Balansa Clover Research Articles

Determination of Physicochemical Characteristics, Phytochemical Profile and Antioxidant Activity of Various Clover Honeys.

This paper reports on some physicochemical and phytochemical characteristics (i. e. pH, electrical conductivity, colour, moisture content, total phenolic content, sugar profile) and in vitro antioxidant activity of honeys harvested from five legume species, red clover (Trifolium pratense), balansa clover (T. michelianum), Persian clover (T. resupinatum), purple clover (T. purpureum) and sanfoin, also known as holy clover (Onobrychis viciifolia), that were grown in enclosed shade houses to ensure that the honeys' characteristics are reflective of a truly monofloral honey. Glucose and fructose, determined via High-Performance Thin-Layer Chromatography (HPTLC) analysis, were found as the main sugars in all investigated honeys with the ratio of fructose to glucose ranging from 1 : 1.2 to 1 : 1.6. The honeys' pH values ranged from 3.9 to 4.6 which met Codes Alimentarius (CA) requirements. The moisture content was found to be between 17.6 and 22.2 % which in some cases was slightly higher than CA requirements (≤20 %). The honeys' colour values, prior and after filtration, were between 825.5-1149.5 mAU and 532.4-824.8 mAU respectively, illustrating golden yellow to deep yellow hues. The total phenolic content (TPC) of the honeys was determined using a modified Folin-Ciocalteu assay. Their antioxidant activity was captured by the Ferric Reducing-Antioxidant Power (FRAP) assay as well as HPTLC analysis coupled with 2,2-diphenyl-1-picrylhydrazyl (DPPH) derivatisation. The highest total phenolic content was found in red clover honey (45.4 mg GAE/100 g) whereas purple clover honey showed the highest level of activity in the FRAP assay (7.3 mmol Fe2+/kg). HPTLC-DPPH analysis of the honeys' organic extracts demonstrated the presence of various bioactive compounds that contribute to their overall antioxidant activity. This study developed a methodology for producing monofloral clover honeys in a space limited, enclosed production system, which allowed to collate important baseline data for these honeys that can serve as the foundation for their potential future development into commercial honeys, including honeys that can be used for medicinal purposes.

The Impact of Peach Rootstocks and Winter Cover Crops on Reproduction of Ring Nematode

Two peach rootstocks (‘Guardian’ and ‘MP-29’) and ten winter cover crops (rye, wheat, barley, triticale, oat, Austrian winter pea, crimson clover, balansa clover, hairy vetch, and daikon radish) were evaluated in a greenhouse environment to determine their suitability to host ring nematode, Mesocriconema xenoplax. Each crop was inoculated with 500 ring nematodes, and the experiments were terminated 60 days after inoculation. The reproduction factor (ratio of final and initial nematode population) ranged from 0 to 13.8, indicating the crops greatly varied in their host suitability to ring nematode. ‘Guardian’ has been known to tolerate ring nematode; however, results from the current study suggest the tolerance statement is anecdotal. Another peach rootstock, ‘MP-29’, was also a good host for ring nematode, suggesting an urgency to develop ring nematode-resistant peach rootstocks. Wheat supported the least to no nematode reproduction while pea supported the greatest reproduction. The rest of the cover crops were poor to good hosts to ring nematodes. Although planting cover crops in peach orchards is not common, employing non or poor host crops can help suppress nematodes in addition to having soil health benefits. Furthermore, peach breeding programs should focus on finding and introgressing ring nematode resistance in commercial rootstocks.

Management of perennial forbs sown with or without self‐regenerating annual clovers for forage and nectar sources in a low‐input dryland production system

AbstractForage systems can be designed to produce high quality feed for ruminant livestock while providing habitat for insect pollinators. We compared forage productivity, nutritive value, and selenium uptake as well as late summer nectar production of perennial forage species; alfalfa (Medicago sativa), birdsfoot trefoil (Lotus corniculatus), red clover (Trifolium pratense), sainfoin (Onobrychis viciifolia), and chicory (Cichorium intybus) as monocultures and intercropped with either subterranean clover (Trifolium subterraneum) or balansa clover (Trifolium michelianum) for two successive years in Oregon. Red clover intercropped with balansa clover out‐performed other stands, producing over 11 t DM ha−1 in 2019 and 9.4 t DM ha−1 in 2020. Birdsfoot trefoil and sainfoin mixtures were dominated by subterranean clover, negatively affecting total forage yield and flower abundance. Chicory intercropped with subterranean clover formed a more balanced mixture with improved DM yield and nutritive value relative to chicory monocultures. Chicory was most responsive to Se‐fertilisation in both years, having a higher concentration of Se relative to the other perennial species. Chicory also had high levels of condensed tannins (18.1–43.3 mg/g DM) relative to the other forages (1.8–17.5 mg/g DM). Red clover had the most consistent bloom in 2019, with 170 inflorescences per square meter at peak bloom and yielded an estimated total of 16.9 kg ha−1 sucrose. Birdsfoot trefoil produced the most inflorescences during peak bloom in 2020 at 279 inflorescences per square meter. However, alfalfa had a higher estimated sucrose yield in 2020 at 241 kg ha−1.

Impact of Smoke from Wheat, Oat, and Clover Stubble Burning on Cabernet Sauvignon Grapes and Wine

Background and Aims. Stubble burning is an agricultural practice employed by some grain growers to prepare farmland for sowing and/or to control weeds and pests. Grapegrowers and winemakers have questioned whether the resulting smoke can contaminate grapes in nearby vineyards. This study therefore sought to determine the potential for smoke from three different stubble burns to taint grapes and wine. Methods and Results. Excised bunches of mature Cabernet Sauvignon grapes were exposed to smoke from prescribed burning of wheat, oat, and Balansa clover stubble windrows. Environmental sensors monitored the concentration of particulate matter as a measure of smoke density, while chemical and sensory analysis established the extent to which grapes and wine were tainted by smoke. Only grapes that were positioned among the burning wheat windrows or downwind, but in close proximity (∼200 m) to the oat stubble burn, were exposed to sufficient quantities of smoke to result in a detectable concentration of volatile phenols (up to 12 µg/kg), as chemical markers of smoke taint. These grapes yielded wines with two to threefold higher volatile phenol concentrations (up to 18 µg/L) than other wines, including the control wine, and low intensity, but perceptible smoke-related sensory attributes, indicative of low-level smoke taint. Conclusions. Chemical and sensory analyses suggest the risk of smoke taint from stubble burning is low, except where vineyards are immediately downwind and/or prolonged or repeated smoke exposure occurs. However, stubble moisture content and prevailing weather conditions affect smoke density and dispersion, and will therefore affect the potential for smoke contamination by grapes. Significance of the Study. This study will assist colocated grain growers and grape and wine producers to undertake commercial operations, without negatively impacting one another.

Determining cardinal temperatures for eight cover crop species

AbstractGrowing degree days (GDD) is a tool to predict plant growth and can be adapted for use in any plant species, including cover crops. A limitation of the GDD calculation is accurate temperature parameters used to predict plant development. For most cover crop species, the cardinal temperatures are not well defined in the literature, leading to a less accurate calculation of GDD. The objective of this study was to determine the cardinal temperatures of eight cover crop species, including Austrian winter pea (Pisum sativum), balansa clover (Trifolium michelianum), barley (Hordeum vulgare), black‐seeded oats (Avena sativa), common vetch (Vicia sativa), cereal rye (Secale cereale), crimson clover (Trifolium incarnatum), and hairy vetch (Vicia villosa), using a growth chamber experiment. Seven different temperature regimes from 4 to 34°C were implemented, and the number of leaves was counted from day 0 to 21. As a result, the data were regressed to estimate the cardinal temperatures for each species. The results of this research identified base (2), optimum (3), and maximum (8) temperatures for cover crops that were not previously reported. Five cardinal temperatures determined in this study were different from what was previously recorded; base and optimum temperatures were −4.5 and 24.8°C for cereal rye, 3.9 and 26.6°C for crimson clover, and the base temperature was 3.4°C for balansa clover. The successful identification of these cardinal temperatures for cover crops will allow the development of plant growth and biomass prediction models to aid in cover crop termination decision support tools.

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems

Legume cover crops in temperate cropping systems can fix substantial amounts of nitrogen (N) and reduce N fertiliser requirements for subsequent crops. However, little is known about potential biological N2 fixation by summer cover crop legumes in the short summer fallow in Mediterranean-type cropping systems. Six legume species (balansa clover, barrel medic, mung bean, sunn hemp, lablab and cowpea) were grown for 8–9 weeks in the field in semi-arid southern Australia during the summer fallow, and in a glasshouse experiment, to estimate N2 fixation using the 15N natural abundance method. Cowpea, sunn hemp and lablab produced 1.2–3.0 t ha−1 biomass in the field while balansa clover and barrel medic produced < 1.0 t ha−1. The percent of N derived from the atmosphere (%Ndfa) in the field ranged from 39% in barrel medic to 73% in sunn hemp, but only 15% (balansa clover) to 33% (sunn hemp) in the glasshouse experiment, likely due to higher soil mineral N availability in the glasshouse study. Biological N2 fixation of cowpea and sunn hemp in the field was 46–55 kg N ha−1, while N2 fixation in lablab and mung bean was lower (around 26 kg N ha−1). The N2 fixation in cowpea and sunn hemp of around 50 kg N ha−1 with supplementary irrigation in the field trial likely represents the upper limit of N contributions in the field in typically hot, dry summer conditions in Mediterranean-type climates. Given that any increase in summer cover crop biomass will have implications for water balances and subsequent cash crop growth, maximising N benefits of legume cover crops will rely on increasing the %Ndfa through improved rhizobium strains or inoculation technologies. This study provides the first known estimates of biological N2 fixation by legume cover crops in the summer fallow period in cropping systems in Mediterranean-type environments, providing a benchmark for further studies.

Assessment of Mineralized Nitrogen During Maize Growth Succeeding Different Winter Cover Crops in the Mediterranean Environment

Background: Understanding soil nitrogen (N) dynamics is essential to find alternative N sources and improve N use efficiency in agriculture. Objective: The aim of this study was to assess N mineralization rates from residues of winter cover crops, during maize crop season, under Mediterranean conditions. Methods: A field experiment was carried out from May to September in central Portugal, with four replications, two sowing dates of cover crops (15/10/2011 and 29/11/2011) and three cover crops residues (balansa clover, ryegrass and yellow lupine) that were incorporated in the soil. Plots were cropped with local maize and net N mineralization was measured during the crop cycle, using soil cylinders placed inside micro-perforated polyethylene bags. Results and Discussion: Early sowing of the cover crops residues increased the NH4+ and NO3- contents in the soil. Yellow lupine residue had the highest rate of daily N mineralization (0.71 mg N kg-1 day-1). For all treatments, the highest mineralization rate was found in the last incubation period, ranging between 0.78 mg N kg-1 day-1 and 1.84 mg N kg-1 day-1, both for balansa clover, from the second and the first sowing date, respectively. Conclusion: The present study suggests that, under Mediterranean field conditions, cover crops residue of Italian ryegrass, balansa clover and yellow lupin can be used as a nitrogen source namely for sustainable maize crops.

The effects of self‐regenerating annual clovers on plant species composition and heifer performance in an irrigated pasture in western Oregon, USA

AbstractThe addition of self‐regenerating annual legumes into permanent pastures can benefit rapid forage growth in early spring, leading to increased pasture production and animal live weight gain (LWG). The objective of this 2‐year grazing study was to evaluate the effects of balansa clover (Trifolium michelianum) and subterranean clover (Trifolium subterraneum) on pasture and animal production in an irrigated dairy system in western Oregon, USA. Study results showed that balansa clover has a high potential to increase legume content of establishing pastures in early spring. Legume content of pastures sown with annual legumes increased by 25.3% in early spring compared to pastures sown without annual legumes. However, no significant increase in legume content was observed past the initial year of establishment. The persistence of balansa clover and subterranean clover was low in 2021, at <1% of the botanical composition. The overall benefits of balansa clover in early spring in 2020 were offset by reduced perennial forbs, white clover (Trifolium repens) and chicory (Cichorium intybus), in paddocks that were sown with annual legumes. However, this did not negatively affect the LWGs of heifers. This study found no significant difference between pastures sown with and without annual clovers pastures on dry matter production and animal production. Balansa clover was competitive in the establishment year; however, further research into improving its persistence past establishment is warranted.

Yield and botanical composition of four dryland pastures at Ashley Dene Research Farm over 8 years

Dry matter yield and botanical composition of four grazed dryland pasture types were compared over 8 years in summer-dry conditions at Ashley Dene, Canterbury, New Zealand. The experiment was sown in March 2013 to evaluate cocksfoot (CF)- or meadow fescue/ryegrass hybrid (RG)-based pastures established with either subterranean (Sub) or subterranean and balansa (S+B) clovers. Plantain was included in all pasture types. Perennial ryegrass established poorly on the low soil moisture holding capacity Lismore soil and in Year 2 was re-broadcast into the RG pastures. Despite this, plantain was the main sown species in RG pastures beyond Year 3. Total spring yield was greatest in Year 5 at 6720 kg DM/ha and varied with spring rainfall. Cocksfoot-based pastures had 60% of sown species present in the spring of Year 8, compared with 28% in RG-based pastures. Balansa clover was only present up to Year 5 after a managed seeding event in the first spring. White clover did not persist in the dryland environment past Year 2. Sub clover yield depended on the time and amount of autumn rainfall but contributed up to 45% of the spring yield. Cocksfoot-sub clover pastures appear to be most resilient in this summer-dry environment with variable spring rainfall.

A 3-year field study to assess winter cover crops as nitrogen sources for an organic maize crop in Mediterranean Portugal

Current environmental concerns, the rising economic and environmental costs of mineral fertilizers and the need to respond to the limitations of N fertilization in organic farming motivate the search for alternative sources of N in maize cropping. Forage legumes used as winter cover crops may improve soil N fertility and offer benefits to the environment. The aim of this study was to examine the effects, in a factorial field experiment, of two sowing dates (SD) and nine different cover crop treatments (balansa clover, crimson clover, gland clover, arrowleaf clover, French serradella, yellow lupin, Italian ryegrass, a cover mixture and a weedy fallow) as a potential alternative N source in an organically managed maize crop. The experiment was conducted at Viseu (Portugal) for three years (2007/2008, 2008/2009 and 2011/12), in the same field. Results showed that maize grain yield was not influenced by cover crop species but was affected by SD and the higher dry matter (DM) aboveground biomass production was observed in early SD (6.1 t ha−1). The cover crops revealed their importance in maize N uptake: yellow lupin of earlier SD had the highest N uptake (83.6 kg N ha−1), but this was not significantly different from balansa clover (83.2 kg N ha−1). Ryegrass was the most efficient in depleting soil mineral N but values were just significantly lower than yellow lupin.Lupin was the least efficient, leaving more mineral N in the soil than the others cover crops, immediately before the period when the risk of leaching is high. It was concluded that, under the edaphoclimatic conditions tested, most of the tested cover crops were efficient in supplying N to maize, and balansa clover had the best performance.

Salinity tolerance and avoidance mechanisms at germination among messina (

Messina (Melilotus siculus) cv. Neptune, an annual pasture legume native to the Mediterranean Basin, has recently been released for saltland pastures in southern Australia following demonstration of biomass production and persistence superior to other commercial pasture legumes in saline environments prone to winter waterlogging. Self-regenerating annual pasture legumes also require seed adaptations for both tolerating and avoiding salinity at germination in these environments. This study examined diversity within Neptune and 20 other messina accessions for salt tolerance at germination, recovery of germinability from temporary salt stress, and timing and extent of hardseed softening, compared with balansa clover (Trifolium michelianum) cv. Frontier, burr medic (Medicago polymorpha) cv. Scimitar and white melilot (Melilotus albus) cv. Jota. Germination rates after 14 days at 300 mM NaCl relative to 0 mM NaCl were ≥99% for Neptune and 18 other messina accessions, 66% for Scimitar, 21% for Jota and 11% for Frontier. No genotype germinated at 600 mM NaCl; however, when transferred to 0 mM NaCl after 14 days at 600 mM, all genotypes except Scimitar and Jota recovered partial germination, ranging from 13% to 93% of controls (0 mM NaCl for 28 days). The softening rate of hard (impermeable) seeds in the field varied among genotypes, with deferral of hardseed softening until late autumn–early winter, when rainfall is more likely, indicating greater persistence. The months in which the hardseed level first became significantly lower than the initial level (in freshly harvested seeds) after placement on the soil surface in December were: March for Frontier; April for Scimitar, Jota and Neptune; and March–July for all messina accessions. This study confirmed that messina has high salt tolerance and several avoidance mechanisms at germination that contribute to its adaptation to saline soils in southern Australia. Several messina accessions were superior to Neptune for individual traits which could be exploited for plant breeding. These results also have implications for saltland pastures in other regions of the world with Mediterranean-type climates.

Pasture production, persistence of legumes and lamb growth in summer‐dry hill pastures

AbstractPasture legumes that persist under challenging agroecological conditions are crucial to ensure high lamb growth rates in dryland pastures. Pasture and lamb production from binary and diverse mixtures (Mix) of tall fescue (TF) with white clover (Whc), balansa clover (Bc), subterranean clover (Sc) and birdsfoot trefoil (Bft) were compared in a summer‐dry hill site in Corvallis, Oregon over a two‐year period. In 2018, all pasture combinations provided similar lamb liveweight gains (LWG, mean 177 g/day) in the first half of spring. Lambs in TF‐Bc and TF‐Mix pastures grew 31 to 41 g/day faster than those grazing TF‐Sc, TF‐Whc and TF‐Bft in the second half of spring (p < .05). Overall, TF‐Bc and TF‐Mix had higher (p < .05) legume contents (32% and 37% respectively) compared to other pasture combinations. In spring 2019, lambs that grazed the TF‐Mix and TF‐Whc pastures had higher LWG than those on other pastures (p < .05). The superior lamb growth rates were associated with the higher legume content and pasture quality maintained into the late spring period. Overall, the legume content of all pastures decreased over the course of the two‐year trial, with the decline being substantial for balansa clover. The present study confirmed that a high legume content of pastures leads to greater lamb growth rates. Total annual yields of pastures that had greater legume contents were superior to others (p < .05). Thus, a combination of self‐regenerating annual clovers with perennial legumes in pasture mixtures may ensure a higher legume content and longer persistence in dryland hill pastures.

Milk production, nitrogen utilization, and methane emissions of dairy cows grazing grass, forb, and legume-based pastures.

Achieving high animal productivity without degrading the environment is the primary target in pasture-based dairy farming. This study investigated the effects of changing the forage base in spring from grass-clover pastures to forb or legume-based pastures on milk yield, N utilization, and methane emissions of Jersey cows in Western Oregon. Twenty-seven mid-lactation dairy cows were randomly assigned to one of three pasture treatments: grass-clover-based pasture composed of festulolium, tall fescue, orchardgrass, and white clover (Grass); forb-based pasture composed of chicory, plantain, and white clover (Forb); and legume-based pasture composed of red clover, bird's-foot trefoil, berseem clover, and balansa clover (Legume). Pastures were arranged in a randomized complete block design with three replicates (i.e., blocks) with each replicate grazed by a group of three cows. Production and nutritive quality of the forages, animal performance, milk components, nitrogen partitioning, and methane emissions were measured. Feed quality and dry matter intake (DMI) of cows were greater (P ≤ 0.05) for Legume and Forb vs. Grass, with consequent greater milk and milk solids yields (P < 0.01). Cows grazing Forb also had more (P < 0.01) lactose and linoleic acid in milk compared with cows grazing the other pastures, and less (P = 0.04) somatic cell counts compared with Grass. Cows grazing Forb had substantially less (P < 0.01) N in urine, milk, and blood compared with cows grazing the other pastures, with not only a greater (P < 0.01) efficiency of N utilization for milk synthesis calculated using milk urea nitrogen but also a larger (P < 0.01) fecal N content, indicating a shift of N from urine to feces. Both Forb and Legume had a diuretic effect on cows, as indicated by the lower (P < 0.01) creatinine concentration in urine compared with Grass. Methane emissions tended to be less (P = 0.07) in cows grazed on Forb vs. the other pastures. The results indicate that Forb pasture can support animal performance, milk quality, and health comparable to Legume pasture; however, Forb pasture provides the additional benefit of reduced environmental impact of pasture-based dairy production.

Assessing Establishment and Growth of Agricultural Plantings on Reservoir Mudflats

AbstractWinter drawdowns in flood control reservoirs create expansive mudflats that lack the vegetation typical of littoral zones, which reduces the amount of structure available for fish habitat. This study investigated the feasibility of establishing agricultural plantings as a management action to ameliorate mudflats by providing structural cover following reservoir refilling. We tested cool‐season annual grasses and clovers applied in several mixed and monoculture treatments that were sown on the mudflats of Enid Reservoir, Mississippi, during the winter drawdown in three consecutive years. Soil samples were taken for analysis of pH and macronutrients prior to planting. Plantings were monitored until the following spring to evaluate effectiveness of establishment through ground coverage, height, and stem density sampling. Plots were assigned a seeding treatment of either grasses (ryegrass Lolium spp. or triticale x Triticosecale sp.), clovers (balansa clover Trifolium michelianum or berseem clover Trifolium alexandrinum), or both (mixed plantings) or left as an unseeded control. Differences among plant treatments were assessed via repeated measures analysis of variance and differences among means evaluated with Tukey's honestly significant difference test. Soil productivity within the study area was poor all 3 years. Grasses germinated both when disked into the soil and when top sown, while clover only germinated when disked. Plots seeded with grasses performed better than control plots with respect to stem density, height, and ground coverage, while plots seeded with grass and clover mixtures performed better than control plots only with respect to height, and plots seeded with only clover did not perform significantly better than control plots. Results serve as an evaluation of the efficacy of agricultural plant establishment on the mudflats of a flood control reservoir, inform the direction of future research, and identify considerations regarding the application of agricultural plantings as a management tool to create fish habitat.

Interseeding cover crops into maize: Characterization of species performance under Mediterranean conditions

Cover crop (CC) benefits and adoption in crop rotations may be limited by the short planting window after the cash crop. Interseeding or relay intercropping of CC is a technique that could overcome short planting windows constraints and allow CC establishment and growth. However, in Mediterranean regions this technique has been poorly implemented.Field experiments were established in Central Spain during two consecutive growing seasons to assess the performance of different species as interseeded crops into irrigated maize (Zea mays L.). The treatments included annual ryegrass (Lolium multiflorum L.) and eight legumes: burr medic (Medicago polymorpha L.), barrel medic (Medicago truncatula L.), yellow sweetclover (Melilotus officinalis L.), berseem clover (Trifolium alexandrinum L.), balansa clover (Trifolium michelanium L.), red clover (Trifolium pratense L.), Persian clover (Trifolium resupinatum L.), and common vetch (Vicia sativa L.). A bare soil was included as control treatment. After the maize harvest, the four species with the best performance were planted as autumn cover crops in adjacent plots. The ground cover was studied throughout the experimental period, and biomass and N content for each species were determined in the autumn and in the following spring prior to the cover crop termination. The soil inorganic N content was determined in spring.Barrel medic, yellow sweetclover, common vetch and annual ryegrass were the species with the best performance in terms of soil coverage during the summer. Red clover and Persian clover had good establishment in one out of two years. None of the interseeded species impaired maize grain yield or quality. Interseeded species achieved better soil coverage and increased the biomass accrued at autumn compared to cover crops sown in October. Therefore, interseeded species ensured longer ground coverage, increasing the potential for soil quality improvement or weed suppression. Moreover, the higher biomass achieved by interseeded species ensured the survival of yellow sweetclover, which was winter killed when planted in the autumn. Interseeded cover crops enhanced the potential of N leaching reduction compared to autumn cover crops.This experiment confirms the suitability of different species interseeded in summer into irrigated maize in Mediterranean regions, and highlights the extra benefits of this practice in annual rotations.

Establishment, production and regeneration of subterranean clovers in the Mackenzie Basin, New Zealand

The ‘Red Flats’ on Omarama Station in the Mackenzie Basin, has a winter cold, summer dry environment and soils with low plant available water (&lt;60 mm in the top 1 m), and low pH(H2O) (5.2) and high aluminium (8 mg/kg) below 75 mm. The site received 3 t of lime, 300 kg sulphur-super, boron (B), molybdenum (Mo) and herbicides to eliminate hieracium (Hieracium pilosella). Twelve cultivars of subterranean clover (Trifolium subterraneaum), ‘Bolta’ balansa clover (T. michelianum), and perennial ‘Rossi’ red clover (T. pratense), were direct-drilled in February 2016. Over the next 3 years their frost tolerance, productivity and persistence were compared with the resident haresfoot clover (T. arvense). Balansa and the subterranean clovers all survived the 2016 and 2017 winters. The subterranean clovers maximum yield was 4.3 t DM/ ha after successful germination in February 2016 when sufficient rain extended the spring growing season into November. Subterranean clover cultivars from subspecies subterraneum yielded well in 2016, averaging 3.3 t DM/ha, as did the brachycalycinum ‘Antas’ with 3 t DM/ha. During the short season of 2017, the subterraneum ssp. cultivars ‘Denmark’ and ‘Karridale’ established the highest ground covers and ‘Antas’ the lowest. In 2018, ‘Antas’ had the lowest emergence rate and autumn yield. ‘Karridale’ had the highest re-establishment rate and the yanninicum ‘Trikkala’ the highest autumn yield (1.3 t DM/ha). Cultivars with low hardseededness ratings were the most successful at re-establishment in autumn 2017. Balansa clover was also persistent. In the favourable 2016 growing season the late-flowering resident haresfoot clover grew into early summer and yielded 3.7 t DM/ha. Red clover yielded 1 t DM/ha in 2016, but did not persist. Results suggest that medium-late flowering softer seeded subterranean clover cultivars and ‘Bolta’ balansa clover, are suitable for this environment.

Dry matter yield of six perennial legume species in response to lime over 3 years at Glenmore Station, Mackenzie Basin

The production and persistence of legumes which may improve South Island high-country pasture in the Mackenzie Basin were studied. The initial soil test results confirmed toxic levels of aluminium (9 mg/kg, 0-150 mm soil depth) that has prevented the development of large areas of land traditionally grazed by merino sheep and beef cattle. A 3-year field experiment was direct-drilled in December 2012 with five rates (0, 0.5, 1, 2, and 4 t/ha) of surface applied lime and six legumes (lucerne, ‘Russell’ lupin, Caucasian clover, white clover, balansa, and Lotus pedunculatus) in three replicates. In Year 1, balansa clover and Russell lupin were the highest yielding legumes (7 t DM/ha), regardless of lime application rates. In Year 2 ‘Russell’ lupin was the highest (10.4 t DM/ha). Caucasian clover produced 4.6 t DM/ha and white clover and lucerne around 4.0 t DM/ha. Balansa clover (1.4 t DM/ha) and Lotus pedunculatus (2.5 t DM/ha) were the lowest yielding and they did not recover or persist after the initial grazing by merino sheep. These results confirmed that ‘Russell’ lupin and Caucasian clover thrived without the application of lime in this acidic soil with high Al levels.

Legume Cover Crops and Tillage Impact Nitrogen Dynamics in Organic Corn Production

Core Ideas Reduced tillage of legume cover crops releases significant amount of N coupled with corn N uptake.Roller crimper termination of legumes releases nitrogen at similar total amounts to disking.Increased experimentation needed to improve corn population and yields in roller crimped stands. Cover cropping and reduced tillage are two management practices that increase ecosystem services in agroecosystems. However, their interactive effects on N dynamics and cash crop yield are underexplored. In this study, four different termination approaches, employing no‐till and tillage, and organic and conventional techniques were used with four winter annual leguminous cover crop species to investigate the combined effect on plant‐available nitrogen (PAN) and subsequent organic corn (Zea mays L.) yield. Termination treatments included roller‐crimping, flail‐mowing, disking, and herbicide application with cover crops of Austrian winter pea (Pisum sativum L. subs. arvense, AWP), hairy vetch (Vicia villosa var. AU Early Cover, HV), balansa clover [Trifolium michelianum Savi ssp. balansae (Boiss.) Ponert, BC] and crimson clover (Trifolium incarnatum var. Dixie, CC). Plant‐available N (NO3− and NH4+) was determined using biweekly soil inorganic N extractions and resin probes. Cover crop biomass, cover crop C/N ratio, and cover crop total N were measured prior to termination. Nitrogen was most available from AWP and HV across termination methods at 6 to 10 wk after termination. Disked HV contributed highest levels of N across all 16 cropping by termination combinations. Highest biomass N was found in HV (226 kg ha−1), followed by AWP (189 kg ha−1) and CC (181 kg ha−1). Corn yield ranged widely, from 0.23 Mg ha−1 in 0 N control to &gt;9 Mg ha−1 in HV and AWP treatments. Cover crop species plays an important role in N dynamics, frequently influencing soil processes to a more significant degree than termination approach.

Carbon and nitrogen mineralisation from green manures as alternative nitrogen sources in Mediterranean farming

ABSTRACTThe soil incorporation of green manures is a practice that can be used in sustainable agriculture and in organic farming, where nitrogen (N) sources are limited. The aim of this study was to evaluate balansa clover (Trifolium michelianum Savi), yellow lupine (Lupinus luteus L.) and ryegrass (Lolium multiflorum Lam.) as potential alternative N sources. A total of nine treatments were considered in this study: control, aerial of balansa clover, roots of balansa clover, aerial of yellow lupine, roots of yellow lupine, aerial of ryegrass, roots of ryegrass, mixture aerial + roots of yellow lupine and mixture aerial + roots of ryegrass. A laboratory incubation experiment was conducted under controlled conditions during 196 days and carbon and N mineralisation were followed. Results showed that green manures are appropriate N sources for Mediterranean farming. No significant differences in terms of N mineralisation were observed between aerial or roots biomass of the green manures. Besides, 37–55% of total N applied was mineralised in treatments amended with balansa clover or yellow lupine, whereas 13–21% of total N applied was mineralised in ryegrass. It can be concluded that the most efficient green manure for supplying mineral N to the succeeding crop was yellow lupine.

Tolerance of newly sown cocksfoot-clover pastures to the herbicide imazethapyr

In New Zealand, subterranean clover is recommended as a companion legume in mixed swards, particularly in dryland cocksfoot-based pastures. However, establishment of cocksfoot is slower than perennial ryegrass and therefore weed ingress is more common. An experiment at Lincoln University, Canterbury showed imazethapyr applied when clover was at the 3-4 trifoliate leaf stage, and cocksfoot at the 2+ leaf stage, increased the subterranean clover content of the pastures by at least 1000 kg DM/ha, despite initial visual phytotoxicity responses. Balansa and white clover pasture yields were not different to their unsprayed unweeded controls. Imazethapyr application controlled broadleaf weeds from early in the season. The herbicide application reduced cocksfoot yields by 70% in early spring, but yields recovered and were not different to the unsprayed unweeded controls at 1350 ± 260 kg DM/ha after grazing. Imazethapyr application improved subterranean clover pastures through an increase in clover content by suppressing weeds and temporarily reducing the rate of cocksfoot growth. Keywords: subterranean clover, Spinnaker herbicide, seedling, white clover, balansa clover