Effect Of Glyphosate Application Research Articles

Effects of Glyphosate Application on Preharvest Fruit Drop and Yield in ‘Valencia’ Citrus

The use of glyphosate as a post-emergent weed management tool is crucial in Florida citrus production. However, extensive and nonjudicious application of glyphosate has drawn increasing concerns about its inadvertent effects on citrus, mainly linked to its possible impacts on preharvest fruit drop. Our study investigated the effect of applying glyphosate in the tree rows near the fruit harvesting window on fruit drop and yield in ‘Valencia’ sweet orange. Field trials were conducted at Southwest Florida Research and Education Center, Immokalee, FL. The experiments had a randomized complete block design with four replications. Three different doses of glyphosate within the labeled range of rates in citrus (i.e., low, medium, and high at 0.84, 2.10, and 4.20 kg acid equivalents of glyphosate per hectare, respectively) along with a water control treatment were sprayed in ‘Valencia’ citrus tree rows close to the harvesting period and assessed for their effects on preharvest fruit drop and yield. Our findings show that glyphosate application near the harvesting window may influence the fruit detachment force (FDF) in Valencia citrus; however, no significant effect on increasing fruit drop or reducing yield was observed during this 2-year study.

Effects of Glyphosate Application on Physiologically Integrated Clones of the Invasive Plant Carpobrotus edulis

Management of invasive alien species is a high priority for biodiversity conservation. Here, we studied the effects of glyphosate application, at 0.06 g/m2 concentration, on physiologically integrated basal and apical ramets of the invasive clonal plant Carpobrotus edulis. Physiological integration allows the transport of resources and other substances between connected ramets in clonal plants. We found a significant reduction of growth and photochemical efficiency both in basal and apical ramets of C. edulis after glyphosate application. Interestingly, we also observed a significant growth reduction in untreated basal ramets when they remained connected to apical ramets treated with glyphosate. This result was interpreted as a cost for basal ramets due to supporting severely stressed apical ramets. Therefore, local application of glyphosate to apical ramets of C. edulis can negatively affect not only their own growth, but also the growth of their interconnected, untreated basal ramets. Our results suggest that glyphosate effectiveness can be maintained when applied only to one part of the clone so that the amount of herbicide used in eradication programs can be greatly reduced, which can minimize the negative impact of chemical herbicides on ecosystems.

Impact of glyphosate applied preharvest on oat kernel quality

AbstractBackground and objectivesPreharvest glyphosate is applied to oats for weed control and as a desiccant. The effect of glyphosate applied at various stages of oat physiological maturity on oat end product quality has not been reported previously. In this study, the effects of glyphosate application at two separate stages of physiological maturity on oat groat quality and rolled oats quality were determined.FindingsOat was grown at two locations. Glyphosate was applied at the soft dough, physiological maturity stages, or not applied. Effect of preharvest glyphosate application at the oat soft dough stage on groat hardness, groat percentage (0.7%–3.7% decrease by cultivar), and percent plump groats (0.3%–6.1% decrease by cultivar), when compared to untreated oats, was noticeable. However, glyphosate applied at physiological maturity (manufacturer's recommendation) did not detrimentally affect groat starch (average 60.3%) or end product quality.ConclusionsTherefore, from an end‐user perspective, applying glyphosate preharvest at oat physiological maturity does not impact oat quality.Significance and noveltyGlyphosate when applied preharvest to oats can control weed and facilitate harvest, a boon to farmers. Final oat quality, a decisive factor for commercial processor use, was not detrimentally affected when glyphosate was applied at oat physiological maturity.

Development of RR soybean in function of glyphosate doses and Bradyrhizobium inoculation

ABSTRACT Soybean has traditionally been produced in systems that include the use of herbicides, often in higher than recommended doses. The process of symbiotic nitrogen fixation in legumes can be hampered by these herbicides, both by direct effects on rhizobia and indirect effects on the host plant. An outdoor experiment was performed to evaluate the effects of different doses of a glyphosate herbicide on Bradyrhizobium strains and biological nitrogen fixation in soybean BMX Potência RR plants. Soybean seeds were inoculated with Bradyrhizobium elkanii (SEMIA 5019) and Bradyrhizobium japonicum (SEMIA 5079) strains in a commercial liquid inoculant. The treatments consisted of the absence and presence of Bradyrhizobium genotypes inoculated via seed and four doses of the herbicide glyphosate applied on the leaves (0, 1.0, 2.0, and 4.0 L ha-1 of the commercial product) at the V3 stage. The leaf chlorophyll index of inoculated RR soybean plants did not change on the application of glyphosate and, regardless of inoculation, plants had the capacity to recover from the effects of glyphosate application, without impaired development.

Impact of Glyphosate on the Rhizosphere Microbial Communities of An EPSPS-Transgenic Soybean Line ZUTS31 by Metagenome Sequencing.

Background:The worldwide use of glyphosate has dramatically increased, but also has been raising concern over its impact on mineral nutrition, plant pathogen, and soil microbiota. To date, the bulk of previous studies still have shown different results on the effect of glyphosate application on soil rhizosphere microbial communities.Objective:This study aimed to clarify whether glyphosate has impact on nitrogen-fixation, pathogen or disease suppression, and rhizosphere microbial community of a soybean EPSPS-transgenic line ZUTS31 in one growth season.Method:Comparative analysis of the soil rhizosphere microbial communities was performed by 16S rRNA gene amplicons sequencing and shotgun metagenome sequencing analysis between the soybean line ZUTS31 foliar sprayed with diluted glyphosate solution and those sprayed with water only in seed-filling stage.Results:There were no significant differences of alpha diversity but with small and insignificant difference of beta diversity of soybean rhizosphere bacteria after glyphosate treatment. The significantly enriched Gene Ontology (GO) terms were cellular, metabolic, and single-organism of biological process together with binding, catalytic activity of molecular function. The hits and gene abundances of some functional genes being involved in Plant Growth-Promoting Traits (PGPT), especially most of nitrogen fixation genes, significantly decreased in the rhizosphere after glyphosate treatment.Conclusion:Our present study indicated that the formulation of glyphosate-isopropylamine salt did not significantly affect the alpha and beta diversity of the rhizobacterial community of the soybean line ZUTS31, whereas it significantly influenced some functional genes involved in PGPT in the rhizosphere during the single growth season.

Effects of glyphosate application and nitrogen fertilization on the soil and the consequences on aboveground and belowground interactions

The application of nitrogen (N) and herbicides are commonly used to fertilize crops and protect them against weed development, but are also considered as soil and environment pollutants. Even so, the individual and combined non-target effects of N fertilizers and herbicides on multitrophic interactions within agrosystems are not well known. From soil samples collected in the field, we examined the effects of the direct application of glyphosate and/or N fertilization on microbial activities and soil nutrient status. In addition, we investigated the increase in biomass and, nutrient acquisition of the bean (Phaseolus vulgaris) and the consequences of the applications of N and glyphosate on the performance of the herbivore aphid (Aphis fabae). From soils that did (N+) or did not receive (N0) synthetic N fertilization over a 6-year period, we assessed the effects of glyphosate (CK, without glyphosate; FR, field rate of glyphosate) and N fertilization (N+, with N fertilization; N0, without N fertilization) applications in a mesocosm experiment for 75-days. Following the 75 day treatment, the biological and physiological consequences, both belowground and aboveground were determined. The growth of arbuscular mycorrhizal fungi (AMF) and dehydrogenase activity, were negatively affected following N+ fertilization and the application of the FR of glyphosate, while in the absence of glyphosate, alkaline phosphatase (AIP) activity was reduced. Functional microbial responses were unaffected by both N and glyphosate, even when applied in combination. Conversely, the N fertilization significantly increased the nitrate content (NO3−) in the CK soils and the total N in the FR soils, compared to CK/N0 and FR/N0 soils. The combined effects of glyphosate and nitrogen fertilization (FR/N+) significantly decreased the soil C:N ratio, but significantly increased nitrification compared to CK/N0 and FR/N0 soils. The FR/N+ treatments positively affected plant performance, improving the total chlorophyll, sucrose, ammonium, amino acid content, and pod biomass, compared to the CK/N0 and FR/N0 soils. Unlike glyphosate, which did not appear to exert an effect when applied alone or in combination, N fertilization significantly increased aphid nymph survival. The non-metric multidimensional scale allowed us to establish belowground and aboveground interactions with glyphosate and N fertilization. We conclude that glyphosate and N fertilization have negative effects on soil microflora and potential pests, but do not necessarily affect belowground and aboveground interactions, and may offer equal or superior benefits to crop productivity.

Glyphosate impacts on polyphenolic composition in grapevine (Vitis vinifera L.) berries and wine

Glyphosate is the most widespread herbicide for weed management, being extensively used in viticulture. In this study we tested, under field conditions, the effects of glyphosate applications on the quality of berry and wine, from cv. Ancellotta (Vitis vinifera L.), with particular regard to anthocyanin concentration and composition. Ripening and growth were monitored by analyzing berry technological parameters and weight. Additionally, microvinifications were performed, in order to analyze the concentration of anthocyanins, other flavonoids and phenolic acids in wine. Our findings indicated that, at harvest, both pH and anthocyanin concentration were significantly lower and titratable acidity higher in berries collected from vines of plots under glyphosate-treatment compared with those of non-treated parcels. Data suggest that treatment with glyphosate did not change the concentration of anthocyanins, other flavonoids and phenolic acids in the wine. Our results indicate that treatment with glyphosate may affect fruit metabolism and nutritional value in non-target plants.

Effect of Glyphosate Application on Sudden Death Syndrome of Glyphosate-Resistant Soybean Under Field Conditions.

Sudden death syndrome (SDS), caused by Fusarium virguliforme, is an important yield limiting disease of soybean. Glyphosate is used to control weeds in soybean; however, its effect on SDS is not clearly understood. The objective of this study was to examine the impact of glyphosate on SDS, yield, and plant nutrition under field conditions. Fourteen field experiments were conducted in Iowa, Illinois, Indiana, Michigan, Wisconsin, and Ontario, Canada during 2011 to 2013. The experiment consisted of six treatment combinations of glyphosate and herbicides not containing glyphosate. Disease index was significantly different across the location-years, ranging from 0 to 65. The highest disease was noted in locations with irrigation, indicating that high soil moisture favors development of SDS. There were no effects of herbicide treatments or interactions on disease. The foliar disease index among the treatments over all years ranged from 9 to 13. Glyphosate-treatments also tended to yield more than treatments of herbicides not containing glyphosate. There were no interactions between glyphosate-treatments and total manganese in plant tissue. The interaction of glyphosate with other nutrients in plant tissue was inconclusive. This 14 location-year study demonstrated that glyphosate application did not increase SDS severity or adversely affect soybean yield under field conditions.

The effect of glyphosate application on soil microbial activities in agricultural land

In recent years, intensive use of herbicides has increasingly become a matter of environmental concern partially because of the effects of these chemicals on soil microorganisms. Glyphosate [N- (phosphonomethyl) glycine] (GP) is a broad-spectrum, non-selective, post emergence herbicide that is widely used in agriculture. In this study, glyphosate effects as N, P and C nutrient sources on microbial population and the effect of different concentration of it on dehydrogenease activity and soil respiration were investigated. The results show that in a soil with a long historical use of glyphosate (soil 1), the hetrotrophic bacterial population was significantly (p<0.05) increased. Also, by increase in the bacterial population, the herbicide existence as the possible nutrient source is enhanced. According to results, bacterial populations in the presence of glyphosate as P source was significantly (p<0.01) higher than N and C sources. The application of GP to the soil led to a significant increase in dehydrogenase activity with respect to untreated control soil samples. Also, respiration rates increased with increasing glyphosate application up to 50 mM but in 500 mM the inhibitory effect of glyphosate was observed. It can be concluded that glyphosate application may alter (increase) soil microbial activity and population. Increased microbial activity may be beneficial or detrimental toward plant growth, soil microbial ecology, and soil quality. Key words : Glyphosate, bacterial population, dehydrogenease activity, soil respiration.

Elevated antioxidant response and induction of tau-class glutathione S-transferase after glyphosate treatment in Vigna radiata (L.) Wilczek

Glyphosate (N-(phosphonomethyl) glycine) is a broad-spectrum herbicide, acting on the shikimic acid pathway inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), thus obstructing the synthesis of tryptophan, phenylalanine, tyrosine and other secondary products. It has also been reported to generate oxidative stress which influences the antioxidant response of target plants. The effect of glyphosate application on total protein, CAT, POD and GST activities was investigated and elevated expression of the oxidative stress enzymes was obtained after glyphosate treatment. Tau-class GSTs are plant-specific, and are chiefly involved in xenobiotics and oxidative stress metabolisms. Many herbicides and safeners have been known to selectively induce tau-class GSTs in different plant species. Here we also report the induction of tau-class GSTs after glyphosate treatment in the seedling roots of two Vigna radiata varieties (PDM11 and PDM54). GSH-agarose affinity chromatography and mass spectrometry revealed that the tau-class GSTs induced in the two varieties were different; the tau-class GSTs present in the untreated controls were also different in the two varieties. The present study highlights the elevated antioxidant response, the induction of tau-class GST and the genotypic variation in the type of tau-GST in control and glyphosate treated varieties of V. radiata.

Glyphosate Tolerance in Enhanced Glyphosate-Resistant Cotton (Gossypium hirsutum)

Glyphosate applied to glyphosate-resistant (RR) cotton varieties after the four-leaf stage can decrease boll retention resulting in severe yield reductions. Enhanced glyphosate-resistant cotton (RR Flex), released for commercial use in 2006, offers a wider window of glyphosate applications without the risk of yield loss. However, no data exist regarding the effect of glyphosate application, especially late season applications, on fruit partitioning in RR Flex cotton. The objective of this research was to determine the effect of glyphosate rate and application timing on RR Flex cotton yield and fruit partitioning compared with current RR cotton. Studies were conducted during a 3-yr period (2004 to 2006), throughout the cotton growing regions of Mississippi. Roundup Ready (ST 4892 Bollgard/Roundup Ready [BR]) and Roundup Ready Flex (Mon 171 Enhanced Roundup Ready and ST 4554 Bollgard II/Roundup Ready Flex [B2RF]) cotton was planted, and glyphosate was applied at various rates and cotton growth stages. Data were collected using box mapping, a technique designed to depict yield partitioning on a cotton plant. RR Flex cotton yields were unaffected by glyphosate application timing or rate. Yields for ST 4892 BR were affected by application timings after the sixth leaf. ST 4892 BR had increased yield partitioning to position-three bolls and upper nodes with later application timings of glyphosate. Increases in seed cotton partitioned to higher nodes and outer fruiting positions were unable to compensate for fruit shed from innermost, lower fruiting sites. These data indicate that RR Flex cotton has excellent tolerance to late-season glyphosate applications.

Effects of Glyphosate Application on Seed Iron and Root Ferric (III) Reductase in Soybean Cultivars

Previous research demonstrated that plant nutrient assimilation was reduced by glyphosate (Gly). A 2 year field experiment investigated the effects of Gly at drift rate (12.5% of commercial use rate) on Fe concentrations in leaves and seeds of Gly-sensitive (GS) soybean, and a greenhouse experiment evaluated Gly effects on Fe assimilation using root in vivo ferric reductase activity (FRA) in two GS and one Gly-resistant (GR) soybean cultivars. Field studies showed that Gly drift rates resulted in a significant decrease in the Fe concentration in seeds and leaves compared to the nontreated plants. In greenhouse studies, leaf Fe and FRA were inhibited in GS cultivars Hutcheson and DP 5110 and the GR cultivar AG 4604RR and leaf Fe was positively correlated with root FRA (p < 0.0001). These results indicate that Gly can interfere with Fe assimilation in both GS and GR soybean. Understanding the implication of Gly on Fe nutrition in soybean seed would help soybean agronomists and breeders seeking to improve seed mineral nutrition qualities.

Biochemical responses of glyphosate resistant and susceptible soybean plants exposed to glyphosate

Glyphosate is a wide spectrum, non-selective, post-emergence herbicide. It acts on the shikimic acid pathway inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), thus obstructing the synthesis of tryptophan, phenylalanine, tyrosine and other secondary products, leading to plant death. Transgenic glyphosate-resistant (GR) soybean [Glycine max (L.)] expressing an glyphosate-insensitive EPSPS enzyme has provided new opportunities for weed control in soybean production. The effect of glyphosate application on chlorophyll level, lipid peroxidation, catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GOPX) and superoxide dismutase (SOD) activities, soluble amino acid levels and protein profile, in leaves and roots, was examined in two conventional (non-GR) and two transgenic (GR) soybean. Glyphosate treatment had no significant impact on lipid peroxidation, whilst the chlorophyll content decreased in only one non-GR cultivar. However, there was a significant increase in the levels of soluble amino acid in roots and leaves, more so in non-GR than in GR soybean cultivars. Root CAT activity increased in non-GR cultivars and was not altered in GR cultivars. In leaves, CAT activity was inhibited in one non-GR and one GR cultivar. GOPX activity increased in one GR cultivar and in both non-GR cultivars. Root APX activity increased in one GR cultivar. The soluble protein profiles as assessed by 1-D gel electrophoresis of selected non-GR and GR soybean lines were unaffected by glyphosate treatment. Neither was formation of new isoenzymes of SOD and CAT observed when these lines were treated by glyphosate. The slight oxidative stress generated by glyphosate has no relevance to plant mortality. The potential antioxidant action of soluble amino acids may be responsible for the lack of lipid peroxidation observed. CAT activity in the roots and soluble amino acids in the leaves can be used as indicators of glyphosate resistance.

Effect of Glyphosate Application on Hagberg Falling Number of Wheat

ABSTRACTA study was conducted to investigate management of Hagberg Falling Number (HFN) by creating more homogenous wheat through glyphosate applications at soft and hard dough stages individually, without compromising wheat quality. The effect of the treatments varied over cultivars and seasons. Thousand kernel mass (2003/04), hectolitre mass (2003/04 and 2004/05), and protein content (2003/04 and 2004/05) were negatively affected by soft dough stage treatments for all three cultivars included in the study. Days to harvest and growing degree days were significantly reduced with the soft dough treatment. Yield and preharvest sprouting were not affected. α‐Amylase activity varied over season, cultivar, and treatment. HFN measured for Tugela‐DN treated at soft dough stage produced a significantly higher HFN compared with the control (2004/05). None of the other cultivars at the various treatments indicated any HFN response to glyphosate application. Germination was severely affected by soft dough stage glyphosate application in the first year of evaluation. Studies into the effect of the various treatments on the repeatability of the HFN test, indicated that glyphosate treatment managed to produce a certain amount of stability for two of the three cultivars, but the treatment that resulted in the stability varied between seasons.

Weed density and diversity under glyphosate-resistant crop sequences

The effect of regular and exclusive application of glyphosate in crop sequences on associated weed composition, richness and diversity was studied over five years. Three sequences (wheat–soybean, soybean monoculture and soybean–maize) including soybean and maize glyphosate-resistant cultivars were investigated under two tillage systems (conventional or no-tillage). Regardless of sequence and tillage system, regular glyphosate application appeared to reduce richness and density of the most competitive weeds such as early-emergence annual broad-leaved and grassy annuals and increase that of the less competitive late-emerging annual broad-leaved weeds in no-tillage systems. Some late-emerging annual broad-leaved species, e.g. Bowlesia incana Ruiz et Pav. were present from the beginning of the experiment and others species, e.g. Parietaria debilis G. Foster were not present before initiating the study. This species was the only tolerant to glyphosate at the recommended dose of the herbicide. Species richness in pre-glyphosate application counts showed no response in the wheat–soybean rotation but decreased in the soybean–maize rotation and soybean monoculture in both tillage systems. In post-glyphosate application counts, richness increased for all sequences. Diversity showed an inconsistent response with time. It can be concluded that the effect of glyphosate application was a more important factor than crop sequence to explain weed community changes in summer crops. It may be predicted that continual glyphosate application for longer periods of time might lead to the development or higher increases in abundance of weeds tolerant to the herbicide.

SOBRE-SEMEADURA DE FORRAGEIRAS HIBERNAIS EM PASTAGEM DEGRADADA DE PENSACOLA COM DOSES DE GLIFOSATO

O presente trabalho foi conduzido na Fazenda Capão Redondo, situada no município de Candói - PR. Foi realizado nos anos agrícolas de 2000 e 2001, com o objetivo de avaliar a participação das forrageiras sobre-semeadas em pastagem degradada de pensacola, submetida à aplicação de glifosato, bem como o efeito desta aplicação no restabelecimento e na composição botânica da pastagem de pensacola. O delineamento experimental foi o de blocos ao acaso com seis tratamentos e duas repetições. Foram sobresemeados azevém, trevo branco, trevo vermelho e cornichão, após dessecação da pastagem de pensacola com doses de glifosato (T2=zero; T3=0,5; T4=0,75; T5=1,0; T6=1,25 L.ha-1). A testemunha (T1) não recebeu herbicida, nem sobre-semeadura e adubo. Para a estimativa da participação de cada espécie na matéria seca disponível (MSd), foi utilizada a metodologia Botanal em quatro avaliações (08/12/00; 09/02/01; 06/06/01; 20/12/01). Observou-se que no tratamento sem herbicida houve excelente estabelecimento das forrageiras hibernais na época fria e restabelecimento da pensacola no verão. Concluiu-se que, nas condições em que este trabalho foi desenvolvido, não foi necessária a aplicação de glifosato para o estabelecimento das espécies em sobre-semeadura. A sobre-semeadura de espécies hibernais em pastagem naturalizada, com e sem a aplicação do herbicida glifosato, melhorou a qualidade da composição botânica da matéria seca disponível, mas influenciou negativamente a participação da pensacola no campo naturalizado. Observou-se também, que esta prática foi responsável pelo decréscimo das espécies naturais do campo, um ano após a sobre-semeadura. As diferentes dosagens de glifosato não influenciaram a participação das espécies sobre-semeadas, excetuando-se o trevo vermelho e o trevo branco, 8 meses e 18 meses após a sobre-semeadura, respectivamente. A pensacola sempre permaneceu inversamente proporcional à participação da espécies sobre-semeadas.

Glyphosate application and timing of tillage of red clover affects potato response to N, soil N profile, and root and soil nematodes

The effects of glyphosate application and time of tillage of red clover on soil NO3-N profiles, the response of the subsequent potato crop to varying rates of N fertilizer application, and root and soil nematodes, were evaluated. The study was conducted over three cropping seasons on a Charlottetown fine sandy loam on Prince Edward Island. Red clover was moldboard ploughed in mid-September (early fall), or moldboard or chisel ploughed in mid-October (late fall), or moldboard ploughed in the spring. Glyphosate was applied in early fall and the dead clover was moldboard or chisel ploughed in mid-October or left undisturbed until spring. A barley control, where barley was harvested and straw incorporated with a tandem disc harrow in early September, was included. Potato were planted with 6 rates of N (0 to 250 kg ha–1 in 50-kg increments) band applied at planting. The barley control treatment produced lower potato yield without fertilizer N in all 3 yr of the study compared to red clover treatments, but potato yields were similar at high rates of applied N. Potato tuber yields after spring moldboard ploughing of red clover were higher at low N rates and lower at high N rates than yields after late fall treatment in one year of the study. Concentrations of nitrate-N in the soil in mid-November were highest following the early fall moldboard ploughing and lowest in the undisturbed clover plots. Fall soil nitrate-N levels were intermediate following the glyphosate application and late fall tillages. Early spring soil nitrate-N levels in the surface 30 cm were generally highest with the spring and late fall tillage and lowest with the early fall tillage. Levels of nitrate-N in potato petioles increased with increased rates of N application and generally increased as tillage of the red clover was delayed from early fall to late fall to spring. In general, cultivation and the application of glyphosate did not affect soil and root nematode populations. In two instances, the moldboard plough tillage treatments were associated with higher levels of the clover-cyst nematode, Heterodera trifolii. One of the tillage treatments was combined with glyphosate, but this was the only case where the herbicide had an impact on nematodes. To maximize the benefits to the subsequent potato crop and to minimize leaching of nitrate, incorporation of legume residue should be delayed until the rate of mineralization and nitrification of the legume N is minimized. It is suggested that incorporation of red clover be delayed until after mid-October for clover–potato systems on PEI. Key words: Glyphosate, nematodes, nitrate leaching, petiole nitrate-N, potato, soil nitrate-N, tillage time

Plantation establishment success of pinus contorta dougl. ex loud, and larix sibirica (Munchh.) Ledeb. using various methods and stock

Comparison of seedling survival, by types of stock of lodgepole pine (Pinus contorta Dougl. ex Loud.) and Siberian larch (Larix sibirica (Munchh.) Ledeb.), was made on mineral soils at four locations in Iceland. Planting tools and site preparation were also tested. After three growing seasons, variations in survival by locations were greater for Siberian larch (0–81 %) than for lodgepole pine (34–65 %). Large variations in survival were observed by types of stock and site preparation. The influence of planting tools was of minor significance. Container stock and transplants of lodgepole pine and Siberian larch, respectively, generally had the greatest survival. In general, site preparation had negative effects on lodgepole pine and positive effects on Siberian larch. The results imply, furthermore, that effects of glyphosate application on lodgepole pine are site specific. In conclusion, for given sites and species, a proper choice of stock and site preparation may greatly improve afforestation success in...