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

Lime, phosphorus and sulphur response of French serradella (Ornithopus sativus) grown in an acid upland soil

Soil acidity severely restricts legume persistence and growth in grazed upland agriculture in New Zealand. An alternative and potentially acid tolerant forage legume, French serradella (Ornithopus sativus), was examined in a climate controlled experiment. Plants were grown for 48 weeks in an acid (pHH20 4.9) upland soil and shoot yield measured every 8 weeks. Treatments were fully replicated combinations of lime (CaCO3; 0, 2, 4 or 8 t ha-1), phosphorus (P; 0, 50, 150 or 500 mg P L soil-1) plus various controls. Shoot yield varied significantly between lime treatments (P < 0.001), but were not strongly affected by P rate. Importantly, yields on the unlimed control treatments were 85% of maximum yield, suggesting that high yields are potentially achievable on even very acid soils. french serradella grew 16.9 g DM pot-1compared to 5.3 g DM pot-1 for the commonly grown reference species, subterranean clover (Trifolium subterraneum). French serradella showed significant potential as a new pasture legume suitable for acidic upland soils

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

Changes in New Zealand red meat production over the past 30 yr

Implications • Consumer attitudes globally and nationally influence pasture production systems in New Zealand. • New Zealand red meat production has decreased its environmental footprint per unit of production over the last 30 years. • The national ewe flock has halved but gains in animal production have maintained similar levels of meat production. • Meat production has been improved through increased lambing percentages and lamb growth rates on fewer but larger farms. • Greater animal production has been supported through improved pastures with an emphasis on their legume component which has increased lamb growth rates and reduced methane emissions per unit of product

Effect of rate and method of phosphorus application on the growth and development of 'Pasja' crops

‘Pasja’ (Brassica campestris x napus) was grown at Lincoln in 2008, with banded or broadcast phosphorus (P) fertiliser applied at 0, 20, 40 or 60 kg/ha at establishment on a Templeton silt loam soil of moderate fertility (Olsen P of 9-17 mg/ kg range for individual plots). Total dry matter (DM) production, leaf to stem ratios and leaf area development were measured over time and related to the biophysical environment. Final DM yield increased with P rate from 3,730 kg DM/ha for the control to ~5,000 kg DM/ha at 60 kg P/ha. The leaf to stem ratio declined from between 22 and 31 at 17 days after emergence to 10.3 at the final harvest. Leaf area index (LAI) for the control crops was lower than for those that received P fertiliser, but there were no differences among the P fertilised crops. Total accumulated intercepted solar radiation (RIcum) was 8% greater when P was applied compared with the control. This difference was the main contributor to differences in total dry matter yield and was independent of the application method. Keywords: BrassicaPastoral 21’ program and New Zealand Institute for Plant & Food Limited

Productivity and composition of perennial lupin pastures in response to six growing rates, lime application and lupin type at Glenmore Station, Lake Tekapo

This study aims to identify the sowing rate necessary to produce lupin dominant and productive pastures in the New Zealand high country under low-moderate fertility, and a regime of late spring/early summer grazing. Blue and Russell lupin were sown on 12 December 2012 at rates of 2, 4, 8, 12, 16 and 32 kg/ha with cocksfoot at 2 kg/ha, and ± 3 t/ha lime. Low lupin sowing rates (<8 kg/ha) produced an open canopy with lupin density <4 plants/m², suitable for cocksfoot but also prone to reinvasion by resident species. The blue lupin population was ~5 plants/m² for sowing rates ≥8 kg/ha. The Russell lupin population was <4 plants/m² at sowing rates ≤16 kg/ha. Cocksfoot population was 1.3 and 1.9 plants/m² with blue and Russell lupin, respectively. Dry matter (DM) yield (excluding dead material) was 4.9 t/ha for spring 2014 and 2.1 t/ha for spring 2015, a difference attributed to the low spring rainfall in 2015. Blue lupin contributed more to the total DM yield than did Russell lupin as sowing rates increased. Cocksfoot dominated the remainder of production in spring 2014 but was on a par with resident species production in spring 2015. Summer and autumn regrowth to March 2015 was limited to ~1 kg DM/ha. There was no appreciable regrowth during December 2015 - March 2016. A lupin sowing rate of 8 kg/ha was adequate. Blue lupin population was greater than Russell lupin

Clover species cover on summer dry hill country in Central Otago

The prevalence of annual clover species and white clover (Trifolium repens) during the critical late winter to early summer period (mid Aug – Dec) are compared in relation to aspect, altitude, temperature and rainfall on Mt Grand at Hawea Flat. Measurements were at four north facing sites (450, 620, 750, 910 m a.s.l.) and one shady site at 630 m a.s.l. The rainfall was similar for all altitudes and aspects but annual clovers dominated on sunny faces and the perennial white clover dominated on the shady face with suckling (T. dubium) the only adventive annual clover present. Annual cluster clover (T. glomeratum) dominated on the lower sunny faces at 450 and 620 m and sub clover (T. subterraneum) dominated at 750 m. Suckling and striated clover (T. striatum) were present on all sunny aspect sites and were unaffected by altitude while haresfoot (T. arvense) presence increased with altitude. Air thermal time accumulation for the mid Aug-Dec period was 1440 °Cd at the 450 m site and declined at 100 °Cd per 100 m of elevation (r² = 0.99). Thermal time at 910 m was <1000 °Cd and may limit seed production of some annual clover species at or above this altitude. The dominance of adventive annual clovers on the sunny aspects indicates areas that are probably suitable for introduction of improved annual species such as balansa clover (T. michelianum) or modern cultivars of sub. Productivity of perennial white clover which has persisted on the shady faces may be increased by more intensive grazing management

Impact of autumn (fall) dormancy rating on growth and development of seedling lucerne

To quantify the influence of autumn (fall) dormancy (FD) on DM production and phenological development during the seedling phase, three lucerne genotypes with contrasting ratings were grown at Lincoln University, New Zealand. A dormant (FD2), a semi-dormant (FD5), and a winter-active (FD10) genotype were inoculated and sown at a rate of 290 plants/m² on 8 October 2014. By the end of the seedling phase (15 January 2015) the FD10 genotype had produced 20% higher shoot yield and 17% higher root yield than the other two genotypes. The percentage of total biomass partitioned to roots (Proot) was 50% for all genotypes. Total plant biomass (root + shoot yields) was 6.55 t DM/ha for FD10 compared with 5.57 t DM/ha for FD 2 and FD5. Plant height at the open-flower stage was 39.5 cm for FD10 compared with 34.5 cm for FD5 and 33.5 cm for FD2. Maximum leaf area index was similar amongst genotypes at 2.5. However, individual leaf area was 142, 119 and 111 cm²/stem for FD10, FD5 and FD2, respectively. The phyllochron was 52⁰Cd per primary leaf (base temperature of 1⁰C) and consistent amongst genotypes. The number of primary leaves and branches were also conservative at 17 and 14/shoot, respectively. Therefore, differences in shoot yield among these lucerne genotypes during the seedling stage were mainly due to differences in plant height and individual leaf area expansion per plant. This led to greater light interception and therefore higher total biomass accumulation for FD10 than for the other two genotypes