P. D. Kemp

Forage Chicory (Cichorium intybus L.): A Review of Its Agronomy and Animal Production

Chicory ( Cichorium intybus L.) is a perennial herb that has been used as a forage for livestock in many parts of the world. Forage chicory produces a large quantity of high quality feed in the warm season under favorable conditions. Animal performance on chicory is similar to that on legumes and superior to grass‐based pastures. In addition, grazing chicory can decrease some internal parasites in livestock, and therefore has potential to reduce the use of anthelmintics. Being a deep‐rooted perennial herb, chicory can reduce nitrate leaching, deep drainage, thereby reducing the rate of soil acidification and the occurrence of dryland salinity. This paper reviews the published research work on the agronomic characteristics, herbage production, grazing management, persistence under grazing, nutritive value, and animal performance of forage chicory, as well as the problems encountered when incorporating chicory into farming systems.

The effect of condensed tannins in Lotus corniculatus upon reproductive efficiency and wool production in sheep during late summer and autumn

A grazing experiment, conducted for 55 days (from 4 March to 29 April) in the late summer/autumn of 1997, at Massey University, Palmerston North, New Zealand, compared the reproductive efficiency and wool growth of ewes grazing Lotus corniculatus (birdsfoot trefoil) or perennial ryegrass (Lolium perenne)/white clover ( Trifolium repens ) dominant pasture (pasture). Half the ewes grazing each forage were given daily oral polyethylene glycol (PEG: molecular weight 3500) supplementation to inactivate the condensed tannins (CT) in lotus. A rotational grazing system with 200 mixed age ewes (54·2±0·88 kg/ewe; 50 ewes/treatment) was used. The effect of forage species and PEG supplementation upon voluntary feed intake (VFI), concentration of plasma metabolites, reproductive efficiency, wool production and wool characteristics was measured during two synchronized oestrous cycles. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad libitum for the 6 days prior to and including ovulation. Lotus contained 17 g total CT/kg dry matter (DM) in the diet selected. There were only trace amounts of total CT in pasture. In vitro organic matter digestibility (OMD) was higher for lotus (0·82 v. 0·74) than for pasture, whilst lotus contained less nitrogen (N; 37·8 v. 44·5 g/kg OM). Mean ovulation rates (OR) for CT-acting and PEG sheep grazing pasture and lotus were respectively 1·33 v. 1·35 and 1·78 v. 1·56, with corresponding lambing percentages being 1·36 v. 1·36 and 1·70 v. 1·42. Fecundity (number of corpora lutea/ewe ovulating) was greater for ewes grazing lotus than pasture ( P <0·01), and tended to be greater for CT-acting than for PEG sheep grazing lotus ( P =0·06). In unsupplemented sheep, ewes grazing lotus had increased plasma concentrations of branched chain amino acids (BCAA; 57%) and essential amino acids (EAA; 52%) compared to ewes grazing pasture. In ewes grazing pasture, PEG administration had no effect on plasma concentrations of urea and free amino acids, VFI, reproductive efficiency and wool production. However, in sheep grazing lotus, plasma concentrations of urea were significantly lower and concentrations of most amino acids were significantly higher for CT-acting than for PEG supplemented ewes (CT not acting); there was no difference in VFI between these two groups. Compared to ewes grazing pasture, ewes grazing lotus had similar VFI but produced more wool with longer staples and thicker fibre diameter, with there being no effect of PEG supplementation. It was concluded that feeding lotus increased the efficiency of both reproduction and wool production without an increase in VFI, and that a possible cause was the action of CT in increasing plasma EAA and especially BCAA concentration.

The effects of salinity and osmotic stress on barley germination rate: sodium as an osmotic regulator

BACKGROUND AND AIMS Seed germination is negatively affected by salinity, which is thought to be due to both osmotic and ion-toxicity effects. We hypothesize that salt is absorbed by seeds, allowing them to generate additional osmotic potential, and to germinate in conditions under which they would otherwise not be able to germinate. METHODS Seeds of barley, Hordeum vulgare, were germinated in the presence of either pure water or one of five iso-osmotic solutions of polyethylene-glycol (PEG) or NaCl at 5, 12, 20 or 27 °C. Germination time courses were recorded and germination indices were calculated. Dry mass, water content and sodium concentration of germinating and non-germinating seeds in the NaCl treatments at 12 °C were measured. Fifty supplemental seeds were used to evaluate the changes in seed properties with time. KEY RESULTS Seeds incubated in saline conditions were able to germinate at lower osmotic potentials than those incubated in iso-osmotic PEG solutions and generally germinated faster. A positive correlation existed between external salinity and seed salt content in the saline-incubated seeds. Water content and sodium concentration increased with time for seeds incubated in NaCl. At higher temperatures, germination percentage and dry mass decreased whereas germination index and sodium concentration increased. CONCLUSIONS The results suggest that barley seeds can take up sodium, allowing them to generate additional osmotic potential, absorb more water and germinate more rapidly in environments of lower water potential. This may have ecological implications, allowing halophytic species and varieties to out-compete glycophytes in saline soils.

Morphological and physiological effects of water deficit and endophyte infection on contrasting tall fescue cultivars

Abstract Morphological and physiological responses to water deficit of two tall fescue (Festuca arundinacea) cultivars were compared in a glasshouse experiment and the effect, on those responses, of artificial infection of the tall fescue plants with two fungal endophyte (Neotyphodium coenophialum) strains was evaluated. The cultivars were Maris Kasba (MK), of Mediterranean origin, and El Palenque (EP), an Argentinian cultivar of temperate origin. The endophyte strains AgResearch isolate (AR501) and the Kentucky (KY31) wild type were compared with nil‐endophyte controls. Leaf growth rate of EP plants under water deficit was higher and leaf senescence rate lower than for MK plants (P < 0.05). MK plants showed a greater increase in the proportion of dead leaf tissue than EP plants as water deficit increased (P < 0.05). Stomatal conductance and lamina osmotic adjustment at low soil moisture were lower for MK than EP (P < 0.05). Endophyte‐infected plants had a lower dry weight and tiller number, but a higher net growth rate during water deficit treatments than endophyte‐free plants (P < 0.05). A significant cultivar × endophyte interaction (P < 0.05) was observed for many variables studied. This implies that any new endophyte strain should be evaluated in combination with the plant genotypes with which it is likely to be associated in commercial practice. MK‐KY31 and EP‐AR501 associations appeared to tolerate short‐term water deficit more effectively than other associations studied. There was evidence that the two endophyte strains studied had different physiological effects on their tall fescue host plants.

Invasion of temperate grassland by a subtropical annual grass across an experimental matrix of water stress and disturbance

Abstract. An experimental matrix of water stress and disturbance was superimposed on a Lolium perenne-Trifolium repens grassland using a crossed-gradient design, and the annual subtropical grass Digitaria sanguinalis was introduced into the pasture as seeds and transplanted seedlings. Digitaria plants achieved maximum biomass at high water availability and high disturbance. Digitaria plants grown from transplanted seedlings attained greater biomass further from the conditions of high water availability and high disturbance, compared with those that had grown from seed. The biomass of the temperate species was maximized with high water availability and low to intermediate disturbance conditions. The reproductive effort of Digitaria was maximized under intermediate to high water availability and intermediate to low disturbance. Combinations of water stress and disturbance that gave rise to maximum growth of the temperate and subtropical species were consistent with those predicted by C-S-R theory. Results suggest that processes in the regenerative phase of the plant life cycle were constraining the success of Digitaria in New Zealand grassland. Addition of seed to the soil seed bank would probably be maximized in patches of grassland with high disturbance and water availability; these patches will subsequently act as foci for future invasions by Digitaria.

Agricultural Science in the Wild: A Social Network Analysis of Farmer Knowledge Exchange

Responding to demands for transformed farming practices requires new forms of knowledge. Given their scale and complexity, agricultural problems can no longer be solved by linear transfers in which technology developed by specialists passes to farmers by way of extension intermediaries. Recent research on alternative approaches has focused on the innovation systems formed by interactions between heterogeneous actors. Rather than linear transfer, systems theory highlights network facilitation as a specialized function. This paper contributes to our understanding of such facilitation by investigating the networks in which farmers discuss science. We report findings based on the study of a pastoral farming experiment collaboratively undertaken by a group of 17 farmers and five scientists. Analysis of prior contact and alter sharing between the group’s members indicates strongly tied and decentralized networks. Farmer knowledge exchanges about the experiment have been investigated using a mix of quantitative and qualitative methods. Network surveys identified who the farmers contacted for knowledge before the study began and who they had talked to about the experiment by 18 months later. Open-ended interviews collected farmer statements about their most valuable contacts and these statements have been thematically analysed. The network analysis shows that farmers talked about the experiment with 192 people, most of whom were fellow farmers. Farmers with densely tied and occupationally homogeneous contacts grew their networks more than did farmers with contacts that are loosely tied and diverse. Thematic analysis reveals three general principles: farmers value knowledge delivered by persons rather than roles, privilege farming experience, and develop knowledge with empiricist rather than rationalist techniques. Taken together, these findings suggest that farmers deliberate about science in intensive and durable networks that have significant implications for theorizing agricultural innovation. The paper thus concludes by considering the findings’ significance for current efforts to rethink agricultural extension.

Effects of water deficit on Mediterranean and temperate cultivars of tall fescue

Two glasshouse experiments were carried out to evaluate the morphological and physiological responses to water deficit of Mediterranean and temperate tall fescue (Festuca arundinacea Schreb.) cultivars. In Expt 1, 3 cultivars were studied: 2 temperate cultivars, Grasslands Advance (GA) and El Palenque (EP); and a Mediterranean cultivar, Maris Kasba (MK). Water deficit was induced in containers of 4 plants of a single cultivar by withholding water. In Expt 2, plants of EP and MK were grown together in the same container and received water daily with gradation in intensity of water deficit achieved by varying the daily water ration per container. All cultivars in each experiment exhibited commonly reported responses to water deficit, characterised by diminished evaporative surface area and increased root : shoot ratio. The response of MK was primarily morphological and MK plants had smaller plant size, higher root : shoot ratio, and a lower growth rate compared with temperate cultivars. By contrast, response of temperate cultivars was primarily physiological; stomatal conductance of temperate cultivars was lower and these cultivars had a greater tendency for leaf lamina osmotic adjustment than MK under the most stressful water deficit conditions studied. The morphological adaptations of MK were very effective in delaying the onset of water deficit in Expt 1 when plants were grown with others of the same cultivar, but rendered MK plants uncompetitive and more susceptible to water deficit in Expt 2 where plants of MK where interspersed with plants of a temperate cultivar.

Herbage production and persistence of Puna chicory (Cichorium intybus L.) under grazing management over 4 years

Abstract Three grazing experiments were conducted at the Pasture and Crop Research Unit (PCRU) and Deer Research Unit (DRU), Massey University, Palmerston North, New Zealand, from November 1993 to January 1996. Experiments 1 and 3 examined effects of grazing frequency and grazing intensity on the herbage production and persistence on year 1 and year 4 chicory stands, respectively. In Experiment 2, the plant density and plant size (shoots/plant) were monitored over 3 years starting from the second growing season. Results showed that year 1 and year 2 chicory accumulated 8460 + 668 and 9360 ± 640 kg DM/ha over 6 months, which was double that of year 4 chicory (4590 ± 343 kg DM/ha). The average plant densities for year 1 and year 2 chicory were 66 ± 2.1 and 68 ± 4.0 plants/m2, respectively, significantly higher than those for year 3 and year 4 chicory of 49 ± 0.6 and 24 ± 1.3 plants/m2, respectively. However, plant size increased from 2.9 ± 0.04 and 2.7 ± 0.15 shoots/plant for the first 2 years to 4.1 ±0.15 ...

Mixed herb and legume pasture improves the growth of lambs post-weaning

The potential of mixed herb and legume pastures to increase post-weaning growth rates of lambs in comparison to ryegrass-based pastures was evaluated. Unrestricted allowances of pasture treatments were offered to weaned, Romney lambs in consecutive autumns of 2007 and 2008. In Experiment 1 (2007), 300 ewe lambs were allocated for 64 days to one of four permanent sward mix treatments; chicory, plantain, red clover and white clover [herb/clover (n = 75)]; plantain, perennial ryegrass and white clover [plantain/pasture (n = 75)]; tetraploid perennial ryegrass and white clover [new pasture (n = 75)]; or diploid perennial ryegrass, other grass species and white clover [old pasture (n = 75)]. In Experiment 2 (2008), the first three pasture treatments from Experiment 1 were re-used (‘old pasture’ not used) with 168 wether lambs allocated for 35 days; herb/clover (n = 56); plantain/pasture (n = 56); and new pasture (n = 56). Unfasted liveweights of all lambs were recorded at weekly intervals and before slaughter. A sub-sample of 78 lambs from Experiment 2 was slaughtered to obtain the carcass weights, tissue depth (11 cm from the spine over the 12th rib) and commercial meat percentages. At the conclusion of Experiment 1 the herb/clover treatment lambs were heavier than the new pasture and plantain/pasture treatment lambs, which were heavier than the old pasture treatment lambs (47.4 vs 41.5 vs 41.5 vs 39.6 ± 0.4 kg, respectively) (P < 0.05). At the conclusion of Experiment 2 the herb/clover treatment lambs were heavier than the new pasture treatment lambs, which were heavier than the plantain/pasture treatment lambs (35.6 vs 32.8 vs 28.8 kg ± 0.4, respectively) (P < 0.05). In Experiment 1 a higher percent of herb/clover treatment lambs grew faster than 200 g/day (P < 0.001) than of the pasture/plantain, new pasture and old pasture treatment lambs (87 vs 4 vs 3 vs 0 percent, respectively). In Experiment 2 only the herb/clover lambs (71%) grew faster than 200 g/day (P < 0.05). In Experiment 2 herb/clover treatment lambs had heavier (P < 0.05) final carcass weight (15.7 ± 0.20 vs 14.8 ± 0.38 vs 14.6 ± 0.27 kg) compared with the plantain/pasture and new pasture lambs, respectively. It was demonstrated that a herb/clover mixed sward can increase post-weaning lamb liveweight gains during unrestricted feeding conditions compared with traditional perennial ryegrass-based pastures.

Can a herb and white clover mix improve the performance of multiple-bearing ewes and their lambs to weaning?

The productive performance of highly fecund ewes and their progeny on ryegrass-based swards is limited in late pregnancy and lactation. Alternative herbages, such as chicory, plantain and red and white clover, have the potential to improve performance levels. In the present study, 49 twin- and 42 triplet-bearing Romney composite ewes bred to either Suffolk or Romney rams were allocated to one of three nutritional treatments from Day 131 of pregnancy [19 twin ewes on a ryegrass–white clover sward mix (Rye/WC); 16 twin ewes on a plantain–ryegrass sward mix (Plant/Rye); 14 twin ewes on a chicory–plantain–red and white clover sward mix (Herb); 13 triplet ewes on Rye/WC; 16 triplet ewes on Plant/Rye; and 13 triplet ewes on Herb] and remained on these sward treatments with their lambs until 75 days after the midpoint of the lambing period (L75). Nutritional treatment had no effect (P > 0.05) on ewe liveweight, body condition score (BCS) or non-esterified fatty acid and β-hydroxybutyrate concentrations on Day 145 of pregnancy. At L75, ewes on the Herb treatment sward were heavier than ewes on Plant/Rye (70.75 ± 1.31 v. 61.43 ± 1.28 kg, respectively) and had a higher BCS than ewes on either Plant/Rye or Rye/WC (2.7 ± 0.1, 2.2 ± 0.1 and 2.3 ± 0.1, respectively). Sire type and nutritional treatment had no affect (P > 0.05) on lamb birthweight or weight at L75. At L20, lambs born to ewes on the Herb sward treatment were heavier than those on the Rye/WC and Plant/Rye treatments (8.74 ± 0.23 v. 7.98 ± 0.23 and 7.79 ± 0.22 kg, respectively; P 0.05) on maximum heat production on a per kg liveweight basis or total heat production. Romney-sired lambs on the Herb sward treatment had higher (P 0.05) in Suffolk-sired lambs. In conclusion, the present study indicates that there is the potential to improve the productive performance of multiple-bearing ewes and their lambs by grazing on a Herb sward mix.