Germination Of Grasses Research Articles

Evaluation of Germination and Early Seedling Growth of Different Grasses Irrigated with Treated Mine Water

Coal mining is known to have negative impacts on the environment, necessitating land rehabilitation after mining activities. Amongst the problems associated with coal mining is the accumulation of acid mine drainage characterized by large amounts of heavy metals and high acidity. The impact of these environmental problems on the ecosystem around mining areas underscores a need to devise strategies that will ensure sustainable restoration of the ecosystem integrity to ensure environmental protection. Of these, treatment of acid mine drainage using calcium sulfate dihydrate, which is subsequently used for irrigation during phytoremediation, holds great promise for restoration of open-cast mines. However, although grasses are used for rehabilitation of coal mined areas, the impacts of treated mine water on the germination, seedling emergence, and plant growth of grasses are not well known. The aim of the study was to evaluate the germination and early seedling growth responses of different forage grasses to treated mine water. Seven forage grass species were selected, with four species represented by two varieties while others were represented by one variety, totaling 11 forage grasses. For each plant entry, 100 seeds were placed in J.R. Petri’s dishes lined with Whatman No. 2 filter paper and watered with distilled and mine water to assess germination. For the seedling establishment experiment, only five species were studied, in which twenty seeds per species were sown in pots containing mine soil and irrigated using distilled and treated mine water. The final germination percentage (FGP), germination rate index (GRI), corrected germination rate index (CGRI), and T50 were determined for the germination trail and total biomass was assessed for the seedling growth trail. The highest FGP for all grasses was attained under controlled conditions, using distilled water, ranging from 38–94%. All grasses germinated when watered using treated mine water and had a FGP ranging from 20–91%. Relative to distilled water, GRI and CGRI were highest only for L. multiflorum cv AgriBoost when seeds were watered using the treated mine water. All grasses watered with treated mine water produced high biomass for the first two weeks, after which biomass production started to decline. Two grasses, Eragrostis curvula cv Ermelo and Lolium multiflorum cv Archie, showed tolerance to treated mine water irrespective of its high electrical conductivity (557 mS∙m−1). Therefore, these grasses could be used in the rehabilitation of coal-mined areas irrigated with treated mine water.

The effect of bubbling on the germination of Sudan grass seeds

In the article the results of experiments to study the effect of bubbling on the germination of Sudan grass seeds before and after cryopreservation were presented. The obtained statistical data were processed using the R-studio program. We calculated the indicators of humidity and germination energy of Sudan grass seeds, and determined the statistically reliable significance between the control and experimental varieties. To conduct the experiment, a bubbler installation was created from a cylindrical container filled with water and a bubbler to supply oxygen. The results of pre-sowing seed treatment were obtained for 4 varieties of Sudan grass: Nika, Tugai, Alina, Novosibirskaya 84. Bubbling increases seed germination compared to the control by 13 % for the Nika variety, by 7 % for the Novosibirskaya 84 variety. While bubbling after cryopreservation significantly reduces the germination of seeds in the Tugai variety by 25 %, in the Alina variety by 32 %, in the Novosibirskaya 84 variety by 33 %, and in the Nika variety by 7 %. Thus, bubbling, in general, had a positive effect on the germination of Sudan grass seeds and may be one of the methods of pre-sowing seed treatment. As a recommendation for improving the germination of Sudan grass seeds, we suggest using bubbling without cryopreservation.

Influence of Neltuma flexuosa and rainfall event on the germination of Leptochloa crinita and Pappophorum caespitosum in two different locations along a stress gradient in the central Monte desert

AbstractIn drylands, grass germination occurs after a large rainfall event. However, trees influence the water requirements for germination either by decreasing the rate of evaporation from soil surface or by interception rainfall with their canopy. The aim of this work was to evaluate the role of Neltuma flexuosa tree on the germination of Leptochloa crinita and Pappophorum caespitosum grasses in response to precipitation events of different sizes. The experiment was conducted in two locations within the Monte desert, Argentina: a semi‐arid location with an average annual precipitation of 345 mm and an arid location with an average annual precipitation of 156 mm. Six microsites were established under N. flexuosa canopies and six microsites in open areas at both locations. Within each microsite, 35 seeds of each grass species were exposed to precipitation events of varying sizes. This procedure was repeated 14 times across two growing seasons. Germinated seeds were counted in the laboratory. Generalized linear mixed models were then applied to evaluate the effects of accumulated precipitation and the microsite on the grass germination in both locations. Results showed that N. flexuosa did not influence the germination of either grass species in the arid location. However, in the semi‐arid location, N. flexuosa facilitated the germination of P. caespitosum only. Large precipitation events would act as an environmental signal for these perennial grasses, allowing them to germinate in favorable years regardless of the microsite or the location.

Effects of neighbor shrub propagules and soils from shrubby patches on perennial grass germination in arid rangelands of the Patagonia Monte, Argentina

AbstractQuestionDo shrubs negatively affect the germination of perennial grass species in regeneration microsites? We experimentally analyzed the effect of soils from plant patches dominated by two shrub species (Larrea divaricata and Schinus johnstonii) and their propagules on the germination of three co‐dominant herbivore‐preferred perennial grass species (Poa ligularis, Nassella tenuis and Pappostipa speciosa).LocationPatagonian Monte, Chubut Province, Argentina (42°07′ S, 64°59′ W; 43°06′ S, 65°43′ W; 42°29′ S, 66°34′ W).MethodsWe conducted two simultaneous microcosm experiments. In the first experiment, we sowed perennial grass propagules of the three species alone and combined with non‐scarified shrub propagules in Petri dishes with three substrate types (filter paper, inert soil and soil from shrub patches). In the second experiment, we sowed perennial grass propagules of each species combined with scarified and non‐scarified propagules of both shrub species in Petri dishes with soil taken from plant patches dominated by L. divaricata and by S. johnstonii. Both experiments lasted 3 months. We calculated the germination proportion and mean germination time (MGT) of propagules for each perennial grass species in each treatment.ResultsPropagules from neighboring shrubs had a clearer negative effect on grass germination compared with shrub soils. Shrub propagules negatively affected the germination proportion of P. ligularis and N. tenuis, and induced longer MGT in the three perennial grass species. The combination of S. johnstonii soil and propagules negatively affected P. ligularis and P. speciosa germination. The combination of L. divaricata soil and scarified propagules completely inhibited P. speciosa germination.ConclusionsOur results highlighted the complexity of interactions between shrubs with high phenolic contents (soils and propagules) and the germination of perennial grass species in arid environments. Schinus johnstonii soil and propagules had stronger effects on perennial grass germination than L. divaricata soil and propagules. The negative effects of shrubs on microsite quality and germination processes depended on the specific shrub/grass interaction.

Eastern redcedar roots create legacy effects that suppresses growth of prairie species.

The expansion of woody species from their historical ranges into grasslands is a global problem. Understanding the mechanisms that enable species to successfully establish and then re-encroach following their removal is critical to effectively managing problem species. Legacy effects are a mechanism that could be critical to the reestablishment of woody encroachers following their removal. Legacy effects occur when a species alters the biotic and abiotic environment in a way that affects communities that establish subsequently. In this study, we assess whether the eastern redcedar (Juniperus virginiana), a North American woody encroacher, generates legacy effects that affect communities that establish following removal of this species from an experimental grass community. We conducted a series of experiments to evaluate the effects of J. virginiana, roots on the germination and growth of grasses and to determine if the effects of root-addition treatments were derived from a microbial or allelopathic origin. Aqueous extracts of J. virginiana roots were found to inhibit the germination of grasses. We found escalating suppression of overall community biomass and the biomass of each individual species with increasing root treatments. Finally, we determined the origin of the observed suppressive effect is unlikely to be of microbial origin. Synthesis: Our results suggest that J. virginiana exudes an allelochemical into soils that inhibits the growth of certain grasses and thus has the potential to have legacy effects on future occupants. We suggest that the inhibition of the development of grasses in areas where J. virginiana has been removed is a mechanism that may favor the reestablishment of J. virginiana. Our results indicate the legacy effects of J. virginiana must be considered when conducting removal and restoration of J. virginiana infested lands.

Fertilization of Annual Grasses on Gray Forest Soils of the Vladimir Opole

In a long-term stationary experiment, the effect of fertilizers on the yield of annual grasses (vetch and pea mixtures) and the nitrifying activity of gray forest soils were studied. For 8 years, both without the use of fertilizers and with them, the yield of herbs changed by 1.72–1.88 times. It was found that the use of nitrogen of mineral fertilizers provided 88.3% of the total variation in their yield, the aftereffect of manure – 8.1, the aftereffect of РК fertilizers – 1.8%. For 7 out of 8 years, a high degree of correlation between the yield of grasses and the reserves of N-NO3 in the 0–40 cm layer of soil in the phase of grass germination was revealed. At the same time, the minimum reserves of N-NO3 were formed at a hydrothermal coefficient for the growing season equal to 1.21. The use of fertilizers, increased moisture content and temperatures during the growing season of grasses led to an increase in the nitrification activity of gray forest soil. It is proposed to evaluate the participation of mobile forms of nitrogen in plant nutrition in relation to the content of N-NO3 in the soil to the content of N-NH4 in the water extract (1 : 1). The values of this parameter in the phases of germination and harvesting of grasses confirmed the determining role of N-NO3 reserves in the nutrition of annual grasses. The difference coefficients of the use of nitrogen Naa in doses N60 and N75, which ranged from 40 to 49%, were calculated. An algorithm for calculating the size of the accumulation of N-NO3 during the growing season of grasses is proposed. In nitrogen-fertilized variants, a good coincidence of the utilization coefficients of accumulating N-NO3 reserves with the difference ones has been established.

Effect of sowing depth and soil cover on Paspalum virgatum L. seedling emergence

Paspalum virgatum L. is a grass weed common in pasture and has difficult control, mainly due to its similarity to forage, is found in areas of degraded pastures in the state of Mato Grosso. The objective of this work was to evaluate seed germination and seedling emergence of razor-blade grass (P. virgatum L.) when exposed to different sowing depths. Two independent experiments were carried out, one using straw from Brachiaria brizantha cv. Marandu (Experiment I) and another from Panicum maximum cv. Mombasa (Experiment II). The treatments for both experiments were organized in a 7x2 factorial scheme, considering seven depth levels (0, 1, 2, 3, 4, 5, and 10 cm). The bottom of the pots was sealed with filter paper and gauze. The emergence of seedlings was recorded daily until 28 days after sowing. The data obtained were submitted to analysis of variance. For experiment I, there was a significant effect on the soil cover factor in relation to %E and IVE, where the use of straw was more efficient. For experiment II, there was no effect of the soil cover factor in relation to %E and IVE. The greater the depth, the lower the emergence of razor-blade grass seedlings.

Allelopathic effects of tamarind husk, lemongrass and citronella residues to suppress emergence and early growth of some weeds

The allelopathic effects were evaluated of water extracts from tamarind (Tamarindus indica L.) husk and from lemongrass (Cymbopogon citratus Stapf.) or citronella (Cymbopogon nardus Rendle.) leaves on 2 test plants: ruzi grass (Brachiaria ruziziensis Germ. & C.M. Evrard) and popping pod (Ruellia tuberosa L.). In the laboratory, the seeds were subjected to the different extracts at concentrations of 0, 1.25, 2.5, 5 and 10 % (w/v). The number of germinated seeds was counted daily for 6 days. The shoot/root length was measured 5 days after sowing (DAS). The results showed that the aqueous extract of tamarind husk did not inhibit the germination of either ruzi grass or popping pod. The lemongrass and citronella extracts had higher inhibition effects at high concentrations and clearly delayed seed germination at 10 % (w/v). With the seedling growth bioassays of the 3 extracts, only the citronella extract at the highest concentration had any effect on the shoot/root lengths of ruzi grass. Popping pod was susceptible to all 3 extracts, especially the popping pod roots treated with lemongrass and citronella extracts. The lemongrass and citronella extracts caused cell death and induced lipid peroxidation in both plants. Therefore, the primary action of these extracts on seedling growth inhibition might have been related to the loss of cell viability and triggering lipid peroxidation in affected tissues. The residue incorporation bioassay determined the effects of residue mixed in soil at concentrations of 0, 2.5, 5 and 10 % (w/w) on the growth of ruzi grass and popping pod at 30 DAS. Both plants showed an adverse effect than for the control, based on reduced leaf numbers and greater chlorosis, especially with soil incorporation of the lemongrass and citronella residues at 10 % (w/w). Mixing soil with lemongrass and citronella leaves at 2.5 % (w/w) and above resulted in reductions in the shoot/root lengths and shoot/root biomass values. Catechin, gentisic acid, syringic acids, p-coumaric acid and ferulic acid were the dominant allelochemicals found in the lemongrass and citronella residues.

Evidence of plant-soil feedback in South Texas grasslands associated with invasive Guinea grass

Plant-soil feedback (PSF) processes play an integral role in structuring plant communities. In native grasslands, PSF has a largely negative or stabilizing effect on plant growth contributing to species coexistence and succession, but perturbations to a system can alter PSF, leading to long-term changes. Through changes to soil abiotic and biotic properties, invasion by non-native plants has a strong impact on belowground processes with broad shifts in historical PSFs. Guinea grass, Megathyrsus maximus, an emerging invasive in South Texas, can efficiently exclude native plants in part due to its fast growth rate and high biomass accumulation, but its impacts on belowground processes are unknown. Here, we provide a first look at PSF processes in South Texas savannas currently undergoing invasion by Guinea grass. In this pilot study, we addressed the question of how the presence of the invasive M. maximus may alter PSF compared to uninvaded grasslands. Under greenhouse conditions, we assessed germination and growth of Guinea grass and the seed bank in soil collected from grasslands invaded and uninvaded by Guinea grass. We found that Guinea grass grown in soil from invaded grasslands grew taller and accumulated higher biomass than in soil from uninvaded grasslands. Plants grown from the seed bank were more species rich and abundant in soil from uninvaded grasslands but had higher biomass in soil from invaded grasslands. In South Texas savannas, we found evidence to support shifts in the direction of PSF processes in the presence of Guinea grass with positive feedback processes appearing to reinforce invasion and negative feedback processes possibly contributing to species coexistence in uninvaded grasslands. Future work is needed to determine the mechanisms behind the observed shifts in PSF and further explore the role PSF has in Guinea grass invasion.

A Preliminary Assessment of Utilizing Solid Waste Fractions as an Agricultural Growth Medium in Arid Soils

The fast-paced and globalized industrial/population growth has generated a vast consumerism-based culture, resulting in the rapid increase in municipal solid waste generation. Considering the case of Kuwait, the collection and disposal of waste has become a major economic and health issue for both the general public and the Kuwaiti government. Addressing and improving current waste disposal challenges, through utilizing (or recovering) basic materials from waste, will benefit society in terms of reductions in costs, pollution and associated negative health impact. The objective of this study was to assess the re-utilization prospects of waste materials (paper, cardboard and cotton) as a substrate for plant growth, consequently serving as a growing medium material, apart from naturally occurring soil. This investigation was conducted across two land plots in the Wafra region, located in Southern Kuwait. The plots were planted with Rhanterium epapposum and Festuca rubra seeds. Temperature, humidity and growth rates were measured during this study. Study results indicated that chemical composition of the growth medium is suitable for local conditions. Furthermore, the soil plot with added growth medium was found to retain moisture for prolonged periods in comparison to the plot lacking in growth medium. Field studies on grass germination and growth rates highlighted that waste-derived substrate is favorable to their development and adaptation within challenging environmental conditions. This investigation can play an important part for introducing and developing the concept of a circular economy within Kuwait, with potential to improve waste management within the country.

Effect of water stress on weed germination, growth characteristics, and seed production: a global meta-analysis

AbstractWeeds compete with crops for soil moisture, along with other resources, which can impact the germination, growth, and seed production of weeds; however, this impact has not been systematically recorded and synthesized across diverse studies. To address this knowledge gap, a global meta-analysis was conducted using 1,196 paired observations from 86 published articles assessing the effect of water stress on weed germination, growth characteristics, and seed production. These studies were conducted and published during 1970 through 2020 across four continents (Asia, Australia, Europe, and North America). Imposed water stress was expressed as solution osmotic potential (ψsolution), soil water potential (ψsoil), or soil moisture as percent field capacity. Meta-analysis revealed that water stress inhibits weed germination, growth, and seed production, and the quantitative response intensified with increasing water stress. A ψsolutiongreater than −0.8 MPa completely inhibits germination of both grass and broadleaf weeds. A ψsolutionfrom −0.09 to −0.32 MPa reduces weed germination by 50% compared with the unstressed condition. Moderate soil water stress, equivalent to 30% to 60% field capacity, inhibits growth characteristics (branches or tillers per plant, leaf area, leaves per plant, plant height, root, and shoot biomass) by 33% and weed seed production by 50%. Severe soil water stress, below 30% field capacity, inhibits weed growth by 51% and seed production by 88%. Although water stress inhibits weed growth, it does not entirely suppress the ability to germinate, grow, and produce seeds, resulting in weed seedbank accumulation. This creates management challenges for producers, because weed seeds can survive in the soil for many years, depending on weed species and environmental conditions. Quantitative information compiled in this meta-analysis can be instrumental to model the weeds’ multidimensional responses to water stress and designing integrated weed management strategies for reducing the weed seedbank.

Germination and vigor of buffel grass seeds stored in environmental conditions

One of the main limitations for the cultivation of forages refers to seed dormancy, which can compromise the emergence of seedlings in the field and the establishment of pastures. Therefore, the objective was to evaluate the germination and vigor of buffel grass seeds cv. Aridus stored under environmental conditions. The experimental design used was completely randomized, with six evaluation periods (0, 6, 12, 18 and 24 months after harvest) and four replications. Right after the harvest, and at each evaluation period, the seeds were evaluated for water content, germination and vigor. The water content of the seeds did not differ. There were increases in the percentage of seed germination from the initial evaluation period up to 17.96 months, reaching an estimated maximum value of 62.74%. The buffel grass seeds showed progressive increases in seedling emergence and in the emergence speed index (IVE) evaluated over the storage time. It is recommended that pastures of buffel grass cv. Aridus are formed using seeds stored between 13.97 to 18.98 months under environmental conditions, as they present greater germination and vigor.

Postplanting Microclimate, Germination, and Emergence of Perennial Grasses in Wyoming Big Sagebrush Steppe

Several recent studies have hypothesized that postgermination/preemergence soil freezing can have a major negative impact on spring emergence of seeded perennial grasses in the Intermountain western United States. In this experiment, we measured germination and emergence of 4 fall-seeded perennial grasses at 15 sites in southeastern Oregon, north-central Nevada, and southwestern Idaho in 2 different yr. We used hydrothermal germination and seedbed microclimatic models to estimate planting date effects on germination and preemergence mortality and evaluated these simulations relative to measured germination and seedling emergence in the field. There were clear indications that both germination and emergence were responsive to site-year effects, but premature fall germination before winter freezing events was not a factor in emergence rates. In all cases, planting was sufficiently late in the fall to avoid significant postgermination/preemergence freezing injury for the sites and years tested. Emergence was weakly correlated to seedbed favorability in the late winter and spring after the principal period of soil freezing. Our data show that for the 2 yr of this study, we can only account for a relatively small portion of any abiotic effects on spring emergence. General inferences about planting date effects, however, may have been limited by arid conditions during the 2-yr field study relative to long-term climate normals.

Abandoned pastures and restored savannas have distinct patterns of plant–soil feedback and nutrient cycling compared with native Brazilian savannas

Abstract Around 40% of the original Brazilian savanna territory is occupied by pastures dominated by fast‐growing exotic C4 grasses, which impact ecosystem nutrient cycling. The restoration of these areas depends on the re‐establishment of soil processes. We assessed how restoration of abandoned pastures through direct seeding of native species and land‐management practices (burning and ploughing) affect soil nutrient cycling dynamics compared with native savannas. We compared the activity of soil enzymes related to carbon, nitrogen (N) and phosphorus (P) cycling as well as soil microbial biomass and soil chemical properties (pH and the concentration of N, P, potassium [K] and soil organic matter) among abandoned pastures, native savanna and restored areas. Abandoned pastures had faster nutrient turnover than native savanna, dominated by slow‐growing native species. This pattern was evident from the overall higher biomass‐specific enzyme activities in abandoned pastures than in native savanna. Compared with native savanna, restored areas had similar levels of soil enzyme activities, but lower microbial biomass and soil organic matter. The low enzyme activity in restored areas was likely related to a reduced soil organic carbon concentration due to practices such as burning and ploughing, rather than the restoration of plant–soil feedback. The lower immobilization of nutrients in microbial biomass and lower retention of nutrients in restored areas, compared with native savanna, is expected to favour the re‐establishment of fast‐growing exotic species. Synthesis and application. Despite reducing the resprouting and germination of exotic grasses and improving the establishment of native grasses in the short term, restoration practices have major impacts on the soil microbial community and soil fertility. The reduction of soil microbial biomass and organic matter content reduces the immobilization of soil nutrients and is expected to favour a fast nutrient turnover in the ecosystem. This may result in the re‐establishment of exotic grasses in the long term. Future efforts should focus on the recovery of soil organic matter content and the establishment of soil microbial communities similar to native ecosystems after the application of land‐management practices. Therefore, the restoration of abandoned pastures should consider a greater focus on restoring soil carbon and nutrient cycling

Effect of soil contamination with polycyclic aromatic hydrocarbons from drilling waste on germination and growth of lawn grasses

In many studies, grasses were used to increase the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in soil because they are the most common plant species on the ground level and are quite resistant to contamination with these compounds. One of the main failures in PAH remediation in soil using plant species was the negative impact on germination and seedling growth. The objective of this study was to evaluate grass seed germination and seedling growth affected by drill cuttings to determine the resistance of selected grass species to the impact of PAH and their suitability for an effective phytoremediation of soils contaminated with waste that contain compounds from this group. In the study four grass species: tall fescue (Festuca arundinacea), red fescue (Festuca rubra), perennial ryegrass (Lolium perenne) and common meadow-grass (Poa pratensis). The germination energy of all species decreased as the amount of drill cuttings increased. Among the species studied, the highest germination energy and capacity were found in Lolium perenne (54.1 and 73.2 respectively), and the lowest – in Poa pratensis (16.7 and 23.3 respectively). With an increasing amount of drill cuttings, the root and seedling height were decreased. Festuca arundinacea seedlings were distinctly the highest and had the longest roots (96.7 and 52.7, respectively), while Poa pratensis seedlings showed the significantly slowest seedling and root elongation rate (30.4 and 12.4, respectively). However, the strongest decrease in seedling height and root length compared to the control was observed in Festuca rubra. Based on IC50, the greatest tolerance to the addition of drilling waste to the substrate was found for Festuca arundinacea and Festuca rubra. The conducted investigation indicates that Festuca arundinacea and Lolium perenne are grass species that are least sensitive to drilling waste in the substrate because no significant differences were found in root length and seedling height between the control soil and the soil where a PAH dose of 5% and 10% was applied.

Smoke and heat can increase germination of common wildflowers and grasses—implications for conservation and restoration of critically endangered grassy ecosystems

SummaryCritically endangered grasslands and grassy woodlands were once widespread across south‐eastern Australia. However, more than 200 years of European land use means less than 1% of their pre‐European extent remains today. Conservation and restoration of these ecosystems involves reintroducing fire to periodically reduce competition and allow smaller species to establish. Furthermore, seeds of native species are sown – but often fail to establish as many forbs and grasses are hard‐to‐germinate. Therefore, data on how these species respond to fire‐related germination cues, such as smoke and heat, can benefit our understanding of both how species respond to fire and identify treatments which can be used to increase germination. We conducted a germination trial to determine if smoke and heat cues increase percent germination and germination speed of 55 common grassy ecosystem species. Fire cues increased germination speed and/or percent germination of 44 of the 55 study species. These results have three implications for grassy ecosystem conservation and restoration: (i) fire may aid conservation by maximizing germination of native species; (ii) pre‐treating seed with smoke and/or heat prior to sowing may increase germination when restoring these ecosystems via direct seeding; and (iii) smoke and heat can be used to increase germination when growing seedlings for plantings.

Allelopathic Potential of Green Manure Cover Crops on Germination and Early Seedling Development of Goose Grass [Eleusine indica (L.) Gaertn] and Blackjack (Bidens pilosa L.)

Green manure cover crops (GMCCs), which are recommended for improving soil fertility, also have the potential of reducing weed populations in cropping systems through allelopathy. The objective of this study was to evaluate the effect of eight GMCCs on the germination and seedling development of two weeds of divergent morphology, namely, goose grass [Eleusine indica (L.) Gaertn] and blackjack (Bidens pilosa L.). Aqueous leaf, stem, and root extracts of hyacinth bean (Lablab purpureus L), red sunnhemp [Crotalaria ochroleuca (G.) Don], showy rattlebox (Crotalaria grahamiana Wight & Arn.), common bean (Phaseolus vulgaris L.), common rattlepod (Crotalaria spectabilis Roth.), radish (Raphanus sativus L.), tephrosia (Tephrosia vogelii L.), and black sunnhemp (Crotalaria juncea L.) at 0, 1.25, 2.5, 3.75, and 5% wv−1 were applied to weed seeds in Petri dishes to determine their effect on germination, radicle and plumule growth, and germination vigor index. The experimental design was 3(tissue types) ∗ 5(concentrations) treatment combinations replicated four times in a completely randomized design. In the pot study, 25 seeds of either goose grass or blackjack were planted separately in approximately 400 g of soil mixed with cover crop tissue powder at 1% concentration per pot. The experimental design was cover crop residues + control replicated four times in randomized complete blocks. There was a significant (p<0.05) extract ∗ concentration interaction on all germination parameters across all GMCCs. The different cover crop aqueous extracts differentially reduced all germination parameters of both weeds in the order leaf > stem > root extract except for radish root extracts being most inhibitory to all germination parameters of goose grass. The leaf, stem, and root soil-incorporated residues of GMCCs significantly (p<0.05) affected seedling emergence, dry weight, and vigor indices of both weeds. Based on the results of this study, it was concluded that the different GMCC tissues contain allelochemicals that inhibit the emergence of both monocotyledonous and dicotyledonous weeds.

Improving the Properties of Degraded Soils from Industrial Areas by Using Livestock Waste with Calcium Peroxide as a Green Oxidizer.

Over the past years, the treatment and use of livestock waste has posed a significant problem in environmental engineering. This paper outlines a new approach to application of calcium peroxide (CaO2) as a green oxidizer and microbiocidal agent in the treatment of poultry manure. It also presents the application of pretreated waste in improvement of degraded soils in industrial areas. The CCD (Central Composite Design) and RSM (Response Surface Methodology) were employed for optimizing the process parameters (CaO2 concentration 1.6–8.4 wt %, temperature 5.2–38.8 °C and contact time 7–209 h). The analysis of variance (ANOVA) was used to analyze the experimental results, which indicated good fit of the approximated to the experimental data (R2 = 0.8901, R2adj = 0.8168). The amendment of CaO2 in optimal conditions (8 wt % of CaO2, temperature 22 °C and contact time 108 h) caused a decrease in bacteria Escherichia coli (E. coli) in poultry manure from 8.7 log10 CFU/g to the acceptable level of 3 log10 CFU/g. The application of pretreated livestock waste on degraded soils and the studies on germination and growth of grass seed mixture (Lollum perenne—Naki, Lollum perenne—Grilla, Poa pratensis—Oxford, Festuca rubbra—Relevant, Festuca rubbra—Adio and Festuca trachypylla—Fornito) showed that a dose of 0.08 g of CaO2 per 1 gram of poultry manure induced higher yield of grass plants. The calculated indicators for growth of roots (GFR) and shoots (GFS) in soils treated with poultry manure were 10–20% lower compared to soils with amended CaO2. The evidence from this study suggests that CaO2 could be used as an environmentally friendly oxidizer and microbiocidal agent for livestock waste.

Germination and early establishment of dryland grasses and shrubs on intact and wind-eroded soils under greenhouse conditions

AimsGrassland-to-shrubland transition is a common form of land degradation in drylands worldwide. It is often attributed to changes in disturbance regimes, particularly overgrazing. A myriad of direct and indirect effects (e.g., accelerated soil erosion) of grazing may favor shrubs over grasses, but their relative importance is unclear. We tested the hypothesis that topsoil “winnowing” by wind erosion would differentially affect grass and shrub seedling establishment to promote shrub recruitment over that of grass.MethodsWe monitored germination and seedling growth of contrasting perennial grass (Bouteloua eriopoda, Sporobolus airoides, and Aristida purpurea) and shrub (Prosopis glandulosa, Atriplex canescens, and Larrea tridentata) functional groups on field-collected non-winnowed and winnowed soils under well-watered greenhouse conditions.ResultsNon-winnowed soils were finer-textured and had higher nutrient contents than winnowed soils, but based on desorption curves, winnowed soils had more plant-available moisture. Contrary to expectations, seed germination and seedling growth on winnowed and non-winnowed soils were comparable within a given species. The N2-fixing deciduous shrub P. glandulosa was first to emerge and complete germination, and had the greatest biomass accumulation of all species.ConclusionsGermination and early seedling growth of grasses and shrubs on winnowed soils were not adversely nor differentially affected comparing with that observed on non-winnowed soils under well-watered greenhouse conditions. Early germination and rapid growth may give P. glandulosa a competitive advantage over grasses and other shrub species at the establishment stage in grazed grasslands. Field establishment experiments are needed to confirm our findings in these controlled environment trials.

Effect of magnetic fields and fertilizers on grass and onion growth on technogenic soils

The article deals with effect the use of organic (biohumus) and mineral (biochar) fertilizers based on the products of chicken vital activity on changing the fertility of technogenic sod-podzolic soils exposed to constant and unstable magnetic fields. The germination and growth dynamics of grasses and onions were investigated. The rational rate of introduction of the studied fertilizers into the technogenic soil is determined. Running (RMF) and direct (DMF) magnetic fields were applied in two ways: with fertilizers added and without fertilizers added. It has been established that the effect of preliminary magnetization of technogenic soil has a significant effect on lawn grass germination and the length of onion feathers, which are more than twice the height when exposed to the RMF, as compared with DMF. The effect of RMF on grass germination was also twice as high for DMF, when fertilizers were added. The DMF mag-netization and biohumus helps to increase the grass sprout height by 10–20%. Onion sprouts were higher in two cases: DMF and biohumus; RMF and biochar. The influence of the factor of fertilizer type has a significant effect in 30–40% of cases, whilst at a spread rate of more than 5%, significant chemical activity of biochar negatively affects the germination of both grass and onion.