Greenhouse Study Research Articles

Growing Media pH and Nutrient Concentrations for Fostering the Propagation and Production of Lingonberry (Vaccinium vitis-idaea L.)

The lingonberry (Vaccinium vitis-idaea L.), recognized for its nutritional value and adaptability to cold climates, faces cultivation challenges, particularly in soil pH and fertility optimization. In a greenhouse study, lingonberry transplants were grown in media with pH levels of 6.5 (3:1:1 PRO-MIX BX/peat moss/perlite) and 5.2 (2:1 peat moss/perlite). Seven months post-exposure to different media pH, various fertility treatments (NPK) were tested, including a control (0–0–0), a balanced 5–5–5 kg ha−1 rate, a standard 36–24–48 kg ha−1 rate, and both higher (up to 54–36–72 kg ha−1) and lower (down to 9–6–12 kg ha−1) rates, applied every three weeks for fifteen weeks across six replications with a standard micronutrient rate. Results showed that media pH significantly affected plant height and volume, with plants at pH 6.5 growing 27% taller and larger than plants at pH 5.2. Fertility levels influenced plant volume, peaking at a moderate fertility rate (18–12–24 kg ha−1) before declining at higher rates. Interactions between pH and fertility significantly impacted shoot biomass, where higher fertility rates (above 36–24–48 kg ha−1) had a more pronounced negative effect on shoot biomass at pH 6.5 compared to pH 5.2. Root dry biomass was consistently 1.2–2.3 times greater than shoot dry biomass and less influenced by the treatments. Shoot death rates increased sharply at fertility rates above 18–12–24 kg ha−1, peaking at 21–35%. Nitrogen concentration in shoots and roots increased with higher fertilizer rates, peaking at 1.74% in the 45–30–60 kg ha−1 treatment. Fertility treatments raised growing media’s electrical conductivity (EC, 1:20 ratio), with a maximum of 1.41 dS m−1 in the 54–36–72 kg ha−1 treatment, though pH remained unchanged. Growing media nitrate levels increased with higher N rates, while ammonium levels were unaffected. Shoot death rates rose significantly with higher nitrate concentrations, particularly above 17.5 mg L−1, but showed no link to ammonium levels. Lingonberries can survive and thrive across a wide range of pH levels. These results indicate that lingonberries are resilient and low maintenance, requiring modest nutrient levels, and excessive fertilization hampers their growth.

Impacts of black soldier fly, Hermetia illucens, larval frass on the emergence and seedling vigor of three vegetable crop species

Abstract The waste material from rearing black soldier fly, Hermetia illucens (L.), (Diptera: Stratiomyidae), larvae (BSFL), frass, could serve as a partial replacement for fertilizer or growing media, such as peat. Studies have shown that depending on the crop life cycle, long or short, the incorporation of frass can have positive impacts on vegetable growth. Investigating the earlier stages of growth, such as emergence, can provide more information on the acute impacts of insect frass on plant production. Two greenhouse studies were designed to investigate the use of frass in vegetable production at the seedling stage: BSFL frass as a partial replacement for peat in a growth germination medium and BSFL frass as a fertility replacement in a growth germination medium. Tomato, lettuce, and arugula seeds were grown in a standard control growing media, a growing media amended with frass to partially replace peat, and a growing media with frass applications to substitute the fertility source. In all treatments and varieties, the control growing media produced better or comparable results to the treatments. As a peat replacement, the two tomato varieties, lettuce, and arugula seedlings grown in frass had comparable seedling vigour and days to emergence to those grown in the control. As a fertility replacement, seedlings grown in frass had significantly lower percent emergence in all four cultivars when compared to the control. The tomato varieties also had significantly lower seedling vigour in the BSFL fertility treatments than the control. Depending on crop and growing media composition, the impacts of frass on early plant development vary. The adoption of frass into growing practices should include preliminary tests for nutrient composition and microbial contamination.

Rhizobial variation, more than plant variation, mediates plant symbiotic and fitness responses to herbicide stress.

Symbiotic mutualisms provide critical ecosystem services throughout the world. Anthropogenic stressors, however, may disrupt mutualistic interactions and impact ecosystem health. The plant-rhizobia symbiosis promotes plant growth and contributes to the nitrogen (N) cycle. While off-target herbicide exposure is recognized as a significant stressor impacting wild plants, we lack knowledge about how it affects the symbiotic relationship between plants and rhizobia. Moreover, we do not know whether the impact of herbicide exposure on symbiotic traits or plant fitness might be ameliorated by plant or rhizobial genetic variation. To address these gaps, we conducted a greenhouse study where we grew 17 full-sibling genetic families of red clover (Trifolium pratense) either alone (uninoculated) or in symbiosis with one of two genetic strains of rhizobia (Rhizobium leguminosarum) and exposed them to a concentration of the herbicide dicamba that simulated "drift" (i.e., off-target atmospheric movement) or a control solution. We recorded responses in immediate vegetative injury, key features of the plant-rhizobia mutualism (nodule number, nodule size, and N fixation), mutualism outcomes, and plant fitness (biomass). In general, we found that rhizobial variation more than plant variation determined outcomes of mutualism and plant fitness in response to herbicide exposure. Herbicide damage response depended on plant family, but also whether plants were inoculated with rhizobia and if so, with which strain. Rhizobial strain variation determined nodule number and size, but this was herbicide treatment-dependent. In contrast, strain and herbicide treatment independently impacted symbiotic N fixation. And while herbicide exposure significantly reduced plant fitness, this effect depended on inoculation state. Furthermore, the differential fitness benefits that the two rhizobial strains provided plants seemed to diminish under herbicidal conditions. Altogether, these findings suggest that exposure to low levels of herbicide impact key components of the plant-rhizobia mutualism as well as plant fitness, but genetic variation in the partners determines the magnitude and/or direction of these effects. In particular, our results highlight a strong role of rhizobial strain identity in driving both symbiotic and plant growth responses to herbicide stress.

Short‐term survival and growth of 32 native boreal plants on treated oil sands tailings

AbstractThe consolidation of oil sands tailings is a cost‐ and time‐consuming process that requires treatment via active (e.g., centrifugation) and passive (e.g., self‐weight consolidation) methods. The use of plants to dewater tailings is a promising concept and has previously been evaluated using agronomic grass species in greenhouse studies. This greenhouse study evaluated the short‐term survivorship and growth of 32 upland and lowland native plant species (12 forbs, 14 graminoids, and six woody plants) in centrifuged tailings and benchmarked their performance against reclamation soil and undisturbed forest soil. All plant species were propagated from seed and transplanted as seedlings into containers filled with one of the three substrates. After 42 days, the height (woody species only) and total aboveground biomass were determined for all living plants. As expected, the mortality of seedlings in tailings was higher than plants grown in the other two substrates. Graminoid species, regardless of species community type (wetland or upland), had higher survival probabilities and growth compared to forb or woody species across all substrates. Of forbs and woody species evaluated, Geum aleppicum and Populus tremuloides showed the most promise amongst the upland species, and Rumex occidentalis was the wetland equivalent.

Enhancing the sustainability of cowpea production through the integrated use of fish effluents and animal manure

AbstractThe integration of aquaculture and agriculture in arid and semi‐arid environments is crucial for maximizing water and land productivity, especially considering the increasing global water scarcity and the simultaneous use of water for crop and fish production. A greenhouse study was conducted to determine the effects of fish effluent on the growth, yield parameters, and yield of cowpea (Vigna unguiculata). The experiment involved 13 fertilization treatments, including three types of irrigation water (river water—control, Nile tilapia (Oreochromis niloticus), African sharp‐toothed catfish (Clarias gariepinus), four fertilizers (poultry, cattle, and sheep manures at 10 t ha−1), recommended rate of inorganic fertilizer (150 kg ha−1 of NPK 6‐20‐10), and six mixed treatments with fish effluent and 50% of the applied rate of manure alone (5 t ha−1). The combined use of C. gariepinus effluent + 50% poultry manure significantly increased stem diameter, nodules per plant, pods per plant, and seed yield compared to NPK treatments. The shortest days to reach 50% flowering were obtained with the effluent of O. niloticus + 50% sheep manure, C. gariepinus/O. niloticus + 50% poultry manure, and 10 t ha−1 poultry manure. However, fertilization treatments did not significantly influence the number of branches, pod and root length, number of pods per plant, 100‐seed weight, and leaf chlorophyll concentrations. This study suggests that fish effluents, when combined with manure, can improve plant growth and seed yield, providing a cost‐effective alternative to inorganic fertilizers for smallholder farmers.

Biochar and Deactivated Yeast as Seed Coatings for Restoration: Performance on Alternative Substrates

Seedling establishment is often a critical bottleneck in the revegetation of mine tailings and similar substrates. Biochar and deactivated yeast are potential sustainable materials that could be used in this context as seed coatings to aid in seedling establishment. We conducted a greenhouse study on biochar and deactivated yeast use as seed coatings, assessing germination, establishment, and early growth of white clover (Trifolium repens) and purple prairie clover (Dalea purpurea). Coated seeds were applied to a mine tailing, a coarse granitic sand, and potting soil mix substrates; seedling establishment and growth were monitored over 75 days. Biochar coatings enhanced the seedling establishment of Trifolium, with biochar and biochar plus yeast coatings giving the best results. In some cases, these effects persisted throughout the experiment: biochar coatings resulted in a ~fivefold increase in Trifolium biomass at harvest for plants in the potting soil mix but had neutral effects on sand or tailings. Biochar seed coatings also enhanced Dalea germination in some cases, but the benefits did not persist. Our results indicate that biochar-based seed coatings can have lasting effects on plant growth well beyond germination but also emphasize highly species-specific responses that highlight the need for further study.

Effects of Silicon on Development and Controlling of Powdery Scab in Irish Potato (Solanum tuberosum)

Effects of different silicon levels on plant height, stem diameter, disease incidence and severity and its activity on polyphenol oxidase and peroxidase enzymes on powdery scab caused by Spongospora subterranean on Irish potatoes (BP1) was assessed. This was a greenhouse study at the University of Zimbabwe Crop Science department. A mixture of 50% sterilised vermiculite and 50% sterilised sand was used as growing media. 0, 250, 500 and 750ppm silicon concentrations were used. Irrigation water, other fertilizers and insecticides applied were made uniform across all treatments. Variations among treatments were monitored from three weeks after planting then on weekly basis for the coming eighty weeks. Silicon concentrations showed significance difference (p<0.001) on plant height and stem diameter of Irish potatoes. It proved to play a significant role in the growth of the potato plants. Silicon levels showed no significant difference on powdery scab incidence with all plants getting diseased. Silicon reduced the infestation severity at high concentrations. It also increased the activity of polyphenol oxidase and peroxidase enzymes in potatoes at different response rates. Results from the study indicates great potential of silicon based fertilizers in controlling powdery scab as well as growth rate of Irish potatoes.

The role of maize sap beetles (Coleoptera: Nitidulidae) and maize weevils (Coleoptera: Curculionidae) in the spread of Aspergillus flavus in pre-harvest maize in Kenya

Abstract The spread of toxigenic Aspergillus into maize by insects and the subsequent aflatoxin contamination poses a risk to humans and animals and has been investigated in North and South America. To evaluate this effect in an African context, Greenhouse studies were conducted in 2022 to determine the role of sap beetles, Carpophilus dimidiatus Fabricius, 1792 (Coleoptera: Nitidulidae) and maize weevils, Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) on infection of maize kernels by Aspergillus flavus Link and the resultant aflatoxin accumulation. To test the beetles’ efficacy, treatments were applied on partially opened primary ears at 3 different stages of kernel development (BBCH 75, 83, and 87). The treatments were: (i) distilled water, (ii) water with A. flavus spores, (iii) maize grits, (iv) maize grits with A. flavus spores, (v) C. dimidiatus, (vi) C. dimidiatus with A. flavus spores, (vii) S. zeamais, and (viii) S. zeamais with A. flavus spores. Data on kernel infection, maize rotting, yield, and aflatoxin content in kernels were collected. The highest kernel spoilage and yield loss were recorded for the co-inoculation of S. zeamais and A. flavus spores, followed by S. zeamais without A. flavus spores, and then C. dimidiatus with the fungal spores. Inoculation of maize at the BBCH 83 growth stage resulted in the highest kernel damage and aflatoxin contamination. S. zeamais and, to a lesser extent, C. dimidiatus effectively spread the A. flavus inoculum into non-wounded ears, resulting in fungal and aflatoxin contamination. The yield loss from S. zeamais-Aspergillus co-inoculation occurred due to the grain rotting and actual feeding of the maize weevils. Thus, insect management is important in reducing pre-harvest contamination of maize with mycotoxigenic fungi and their resultant toxins.

From wastewater to feed: Understanding per- and polyfluoroalkyl substances occurrence in wastewater-irrigated crops.

Reusing treated wastewater for irrigation is a sustainable way to recycle nutrients and reduce freshwater use. However, wastewater irrigation inadvertently introduces per- and polyfluoroalkyl substances (PFAS) into agroecosystems, causing concerns regarding potential adverse effects to ecosystem, animal, and human health. Therefore, a better understanding of the pathways by which PFAS accumulate in forage crops is needed. A greenhouse study was conducted to (1) quantify the contribution of root uptake versus foliar sorption of PFAS in corn (Zea mays) and orchard grass (Dactylis glomerata), (2) assess effects of PFAS-impacted wastewater irrigation on plant health, and (3) determine the potential implications for bioaccumulation. The greenhouse study was composed of four treatments for each forage crop to isolate the relative contribution of two uptake pathways. Results suggested that foliar sorption was an unlikely contributor to PFAS concentrations observed in crop tissue. Root uptake was identified as the predominant uptake pathway. PFAS were detected more frequently in orchard grass samples compared to corn silage samples. Additionally, corn exhibited a lower uptake of long-chain PFAS compared to grass. Overall, no plant health effects on growth attributable to PFAS concentrations were observed.Forage data suggest cattle exposure to PFAS would be largely short-chain PFAS or long-chain "replacement" compounds(>50%). However, cattle may still be exposed to potentially harmful long-chain PFAS; levels in the forage crops exceeded the tolerable weekly intake set by the European Food Safety Authority. This study provides insights on PFAS entry into the food chain and potential implications for livestock and human health.

Insect Pollinivores of Sorghum bicolor and Plant Traits that Influence Visitation1

Abstract Grasses such as sorghum, (Sorghum bicolor (L.) Moench), are rarely considered as an important food resource for pollinators. Here, we report insects collecting or consuming pollen of sorghum over the 8-wk flowering period of a mapping population in Tifton, GA. We also examine the response of insects to plant morphological traits and disease damage and the ability of bumble bees (Bombus impatiens) to cross-pollinate sorghum. The most numerous insect observed collecting/consuming sorghum pollen was the hover fly Toxomerus politus Say (i.e., the maize calligrapher) followed by honey bees (Apis mellifera L.), lined earwigs (Doru taeniatum Dorhn), lovebugs (Plecia nearctica Hardy), southern carpenter bees (Xylocopa micans Lepeletier), common eastern bumble bees (Bombus impatiens Cresson), exotic stripetails (Allograpta exotica Wiedemann), margined soldier beetles (Chauliognathus marginatus F.), a signal fly (Rivellia sp. Robineau-Desvoidy), and a dusky-winged hover fly (Ocyptamus fuscipennis Say). Maximum flowering occurred at Week 3, which coincided with the maximum number of maize calligraphers, bumble bees, and honey bees observed. A positive linear relationship was seen between the number of flowering plots and the number of maize calligraphers and honey bees. The probability of observing a bee on a panicle increased as plant height increased, whereas the probability of observing a bee or hover fly decreased as plant disease percentage increased. These results suggest that inflorescence abundance, plant height, and plant disease impact bee visitation in sorghum. Furthermore, field-captured bumble bees successfully fertilized sorghum in a greenhouse study, suggesting that bumblebees can pollinate sorghum flowers in field conditions.

Phytomanagement of cadmium using Tagetes erecta in greenhouse and field conditions

Greenhouse and field studies investigated the phytoextraction potential of soil cadmium (Cd) by Tagetes erecta L., a popular ornamental flower in Asia. The effects of organic fertilizer, cattle manure, and pig manure in supporting plant growth and enhancing Cd uptake were also examined. Plants grown in soil supplemented with pig manure produced greatest biomass (12.8 ± 1.6 and 11.8 ± 0.9 g plant−1 in greenhouse and field experiments, respectively). Plant parts accumulated Cd in the order: shoot > root > flower in all treatments. Furthermore, T. erecta had a high phytoextraction potential as evidenced by translocation factors and enrichment coefficients > 1 for shoots. Marigolds cultivated in Cd-contaminated soil supplemented with organic fertilizer (CdOrg) exhibited Cd concentrations in flowers below the Maximum Permissible Level for consumption (< 0.2 mg kg−1), indicating that the edible flowers pose no health risk to humans. The flowers additionally contained significant quantities of total phenolics and phenolic acids, which may indicate their potential as an indicator of Cd-initiated oxidative stress. The phenolic compounds can furthermore function as precursors for manufactured medicinal products by acting as antioxidants and antimicrobials. Application of organic fertilizer and selected organic amendments may have contributed to the greater concentrations of phenolics. The Cd alone treatment resulted in lowest production of bioactive compounds and antioxidant capacity. It is proposed that T. erecta be applied for Cd phytoextraction while enhancing local economies as an ornamental species, and for plant extracts for application of bioactive compounds and antioxidant capacity.

Optimal Irrigation and Fertilization Enhanced Tomato Yield and Water and Nitrogen Productivities by Increasing Rhizosphere Microbial Nitrogen Fixation

Irrigation and nitrogen application rates have significant effects on greenhouse tomato yields, as well as water and nitrogen use efficiencies, but little is known regarding how these rates affect plant–microbiome interactions and how the associated changes might impact tomato yields. In this greenhouse study conducted over two years, the effects of three irrigation levels (moderate deficit with 65–75% water holding capacity threshold, slight deficit with 75–85%, and sufficient irrigation with 85–95%) and four nitrogen application levels (60, 120, 240, and 360 kg ha−1) on tomato growth, yield, water and nitrogen productivities, and rhizosphere microbial diversities and functions were investigated. The results demonstrated that the highest tomato leaf area, dry biomass, yield, and water and nitrogen productivities were obtained under the treatment with sufficient irrigation. With increasing nitrogen application, the tomato leaf area, dry biomass, yield, and water and nitrogen productivities showed a trend of first increasing and then decreasing. Overall, the treatment (N2W3) with sufficient irrigation and 240 kg ha−1 N was associated with the highest tomato growth, yield, and water and nitrogen productivities. Moreover, optimal irrigation and nitrogen application obviously altered the structures of rhizosphere bacterial and fungal communities, particularly recruiting microbiota conferring benefits to tomato growth and nitrogen fixation—namely, Lysobacter and Bradyrhizobium. Ultimately, optimal irrigation and nitrogen application significantly increased the relative abundances of functions related to carbon, sulfur, and nitrogen metabolism, especially nitrogen fixation. In summary, optimal irrigation and fertilization enhanced tomato yield, as well as water and nitrogen productivities by increasing the nitrogen fixation functions of the rhizosphere microbiome. Our results provide significant implications for tomato cultivation in greenhouses, in terms of optimized irrigation and fertilization.

Mechanistic insights to Paenibacillus lentimorbus mediated biocontrol of Alternaria solani in Solanum lycopersicum L. through carbohydrate reallocation and sweet immunity suppression

Researchers envisaged that PGPR (plant growth promoting rhizobacteria) has vast possibilities as a bioinoculant that will lead to revolution. However, it's still very far from becoming commercially successful. Here, the information regarding the root colonization of PGPR in host plants and plant response towards PGPR is inadequate. It can provide valuable information for developing successful biofertilizers and biocontrol agents. PGPR (Paenibacillus lentimorbus NRRL B-30488 or CHM12) has been previously reported as a successful commercial biofertilizer and biocontrol agent. However, the exact mechanism of plant growth promotion and biocontrol is poorly studied. So, CHM12 was appraised for biotic stress amelioration of pathogen Alternaria solani in Tomato (Solanum lycopersicum L.) var. S-22 plants. PGPR CHM12 was assessed for various plant growth parameters such as proline, sugar content, etc. in pathogen A. solani (AS) challenged plants and compared with the CHM12 treated plants in a greenhouse study. Then, the metabolomics tool (GC-MS) was used to identify metabolites and their respective genes playing pivotal roles in colonization tactics availed by PGPR. Further, gene expression analysis was done to affirm the involvement of various genes related to metabolites providing biotic stress tolerance in Tomato plants. The current research discerned that PGPR CHM12 revealed significant differences in different plant growth parameters studied. There were 33 distinct metabolites identified, which stipulated the involvement of carbohydrate metabolism mainly in combating biotic stress in this study. Thus, our study reconfirmed very few reported previous results through gene expression analysis, suggesting the downregulation of carbohydrate metabolism genes in PGPR-treated plants. This downregulation of carbohydrate genes might be the critical factor for suppressing the plant's immune response to gaining entry inside the host plant. This also helps in retaining and reallocating carbohydrates in plant cells to reduce pathogen proliferation.

Effect of fortified pine needle biochar on green fodder yield, nutrient uptake of oat and soil properties

In the Himalayan region, the low green fodder supply to livestock necessitates agronomic interventions, including the use of fortified pine needle biochar, a viable option for slow-release nutrients, to enhance fodder oat production, improve soil health, and safely manage the abundant pine needles that pose a fire risk. In a greenhouse study, the effect of different levels of pine needle biochar (0, 0.02, 0.04, 0.11 and 0.22 % of soil weight) fortified with 0, 75 and 100 % of the recommended dose of fertiliser (RDF, 80 kg N: 60 kg P2O5: 40 kg K2O ha−1) was examined on the green fodder yield, nutrient concentration and uptake of oat, and general soil properties and extractable nutrients. Application of 0.02 % biochar fortified with 75 % RDF gave a fodder yield (56.9 g pot−1) which was 46.6 percent higher than the control (38.8 g pot−1) but statistically similar to the yield with 100 % RDF alone (54.9 g pot−1). The highest fodder yield (72.0 g pot−1) was recorded with 0.22 % biochar fortified with 100 % RDF. Higher doses of biochar without fortification decreased the N concentration but increased the K concentration and brought no significant change in P concentration in the fodder oat. Biochar fortified with 75 and 100 % RDF enhanced the uptake of N, P, and K by fodder oat. The moderate levels of biochar (0.02 and 0.04 %) fortified with 75 % RDF and all levels of biochar fortified with 100 % RDF decreased soil pH while higher levels of biochar fortified with 100 % RDF increased soil EC and organic C. The treatments receiving the highest level of biochar addition (0.22 %) with 0 % RDF, 0.11 and 0.22 % biochar fortified with 75 % RDF and all levels of biochar fortified with 100 % RDF significantly increased soil extractable N, P and K after crop harvest except for K under 0.22 % biochar fortified with 100 % RDF. Pine needle biochar fortified with RDF helped to achieve higher oat fodder production and maintain soil fertility than solo application of biochar or chemical fertilisers.

Genome of Dietzia cinnamea 55, a desert-isolated microbe with plant growth-promoting properties for grain crops.

Here, we report the genome sequence of Dietzia cinnamea 55, isolated from the Negev Desert, Israel. D. cinnamea 55 was found to promote the growth of several cereal crops (corn, wheat, and pearl millet) in greenhouse and field studies.

Arbuscular mycorrhizal fungi equalize differences in plant fitness and facilitate plant species coexistence through niche differentiation.

Mycorrhizal fungi are essential to the establishment of the vast majority of plant species but are often conceptualized with contradictory roles in plant community assembly. On the one hand, host-specific mycorrhizal fungi may allow a plant to be competitively dominant by enhancing growth. On the other hand, host-specific mycorrhizal fungi with different functional capabilities may increase nutrient niche partitioning, allowing plant species to coexist. Here, to resolve the balance of these two contradictory forces, we used a controlled greenhouse study to manipulate the presence of two main types of mycorrhizal fungus, ectomycorrhizal fungi and arbuscular mycorrhizal fungi, and used a range of conspecific and heterospecific competitor densities to investigate the role of mycorrhizal fungi in plant competition and coexistence. We find that the presence of arbuscular mycorrhizal fungi equalizes fitness differences between plants and stabilizes competition to create conditions for host species coexistence. Our results show how below-ground mutualisms can shift outcomes of plant competition and that a holistic view of plant communities that incorporates their mycorrhizal partners is important in predicting plant community dynamics.

Assessing the effects of allelopathic properties of organic mulches on liverwort control in container-grown ornamentals

Liverwort (Marchantia polymorpha) is a problematic weed in ornamental crop production. The major limitation of liverwort control is lack of herbicide options inside greenhouses and their potential to cause injury. The current research was undertaken to study the effectiveness of allelopathic properties of six different organic mulches including rice hull (RH), cocoa hull (CH), pine bark (PB), maple leaf (ML), shredded cypress (SC), and red hardwood (HW) for liverwort control. Mulch extracts were prepared and used to impregnate agar media at an increasing dose at 1X (2 mL mulch extract), 2X (4 mL), 3X (6 mL), and 4X (8 mL) rates, in a randomized complete block design. Ten liverwort gemmae were transferred to each petri dish and they were maintained inside a growth chamber. The number of gemmae germinating in each petri dish after 1 week and gemmae surviving at the end of 2 weeks was recorded. In greenhouse study, mulch extracts were applied to containers filled with substrate for assessing liverwort control. The mulch extracts or no extract (control) were applied to the containers uniformly at 1X (15 mL), 2X (30 mL), 3X (45 mL) or 4X (60 mL) rates, in a randomized complete block design. The percentage of substrate surface covered by liverwort thalli was visually estimated bi-weekly for 10 weeks. Fresh biomass of the thalli and gemmae cup counts in each pot were also recorded. After 1 week in the growth chamber, ML followed by SC, PB and RH extracts showed maximum suppression of liverwort gemmae germination. At 2 weeks, ML applied at either of the rates provided complete inhibition of liverwort growth. In greenhouse, all the mulch extracts were able to provide complete liverwort control for the first two weeks. All the mulches and rates of applications were significantly different from the control after 6, 8, and 10 weeks. PB and HW mulches showed excellent liverwort control and minimum fresh biomass of liverwort after 10 weeks as compared to other mulches. The allelopathic potential of the organic mulches can be a promising option for biopesticidal control of liverwort and a component of integrated liverwort management.

Effect of Chicken Feather Hydrolysate on Growth of Spinach through Soil Amendment Method: Unraveling A Potential Liquid Biofertilizer

The study aims to investigate the effectiveness of chicken feather hydrolysate for promoting the growth of Spinacia oleracea L., a commonly consumed leafy green vegetable. An earlier isolated and identified keratinolytic bacterial species Bacillus tropicus was utilized for the preparation of chicken feather hydrolysate through submerged fermentation. Minimal media which was supplemented with chicken feather was used for the preparation of hydrolysate. The bacterial strain degraded chicken feather within 4 days of incubation after which the feather hydrolysate was collected and tested to check plant growth promoting activity through the seed germination trials and greenhouse study. Upon characterization of feather hydrolysate, it was found that the hydrolysate was a cocktail of Nitrogen, Phosphorus and Potassium (NPK) as well as other micro elements needed for plant growth. Four different concentrations of feather hydrolysate were employed for both the seed germination and greenhouse study which ranged from 25% (v/v), 30% (v/v), 35% (v/v) and 40% (v/v) including a control group (CN) which was not supplemented with feather hydrolysate. The hydrolysate supplementation brought about plant growth in all the four test concentrations with 35% (v/v) giving the highest result of 14 cm and 27.6 mg/g for tested parameters like plumule length and total chlorophyll content, respectively. The same concentration supported maximum seed germination and highest radicle extension for the germination studies as well. This study investigates the efficacy of chicken feather hydrolysate in promoting spinach growth, elucidating its potential as a fertilizer.

Effects of glyphosate on glyphosate‐resistant maize growth and metabolic parameters in the greenhouse and field

AbstractThe potential adverse effects of glyphosate on glyphosate‐resistant (GR) crops are still a matter of controversy. The effects of glyphosate at recommended application rates (either a single application of 580 g ae ha−1 of glyphosate at stage V5 or a sequential application of 580 + 980 g ae ha−1 at stage V3 and V7, respectively) on growth, mineral content, and metabolic parameters of GR maize (Zea mays) were determined in greenhouse and field studies, each replicated in different years. No effects on any growth parameter (including grain yield), mineral content (leaf and grain), grain starch, crude protein, or total lipids were found. The only significant negative effect was a slight reduction in tyrosine content of leaf tissue with the sequential treatment, however, there was no increase in shikimic or quinic acids in leaf tissue with any treatment. In a separate greenhouse experiment, there was no sign of oxidative stress, as determined by levels of chlorophylls, carotenoids, and malondialdehyde (MDA) content as well as superoxide dismutase and guaiacol peroxidase activities 4 and 8 days after treatment with 1080 g ha−1 glyphosate. In fact, there was a reduction of MDA in roots of glyphosate‐treated plants 4 DAT, indicating reduced oxidative stress. No aminomethylphosphonic acid, the primary degradation product of glyphosate, was found in either leaves or grain of treated plants, and no glyphosate was found in grain of treated plants from the field studies. All the results are consistent with there being no adverse effects of glyphosate on GR maize at recommended application rates.

Effectiveness of Anaerobic Soil Disinfestation for Weed and Nematode Management in Organic Sweetpotato Production

Weeds and nematodes are particularly problematic in organic sweetpotato production due to a lack of effective pesticides. Anaerobic soil disinfestation (ASD) has the potential to fit into current pest management practices as an alternative to pesticide application. Greenhouse studies were conducted at the Clemson Coastal Research and Education Center (CREC) in Charleston, SC, to investigate the impact of carbon source amendment and a no carbon source treatment, and soil type on cumulative anaerobicity, weed control, nematode population, and sweetpotato vigor. Microcosms were filled with one of three different soil types (Charleston—loamy/native; Blackville—high coarse sand content; and Clemson—high clay content) and were mixed with cottonseed meal (CSM) or no carbon amendment. The pots were then sealed with plastic totally impenetrable film (Tif) for 6 weeks, followed by the transplanting of sweetpotato (cv Bayou Belle) slips. The results suggested that the CSM-treated microcosms spent more time under anaerobic conditions than those treated with the no carbon amendment. The microcosms that experienced a longer duration of anaerobicity had a lower percent weed cover (49%), fewer nematode egg masses, and a lower gall index when compared to microcosms which experienced a shorter duration of anaerobicity. Significantly higher instances of leaf necrosis were observed in the sweetpotato slips sown in the CSM-treated microcosms. The addition of CSM as a carbon source to facilitate ASD resulted in similar above-ground biomasses of the sweetpotato plants compared to the treatments containing no carbon amendment. However, a significantly lower below-ground biomass of the sweetpotato plants was observed in the CSM-treated microcosms.