas. In contrast with using a direct drill to establish new pastures, conventional cultivation can lower topsoil P quickly and can be used as part of a farm re-grassing programme every six years. We tested if the potential for low P losses (measured by water extractable P; WEP) could be maintained over six years in pastures (ryegrass and white clover monocultures and a ryegrass and clover mixed sward) despite being fertilised (10, 35 and 100 kg P ha-1) and grazed. Cultivation (0–20 cm) decreased WEP and Olsen P in all three pastures and P rates by 30–50 % compared to direct drill and maintained this decrease for six years. A threshold in Olsen P (22 mg L-1) was noted where WEP concentrations increased at a greater rate relative to Olsen P than below. This threshold was like the critical point in Olsen P for 97 % relative yield in the pastures (22–28 mg L-1) and could be used to advise on cultivation and P fertiliser strategies to help avoid the potential for P loss without significantly compromising yield. The data indicated that cultivation could be used to quickly establish and maintain lower soil P concentrations as part of a strategy to decrease P losses and improve profit by using a split grass-clover system.

Legume proportion affects bahiagrass–rhizoma peanut mixture production and nutritive value and legume composition of cattle diets

Our objectives were to (1) quantify the effects of legume proportion on herbage accumulation (HA) and nutritive value of pasture mixtures compared with grass monocultures receiving typical or no N fertilizer application and (2) compare animal selection measures in legume–grass mixed pastures using microhistological and δ13C techniques applied to fecal samples. We evaluated HA and nutritive value in 2 grazing systems: (1) mixtures of Florigraze rhizoma peanut (Arachis glabrata Benth.) and Pensacola bahiagrass (Paspalum notatum Flügge) (MIX-SYS; 6 to 78% legume, grazed to a 15-cm stubble height at 42-d grazing intervals and ~7-d residence periods) and (2) bahiagrass monocultures receiving no N or 50 kg of N/ha per year (BG-SYS and BGN-SYS, grazed to 10-cm stubble height at 21-d grazing intervals with ~7-d residence periods) over 2 yr. Animal [~220 kg, 12-mo-old Brahman (Bos indicus) × Angus (Bos taurus) heifers] diet selection in MIX-SYS was quantified using microhistological and δ13C techniques applied to fecal samples. Herbage in vitro digestible OM (IVDOM) and CP concentrations increased linearly with increasing legume proportion in MIX-SYS up to ~45%, but MIX-SYS HA decreased linearly with increasing legume proportion. Treatment MIX-SYS had greater average HA [5,920 ± 271 (SE) kg/ha vs. 4,890 ± 236 kg/ ha for monocultures] and nutritive value than BG-SYS and BGN-SYS (CP of 12.9 ± 0.7% and IVDOM of 55.8 ± 1.0% for MIX-SYS vs. 9.1 ± 0.4% and 50.7 ± 1.5%, respectively, for monocultures). Results of microhistological and δ13C techniques applied to fecal samples were highly and positively correlated with sward canopy legume proportion, but fecal δ13C tracked legume proportion in the pasture more closely than the microhistological technique. Benefits of legumes to HA and nutritive value were observed at low legume participation, but they did not increase proportionally as legume percentage increased above ~45%. These results support a conclusion that relatively small proportions of legumes have measurable positive effects on important grassland characteristics.

Warm-climate, legume-grass forage mixtures versus grass-only swards: An ecosystem services comparison

Integrating warm-climate forage legumes into grass monocultures has received significant research attention during the past 70 years, but widespread adoption by end users has been elusive. The objectives of this review are to provide historical context regarding legume use in warm-climate grasslands; synthesize the current literature addressing contributions to grassland ecosystem services of warm-climate, grass-only vs. legume-grass mixed swards; and consider how to achieve more widespread adoption of legume technology in warm climates. For this review, warm-climate grasslands are [...]

FORAGE YIELD AND COMPOSITION OF BLACK OAT IN MONOCULTURE AND IN ASSOCIATION WITH WINTER VETCH

Associated grass-legume pastures have advantages over grass monoculture; in order to evaluate them the association of black oat (Avena strigosa Schreb) with winter vetch (Vicia villosa Roth) was analysed. The objective of the study was to evaluate forage yield, the botanical, morphological, and chemical composition of black oat in monoculture and in association with winter vetch, at different crop heights and residual stubble heights. Eighteen treatments were evaluated in randomized complete blocks with divided plots. In large plots, the culture type (monoculture or association); and in small plots, nine harvest management options (combinations) of three crop heights (Ch: 40, 50 and 60 cm) and three residual stubble heights (Rsh: 8, 14 and 20 cm). Forage yield was higher (p ≤ 0.05) in Ch50-Rsh8, Ch60-Rsh8 and Ch60-Rsh14 during the second crop cycle, with an average 8555 kg DM ha-1. In monoculture and in association, more cuts were made (three to four) with Ch40-Rsh14 and Ch40-Rsh20 and fewer cuts (one to two) with Ch60-Rsh8, Ch60-Rsh14 and Ch60-Rsh20. Crude protein concentration was 19 % higher (p ≤ 0.05) in monoculture than in association (19.2 and 16.2 %); the highest concentrations (p ≤ 0.05) of crude protein were obtained in Ch40-Rsh8, Ch40-Rsh14 and Ch40-Rsh20 (average 20.5 %), and the lowest was recorded in Ch60-Rsh8 (13.2 %). The forage with the least neutral detergent fibre (p ≤ 0.05) was harvested in Ch40-Rsh8, Ch40-Rsh14 and Ch50-Rsh14 (average 43.4 %), and the highest (49.3 %) was obtained in Ch60-Rsh20. In monoculture and in association, a greater amount of forage was harvested, distributed in at least two harvests, with Ch of 50 and 60 cm in combination with 8 and 14 cm of Rsh. However, the forage did not have the best composition, due to higher concentrations of neutral detergent fibre and lower crude protein concentration.

Effects of varying PAHs-polluted soils on the morpho-anatomy and physiology of Bermuda grass

ABSTRACT This study was conducted to show the effects of high PAH levels on the external and internal structures as well as the functioning of a Poaceae species – Bermuda grass – during phytoremediation process. Two modalities – Tn: unpolluted planted soil and Tp: polluted planted soil – are applied to the monoculture of Bermuda grass for pollution at 10%, 20%, and 30% (weight/weight) with fuel oil, and co-cropping with Goosegrass in soils polluted at 10%. Morphological results revealed that monoculture is better than co-cropping as the sociability of the two species is negatively affected by PAHs. Contrary to monoculture, in the co-cropping the relative growth rate of Bermuda grass morphological parameters is decreasing over time in Tp. For monoculture, the aboveground plant density of Bermuda grass in Tp is not significantly different to Tn, while its specific root length is higher in Tn than Tp. Anatomical and physiological analyses of Bermuda grass show that PAHs impacted the hydromineral nutrition of this species. In fact, the vascular bundles of the stems and roots of Bermuda grass were less numerous in Tp, and the chlorophyll synthesis was 50% inhibited. Despite the slower physiological processes of Bermuda grass in polluted soils, the phytotoxicity of very high PAH levels is not fatal to this species. Its development and evolution on soils highly polluted with PAHs and its phytoremediation potential (more than 95% for total petroleum hydrocarbons and up to 100% for chrysene) therefore recognize it as particularly suitable for hydrocarbon phytoremediation, with wide geographical application thanks to its cosmopolitan nature.

Seasonal effects reveal potential mitigation strategies to reduce N2O emission and N leaching from grassland swards of differing composition (grass monoculture, grass/clover and multispecies)

Multispecies pastures containing grasses, N-fixing legumes and forage herbs can maintain high herbage dry matter (DM) yield, while reducing the need for fertiliser N inputs thus potentially reducing harmful N losses such as nitrous oxide (N2O) emission and nitrate (NO3−) leaching to the wider environment. However, our understanding of these processes in grassland swards of contrasting composition is still very limited. A lysimeter experiment was carried out over 12 months to test the hypotheses that (1) cumulative and (2) seasonal N2O emission and N leaching would be highest from the Perennial Ryegrass only (PRG, 250 kg N ha-1 yr-1) treatment compared to three other treatments; Perennial Ryegrass and Low White Clover (PRG+LWC, 90 kg N ha-1 yr-1), Perennial Ryegrass and High White Clover (PRG+HWC, 0 kg N ha-1 yr-1) and Perennial Ryegrass, White Clover and Ribwort Plantain (PRG+WC+P, 45 kg N ha-1 yr-1) and (3) that the soil N cycling pathways (nitrification/denitrification) linked to these N losses would be different between treatments. Cumulative N2O emissions (2.74–3.25 kg N2O-N ha-1), leached N (10.91–13.70 kg N ha-1), DM yields (5083–5493 kg DM ha-1 yr-1) and N uptake (122–169 kg N ha-1 yr-1) were not significantly different between treatments. Nitrogen yield scaled N2O emissions were significantly lower from all other treatments compared to the high fertiliser N input PRG monoculture. A significant interaction between treatment and season showed that in Spring, N2O emission was significantly higher from PRG (1.39 kg N2O-N ha-1) and PRG+LWC (1.19 kg N2O-N ha-1) than PRG+HWC (0.81 kg N2O-N ha-1) and PRG+WC+P (0.85 kg N2O-N ha-1). This result was linked to a numerically lower fraction of nitrification (FN) for PRG+WC+P potentially indicating that biological nitrification inhibition associated with ribwort plantain could lessen N2O emissions. This study demonstrates some of the environmental benefits of grassland management systems that require less intensive chemical fertiliser N input.

Effects of Restoration Years on Vegetation and Soil Characteristics under Different Artificial Measures in Alpine Mining Areas, West China

In view of the problem of sustainable restoration of vegetation in alpine mining areas, vegetation communities and physical and chemical properties of soil under different artificial restoration measures (i.e., grass monoculture, sowing quantity and topsoil replacement) were investigated for five consecutive years (2016–2020) in the sloped eastern area of a northern slag mound in the Jiangcang mining area of the Muli coalfield in Qinghai, China. The results showed that the vegetation characteristics of different sowing treatments with different kinds of grass species, such as Elymus nutans, Poa pratensis cv. Qinghai and Poa crymophila cv. Qinghai, were significantly different (p < 0.05). The content of soil available nitrogen and phosphorus was significantly different among different grass species (p < 0.05). Vegetation coverage and ramet density of sowing treatment five were significantly higher than those of a lower sowing quantity (p < 0.05). There was no significant difference in the vegetation characteristics among different grass species treatments five years after the restoration (p > 0.05). There was no significant difference in vegetation height of different soil covering treatments (p > 0.05). In the early stage of restoration, vegetation coverage and ramet density in TR2 (resurfacing soil 10 cm) and TR3 (resurfacing soil 15 cm) were significantly higher than those without treatment. Soil N, P and organic matter under the treatments of TR1 (resurfacing soil 5 cm), TR2 and TR3 were significantly higher than those in CK (p < 0.05) in the early stage of restoration, but there was no significant difference in soil N, P and organic matter after five years of restoration. Overall, the vegetation and soil characteristics showed a trend of increase first and then decrease during the 5-year restoration period under different artificial measures. There were significant differences in the vegetation and soil characteristics among different treatments in the second year of restoration (p < 0.05), but there was no significant difference between the first year and the fifth year of restoration, which indicated that vegetation and soil began to degrade after five years of restoration, and substrate nutrients in the mining waste soil could only support the short-term restoration of vegetation. Therefore, it is necessary to target matrix nutrients in future vegetation restoration in alpine mining areas.

Nutritive value of Urochloa decumbens Stapf R. D. Webster and Mimosa caesalpiniifolia Benth. and performance of cattle in monoculture and silvopastoral systems, in the Agreste region of Pernambuco.

This study evaluated the nutritive value of signalgrass (Urochloa decumbens Stapf R. D. Webster) and sabiá (Mimosa caesalpiniifolia Benth.), and animal performance in grass monoculture pastures and in silvopastoral system (SPS) in the early development stage, in the Agreste of Pernambuco. Four treatments were evaluated in a randomized block design with three replications: signalgrass + Eucalyptus spp.; signalgrass + sabiá; signalgrass monoculture and sabiá monoculture. Holstein × Zebu crossbred calves (170 ± 15kg BW) were managed under continuous stocking with variable stocking rate (SR). The dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and in vitro dry matter digestibility (IVDMD) of signalgrass and sabiá were assessed, as well as forage allowance (FA), stocking rate (SR), average daily weight gain (ADG) and weight gain per area (WGA) over eleven evaluation cycles (March 2019 to January 2020). Signalgrass had the highest DM contents in March 2019 and January 2020 (456 and 507gkg-1, respectively), while for IVDMD the highest values ranged from 436 to 547gkg-1 (April to August 2019). Sabiá presented the highest's IVDMD (311 and 381gkg-1 DM) and DM content (385 and 416gkg-1) and lowest CP (110 and 82gkg-1 DM) and NDF (568 and 500gkg-1 DM) in November 2019 and January 2020, respectively. FA and SR decreased throughout the evaluation cycles. ADG (0.38kg animal-1day-1) and WGA (17.89kgha-1 28days-1) did not differ among treatments, with weight loss in the period of low water availability. In the early development stage of the trees, SPS does not affect the nutritive value of signalgrass, nor the animal performance.

Cover crop functional types differentially alter the content and composition of soil organic carbon in particulate and mineral-associated fractions.

Cover crops (CCs) can increase soil organic carbon (SOC) sequestration by providing additional OC residues, recruiting beneficial soil microbiota, and improving soil aggregation and structure. The various CC species that belong to distinct plant functional types (PFTs) may differentially impact SOC formation and stabilization. Biogeochemical theory suggests that selection of PFTs with distinct litter quality (C:N ratio) should influence the pathways and magnitude of SOC sequestration. Yet, we lack knowledge on the effect of CCs from different PFTs on the quantity and composition of physiochemical pools of SOC. We sampled soils under monocultures of three CC PFTs (legume [crimson clover]; grass [triticale]; and brassica [canola]) and a mixture of these three species, from a long‐term CC experiment in Pennsylvania, USA. We measured C content in bulk soil and C content and composition in contrasting physical fractions: particulate organic matter, POM; and mineral‐associated organic matter, MAOM. The bulk SOC content was higher in all CC treatments compared to the fallow. Compared to the legume, monocultures of grass and brassica with lower litter quality (wider C:N) had higher proportion of plant‐derived C in POM, indicating selective preservation of complex structural plant compounds. In contrast, soils under legumes had greater accumulation of microbial‐derived C in MAOM. Our results for the first time, revealed that the mixture contributed to a higher concentration of plant‐derived compounds in POM relative to the legume, and a greater accumulation of microbial‐derived C in MAOM compared to monocultures of grass and brassica. Mixtures with all three PFTs can thus increase the short‐ and long‐term SOC persistence balancing the contrasting effects on the chemistries in POM and MAOM imposed by monoculture CC PFTs. Thus, despite different cumulative C inputs in CC treatments from different PFTs, the total SOC stocks did not vary between CC PFTs, rather PFTs impacted whether C accumulated in POM or MAOM fractions. This highlights that CCs of different PFTs may shift the dominant SOC formation pathways (POM vs. MAOM), subsequently impacting short‐ and long‐term SOC stabilization and stocks. Our work provides a strong applied field test of biogeochemical theory linking litter quality to pathways of C accrual in soil.

Pasture traits and cattle performance in silvopastoral systems with Eucalyptus and Urochloa: Systematic review and meta-analysis

This study evaluated pasture traits and cattle performance in silvopastoral systems (SPSs) with Eucalyptus spp. and Urochloa spp. through a systematic review and meta-analysis. Systematic searches of databases, scientific journals and references of selected articles found 2,639 articles, of which 29 (120 comparisons) were selected. Comparisons were classified according to the covariates of distance between tree rows, number of trees/ha, tree planting orientation, system age and forage type. Data were submitted to meta-regression followed by subgroup analysis for covariates with a significant effect (P < 0.05) on the response. Data were analyzed in random effects models using mean difference and 95% confidence interval (P < 0.05). Forage mass (FM) was greater for SPSs with up to 99 trees/ha and lower for the other groups, compared to that for grass monoculture. Forage accumulation (FA) was also greater for SPSs with up to 99 trees/ha, but lower for SPSs with more than 300 trees/ha, compared to that for grass monoculture. FM was lower for SPSs of all spacings between tree rows and planting orientations, compared to that for grass monoculture, with the lowest being with smaller spacing and with north-south planting orientation. FA was lower for SPSs with up to 28m between tree rows, compared to that for grass monoculture, while that for SPSs with more than 28m did not differ. Neutral detergent fiber concentration was lower and crude protein greater for SPSs compared to grass monoculture, while lignin was greater and in vitro dry matter digestibility did not differ, which indicated no significant improvement in nutritive value in SPSs. Average daily gain was greater in SPSs with up to 99 trees/ha, and lower in those with more than 400 trees/ha, than in grass monoculture, with other subgroups not differing. Total weight gain per area (GHA) was lower in SPSs with less than 28m between tree rows or with more than 199 trees/ha, but greater in SPSs with more than 28m or with up to 99 trees/ha, compared to grass monoculture. GHA was lower in SPSs with a north-south orientation compared to grass monoculture, but those with an east-west orientation did not differ. The use of U. brizantha cv. Marandu and an east-west planting orientation are efficient strategies in maintaining FM, FA and GHA. GHA was greater in SPSs with more than 28m between tree rows and with up to 99 trees/ha, than in grass monoculture, which may facilitate the implementation of these SPSs in commercial farms.

Evaluation of grass and legume tropical mixtures and performance of grazed sheep

The objective of this research was to determine the pasture structure, nutritional value, animal behaviour, intake, and performance of Santa Inês sheep grazing pastures with various mixtures of grass (Andropogon gayanus) and forage legume (Stylosanthes sp. and Calopogonium mucunoides). A randomized block design was adopted with the treatments arranged in a 3 x 2 factorial scheme, with the factors consisting of cropping systems and grazing cycles. Grass in the mixed species pastures had a greater leaf/stem ratio than in the monoculture. Total forage mass was greater in the mixed pastures, which had the highest concentrations of crude protein and total digestible nutrients, the lowest fibre concentration, and the highest in vitro dry matter digestibility. Legumes were grazed with the highest frequency, and biting rate was highest in Andropogon gayanus with Stylosanthes sp. The highest intake (kg/day) was found in the mixed swards and the highest animal weight gain (143 g/day) in the mixed pastures. The pastures of Andropogon gayanus mixed with Stylosanthes sp. and C. mucunoides showed improved forage nutritive value and intake compared with the grass monoculture.

Silvopastoral systems improve carbon stocks at livestock ranches in Tabasco, Mexico

AbstractSilvopastoral systems have great potential for storing carbon because of carbon assimilation in tree woody biomass, carbon input through litterfall and below‐ground carbon turnover. In this study, we quantified and compared the carbon stocks at livestock ranches in Tabasco, Mexico, containing either scattered trees in grazing pastures (STP) or grass monocultures. Sampling plots were randomly established at each ranch where the above‐ and below‐ground carbon stocks, carbon input from litterfall, grass production and arboreal biomass growth were measured. We found that silvopastoral systems stored an average of 257.45 Mg ha−1 of soil organic carbon (SOC) compared to 119.17 Mg SOC ha−1 at grass monoculture ranches (to 30 cm depth); silvopastoral systems also stored 44.64 Mg C ha−1 in wood biomass; and, grass monocultures had greater cumulative grass biomass production. Overall, it is concluded that livestock ranches in Tabasco, Mexico, with scattered trees in grazing pastures stored 58.8% more carbon than those grass monocultures, with carbon stocks of 327.01 Mg C ha−1and 134.47 Mg C ha−1, respectively. The results are useful for land management decision making for sustainable livestock systems framed in the Sustainable Development Goals (SDGs).

Effect of sod-seeding bloat-free legumes on pasture productivity, steer performance, and production economics

A 5 yr experiment evaluated the effects of sod-seeding sainfoin and cicer milkvetch into monoculture grass (Lanigan, SK) or legume (Lethbridge, AB) stands on pasture productivity, steer performance, and economics. At Lanigan, sainfoin decreased (treatment × year P = 0.01) from 13% in year 1 to 2% in year 2 (% plant population) and did not differ thereafter, whereas cicer milkvetch maintained a proportion of 16% in the stand. Forage yield was greater (treatment × year; P &lt; 0.01) in year 1 in the sainfoin and cicer milkvetch treatments compared with control. Dry matter intake of steers was greater only in year 5 and average daily gain was greater (P &lt; 0.01) in sainfoin and cicer milkvetch treatments compared with control. At Lethbridge, sainfoin decreased (treatment × year; P = 0.01) from 46% to 17% (% dry matter yield), whereas cicer milkvetch maintained its proportion at 11%. Forage yield increased (treatment × year; P &lt; 0.01) only in years 2 and 3 of sainfoin, compared with cicer milkvetch or control. Average daily gain gain was not affected by treatment. At Lanigan, sainfoin and cicer milkvetch generated greater gross returns compared with control; however, once establishment costs were applied, there were no differences in the present value of net returns.

Productivity Performance of Sheep in Silvopastoral Systems With Cashew Tree Compared to Grass Monoculture

The goal in this study was to evaluate the production of sheep and forage silvopastoral systems (SPSs) with cashew trees, compared to the production on grass monoculture. The treatments consisted of three grazing systems: one Massai grass monoculture (Panicum maximum cv Massai) (MONO), and two SPSs: intercrop of Massai grass + cashew tree (Anacardium occidentale) (SM) and intercrop of grass- Massai grass + Estilosantes Campo Grande (Stylosanthes capitata × S. macrocephala) + cashew tree (SME), in a completely randomized split plot design with four replications. The photosynthetically active radiation varied from 45 to 59% in SPSs, the presence of cashew trees created a microenvironment with lower temperatures and higher relative humidity throughout the day. Forage mass in the monoculture and in the SPSs was on average 2,116.65 kg dry matter (DM). ha-1; the participation of the legume in the forage mass was 44%. Greater stocking rate was found in the monoculture, however the gain per area was higher in the SME. In the SPSs, crude protein content of the grass increased by 46.2%, and there was a higher forage intake and weight gain of sheep, mainly in the system with legume. The silvopastoral system with cashew trees, Massai grass, estilosantes and sheep is feasible to optimize land use, with better gain per animal and area in relation to grass monoculture.

Plant Diversity, Functional Group Composition and Legumes Effects versus Fertilisation on the Yield and Forage Quality

Elevating plant diversity and functional group composition amount in the swards may contribute to lower N fertiliser use. The excessive use of fertilisers in agriculture is one of the causes of environmental pollution issues. We investigated the effects of plant diversity, functional community composition, and fertilisation on the dry matter yield and its quality at the Lithuanian Research Centre for Agriculture and Forestry, Central Lithuania. The study aimed to determine the productivity potential of single-species and multi-species swards with three, four, six, and eight plant species in the mixtures including four grasses and four legumes. Two experimental backgrounds were used with N0 and N150 kg ha−1 yr−1 for all treatments. In the two-year experiment manipulating species richness and functional group diversity had a positive effect on the dry matter yield and produced better quality of the forage when compared with single-species swards. Crude protein in the forage of grass–legume mixtures was significantly greater than for grass monocultures. Investigating fertilisation background was a concern; it had a positive effect on the single-species sward yield but decreased the yield of multi-species swards.

Tamani grass-legume intercropping can improve productivity and composition of fodder destined to haylage or hay

ABSTRACT: This research evaluated the biomass productivity and nutritional value of the haylage and hay from intercropping between Tamani grass and different legume species. For the productive characteristics of the different intercrops, we adopted a randomized block design, for evaluation of the combination of intercropping and conservation technic we used 5 x 2 factorial scheme (five intercrops and two types of conservation techniques). The treatments were Tamani grass as monoculture, and the intercrops of Tamani grass with crotalaria, soybean, cowpea, or pigeon pea. The conservation techniques were haylage (520 g/kg of DM) and hay (870 g/kg of DM). Plants were sown in alternate rows, with 45 cm of spacing between the rows. The parameters evaluated were grass and legume biomass production, canopy height, and haylage and hay chemical composition, and in vitro dry matter digestibility (ivDMD). There were no differences in the total biomass production between the intercrops and TA grass monoculture. The treatments intercropped with cowpea and soybean had the highest legume participation in the mixture, promoting an increase in crude protein and ivDMD content of haylage and hay. Haylage and hay had the same chemical composition, although haylage had higher ivDMD than hay. We concluded that intercropping Tamani grass with soybeans or cowpea maintained total biomass productivity and improved the nutritional value of haylage and hay.

Browse from Three Tree Legumes Increases Forage Production for Cattle in a Silvopastoral System in the Southwest Amazon.

Assessing the palatability of forage from locally adapted trees could improve the sustainability of livestock production systems. However, grasses continue to dominate livestock feed across the Amazon. We established a silvopastoral cattle farming system in Peru, comparing three different forage tree species with grass monocultures using a randomised block design. Trees were arranged in alleys of 0.5 × 7.5 m, planted alongside grass, and were directly browsed by cattle. Browse removal was estimated by three methods: destructive sampling, canopy measurements and leaf counts. We found that all three tree species were palatable to cattle. Plots containing trees and grass produced more available forage (mean > 2.2 Mg ha-1) for cattle than the grass monocultures (mean = 1.5 Mg ha-1). Destructive sampling below 1.6 m demonstrated that cattle consumed 99% of the available Erythrina berteroana forage, 75% of the available Inga edulis forage and 80% of the available Leucaena leucocephala forage in 8 days. This research demonstrates methodologies to estimate the intake of locally adapted browse species by cattle and highlights the potential benefits of silvopastoral systems in the Amazon. Planting trees could also benefit animal health and provide ecosystem services such as soil regeneration, enhanced nutrient cycling and carbon capture.

The Use of Temperate Tannin Containing Forage Legumes to Improve Sustainability in Forage–Livestock Production

Greenhouse gas emissions from ruminant livestock production systems contribute significantly to the environmental footprint of agriculture. Emissions are lower for feedlot systems than for grass-based systems primarily because of the extra time required for grass-finished cattle to reach slaughter weight. In contrast, legume forages are of greater quality than grasses, which enhances intake and food conversion efficiencies, leading to improvements in production and reductions in environmental impacts compared with forage grasses. In addition, the presence of certain bioactives in legumes such as condensed tannins (CT) enhance the efficiency of energy and protein use in ruminants relative to grasses and other feeds and forages. Grazing tannin-containing legumes also reduce the incidence of bloat and improve meat quality. Synergies among nutrients and bioactives when animals graze diverse legume pastures have the potential to enhance these benefits. Thus, a diversity of legumes in feeding systems may lead to more economically, environmentally, and socially sustainable beef production than grass monocultures or feedlot rations.

Bioeconomic Assessment of an Alley Cropping Field Trial in North Carolina, U.S.: Tree Density, Timber Production, and Forage Relationships

Silvopasture, the combination of trees, forage, and livestock, is a management practice that is gaining interest throughout the southeastern U.S. This research analyzed a hay-based alley cropping field trial that is transitioning into a silvopasture system. We planted four different tree spacings—2.4 × 2.4 m, 2.4 × 3.0 m, 3.0 × 3.0 m, and 1.8 × 3.0 m (8 × 8 ft, 8 × 10 ft, 10 × 10 ft, and 6 × 10 ft)—of loblolly pine (Pinus taeda L.) and used secondary data for the possible planting of two different grass species—big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.). Tree inventories, forage samples, biometric modeling, and economic analysis of forage and timber monocultures and mixed systems were analyzed with discounted cash flow and capital budgeting analyses. Tree growth on the pasture site was exceptionally fast, generating high projected returns for timber monocultures, which exceeded returns for monoculture grass crops. Projected timber stand returns had the greatest Net Present Values (NPV) at the 4% discount rate, ranging between USD 3196 and USD 3552 per ha (USD 1294 and USD 1438 per ac) for a 2.4 × 3.0 m or 2.4 × 2.4 m tree spacing yield. Representative grass yields were obtained from secondary sources and had lower productivity, with switchgrass having the highest returns at USD 2581 per ha (USD 1045 per ac). Optimal NPVs for mixed silvopasture stands ranged between about USD 1500 per ha and USD 3500 per ha (USD 600/ac and USD 1400/ac), depending on the tree spacing within bands, the alley spacing, and the degree of competition between trees and grasses.

Forage potential of winter‐hardy perennial ryegrass populations in monoculture and binary alfalfa mixture

AbstractPerennial ryegrass (Lolium perenne L.) is a cool‐season grass valued for its grazing characteristics and nutritive value. MSP3984 and MSP4029, breeding populations selected for winter‐hardiness, were evaluated for biomass and nutritive value in monoculture and grass–alfalfa mixtures (Medicago sativa L.). Plots were sampled at conventional hay harvest intervals at three Minnesota locations for two production years, 2017 and 2018. Persistence was evaluated in the spring of the 3rd year, 2019. MSP3984 and MSP4029 were compared to commercial cultivars of perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), tall fescue (F. arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.). Location and year × location effects largely influenced grass monoculture yields (p &lt; .001) and botanical composition of mixtures (p &lt; .001). In general, perennial ryegrass monocultures yielded less and were less persistent (p &lt; .05) compared to the other cool‐season grasses. Biomass, nutritive value, and persistence did not differ among MSP3984, MSP4029, and the perennial ryegrass check ‘Remington’. However, MSP4029 was less competitive in grass–alfalfa mixtures than ‘Remington’ (p = .01). Perennial ryegrasses had lower neutral detergent fiber (NDF) concentrations than meadow fescue (p = .001) and orchardgrass (p &lt; .001). Perennial ryegrasses also had lower acid detergent fiber (ADF) values on average than the other grasses, but cultivar effects were influenced by a year × location interaction (p = .02). This research reinforces (a) the importance of evaluating cool‐season forage grasses across latitudinal and precipitation gradients, (b) the value of grass–legume mixtures for yield stability compared to monocultures across locations and production years, and (c) the sustained need to improve forage production and persistence of perennial ryegrass for cold environments.