Delayed Sowing Decreased Lucerne Dry Matter Yield over Two Seasons

Lucerne (Medicago sativa L.) can be sown in New Zealand from late spring (October) to early autumn (March). In the establishment season, greatest drymatter (DM) yields are normally attained from sowing early and production lost from delayed sowing is only considered in the establishment season. The objective of this research is to determine if sowing date continues to have an effect on DM yield in year two and how the partitioning of DM between the above and below ground plant fractions is influenced by sowing date

A review of legume research and extension in New Zealand (1990-2022)

Legumes have underpinned transformational change on New Zealand sheep and beef farms over the last 30 years. This was through an emphasis on ewe nutrition based on lucerne or red clover dominant pastures, and increased use of subterranean and white clovers on uncultivatable hill country. Pre- and post-weaning lamb growth rates have increased, and enabled earlier slaughter of heavier lambs. The farm systems results include greater numbers of hoggets mated, higher lambing percentages and greater ewe efficiency (kg lamb weaned/kg ewe mated). Extension packages to support legume use have compared growth rates of resident and legume-based pastures, economic analyses of successful farms and management packages for the most appropriate legume in different environments. Over the same period, the dairy industry rapidly expanded in cow numbers and area onto flat irrigated land on the Canterbury Plains. The nitrogen deficiency of perennial ryegrass was overcome by a linear increase in nitrogen fertiliser use. Environmental concerns from this intensification has led to a legislated nitrogen cap of 190 kg/ha.year. This, coupled with a recent trebling in urea price, has returned attention to increasing the white clover content of these pastures. Nitrogen applications can be minimised by using diverse pastures sown with a legume, herb and <8 kg/ha of perennial ryegrass. Work on other legumes, including annuals and those with condensed tannins, has to date failed to increase their use in most pastoral settings, with the exception of the perennial lupin which is adapted to high-aluminium soils in the South Island High Country

Total annual and seasonal DM production of improved and unimproved resident pastures at three farms in Canterbury

Yield differences between resident and improved pastures were quantified over a 3-4 yr period on three rainfed farms located in North Canterbury (Stockgrove, north of Amberley), Banks Peninsula (Willesden Farm) and the Mid-Canterbury foothills (Inverary Station). Improved pastures produced two- to three-times more feed annually than unimproved resident pastures at each property. At Stockgrove, improved chicory/white clover-based pastures produced 14.1±0.66 t DM/ha/yr compared with 4.36±0.41 t DM/ha/yr from unimproved pastures. Spring accounted for 85% (improved) and 72% (unimproved) of total annual DM production. At Willesden, lucerne monocultures produced 11.5±0.97 t DM/ha/yr, which was more than the 4.44±0.45 t DM/ha/yr produced from resident pastures. Improved pastures at Inverary yielded 7.31±0.59 t DM/ha in summer/autumn of 2018/19, which was more than double the 3.34±0.43 t DM/ha from unimproved pastures. In 2019/2020, improved pastures produced 11.7±1.45 t DM/ha compared with 4.45±0.73 t DM/ha. In the third growth season (2020/2021) improved pastures produced 14.1±1.76 t DM/ha compared with 6.67±1.38 t DM/ha from unimproved pastures. In Year 4 (2021/22) the 12.6±1.29 t DM/ha from improved pastures was 56% more than the 8.07±0.85 t DM/ha from the unimproved pastures. Substantial increases in annual and seasonal feed supply patterns can be achieved through hill country pasture improvement

Factors related to productivity and persistence of lucerne (Medicago sativa) genotypes with different fall dormancy levels: A review

The lucerne productive and nutritional potential make it the most used forage legume worldwide. This wide use leads genetic improvement programs to increasingly select the main requirements for a given edaphoclimatic condition. However, in Brazil, the research on genetic improvement of lucerne has been limited over the years, which has hindered the production of this species and the domination of other legumes in animal production, as estilosantes and pigeon pea. This literature review aimed to present results from countries such as New Zealand and Australia that lead the world ranking, as well as Argentina, in the cultivation of this crop and that can be used as showcase to understand the management of lucerne. From extensive bibliometry analyses in the period between 1963 and 2021, variables as persistence and phyllochron in these countries indicate that it is possible to produce lucerne with similar productivity, longevity and quality in Brazil. Nevertheless, to leverage this production, not only genetic improvement should be aimed, but also research and dissemination of knowledge on the ideal management of defoliation and, mainly, on the choice of the genotype and dormancy level to be cropped by the producer

Legumes for hill country

In drought prone hill country, legumes can be introduced to increase nitrogen transfer to companion grasses which increases both the quality and quantity of feed available for grazing livestock. This powerpoint presentation accompanied an oral presentation by Professor Derrick Moot in Wairoa. Topics covered included species selection, and livestock and grazing management practices to aid establishment and ensure persistence. References are included.The New Zealand Merino Company & Sustainable Farming Fund, Ministry of Agriculture and Forestr

Dry matter yield and radiation use efficiency of four autumn sown top flowering annual clovers

Monocultures of arrowleaf (Trifolium vesiculosum), balansa (T. michelianum), gland (T. glanduliferum) and Persian (T. resupinatum) clovers were sown on four dates in autumn and winter 2010. Dry matter (DM) accumulation was dependent on the duration of crop growth which was influenced by the time of sowing. Autumn sown crops which flowered latest had a longer duration of vegetative growth and consequently produced the highest dry matter yields. In the establishment year, autumn sown crops produced up to 17.5 t DM/ha for balansa, 12.5 t DM/ha for Persian, 11.0 t DM/ha for gland and 9.4 t DM/ha for arrowleaf at physiological maturity (P<0.05). Crops that were sown in winter produced the lowest yield, because reproductive development commenced earlier and therefore they matured earlier. ‘Bolta’ balansa clover had the highest radiation use efficiency of 2.1 g DM/MJ photosynthetically active radiation (PAR) absorbed followed by gland (1.6 g DM/MJ PAR), arrowleaf and Persian (1.3 g DM/MJ PAR) clovers. In the second year, regenerated dry matter production at full flower was up to 11.6 t/ha in balansa, 8.3 t/ha in Persian, 2.9 t/ha in gland but only 0.5 t/ha in arrowleaf clover (P<0.05). Thus, over the two years ‘Bolta’ balansa and ‘Mihi’ Persian clovers were the highest yielding and easiest to regenerate from seed in monocultures. ‘Cefalu’ arrowleaf failed to regenerate in the second year due to low population of seedling emergence. ‘Prima’ gland clover was low yielding because it flowered and matured without fully utilising the growing season

An explanation of yield differences in three potato cultivars

Under ideal growing conditions, yield is the product of intercepted photosynthetically active radiation (PARi) and its conversion efficiency to dry matter (radiation use efficiency, RUE). For potato (Solanum tuberosum L.) the ability of the leaf to convert the PARi into carbohydrates (source) and the storage capacity of the tubers (sink) affect the potential growth of individual tubers and therefore crop yield. This study describes these mechanisms for three commercial potato cultivars (Bondi, Fraser, and Russet Burbank) grown in non-limiting field conditions. At final harvest Bondi had the largest tuber yield and produced heavier but fewer tubers compared with Fraser and Russet Burbank. All crops had similar total accumulated radiation interception (Rcum), and yield differences were explained by the RUE which was highest for Bondi, lowest for Fraser, with Russet Burbank intermediate. Fraser had the lowest rate of canopy senescence, maintained the lowest specific leaf area (SLA) for most of the period of tuber bulking and maintained the highest dry matter (DM) allocated to leaves at the end of the tuber filling phase. Throughout the crop growing period Bondi had a larger tuber sink compared with Fraser and Russet Burbank. These results suggest that potato tuber production was limited by the “sink strength” and RUE in the lower yield varieties. The larger sink in Bondi, caused by shorter stolons, enabled higher rates of tuber filling which produced the largest tubers in the middle node positions and the highest average tuber weight per plant among these cultivars

Dryland pasture yields and botanical composition over 5 years under sheep grazing in Canterbury

Annual dry matter (DM) production and botanical composition of six dryland pasture combinations, grown under sheep grazing at Lincoln University for 5 years, are presented. In 4 years, lucerne produced the highest DM yields (13.1-18.5 t/ha/yr) through higher daily growth rates, compared with grass based pastures, particularly during periods of water stress in summer and autumn. Of the grass based pastures, cocksfoot sown with subterranean clover produced yields of 9.9-12.9 t DM/ha/yr which were greater than, or similar to, all other pastures (8.0-12.9 t DM/ha/yr). Cocksfoot established with white clover produced >9.7 t DM/ha/yr in years with wetter than average summers. Over the 5 years the contribution of perennial ryegrass to total DM yield declined by ~0.7 t/ha/yr, from 70% in Year 1, to 44% in Year 5. It was replaced by unsown dicotyledonous weeds and grasses which increased from 4% in Year 1 to 24% by Year 5. Overall results show a dryland pastoral system that includes both lucerne and cocksfoot with subterranean clover pastures is likely to produce more feed in dry years than perennial ryegrass/white clover pastures. The inclusion of white clover with cocksfoot and subterranean clover may allow utilisation of variable and unpredictable rainfall in moist summers.A. Mills acknowledges financial assistance from Meat & Wool NZ through the FoRST Pastoral21 programme, Lincoln University and the Cocksfoot Growers Association

Defoliation frequency and season affected radiation use efficiency and dry matter partitioning to roots of lucerne (Medicago sativa L.) crops

Radiation use efficiency (RUE), and subsequent partitioning between shoots and roots were investigated for ‘Grasslands Kaituna’ lucerne crops grown in the cool temperate climate of Canterbury, New Zealand. Crops were grazed by sheep every 28 or 42 days and yielded 12 and 23 t DM/ha.year, respectively. The RUE for above ground shoots (RUEshoot) was 1.7-2.0 g DM/MJ of intercepted photosynthetically active radiation (PARᵢ) in spring but decreased systematically to ≤1.0 g DM/MJ PARᵢ in autumn. The RUE for total biomass, (RUEtotal) ranged from 1.3 to 3.1 g DM/MJ PARᵢ in response to air temperature and defoliation treatment. The lowest RUEtotal in mid summer for the treatment defoliated every 28 days was related to a 20% decline in the leaf photosynthetic capacity measured at 1000 μmol photons/m2.s (Pn1000) and at saturating light (Pmax). In turn, the reduction in Pn1000 was related to differences in specific leaf nitrogen (SLN), through changes in specific leaf weight (SLW) rather than the leaf N concentration of 4 to 6% DM. The fractional partitioning of DM to roots (proot) increased from near zero in winter/earlyspring to >0.45 in autumn, which explained the observed seasonality of RUEshoot. For the treatment defoliated each 42 days, proot increased linearly from ~0.05 to >0.45 as Pp increased from 10.5 to 16.5 h. In decreasing photoperiods proot averaged 0.45. There was a linear increase (R²=0.52) in proot with Tsoil/Tair but only in the treatment defoliated each 42 days. Agronomic treatments that result in sub optimal N reserves post grazing can be expected to produce conservative canopy characteristics but reduced photosynthetic capacity of the first 5 main stem leaves. Beyond this development stage, canopy expansion may be reduced with more conservative leaf N