Effects of sericea lespedeza residues on warm-season grasses

Soil incorporation of sericea lespedeza [Lespedeza cuneata (Dum. de Cours) G. Don.] residues has been reported to inhibit growth of some forage grasses. No information is available on the performance of sericea lespedeza grown in association with warm-season perennial grasses. Laboratory and greenhouse experiments were conducted to determine if sericea lespedeza residues affect seed germination and seedling growth of bermudagrass [Cynodon dactylon (L.) Pers.] and bahiagrass (Paspalum notatum Flugge); if any such response was cultivar dependent; and if the response was subject to manipulation by N fertilization. Sericea lespedeza residues inhibited bermudagrass and bahiagrass growth, but did not affect their seed germination and emergence. No differences among cultivars of bermudagrass and bahiagrass in response to sericea lespedeza residues were found in the greenhouse. Nevertheless, differences among bermudagrass cultivars for tolerance to sericea lespedeza residues were observed in the laboratory. The harmful effects of sericea lespedeza residues were small (17 and 16% reduction of dry weight for bermudagrass and bahiagrass, respectively) compared to the positive effects of N fertilization.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Effects of sericea lespedeza root exudates on some perennial grasses

Root exudates are substances released into the surrounding medium by healthy and intact plant roots. Research on root exudates has shown that root exudates can reduce seed germination and plant growth. There is no information on the effect of sericea lespedeza [Lespedeza cuneata (Dum. de Cours) G. Don.] root exudates on other plants. In a series of greenhouse experiments we studied (1) if sericea root exudates affect seed germination and seedling growth of the perennial grasses tall fescue (Festuca arundinacea Schreb.), bermudagrass [Cynodon dactylon (L.) Pers.], and bahiagrass (Paspalum notatum Flugge); and (2) if any such responses were cultivar dependent. The effects of the root exudates were measured in 2 experiments. In the first one, coarse perlite was used as a medium to measure seed germination and radicle and coleoptile growth. In the second experiment, soil was used as a medium to measure emergence and biomass. Root exudates from sericea lespedeza had no effect on germination and emergence of tall fescue and bahiagrass but reduced their radicle and coleoptile length and biomass. Germination, radicle, and coleoptile length, and emergence of bermudagrass decreased when exposed to the root exudates; however, biomass was not affected. Cultivars of the grass species differed in their response to the root exudates of sericea lespedeza. Thus, establishment of tall fescue in mixture with sericea lespedeza is not likely to be affected; however, its growth is likely to be decreased. Therefore, tall fescue contribution to total yield will be reduced. Conversely, establishment of bermudagrass is likely to be affected, but once established, its growth is expected to be similar to its grown alone.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Effects of sericea lespedeza residues on cool-season grasses

Incorporation of crop residues into the soil prior to planting has been shown to reduce the growth of subsequent crops. Information is limited on the allelopathic effect of sericea lespedeza [Lespedeza cuneata (Dum. Cours) G. Don.] residues on multiple cropping and rotational systems. Experiments were conducted to determine (1) if sericea lespedeza residues affected seed germination and plant growth of rye (Secale cereale L.), ryegrass (Lolium multiflorum Lam.), and tall fescue (Festuca arundinacea Schreb.); (2) if cultivars of these species varied in response to phytotoxins from sericea lespedeza residues; and (3) if N fertilization nullified the effects of residues. Germination experiments were conducted by using water extracts from low- or high-tannin sericea lespedeza residues, distilled water (control), and topsoil and subsoil obtained from areas in which low- or high-tannin sericea lespedeza plants had grown for 4 years. Greenhouse experiments showed that germination, emergence, seedling growth, above-ground biomass, and N concentration of rye and tall fescue were reduced by sericea lespedeza residues. Although ryegrass germination was not affected by the residues, biomass and N concentration were reduced. Rye and tall fescue germination were not affected by soils where sericea lespedeza previously had grown, but ryegrass germination and seedling growth of all 3 species were reduced. Immobilized N was the main factor limiting plant growth. Fertilizer-N more than compensated for the negative effects of the residues on all species. Establishment of rye and tall fescue in a sericea lespedeza field is likely to require higher seeding rates than normal to compensate for reduced germination, whereas ryegrass would not be affected. Fertilizer-N may be needed to enhance growth of grasses that otherwise would be curtailed by sericea lespedeza residues.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Effects of Organic Farming on Winter Plant Composition, Cover and Diversity in Olive Grove Ecosystems in Central Greece

The present study aimed to assess the effects of organic farming in comparison with conventional on plant composition, plant cover (%), diversity [species richness, Shannon, Simpson, and evenness (Pielou's) indexes] and investigate and describe the relations among plant species richness, plant cover, indexes, and soil parameters (pH and temperature) in olive grove ecosystems during the winter. Organic olive groves had significantly greater values of cover, species richness, and Shannon and Simpson indexes than the conventional ones. Plant species richness was positively correlated to plant cover and Shannon and Simpson indexes but negatively correlated to evenness index for both farming system. Finally, plant cover was positively correlated to the Shannon and Simpson indexes for both farming systems. According to principal component analysis (PCA), for axis 1, positive correlation was detected among the plant species richness, soil temperature, and Shannon and Simpson diversity indexes, whereas for axis 2, negative correlation was detected between plant cover and soil pH. It can be concluded that the organic management system enhances herbaceous plant cover and diversity (species richness, Shannon and Simpson indexes) in olive grove ecosystems during the winter

Energy budget in organic and conventional olive groves

An energy analysis, combined with an economic one, in conventional and organic olive groves is useful in evaluating present situation and deciding best management strategies. The objective of this study was to evaluate the differences in the energy budget between organic and conventional olive groves in three locations in the island of Thasos and to calculate CO2-emissions based on the used fossil energy. The data were collected through personal interviews with farmers during 2000-2003. Twenty-four farmers, who owned olive groves about I ha each, were randomly selected to participate in this study [(4 conventional and 4 organic) x 3 locations]. The means averaged over all locations for fertilizer application energy was significantly higher in conventional than in organic olive groves, while the opposite occurs for insect trapping energy. Means averaged over the two farming systems for weed control energy were significantly higher in the northeastern part of the island, followed by the northwestern and southern part. The means averaged over all locations for labor and fertilizers energy were significantly higher in conventional than in organic olive groves, while the opposite was observed for tools energy. Means averaged over the two farming systems for labor and tools energy were significantly higher in the northwestern part of the island. Means averaged over the two farming systems for electric and pesticides energy were significantly higher in the northwestern part of the island. Total energy inputs were not affected by any of the studied parameters, while outputs were affected by the location, by the farming system and their interaction. Outputs in the northeastern part of the island and production in all parts of the island were significantly lower in organic than in conventional olive groves. Outputs and production were lower in the southern part of the island than in the other parts, since olive groves in southern Thasos are located in slopes with less productive soils. The results show a clear response of energy inputs to energy outputs that resulted from the farming system and location. Global warming potential and CO2-emissions were not affected by the farming system and location. Organic olive groves tended to have lower CO2-emissions caused by the different uses of fossil energy. (C) 2007 Elsevier B.V. All rights reserved

Perdas de forragem em capim-Tanzânia (Panicum maximum Jacq cv. Tanzania-1) manejado sob diferentes alturas sob pastejo Forage losses in Tanzania grass (Panicum maximum Jacq cv. Tanzania-1) managed in different sward height under grazing

RESUMO - O experimento foi conduzido com objetivo de avaliar as perdas de forragem e a acumulação de liteira em uma pastagem de capim-Tanzânia (Panicum maximum Jacq cv. Tanzania-1 ) manejada sob diferentes alturas. Os níveis de altura (tratamentos) estudados foram: 29,8; 32,0; 47,1; 51,5; 57,9; 62,7; 72,6 e 80,0 cm, em um delineamento completamente casualizado e com duas repetições. As taxas de acúmulo e acumulação de liteira e as perdas de forragem foram iguais em todas as alturas. A porcentagem de forragem senescente foi influenciada de forma quadrática pelos níveis de altura. Os resultados indicam que foram altos os níveis de acumulação de liteira e as perdas de forragem, em média, 38,9 kg/ha/dia de MS e 2179 kg/ha de MS, respectivamente. Devido à possibilidade de se reduzirem a persistência da pastagem e a modificação da estrutura das plantas, recomenda-se não utilizar pastagens de capim-Tanzânia em alturas próximas ou iguais a 20 e 80 cm, sob lotações contínuas.<br>The experiment was conducted to evaluate, the forage losses and litter accumulation, in a pasture of Tanzania grass (Panicum maximun Jacq cv. Tanzania) managed in different sward height levels. The studied levels of sward heights (treatments) were: 29.8, 32.0, 47.1, 51.5, 57.9, 62.7, 72.6 and 80.0 cm, in a completely randomized design and two replications. The litter accumulation rate, litter accumulation and forage losses were similar in all heights. The percentage of senescent forage in the plant canopy was influenced on a quadratic way by the sward height levels. The results show that the litter accumulation and forage losses were high, with average DM of 38.9 kg/ha.day and 2179 kg/ha of DM, respectively. Due to the possibility to reduce the pasture persistence and plant structure deteriorate, it is not recommended to utilize Tanzania grass pastures, in levels sward height near or equal of 20 and 80 cm, under continuous stocking rate