Annual Trifolium Species Research Articles

Study of Trifolium angulatum phytomass in Karcag

Our studies were conducted at the Hungarian University of Agricultural and Life Sciences in Karcag, where in 2023, due to favourable precipitation and temperature conditions, we had the opportunity to study the phytomass yields of a massively reproducing annual Trifolium species in a saline soil condition. Yield measurements (green yield, hay yield, crude protein yield, dry matter yield) showed that in all cases higher yields were measured in the Trifolium angulatum-covered grassland than in the control grassland, and statistical analysis showed a close correlation in all cases. Through our studies, we aimed to provide new data on the specific floristic events in environmentally managed grassland in the Pannonian Basin from a farmer's perspective.

Seed Germination and Early Seedling Growth Responses to Drought Stress in Annual Medicago L. and Trifolium L. Forages

Climate change in the Mediterranean-like regions of South Africa has resulted in increased rainfall variability, a delayed start to the wet winter season, and increased occurrences of out-of-season summer rainfall events. These changes in bioclimatic conditions are predicted to become more pronounced and, therefore, could result in poor seedling establishment and false breaks from the soil seed bank, followed by seedling desiccation in annual medic and clover pastures. This study therefore aimed to quantify and compare the responses of three annual Medicago species and five annual Trifolium species to drought stress imposed at the seed germination, seedling establishment, and early seedling growth stages. Three separate controlled trials were conducted. Firstly, the seeds were germinated in seed germination chambers at constant temperatures ranging from 5 to 30 °C, in 5 °C increments, with five osmotic treatments within each temperature, and germination was recorded daily. For the second experiment, seeds were planted at 100, 70, 50, and 30% of the soil’s moisture-holding capacity without subsequent watering, and emergence was recorded daily. For the third experiment, one-month-old seedlings were subjected to two water-limitation periods (15 or 30 days), and their subsequent morphological responses were measured. The results from these experiments indicated that the species differed significantly in their responses to drought, and the best-performing species often differed when drought was imposed at different development stages. Five species—M. polymorpha L., M. truncatula Gaertn., T. alexandrinum L., T. vesiculosum Savi., and T. subterraneum L. ssp. subterraneum—were able to tolerate incidences of drought better than other species and, thus, should be prioritized for further research into the variation in drought tolerance between cultivars within these species.

Nodule occupancy by Rhizobium leguminosarum strain WSM1325 following inoculation of four annual Trifolium species in Canterbury, New Zealand

The genotype of nodule occupants in four annual clovers – balansa (Trifolium michelianum), Persian (Trifolium resupinatum), gland (Trifolium glanduliferum) and arrowleaf (Trifolium vesiculosum) – was investigated. The clovers were inoculated with the ALOSCA® group C granule preparation of strain WSM1325. A total of 224 strains were recovered from root nodules with between 55 and 58 strains for each clover species. Genotyping showed that no strains had fingerprints identical to strain WSM1325. The nodule occupants were diverse with 26, 35, 31 and 32 genotypes identified on arrowleaf, balansa, gland and Persian clovers, respectively. Arrowleaf clover had some specificity for genotype A with 43% of nodules occupied by this strain. The most dominant strain for the other three clovers ranged between 13%–18% occupancy. This work demonstrates a high diversity of naturalized rhizobia strains in New Zealand soils that had the ability to nodulate these top flowering annual clover species.

Nitrogen fixation in annual Trifolium species in alkaline soils as assessed by the 15N natural abundance method

Annual clover species such as Trifolium purpureum Loisel., T. resupinatum L., and T. alexandrinum L. are adapted to alkaline soil conditions and provide certain agronomic advantages over annual medics (Medicago spp.). Annual clovers have not been widely grown in alkaline soils in Australia, and quantifying their dinitrogen (N2) fixation in alkaline soils is important in understanding their potential role in mixed farming systems of southern Australia. Using the 15N natural abundance technique, it was estimated that annual clovers fixed 101–137 kg N/ha at Roseworthy and 59–62 kg N/ha at Mallala, on Calcarosols with soil pH of 8.0 and 8.5, respectively. Species differed in the percentages of fixed N2 estimated in shoot dry matter, which was highest in T. alexandrinum (77–85%), moderate in T. resupinatum (76%), and lowest in T. purpureum (65–74%). Naturally occurring soil rhizobia (Rhizobium leguminosarum bv. trifolii) provided adequate nodulation, as inoculation with different strains of rhizobia had little influence on nodulation or N2 fixation. These results indicate that clovers can provide a significant contribution of fixed N2 to mixed farming systems. Examination of nodules indicated variable nodule occupancy by the inoculant rhizobia and that 69% of shoot N was fixed when clovers were nodulated by the soil populations of rhizobia. A simple model is defined to identify the potential interactions between inoculated legumes and soil rhizobia, and the options for enhancing symbiotic effectiveness are discussed.

Stomatal conductance of semi-natural Mediterranean grasslands: Implications for the development of ozone critical levels

Intra-genus and intra-specific variation and the influence of nitrogen enrichment on net assimilation and stomatal conductance of some annual Trifolium species of Mediterranean dehesa grasslands were assessed under experimental conditions. Also gas exchange rates were compared between some Leguminosae and Poaceae species growing in the field in a dehesa ecosystem in central Spain. The results showed that the previously reported different O 3 sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g s values. In addition, no clear differences on gas exchange rates could be attributed to Leguminosae and Poaceae families growing in the field, with intra-genus variation being more important than differences found between families. Further studies are needed to increase the database for developing a flux-based approach for setting O 3 critical levels for semi-natural Mediterranean species.

Landform and phosphorus effects on nitrogen fixed by annual clovers and its contribution to succeeding cereals in the Ethiopian highlands

Poor drainage of Vertisols and nitrogen (N) and phosphorus (P) deficiencies are some of the major constraints to food and feed production in the Ethiopian highlands. The effects of soil drainage and P supply on N fixation by annual Trifolium species and their residual value to succeeding crops was investigated in field experiments on Vertisols at Addis Ababa and Ginchi. In one experiment, the Trifolium spp. fixed 55–122 kg N/ha when P fertiliser was applied, and the increase in grain yields of oats following different clovers ranged from 20% for T. steudneri to 55% for T. rueppellianum compared with yields of continuous oats. In another experiment, landform treatments designed to effect drainage had no significant effects on N fixation and clover dry matter, or on yields of wheat following the clovers. Phosphorus applied at 50 kg P/ha increased N fixation from 11 to 72 kg N/ha on the broadbed-and-furrow landform and from 10 to 64 kg N/ha on the flat landform, and herbage yield responded similarly. Only the wheat following P-applied clover, particularly when supplemented with N fertiliser at 50 kg N/ha, had significantly higher wheat grain yields compared with continuous wheat grown without N fertiliser. These results confirm the critical importance of P in increasing the productivity of clovers in the Ethiopian highlands.

Agronomic effectiveness and residual effects of Egyptian and Togo phosphate rocks on clover production

The high cost of conventional, water‐soluble phosphorus (P) fertilizers limits their use by resource‐poor farmers in sub‐Saharan Africa. Phosphate rocks are a low‐cost alternative. We evaluated the effectiveness and residual effects of Egyptian phosphate rock (EPR) and Togo phosphate rock (TPR) relative to triple superphosphate (TSP) applied at 0, 20, 40, 80, and 160 kg P ha‐1 to annual Trifolium species grown in a P‐deficient Vertisol. The fertilizers were applied once and their effects were followed on seven consecutive annual clover crops. Clover responded to P at all the rates used. Significant (P<0.05) responses to P at the low 20–40 kg P ha‐1 rates were registered up to the fifth crop after application of P, and responses to higher rates of 80–160 kg P ha‐1 were significant up to the seventh crop. Critical evaluation of residual effects by comparing the response of clover to these fertilizers with response to fresh applications of TSP in the second and third crops confirmed these observations. Over all the seven crops, EPR was 82% as effective as TSP in increasing clover DM and 83% as effective in increasing P uptake. Its substitution rates were 67% for DM yields and 69% for P uptake. For TPR, the relative responses were 54% and 52% for DM yield and P uptake, respectively, and the corresponding substitution rates were 29% and 27%. In separate experiments, the effects of mixing these phosphate rocks with triple superphosphate (TSP) in various proportions (at 60 kg P ha‐1) were also investigated. The highest response of clover was observed with TSP applied alone, but the phosphate rocks applied alone also significantly increased yields compared with the controls without applied P. Mixtures of TPR and TSP increased yields only slightly over pure TPR, and mixtures of EPR and TSP had no effect on yields compared with pure EPR, presumably because EPR is more reactive than TPR. It was concluded that EPR is highly effective in these soils, but the effectiveness of TPR is low. The highly reactive EPR could be used to elevate the P status of the P‐deficient Vertisols and increase feed availability and livestock productivity in the Ethiopian highlands. Mixing of these phosphate rocks with TSP cannot be recommended.

Effectiveness of Egyptian phosphate rock on clover production in Ethiopia1

The majority of soils in Africa are phosphorus (P) deficient, but the high cost of water‐soluble P fertilizers limits their use by resource‐poor farmers. A low‐cost alternative is to use phosphate rocks. We evaluated the effectiveness of Egyptian phosphate rock (EPR) relative to triple superphosphate (TSP) applied at 0, 15, 30, 45, and 60 kg P ha‐1 to annual Trifolium species grown on a P‐deficient Vertisol. The fertilizers were applied once and their effects were followed on seven consecutive annual clover crops. Clover responded to P at all the rates used. Significant (P<0.05) P effects on clover P content and DM yields were observed up to the fourth crop. Over all the seven crops, EPR was 89% as effective as TSP in increasing herbage DM and 93% as effective in increasing herbage P content. Its substitution rates were 79% for DM yield and 86% for clover P content. Therefore, EPR was highly reactive and its use could elevate the P status of the P‐deficient Vertisols and increase feed and livestock productivity in the Ethiopian highlands.

Recruitment and survival of native annual Trifolium species in the highlands of Ethiopia

Germination and survival of indigenous annual Trifolium species were studied. Seedlings naturally emerging in the field and from sown seeds in pots were regularly counted and uprooted, and survival was studied by monitoring colour‐coded seedlings. Differences in recruitment of Trifolium species were strongly related to the rainfall pattern. In the fallow (crop) lands, no seedling survived the dry season between the short and main rainy periods during the year, while in the natural pasture, 8% of the seedlings survived into the main growing (rainy) season. Occasional rains occurring in the dry period (between the two rainy periods) also induced successions of germination and seedlings death, and therefore depleted the soft seed reserve in the soil by the beginning of the main growing season. As temperature fluctuations were minimal during the main rainy season, the rate of seed softening was low, affecting new germinations. This had a significant impact on the quality of the natural pastures on which livestock in the highlands are dependent.

Distribution of annual Trifolium species in Morocco

An ecogeographic survey was conducted in six key agricultural zones in Morocco to study the abundance and the relationship between the natural distribution of annual Trifolium species and environmental factors. Sixteen species of annual Trifolium species were identified. Most prolific was T. scabrum and the least were T. striatum and T. bocconei. Fifty-five percent of the sites had no Trifolium and the average number of species per site was 2.2. An average seed yield of 4.8 kg ha-1 was obtained. Both soil and climatic factors affected the occurrence of Trifolium species. Rainfall, pH and phosphorus content were the most determinant factors affecting the distribution of Trifolium species in Morocco.

The influence of the lucerne bud mite (Eriophyes medicaginis Keifer) on the growth of annual and perennial Trifolium species

Eriophyes medicaginis Keifer was found to cause significant reduction in the growth of seedlings of the annual Trifolium species T. incavnatum and T. subterraneum, but had no influence on the growth of the perennial species T. fragiferum, T. pratense and T. repens. The mite did not reproduce on either annual or perennial Trifolium species. Leaf symptoms on the annual species were similar to those caused by bean yellow mosaic virus on annual clovers. The symptoms on T. incavnatum did not become evident until 10-12 days after infestation, which was the time taken for undifferentiated leaves to fully develop. This indicates that the presumed salivary toxin of the mite is of short-lived activity in the plant or is not readily translocated beyond the leaf upon which feeding takes place, or both.

Preliminary comparisons of several annual Trifolium species on Kangaroo Island, South Australia

The growth and persistence of a number of accessions of seven species of Trifolium were measured. For the first three years the plots were grazed only to remove excess herbage after sampling. For the following three years they were grazed continuously under commercial conditions. In ungrazed swards the annual dry matter production of accessions of T. cherleri, T. globosum, and T. purpureurn was similar to T. subterraneum cultivars Yarloop and Woogenellup. T. cherleri, T. globosum, and Woogenellup made the bulk of their growth during the spring whereas T. purpureum and Yarloop produced half of their total dry matter during the winter. Good plant densities of T. argutum, T. cherleri, T. purpureum, and T. subterraneum were present at the end of three years continuous grazing, but Woogenellup and all other species were markedly inferior to Yarloop in their contribution to total production at the end of this period. Yarloop and T. purpureum were found to be very susceptible to clover scorch (Kabatiella caulivora) ; Woogenellup was moderately susceptible and the other species were unaffected in the field. All test species had low levels of formononetin in their leaves.

KLIPHUIS, E.: Chromosome numbers of some annual Trifolium species, occurring in the Netherlands.

KLIPHUIS, E.: Chromosome numbers of some annual Trifolium species, occurring in the Netherlands.