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In order to estimate the base temperature (Bt) of growth through the appearance of leaves and calculate the phyllochron for kikuyu grass, three plots were established on three farms in the Provincia of Ubaté (Cundinamarca, Colombia) located at different altitudes (2560, 2640, 3143 m. a. s. l.). Measurements were made in four cycles in a period of eight months. The Bt was estimated by the least coefficient of variation method using a second order regression model and the model obtained was validated by the cross-validation method. The Bt values for the first, second, third and fourth leaf were 4.02, 3.68, 3.93, and 3.62 °C, respectively. For the appearance of the first leaf, the kikuyu required more thermal time (TT) (97.5 accumulated growing degree days (AGDD)) than for the second (74.2 AGDD), third (73.8 AGDD) and fourth leaf (76.0 AGDD) (p <0.05). There were no differences in TT among farms (p> 0.05). There was a tendency to a greater number of days required to reach each leaf stage in the farm located at higher altitude and with lower mean temperature. The validation showed an adequate adjustment (r2 = 0.94) and a substantial concordance (CCC = 0.97) between the observed values and the predicted values for the estimated TT with the Bt value obtained for each leaf stage. The results of Bt for kikuyu grass obtained, will allow to make more precise predictions about the phyllochron and generate growth models close to reality. [ABSTRACT FROM AUTHOR]

To determine the optimum harvest time of kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone), according to the number of leaves per tiller and nitrogen fertilization level, an experiment was carried out under greenhouse conditions using a 4×4 factorial design. The factors were the number of leaves per tiller (3, 4, 5, 6 leaves) and level of nitrogen (N) fertilization (0, 50, 100,150 kg of Nitrogen ha-1 year-1). Dry matter (DM) yield and nutritional quality were determined. Additionally, the independent effect of nitrogen fertilization on undisturbed height, tiller density, and the phyllochron were evaluated. When the number of leaves per tiller increased (3 to 6), the leaf yield and dead forage also increased (P<0.05). The leaf-stem ratio (L:S) remained constant (P>0.05) among the number of leaves. Green forage-dead forage ratio (GF:DF) decreased (P<0.05) with a higher number of leaves per tiller. The concentration of crude protein (CP) decreased while the concentration of neutral detergent fiber (NDF) increased with an increment of the number of leaves per tiller (P<0.05). Nitrogen fertilization increased the undisturbed height, the density of tillers, DM yield from leaves, stems and green forage, GF:DF, and CP (P<0.05) while NDF decreased (P<0.05). The phyllochron was higher without N fertilization. The effects of the number of leaves per tiller and N fertilization on the most variables measured were independent of each other. However, due to an increment in DM yield caused by N fertilization, the pasture can be defoliated with fewer leaves per tiller, increasing defoliation frequency and improving forage quality. [ABSTRACT FROM AUTHOR]

This study aimed at determining the nutritional efficiency of Kikuyu grass, when it is cultivated at different altitudes and defoliated with a different number of leaves per tiller. Four farms, with Kikuyu pastures (Cenchrus clandestinus), were selected, two in an average altitude of 2,552 m.a.s.l. and two in average altitude of 2,914 m.a.s.l. In each farm, there were established eight plots of 4 m2 each (four treatments, two replicates). For 10 months, the pastures were defoliated when they presented 4, 5, 6, and 7 leaves per tiller (treatments) at 5 cm above ground when 90% of the tillers reached the number of leaves corresponding to each treatment. Data were analyzed as serial experiments using a completely randomized block (farms) design with an analysis of variance. The leaf appearance interval was higher for the highest altitude (8 vs. 10 days) but vary among treatments at a lower altitude (P<0.05). Pastures at higher altitudes were shorter (8.9 vs. 13.5 cm), but its height varied among treatments depending on the altitude (P<0.001). The quality of the pastures was similar, except for the ones with seven leaves per tiller at 2,552 m.a.s.l. that had less protein and in vitro dry matter digestibility (P<0.01). The nutrient yield was higher for the pastures cultivated at 2,552 m.a.s.l. (P<0.001), and, at this altitude, pastures defoliated with five leaves had the largest nutrient yield. The Kikuyu cultivated at higher altitudes grows slowly and yield fewer nutrients independently of the number of leaves per tiller. [ABSTRACT FROM AUTHOR]

Soil quality of tillage systems receives much attention worldwide, although few studies attempt to link soil quality to yield. Partial least-squares regression analysis is a suitable method to construct predictive models around plural, highly collinear factors, such as soil quality and its effects on yield. This study aimed at identifying the soil quality properties which best model pasture herbage yield by relating soil quality indicators with variations in yield as a result of soil disturbance caused by tillage. The study was conducted on kikuyu ( Pennisetum clandestinum) over-sown with annual ryegrass ( Lolium multiflorum) using different tillage methods. Tillage methods involved over-sowing kikuyu with ryegrass using a minimum-tillage seed drill, eradication of kikuyu with herbicide and ryegrass sown with a minimum-tillage planter, shallow and deep disturbance, and a control. Most changes in soil quality indicators as a result of soil tillage were observed shortly after tillage and occurred mostly at the 0-100 mm soil layer. Few of these effects were still visible 420 d after tillage. Microbiological indicators changed most in response to the treatments, but unlike the chemical and physical indicators, microbiological indicators have no causal link to pasture production. The contribution of individual soil quality indicators to variance in pasture productivity could not be isolated and should thus be seen as complex processes which affect yield. Although mechanisms of how some soil quality indicators affect yield is clear, more research is required to determine mechanisms of how a combination of multiple soil quality indicators affects yield. [ABSTRACT FROM AUTHOR]

Distributions of invasive alien species (IAS) are well documented all over the world, and roads are considered one of the main means by which IAS spread. Bolivia is one of a few countries for which there are no such studies. For this reason, we determined the number of exotic plant species in the vicinity of roads near the city of La Paz, Bolivia. We distinguish two types of roads, paved and gravel roads, and in their vicinity, we studied the floristic composition in three regions, differing mainly in altitude: high Andes, puna grassland and dry valley. We found three exotic species in the vicinity of roads in the high Andes, five in puna grassland and 10 in the dry valley. We found 13 exotic species along gravel roads and nine along paved roads, whilst there was a trend for such species to be more abundant close to the roads than further away. Pennisetum clandestinum was the most frequently recorded exotic species in all regions and associated with both types of roads. The results indicate that exotic species are quite frequent along roads in Bolivia and present a potential threat as invasive species. Therefore, it may be necessary to take measures to prevent IAS from spreading further. [ABSTRACT FROM AUTHOR]

The use of plant growth regulators (PGRs) and biostimulants to enhance phytoextraction is gaining popularity in phytoremediation technology. This study investigated the stimulatory effects of smoke-water (SW), a smoke-derived compound karrikinolide (KAR1) and other known plant growth regulators (PGRs) [gibberellic acid (GA3), kinetin (Kin) and indole-3-butyric acid (IBA)] to enhance the phytoextraction potential ofPennisetum clandestinum. Pennisetum clandestinumseedlings were grown for 10 weeks in vermiculite using Hoagland's nutrient solution and were treated with cadmium (Cd) (2, 5, and 10 mg L−1) and SW, KAR1and PGRs. KAR1exhibited positive effects on shoot and root dry weight (140 and 137 mg respectively) at the highest concentration of Cd (10 mg L−1) compared to all the other treatments. KAR1and SW treatments used in the present study significantly improved the phytoextraction potential ofP. clandestinum(602 and 575 mg kg−1respectively) compared to the other tested PGRs. This is the first report on the use of SW and KAR1to enhance phytoremediation potential inP. clandestinum.Further studies are needed to elucidate the exact mechanisms of smoke constituents involved in phytoextraction potential of plant species. [ABSTRACT FROM AUTHOR]

Background Freshwater comprises about a mere 2·5 % of total global water, of which approximately two-thirds is locked into glaciers at the polar ice caps and on mountains. In conjunction with this, in many instances irrigation with freshwater causes an increase in soil salinity due to overirrigation of agricultural land, inefficient water use and poor drainage of unsuitable soils. The problem of salinity was recognized a long time ago and, due to the importance of irrigated agriculture, numerous efforts have been devoted towards improving crop species for better utilization of saline soils and water. Irrigating plants with saline water is a challenge for practitioners and researchers throughout the world.Scope Recruiting wild halophytes with economic potential was suggested several decades ago as a way to reduce the damage caused by salinization of soil and water. A range of cultivation systems for the utilization of halophytes have been developed, for the production of biofuel, purification of saline effluent in constructed wetlands, landscaping, cultivation of gourmet vegetables, and more. This review critically analyses past and present halophyte-based production systems in the context of genetics, physiology, agrotechnical issues and product value. There are still difficulties that need to be overcome, such as direct germination in saline conditions or genotype selection. However, more and more research is being directed not only towards determining salt tolerance of halophytes, but also to the improvement of agricultural traits for long-term progress. [ABSTRACT FROM AUTHOR]

In Colombia, beef cattle are traditionally raised in lowland areas, whereas dairies are the predominant production systems in the highland areas. Highland grasses are of greater nutritional value (protein content and digestibility) than lowland grasses, but may have an excess of protein, so supplementation strategies should be based on the inclusion of energy feeds. After determining that the protein content in kikuyu grass (Pennisetum clandestinum) is very high (20.6%) and that the availability of energy (2.31 Mcal ME/ kg DM) is the most limiting dietary factor, a study to evaluate the production of beef under tropical highland conditions was carried out in Santa Rosa de Osos, Antioquia. In this study, the growth of 18 steers of different crosses, homogeneously distributed in two groups grazing on Kikuyu pastures was assessed for 122 days until animals reached harvest weight (420 kg). The first group (316 ± 37.0 kg initial live weight) received 0.55 kg/day of a corn, molasses and tallow (51, 12, and 37%, respectively) energy supplement, while the second group (322.8 ± 27.8 kg initial live weight) was only grazing. Supplemented animals (S) grazed in 2.5 ha, whereas non-supplemented animals (NS) grazed in 3.2 ha. Total weight gain for the entire period was 78.8 and 73.3 kg for S and NS animals, respectively. Fattening steers in tropic highlands can be a successful production activity, but it is necessary to identify both an appropriate energy source and its level of inclusion to improve the protein:energy ratio in the diet of beef steers grazing in P. clandestinum pastures. [ABSTRACT FROM AUTHOR]

Abstract: Global attention on biofuels and the potential for Jatropha curcas to produce biodiesel from marginal land with low inputs has recently created world-wide interest in this species. This paper reports on the water dynamics and productivity of J. curcas in a silvopastoral experiment with Pennisetum clandestinum at the Ukulinga research farm of the University of KwaZulu-Natal near Pietermaritzburg, South Africa. Measurements of daily total evaporation rates during December–February (summer) on clear hot days ranged between 3 and 4 mm d−1. However, due to the deciduous nature of the species, water use was negligible (<1 mm d−1) during winter (May–August). The results have shown that two- to four-year-old J. curcas trees were conservative water users. High oil yields are unlikely due to the low seed production. The best seed yield was in 2009 (348.8 kg ha−1) in the J. curcas only plots. The other treatments (where pasture competition was a factor) ranged between 77.8 and 166 kg ha−1. Data collected on the time taken by labourers to harvest and dehusk the seeds, showed that 1 kg of seed took approximately 3 h to process, suggesting that mechanical harvesting would be necessary to make seed production economically viable. J. curcas showed a low tolerance to pests and was prone to diseases. This significantly increased the input costs for insecticides and fungicides. The South African results are so unequivocal that J. curcas under the experimental conditions does not fulfil the claims that it is a wonder biodiesel plant. [Copyright &y& Elsevier]

The volcanic cones of Auckland are distinctive landmarks of that city, currently realized as an ‘archipelago’ of grassy reserved hills. Most of these cones were modified as hill forts during former occupation by Māori. Here, we review the Auckland volcanic reserve network and survey the current groundcover vegetation and soils of four large representative examples. Forty-eight reserves currently occur on remnant volcanic features. As well as two inshore island reserves (2372 ha), the other 46 reserves total 1241 ha. Most of the volcanic reserves support exotic grassland with rare forest patches. Groundcover vegetation follows a topographic sequence from flatter, fertile sites dominated byLolium perenne,Trifolium repensandPennisetum clandestinum, to moderately steep sites dominated by a diverse range of exotic grasses, to steep, lower fertility sites dominated byMicrolaena stipoides.Pennisetum clandestinumis a major component of groundcover vegetation on many sites across all slope classes, its abundance varying in relation to soil N levels rather than to changes in slope. Soil analyses indicate that soils are nutrient-rich with high soil carbon and phosphorus. Future management should restore some native forest and introduce more herbaceous native species where low groundcover vegetation is desirable. Decreasing soil nutrient levels through strategies such as cessation of fertilizer application may assist these processes. [ABSTRACT FROM AUTHOR]

Pennisetum clandestinum (Graminae/Poaceae) an active Si-accumulator, was cultivated in two different substrata, both with reduced Si solubility. Plants growing in organic-rich soils contained much less Ca, K, Na and Si, than species growing in sandy soils. Although the highest macronutrient concentrations were associated to the highest Si levels in the organs of P. clandestinum, the R correlation values indicate that Si does not influence the internal balance and the uptake of these elements. In ca 65% of the cases roots have the highest average values regardless of the type of culture, while the contents of Mg in the shoots and roots of P. clandestinum were generally not significantly different (P>0.05). A significant decline of the macronutrient levels associated to the shoots and roots of P. clandestinum was observed from the 4th to the 6th month assay, especially for Ca in both organs, while for Mg and Na the decline is focused mainly in the shoots; K and Si decline is generally below 10%. When average values of Si in shoots and roots of plants collected from organicrich and sandy soils were plotted against the average concentrations of Ca, K, Mg and Na in the same organs, weak but positive R correlation values were obtained - the highest R values were observed for Na and K and the lowest for Ca and Mg, regardless of the culture. Exception for the high R value observed for K, although the influence of Si on the K status in the whole plant is time-depending - R values, diminished from the 4th to the 6th month, as it happens in the majority of the cases. In conclusion, P. clandestinum can grow well and healthily in substrata with acid pH values and high carbonate content and low solubility of Si suggesting that the definition of the essentiality of Si, even in a Si-accumulator plant is still a matter of great controversy. [ABSTRACT FROM AUTHOR]

Molecular evidence from sequences of three regions of ribosomal DNA (partial SSU, ITS-1, 5.8S and ITS-2, and D2/D3 expansion segments of LSU) is presented to show that the two belonolaimids described from turfgrass in Australia (Ibipora lolii and Morulaimus gigas) are identical. Morulaimus gigas is therefore considered a junior synonym of I. lolii. The decision to place the nematode in Ibipora rather than Morulaimus is supported by molecular studies which showed that I. lolii is not closely related to Morulaimus or Carphodorus, two belonolaimid genera that are only found in Australia. Survey data are presented to show that I. lolii is widespread on turfgrass around Newcastle in New South Wales and in Perth, Western Australia, where the infested area is increasing rapidly, largely because the nematode is being spread in planting material. Ibipora lolii damages all turfgrass species but is particularly damaging to kikuyu grass (Pennisetum clandestinum), the main grass used for sporting fields and recreational areas in warm regions of Australia. Data from an experiment in pots also show that the nematode multiplies to damaging levels on sugarcane. Symptoms on grasses are similar to those caused by the sting nematode, Belonolaimus longicaudatus, in south-eastern USA, but because the two nematodes are taxonomically different, I. lolii is referred to as the southern sting nematode. Ibipora lolii was not found in surveys of natural vegetation on the east and west coasts of Australia, suggesting that it is an introduced species, possibly originating in South America or the Caribbean, where other Ibipora species are found. [ABSTRACT FROM AUTHOR]

Winery wastewater often contains elevated concentrations of sodium (Na), and has a high chemical oxygen demand (COD). In constructed wetlands, Na may be removed through phytoremediation by such macrophytic plants as Typha latifolia, Juncus acutus and Scirpus maritimus. The relative abilities of these plants to absorb Na, and to tolerate high COD wastewaters was determined in a glasshouse pot trial. Also tested were Pennisetum clandestinum (Kikuyu) and Vetiveria zizanioides (Vetiver) grass, which are used on wastewater disposal sites. Treatments consisted of factorial combinations of Na and COD. Toxicity symptoms were not apparent below 16.2 µM Na/L < 5 000 mg COD L, but were marked at ≥ 40 µM Na/L and ≥ 15 000 mg COD/L. Of the macrophytes, J. acutus was the least affected by high Na and COD levels. Averaged across the Na and COD treatments, total plant dry mass (DM) in the macrophytes peaked at 40 µM Na/L, as did ability to tolerate COD. The total Na in the top growth was greatest in J. acutus from which 61.4 mg Na/plant (767 mg/m²) could potentially be harvested after six months. Equivalent figures for T. latifolia and S. maritimus were 38.8 and 25.0 g/plant, respectively. Of the grasses, P. clandestinum produced 35% more total DM than V. zizanioides. Top-growth Na contents were, respectively, 1427 and 29.1 mg/plant. To maximise Na uptake in harvestable plant components, J. acutus should be planted in wetlands, and P. clandestinum in pastures used for wastewater disposal. [ABSTRACT FROM AUTHOR]

Abstract: The conversion of montane cloud forests into pastures for grazing cattle is the main cause of important impacts on rivers and streams in most of the Andes. In order to evaluate the effects of vegetation changes we need to understand water fluxes, particularly canopy interception. We measured net precipitation responses by the canopies of Pennisetum clandestinum Hochst. ex Chiov. and Melinis minutiflora Beauv. under simulated rainfall. The samples were taken from grazed pastures during 1 year, digging out round mats of grass, placing them on wire-mesh devices after eliminating soil and underground biomass, and irrigating with different water amounts. The resulting data allow us to present a validated model for each species that predicts percentage of interception at different precipitation intensities taking into account previous canopy wetness within determined biomass ranges. We use these models to estimate 2 years of interception values for pastures of both species in the upper watershed of El Cañadón, Capaz River, Venezuelan Andes. Mean annual precipitation of El Cañadón is 1244mm and the estimate of pasture interception was 36.5% and 31.8% for P. clandestinum and M. minutiflora, respectively. Interception models, such as the ones derived in this study, provide a basis for quantifying interception rates as a function of previous wetness of canopies and grass species. [Copyright &y& Elsevier]

Kikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.) is an active silicon (Si) accumulator, and Si can reduce the organic-matter digestibility of forage grasses. Calcium carbonate (crushed coral) applications to a low Si Maile silt loam soil (Acrudoxic Hydrudands) had no effect on the in vitro digestible organic matter (IVDOM) concentration of 3-week-old (4.5-leaf-per-tiller stage of development) 'Whittet' kikuyugrass regrowth, whereas calcium silicate (wollastonite) applied at the calcium equivalent of the calcium carbonate rates produced a curvilinear (crescent-shaped quadratic) IVDOM response. Whittet IVDOM decreased when grass Si concentration exceeded about 22 g kg-1 or when 0.5 M acetic acid-extractable soil Si exceeded about 230 mg kg-1. Common and 'Hosaka' kikuyugrass regrowth on the Maile soil had less Si and greater IVDOM concentrations than those observed for high-Si Kohala (Humic Dystrustepts) and Waialua (Pachic Haplustolls) silty clay soils. Whittet had greater crude protein and IVDOM concentrations and lesser fiber concentrations than common. [ABSTRACT FROM AUTHOR]

Hawaiian dry forests currently occupy a small fraction of their former range, and worldwide tropical dry forests are one of the most human-altered systems. Many small-scale projects have been successful in restoring native dry forests in abandoned pastures and degraded woodlands by outplanting after invasive species removal, but this is a costly approach. In this project, we tested forest restoration techniques involving broadcasting seeds pretreated to enhance germination and applying herbicide to reduce non-native grass competition. We compared three treatments: broadcast seeding, herbicide, and broadcast seeding combined with herbicide. After two years our study results suggest that broadcast seeding and the favorable microclimate created by eliminating invasive grasses through herbicide application may increase native seed germination and survival and promote higher species diversity. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate changes in soil bulk density (ρa) induced by Holstein and Jersey cattle grazing in kikuyu grass fields. We took 60 soil samples (Typic Hapludands) at two farms more than 15 years ago involved with milk production, in Cascajal and Nubes Coronado districts, San Jose, Costa Rica, 2008. The "known volume method" was used, following a sampling protocol every five meter in relation to the perimeter of the grazing zone and the next sampling point. It was determined that the variables breed, grazing time (before and after) and grazing zone, are significant for quantifying the changes in soil bulk density. Values of ρa before the livestock was allowed inside the paddocks ranged between 0.47 and 0.58 Mg/m³, with a mean value of 0.52 Mg/m³, while after cattle passage, it ranged between 0.52 and 0.77 Mg/m³, with a mean value of 0.64 Mg/m³. When grazing was performed with Jersey cattle, ρa values varied between 0.52 and 0.72 Mg/m³, with a mean of 0.62 Mg/m³, while Holstein cattle grazing induced changes between 0.62 and 0.77 Mg/m³, with a mean of 0.69 Mg/m³. Soil bulk density changes resulting from trampling cattle on kikuyu grass can fluctuate between 14 and 31%. [ABSTRACT FROM AUTHOR]

Samples of kikuyu foggage (standing hay) were collected in northern KwaZulu-Natal from five adjoining paddocks to measure the changes in nutrient composition of the foggage as winter progressed. Leaves and stems were separated. The first samples collected on the 18th of May contained green to dry material at a ratio of 3 : 1 and that was reduced to practically no green material in July. Although the proportion of leaf decreased from 64.6% to 56.8% as winter progressed, differences were not significant. Crude protein (CP) levels and effective dry matter degradation decreased significantly with time while neutral and acid detergent fibre levels increased. The calcium (Ca) and phosphorus (P) concentrations in the leaves decreased significantly between the first collection and later collections, while these changes were less pronounced in the stems. At all stages the stems contained significantly lower concentrations of Ca than the leaves, while P concentrations between leaves and stems did not differ. Consequently, the Ca : P ratios in the leaves varied between 2.08 and 1.60 and that of the stems between 0.74 and 1.10. These results suggest that the significantly lower Ca levels in kikuyu stems compared to leaves could make a significant contribution to the variation in Ca : P ratios reported for kikuyu. The concentrations of the other elements measured did not differ between the leaves and stems. Concentrations of CP, potassium, magnesium, copper and selenium in the kikuyu foggage decreased rapidly from the first collection that contained a relatively high proportion of green material to later collections when the foggage was dry. [ABSTRACT FROM AUTHOR]

The article presents a study on the kikuyu grass poisoning in cattle in Australia. Such plant refers to a perennial pasture species, which grows during spring and autumn. Despite having no ill effects on animals, incidents of spasms were noted. However, results revealed that the pathogenesis of such poisoning has remained unclear. Thus, it is advised that future studies must focus on the isolation and identification of the toxin, since its seasonal production in such a grass remains unclear.

Pennisetum clandestinum (Kikuyu grass, Graminae ) is an active Si accumulator growing in altitude in Kenya. To verify the influence of Si on mineral uptake, P. clandestinum was cultivated in two different substrata both with low silicon levels. P. clandestinum growing in organic-rich soils (43.3% organic matter) contained much more Cu, Mn and Zn but less Si in the whole plant and Fe in the roots than species growing in a sandy matrix, indicating that Si does not interfere with the uptake of such nutrients. In 90% of the cases, roots have the highest average values regardless of the type of culture considered. Plants in sand substrates (82.2% sand) exhibited much more Si (particularly roots) than plants in organic-rich soils, despite the high carbonate content of both matrices and the acid pH used in the nutrient solution. The more Si is present in shoots and roots, the less P is detected. N/P ratios of shoots of sand culture confirm a nutrient limitation of P. Shoot biomass in organic-rich soils was approximately two times higher than in sand. Conversely, root biomass in sand was almost twice the average value in organic-rich soils. [ABSTRACT FROM AUTHOR]

The turf grass Pennisetum clandestinum Hochst. (kikuyu grass) is one of the candidate plants for utilization and reclamation of salinized areas. The capability of kikuyu grass to grow under saline conditions was tested during 6 months, under various irrigation treatments (tap water control, 80‐mM, 150‐mM, 200‐mM, 240‐mM NaCl). Plant biomass production was visibly affected only at NaCl concentrations greater than 150‐mM NaCl. Plant growth and plant regeneration capability in the 200‐ and 240‐mM NaCl treatments gradually decreased as the experiment progressed in time. The photosynthetic potential of the plants remained unchanged and was neither affected by the treatment nor with time. Proline content of leaves as well as the content of Na + and Cl - increased with increasing salinity stress. Apparently, kikuyu grass can withstand moderate concentrations of NaCl for prolonged periods and under repeated mowing. Thus, this grass can be used as a potential ground cover and as fodder grass in saline habitats. [ABSTRACT FROM AUTHOR]

The response of introduced ( Pennisetum clandestinum Hochst.) and native ( Stipa aristiglumis F. Muell., Themeda australis (R. Br.) Stapf, Danthonia spp. (L.) grasses to the herbicide atrazine was studied in plants with the potential for use in vegetated filters (biofilters) designed to reduce chemical loads in agricultural runoff. The response was detected by photosynthetic inhibition using leaf chlorophyll fluorescence. With continuous short-term (14 days) dosing with atrazine in sand culture, P. clandestinum showed the greatest tolerance, regardless of the dose (20–500 μg/L). In a clay vertosol soil in the glasshouse, the four species were tolerant to longer-term (84 days) application of three successive doses of simulated run-on, each dose containing 100 μg/L atrazine, a concentration which is comparable to the highest reported in runoff from agricultural land in Australia. Even with a subsequent single atrazine dose at ∼ ∼5000 μg/L, established plants of the four species showed signs of quick recovery (7–21 days) to normal photosynthetic activity. In a field experiment with simulated run-on, applied to P. clandestinum pasture in sandy loam soil, repeated doses at concentrations up to 1000 μg/L gave no significant response; only a subsequent single dose of 5000 μg/L had significant effects, from which plants soon recovered. Although damage from atrazine can be demonstrated with continuous dosing in non-adsorbing media, in soil culture the tolerance of the four selected species to repeat doses of atrazine shows they may be used confidently for biofiltering purposes. P. clandestinum was especially tolerant. [ABSTRACT FROM AUTHOR]

Reuse of saline drainage waters is a management option that has been suggested for the San Joaquin Valley (SJV) of California in order to reduce both the area affected by shallow water tables and the volume of drainage effluent requiring disposal. Salt-tolerant forages may play an important role in this strategy, while at the same time producing a food source for sheep and cattle. Crop selection for reuse systems, however, will depend upon production potential under saline-sodic conditions. To identify potentially suitable crops, a controlled study using an elaborate sand-tank system was conducted at the US Salinity Laboratory to evaluate ten promising forage crops irrigated with synthetic drainage waters dominated by Na2SO4 with an EC of either 15 or 25 dS/m each containing 500 μg/L Se and Mo as SeO42- and MoO42-. Forages were cut several times over the year-long duration of the experiment. The forage species tested performed differently in terms of absolute biomass accumulation and biomass production relative to salinity level. Cumulative biomass production of alfalfa (Medicago sativa L.), a relatively salt sensitive crop, was higher than most other forages at moderate salinity. As salinity increased to 25 dS/m, however, cumulative biomass of the alfalfa cultivars were reduced by nearly half whereas biomass of the most salt tolerant grasses was reduced between 0 and 20%. Although most forage species tested showed promise, those that performed particularly well based on biomass accumulation, overall salt-tolerance, and forage quality were ‘Jose’ tall wheatgrass, bermudagrass and ‘PI 299042’ paspalum. [Copyright &y& Elsevier]

Thulin M. & Phillips S.: The identity of Pennisetum longistylum (Poaceae). - Willdenowia 45: 173-175. 2015. - Version of record first published online on 06 July 2015 ahead of inclusion in August 2015 issue; ISSN 1868-6397; © 2015 BGBM Berlin. DOI: Pennisetum longistylum, recently stated to be an older name for the well-known P. clandestinum ( Cenchrus clandestinus), is shown to be a hybrid between P. clandestinum and P. villosum ( C. longisetus). This is a rare hybrid only known from a few gatherings from the highlands of Ethiopia and Eritrea, the most recent one made in 1916. The new combination Cenchrus × longistylus is proposed, and the names P. clandestinum and P. villosum are lectotypified. [ABSTRACT FROM AUTHOR]