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1.
This paper reports on the evaluation of “summer sowing,” an innovative approach to increase the adoption of recently domesticated species of hard seeded annual legumes in Mediterranean and temperate Agriculture. The research revealed that several species of annual legumes whose seed can be readily harvested on‐farm and which possess natural hard seed dormancy, may be sown into dry soil in late summer without additional processing. These studies proved that the hard seed dormancy was broken down sufficiently in the soil over 4–6 weeks to produce robust legume pastures with more than 150 seedlings per m2 following the first winter rains, in replicated field sites established across wide agro‐ecological zones in Western Australia (WA) and New South Wales (NSW). Ornithopus sativus Brot., O. compressus L. and Trifolium spumosum L. were suitable for summer sowing based on both hard seed breakdown patterns and subsequent seedling survival in WA. While in NSW, in addition to these legumes, Biserrula pelecinus L., T. vesiculosum Savi. and T. glanduliferum Boiss. were also suitable for summer sowing. A 1.5‐ to 10‐fold increase in herbage production was achieved relative to conventionally sown T. subterraneum L. This development represents a step change in forage legume development for renovated pastures in these environments. Importantly, the experiments revealed differences in G x E effects on seedling establishment, total herbage production and seed yield in different climatic zones. The summer sowing approach is presented as a revolutionary method for pasture renovation that overcomes significant barriers to adoption.  相似文献   

2.
Knowledge of the hard seed content of annual legumes, and its pattern of breakdown, is critical to the understanding of their ecology and management within farming and natural ecosystems. For logistical reasons, seed that has been stored for varying lengths of time is often used for pasture establishment and agronomy experiments. However, the implications of storage on hard seed physiology are unknown. The aim of this study was to explore the impact of seed storage on its subsequent pattern of hard seed breakdown when exposed to field conditions. Experiments examined seed from six different annual legume cultivars that had been either produced the prior year or stored under ambient conditions for 11–22 years. Comparisons were then made between the two seed sources on hard seed breakdown patterns in situ. Although initial hard seed levels were mostly unaffected by storage (seed of five cultivars remained over 93% hard after more than 11 years of storage), the patterns of release from dormancy during exposure to hard seed breakdown conditions of stored seed differed greatly (p < .05) from freshly produced seed. Hard seed in the stored seed of most cultivars was reduced from >90% to <10% within 68 days over autumn, with shallow burial, whereas fresh seed remained >90% hard during the same period. Given this large and consistent impact, it is recommended that studies of the patterns of hard seed breakdown in legumes compare seed stored under consistent and well‐defined conditions.  相似文献   

3.
Climate variability and current farming practices have led to declining soil fertility and pH, with a heavy reliance on fertilizers and herbicides. The addition of forage and grain legumes to farming systems not only improves soil health but also increases farm profitability through nitrogen (N) fertilizer cost offsets. However, the formation of effective symbioses between legumes and rhizobia can be unreliable and is considered at risk when combined with dry sowing practices such as those that have been designed to obviate effects of climate change. This research was initiated to improve the robustness of the legume/rhizobia symbiosis in low pH, infertile and dry soils. Production from two cultivars of field pea (Pisum sativum) and two species of vetch (Vicia spp.), and symbiotic outcomes when inoculated with a range of experimental rhizobial strains (Rhizobium leguminosarum biovar viciae), was assessed in broad acre field trials which simulated farmer practice. New rhizobia strains increased nodulation, N fixation, produced more biomass and higher seed yield than comparator commercial strains. Strain WSM4643 also demonstrated superior survival when desiccated compared to current commercial strains in the laboratory and on seed when delivered as inoculant in peat carriers. WSM4643 is a suitable prospect for a commercial inoculant in Australia and other agricultural areas of the world where growing peas and vetch on soils generally considered problematic for this legume/rhizobia symbiosis. A particular advantage of WSM4643 may be that it potentiates sowing inoculated legumes into dry soil, which is a contemporary response by farmers to climate variation.  相似文献   

4.
Narrow‐leaved bird's‐foot‐trefoil (Lotus tenuis) is a perennial forage legume adapted to waterlogged and heavy and infertile soils and can replace alfalfa (Medicago sativa) in areas with these soils in Argentina. Its seeds are hard and water‐impermeable but the effects of environmental factors on seed dormancy and germination are not known. The objective was to evaluate the hypothesis that water availability during seed development and maturation affects the degree of hardseededness in L. tenuis by changing seed coat properties, conditioning water uptake through the seed coat; and subsequently affecting dormancy, germination and speed of germination. Seeds were harvested in December/January and in February in both 1993/1994 and 1994/1995 from a permanent pasture of L. tenuis growing in a Hapludol soil in San Miguel del Monte province of Buenos Aires. Environmental conditions of each anthesis‐harvest period were determined. Seeds of each harvest were subjected to chilling, washing and mechanical scarification. After 12 months seeds from each harvest were observed in a scanning electron microscope. The water deficit of the soil and relative humidity were greater in the second than the first anthesis‐harvest period in both seasons. In 1993/1994 the control treatment in December had a higher germination rate than the February control seeds (0·40 vs. 0·20) and a faster germination rate. Mechanical scarification and chilling significantly enhanced the germination rate (0·95) and its speed in seeds of both harvests. Low temperatures significantly enhanced germination rate, starting after 60 d for the seeds harvested in December, and 90 d for the seeds harvested in February. In 1994/1995 the results were similar but both the January and February control treatments had higher germination rates (0·60 vs. 0·40) than in the previous year. Seeds harvested in February were more dormant in both years. These differences could be explained by the conditions in February anthesis‐harvest period in both years that could have hastened the natural dehydration process of seed, changing integument structure and enhancing its impermeability.  相似文献   

5.
Perennial forage legumes may be pivotal for improving the sustainability of Mediterranean rainfed farming systems. This study summarizes the outcomes of a study aimed at characterizing morphological and agronomic traits of new germplasm of Bituminaria bituminosa and B. morisiana in Mediterranean environments. Five B. morisiana and three B. bituminosa native populations were evaluated in a small‐plot field experiment in Sardinia (Italy) and compared with seven Spanish accessions of B. bituminosa. The two Bituminaria species differed greatly in morphological traits and the beginning of the flowering stage, and remarkable variations between species were found for forage production and its seasonal distribution, seed yield and persistence. Average cumulative dry‐matter yield was higher in B. bituminosa than in B. morisiana (+7.6%; 297 vs. 276 g per plant). Average 3‐year seed production varied greatly between accessions (from 0.3 to 141 g per plant). Differences for these traits were also found between Sardinian and Spanish germplasm of B. bituminosa. Four clusters were generated by K‐means clustering. Accessions included in cluster III exhibited a positive combination of favourable forage production, high seed yield and satisfactory persistence. Nonetheless, the cluster analysis did not highlight a sharp discrimination between Bituminaria species. The overall results revealed the potential role of Sardinian accessions of B. bituminosa and B. morisiana in extending the forage season and for increased resilience of grasslands in Sardinia and other Mediterranean regions under rainfed conditions.  相似文献   

6.
Spring‐sown oat (Avena sativa L.) is well adapted for forage production in Central Europe; however, environmental conditions make this crop susceptible to crown rust disease (Puccinia coronata) when grown in summer. The objective of this study was to assess oat cultivars sown in late summer, when conditions for crown rust are less favourable, and harvest in autumn for forage with potential use for feeding lactating dairy cows. Three oat cultivars: Berdysz, Zuch and ForagePlus, the first two from Poland and the latter from United States, were sown 1 and 15 August, and 1 September, over three consecutive years, and harvested for forage in late October. The two Polish cultivars had 61% leaf area affected by rust with 1 August sowing, but ForagePlus was not affected by rust with any sowing date. Sowing 15 August significantly reduced crown rust incidence and increased DM yield of the Polish cultivars 21% relative to the 1 August sowing date, but decreased ForagePlus DM yield by 35%. Sowing 1 September resulted in best forage nutritive value, but the lowest DM yields for all cultivars. Calculated milk production per ton of forage for all cultivars was lowest with the 1 August sowing date. Calculated milk production per hectare was greatest for Berdysz sown in mid‐August. Oat can be sown 15 August and harvested in autumn for forage production, avoiding crown rust disease during summer in Poland. Nutritive value of autumn oat forage is adequate to meet forage requirements of lactating dairy cows.  相似文献   

7.
Provision of an adequate mineral supply in the diets of ruminants fed mainly on grassland herbage can present a challenge if mineral concentrations are suboptimal for animal nutrition. Forage herbs may be included in grassland seed mixtures to improve herbage mineral content, although there is limited information about mineral concentrations in forage herbs. To determine whether herbs have greater macro‐ and micromineral concentrations than forage legumes and grasses, we conducted a 2‐year experiment on a loamy‐sand site in Denmark sown with a multi‐species mixture comprised of three functional groups (grasses, legumes and herbs). Herb species included chicory (Cichorium intybus L.), plantain (Plantago lanceolata L.), caraway (Carum carvi L.) and salad burnet (Sanguisorba minor L.). We also investigated the effect of slurry application on the macro‐ and micromineral concentration of grasses, legumes and herbs. In general, herbs had greater concentrations of the macrominerals P, Mg, K and S and the microminerals Zn and B than grasses and legumes. Slurry application indirectly decreased Ca, S, Cu and B concentrations of total herbage because of an increase in the proportion of mineral‐poor grasses. Our study indicates that including herbs in forage mixtures is an effective way of increasing mineral concentrations in herbage.  相似文献   

8.
《Field Crops Research》1998,55(3):235-243
Annual leguminous forage crops are well adapted to hay production under the climatic conditions of Mediterranean environments, but their seed yield is often reduced by high temperatures and water stress that occur during the reproductive period. Field experiments using four forage legumes, berseem (Trifolium alexandrinum L.), crimson clover (Trifolium incarnatum L.), Persian clover (Trifolium resupinatum L.) and squarrosum clover (Trifolium squarrosum L.) were conducted in Foggia (southern Italy) during 1993 and 1994 under irrigated and non-irrigated conditions, with the aim to evaluate: (i) the effects of water deficit on traits which influence seed yield and (ii) the associations among seed yield components by means of path-coefficient analysis. Seed yield varied among species: Persian and berseem clovers showed the highest and lowest values (74.0 and 27.0 g m−2, respectively). Drought stress, in all species, negatively influenced the dry matter proportion partitioned to reproductive growth and strongly reduced seed yield (about 50% on average) and seed yield components in all species. Negative associations between the principal yield components were found in all species except berseem, suggesting the existence of compensatory relationships. Path-coefficient analysis revealed that for crimson and Persian clovers, the early flowering species, a seed yield increase cannot be achieved without a suitable tiller density. For squarrosum clover, the head fertility was the most important component in determining seed yield; whereas for berseem, seeds per head, heads per tiller and seed weight, all had positive direct effects on seed yield. As the yield components that most affected seed yield were species-specific, general conclusions cannot be drawn. Among the species examined, berseem and squarrosum clover, characterized by a longer vegetative cycle, were more damaged by water stress when it occurred during seed formation and filling.  相似文献   

9.
An investigation of eleven genotypes and two cultivars of Biserrula pelecinus L. (biserrula) was conducted in Western Australia to study their ecological and agronomic traits. All biserrula genotypes were productive in the 2 years of testing, with dry‐matter production ranging from 3·5 to 4·9 t ha?1 and seed yield ranging from 314 to 1381 kg ha?1. Biserrula has high initial levels of hard seededness (95–100%) and a more gradual hard seed breakdown (68–92%) in summer. The high levels of hard seed decreased the seedling densities of biserrula in the second year, while were at highest levels in the third year after the plots were cropped to wheat. A further experiment was conducted to study the interaction between spray‐topping and seed set. This study showed subterranean clover seed yields were more tolerant to herbicides than a number of biserrula genotypes. There were significant responses to the herbicides within the biserrula genotypes, and 95GCN59 was less affected. The rhizobium experiment showed a strong host strain/interaction and has emphasized the importance of simultaneous breeding and selection of plant germplasm run in parallel with the selection of elite strains of rhizobia such as WSM1497 to optimize nitrogen fixation.  相似文献   

10.
Understanding the grazing conditions under which plant populations are limited by seed availability (seed limitation) is important for devising management schemes that aim to manipulate the establishment of weed and forage species. Seeds of three weed species (Cirsium arvense, C. vulgare and Rumex obtusifolius) and five forage species (Lolium perenne, Lotus uliginosus syn. L. pedunculatus, Paspalum dilatatum, Plantago lanceolata and Trifolium repens) were broadcast sown into L. perenne–T. repens pastures in Manawatu, New Zealand and five sheep‐grazing and two slug‐grazing (with and without molluscicide) treatments were imposed in a split‐plot design. Of the five sheep‐grazing treatments, four compared continuous grazing with rotational grazing at intervals of 12, 24 and 36 d in spring, with all four grazed under a common rotation for the remainder of the year. The fifth treatment was continuous grazing all year. Seed sowing increased seedling emergence of C. vulgare, L. perenne, P. lanceolata, R. obtusifolius and T. repens under all sheep‐ and slug‐grazing treatments, with differences in seedling densities persisting for at least 21 months. Seed sowing did not increase seedling densities of C. arvense, L. uliginosus or P. dilatatum. The effects of sheep‐grazing management on seedling emergence and survival were uncoupled. For the five seed‐limited species, seedling emergence was greater on pastures that were rotationally grazed during spring compared with those that were continuously grazed. However, seedling survival was lower in pastures grazed rotationally during summer, autumn and winter, so that after 21 months seedling numbers were greater on plots that were continuously grazed all year. Exclusion of slugs increased seedling recruitment of T. repens but had no impact on the other species. As weed and forage species responded in a similar way to sheep‐grazing management (increased under continuous, decreased under rotational), it is unlikely that the goals of reducing weed invasions and enhancing forage species establishment could be carried out concurrently in established pastures with the same management.  相似文献   

11.
Establishing forage legumes into endophyte‐infected tall fescue (Festuca arundinacae Schreb.) pastures is problematic, especially in well‐established stands. A oversowing field experiment determined if this problem was because of poor nodulation. Four renovation techniques, clipped sward (treatment A), herbicided + rye seeding in the previous autumn (treatment B), herbicided in the autumn and spring (treatment C) and herbicided to suppress the sward (treatment D), were investigated to determine their effect on nodulation and root growth of lucerne (Medicago sativa L.), red clover (Trifolium pratense L.) and white clover (T. repens L.) at 16, 22 and 29 d after sowing the legumes. A pot experiment was also conducted under optimal growth conditions and using the same soil to determine the nodulation and root growth potentials of these legume species. At adequate rhizobial populations (>6 × 104 cfu g?1 soil), substantial nodulation of all species occurred by 29 d after sowing in treatments C and D, whereas nodulation of clovers was usually reduced in treatment A. Total root lengths for all sampling dates, species and treatments were severely restricted, especially under treatment A. A general correspondence of nodulation with root growth was observed for all species, with high correlations (r ≥ 0·85) between these variables for all legume species and treatments, suggesting that soil moisture, and possibly competition for light, were the limiting factors. These results demonstrate that weak stands of forage legumes, typically found when sown into tall fescue swards, are probably not because of inadequate nodulation. Rather, inhibition of root growth by detrimental physical/chemical conditions or allocation of limited photosynthate to shoots instead of roots is suggested.  相似文献   

12.
In Mediterranean areas, water use efficiency (WUE) is mainly increased by maximising crop growth during the rainy seasons. Perennial forage species have a number of advantages in comparison to the predominantly used annuals. They can utilize water from autumn to spring, while annuals need to be sown or to germinate from the soil seed bank. Under Mediterranean annual rainfall pattern, perennial plants must grow from autumn to spring and survive under summer aridity. Drought survival can impact water use efficiency through plant mortality and stand recovery after autumn rainfalls. In order to enhance knowledge of physiological and agronomic traits associated with WUE and persistence, a 3-year study was conducted at two Mediterranean sites, comparing a range of accessions of two perennial species, cocksfoot (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbysh). Within the accessions of predominantly Mediterranean origin, we defined four major functional types, i.e. groups of accessions with similar response to summer drought. One type (FT1) is represented by the only cultivar of a semi-arid cocksfoot (Kasbah) that is completely summer dormant, with high persistence under the most arid situations but with low WUE. The type FT2 all cocksfoot cultivars (Currie, Delta-1, Jana, Medly, and Ottava) that are not or less summer dormant, with good perenniality and intermediate productivity at rainy seasons. The type FT3 includes the cultivars of tall fescue (Centurion, Flecha, Fraydo, and Tanit) that combine an incomplete summer dormancy, a deep rooting system and the highest WUE from autumn to spring. The type FT4 is represented by a cultivar of tall fescue (Sisa) with no summer dormancy, therefore less persistent and also less productive. Dehydration avoidance in tall fescue and cocksfoot and summer dormancy in cocksfoot were the main strategies contributing to persistence under summer drought. WUE in autumn was highly correlated with sward recovery after drought. Seasonal and total WUE were also highly correlated with biomass production over the same period and with depth and density of the root system. Parameterization of functional types of the major species of forage grasses will enhance future modelling work to test the effects of a range of environments and future climate scenarios.  相似文献   

13.
Lunaria annua is a biennial cruciferous oil seed crop. The seeds contain 30–35% oil, which consists of 67% long chain fatty acids (44% erucic acid, C22:1, and 23% nervonic acid, C24:1). The oil is suitable as lubricant. In addition, recent developments indicate that nervonic acid may be used as raw material for the production of a medicine against multiple sclerosis. The biennial character of Lunaria is a main constraint for an economically feasible production of Lunaria oil. The crop has to be sown early in the summer to achieve vigorous plant development required for vernalization during the winter. It would be a great advance when Lunaria could be sown later in the summer after an early harvested crop. From 1993, breeding research in Lunaria has been performed at CPRO-DLO, Wageningen, The Netherlands. A collection of 76 accessions was maintained and evaluated for agronomic performance. In 1995, a selection of 24 accessions were sown at four sowing dates, from end June until end of August and in 1996, 12 promising accessions were sown again at 15 and 30 July. Three accessions showed suitability for delayed sowing until beginning of August. Delay in sowing time caused also delay of flowering and seed ripening. Seed yield amounted to 1200 kg/ha in 1996 and 1700 kg/ha in 1997. Seed oil content varied from 30–38%. Severe infection of Albugo candida and Alternaria occurred and might have reduced seed yield in both years. Most accessions sustained severe winter frost of−17°C very well. It is concluded that within the evaluated gene pool promising variation is available to select for ability for late sowing, to improve the disease resistance and to increase seed yield and seed oil content.  相似文献   

14.
Over the last three decades, farming systems in Europe and Australia have seen a decline in legume plantings, leading to reduced soil carbon and fertility, and an increase in plant disease, reliance on industrial nitrogen fertilizer and herbicides. In Australia, one reason for this decline has been the movement towards sowing crops and forages into dry soil, before the opening rains, as a consequence of climate variability. This practice predicates against the survival of rhizobial inoculants, and hence generates uncertainty about legume performance. The research reported here was initiated to improve the robustness of a specific forage legume/rhizobia symbiosis to increase nitrogen fixation in low pH, infertile soils. Rhizobial strains (Rhizobium leguminosarum biovar viciae) from Pisum sativum L. were sourced from acid soils in southern Italy and southern Australia. Strains were evaluated for N fixation on the forage legumes P. sativum, Vicia sativa and Vicia villosa, then for survival and persistence in acid soils (pHCa 4.6). Fourteen of the strains produced a higher percentage of nitrogen derived from the atmosphere (%Ndfa) compared to commercial comparator strain SU303 (<78%). Twenty‐two strains survived sufficiently into the second season to form more nodules than SU303, which only achieved 3% of plants nodulated. Elite strains WSM4643 and WSM4645 produced six times more nodulated plants than SU303 and had significantly higher saprophytic competence in acid soil. These strains have the ability to optimize symbiotic associations with field peas and vetch in soils with low fertility, carbon and pH that are restrictive to the current commercial strain SU303.  相似文献   

15.
The development of efficient forage management and utilization is facilitated by a knowledge of the changes in nutritive value and patterns of dry matter (DM) distribution within plants. The objectives of this experiment were to determine the patterns of DM accumulation and the change in nutritive value during maturation of crimson clover ( Trifolium incarnatum L.), a cool-season annual forage legume adapted to mild winter areas and acid soils. Crimson clover was established on a Dystric Eurocrept soil with pH 5·4 in Galicia, north-western Spain, during three consecutive years (1990–92). Shoot samples were taken at approximately biweekly intervals in the spring and summer after autumn sowing, and were separated into stems, leaves and seed pods. DM accumulation, crude protein (CP) and acid-detergent fibre (ADF) concentrations and in vitro organic matter digestibility (IVOMD) were determined for each plant part at each stage. Average annual DM production at initial flowering was 4·2 t ha–1, whereas the CP and ADF concentrations and IVOMD values were 134 g kg–1 DM, 302 g kg–1 DM and 0·720 respectively. The nutritive value declined with age, coinciding with a reduction in leaf:stem ratio (from 0·53 at the vegetative stage to 0·13 at the ripe seed stage). This decline was more rapid than that reported for other legumes, possibly because of the low leaf:stem ratio of crimson clover. However, as it is used in the Atlantic coastal areas of north-western Spain, where it is harvested around initial flowering, it can provide forage of good quality.  相似文献   

16.
Forage crops in Mediterranean environments are characterized by variable seed and forage production. Knowledge of the effects of agronomic factors on annual clovers grown in pure stand and in association with grasses is essential for their effective exploitation of the available environmental resources. Herbage and seed production were evaluated in southern Italy in an experiment with winter annual forage crops during the years 1992–95. Clovers (Trifolium alexandrinum L., berseem; T. incarnatum L., crimson; T. resupinatum L., Persian; and T. squarrosum L., squarrosum) and graminaceous forage crops (Hordeum vulgare L., barley; and Lolium multiflorum Lam., Italian ryegrass) were used to examine the agronomic effects of irrigation and harvest management. The clovers were evaluated in pure stand and in mixture, whereas the graminaceous species were evaluated only in mixtures. The mixtures were sown in alternating, equally spaced rows. The parameters evaluated were forage dry-matter yield, seed yield and its components. The results showed wide differences in forage production between clovers in pure stands and in binary mixtures. Mean dry-matter production from forage harvest of pure stands of irrigated clovers taken when 10–15% of the stems were flowering yielded 4·36 t ha–1, that is 0·67 and 0·55 of that of irrigated mixtures of clovers with either Italian ryegrass or barley, respectively, harvested when 10–20% of the graminaceous components were at the heading stage. The forage yield of non-irrigated pure stands of clovers was 0·60 of that of irrigated plots, whereas non-irrigated mixtures yielded 0·82 and 0·86 of that the irrigated treatments for Italian ryegrass or barley mixtures. The mean seed yield of non-irrigated pure stands of the clovers was 0·51 of that of irrigated stands, which yielded 451 kg ha?1. Persian clover gave the highest seed yields (732 kg ha?1 under irrigation). These higher yields were related to a higher number of fructiferous organs per stem in Persian clover. When a forage harvest had previously been taken on irrigated clover plots, the subsequent mean seed yields were greatly reduced to 0·76 for berseem and 0·21 for Persian clover and were almost negligible for crimson and squarrosum clover. When irrigated and grown in mixtures with Italian ryegrass, only berseem produced a worthwhile yield of 0·36 compared with that of pure clover taken for seed without a forage harvest; mixtures with barley gave yields of 0·71, 1·07 and 0·20 for berseem, crimson and Persian clovers, respectively, compared with seed yield from uncut pure clover.  相似文献   

17.
The efficiency of microwave treatment in breaking the hard seed coat dormancy in Stylosanthes seabrana was compared with three other conventional methods including mechanical scarification, hot water treatment (100°C for 1 min) and acid scarification (5 min). The microwave treatment was as efficient in breaking hard seed coat dormancy as the hot water treatment. The ranking of treatments followed the order microwave ≥ hot water ≥ acid > mechanical scarification > control. The electrical conductivity of microwave‐treated seeds, although less than that of hot water, was greater than untreated control seeds, indicating increased permeability of the seed coat for water uptake. Seedling vigour, based on seedling length, was also similar for these treatments. Respiration was found to be higher in microwave‐treated seeds. Although levels of food reserves were not measured, future studies could hypothesize that increased imbibition of water in microwave‐treated seeds could cause a faster breakdown of food‐reserve material that is supplied to the germinating seed, resulting in increased evolution of CO2 through respiration. Scanning electron micrographs indicated the appearance of cracks and blisters on the seed surface of microwave‐treated seeds. These are most likely the sites of water entry during imbibition.  相似文献   

18.
The herbs chicory ( C ichorium intybus L.) and plantain ( P lantago lanceolata L.) are increasingly popular summer forage cropping options for dairy producers. However, the impact of different establishment methods on their productivity is largely unknown. Four establishment methods for chicory and plantain crops sown into non‐cultivated ryegrass pastures in spring were compared. Establishment methods included direct‐drilling or broadcasting seed into existing pastures, with or without herbicide application before sowing in a 2 × 2 factorial design. It was hypothesized that plant establishment and growth would be enhanced by spraying to kill existing ryegrass pasture and direct‐drilling herbs (Spray and Drill, SD) compared with broadcasting seed with no herbicide application (Unsprayed and Broadcast, UB). This hypothesis was supported with an additional 2·1–2·3 t DM ha?1 grown over 201 d from swards established by SD, compared with swards established by UB. The SD method also increased the plant density of the herbs and reduced the proportion of weed species. Spraying and direct drilling is more expensive than broadcasting seed with no herbicide application, but the increase in yield means that extra feed can be supplied at less than half the cost of purchasing the equivalent amount of feed. Therefore, for optimal economic outcomes, chicory and plantain swards should be established by applying herbicide to existing pasture and direct‐drilling seed.  相似文献   

19.
Establishing the radiation‐use efficiency (RUE) of forage brassica crops will aid our understanding of their photosynthetic performance. The concept of RUE has been developed for cereals and legumes, but there is limited information for forage brassica crops. Three experiments defining the influence of different sowing dates on ‘Gruner’ kale (Brassica oleracea acephala L.) dry matter production were conducted at Hastings (Hawkes Bay) and Lincoln (Canterbury) in New Zealand between 2002 and 2009. These trials were also evaluated for radiation interception and RUE. Delayed sowing increased RUE in two out of three experiments across sites: from 1·93 g MJ?1 photosynthetically active radiation (PAR) for December‐sown crops to 2·72 g MJ?1 PAR (P < 0·001) for January‐sown crops at Hastings and from 1·50 for September‐sown crops to 2·00 g MJ?1 PAR (P < 0·001) for November‐sown crops at Lincoln. The different sowing dates and years of experimentation provided a range of mean temperatures (from 13 to 16°C) during the vegetative period. Across years and sowing dates, RUE was strongly correlated with mean temperature (R2 = 0·81) and sowing date (R2 = 0·64), but weakly correlated with season length (R2 = 0·11) and dry matter (R2 = 0·002). There was also a strong correlation (R2 = 0·83) between sowing date and mean temperature. The increase in RUE with delayed sowing was therefore mainly attributed to increased mean temperatures. Radiation‐use efficiency increased at about 0·41 g MJ?1 for each 1°C increase from 13 to 16°C.  相似文献   

20.
Three legumes, red clover (Trifolium pratense L.), alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.), were planted with a minimum-tillage drill into eight grass fields, three in early spring, two in late spring and three in late summer, in Pennsylvania. The objective was to use pesticides at planting time to control slugs and insects which attack legume seedlings and ascertain whether pest control prevented seedling loss and increased yields of grass and legume dry matter (DM), in vitro DM digestibility and crude protein (CP). Methiocarb bait alone or in combination with carbofuran granules or spray applied at planting sometimes controlled the slugs Derocerus reticulatum (Müller), D. laeve (Müller) and Arion fasciatus Nilsson and improved establishment of seedling red clover and alfalfa but not birdsfoot trefoil. Increased yields of DM, digestible DM, CP and legume DM after treatment was greatest in late-spring sowings. Larvae of the clover root curculio, Sitona hispidulus (F.), attacked roots of legumes in the spring following the year of sowing. Late spring and summer sowings without pesticides sustained considerable seedling losses from pests, whereas seedlings from early spring sowings in untreated areas were injured less.  相似文献   

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