A review of exotic earthworm observations in the Canadian boreal forest and taiga zones

In the last decades, concerns have emerged that boreal forests could convert from a carbon sink to a carbon source, thus accentuating climate change. Although forest fire is generally mentioned as the main factor that could cause the boreal forest to transition to a carbon source, other factors, such as exotic earthworm activity, could also play an important role. Invasive exotic earthworms can also affect nutrient cycling, biodiversity and forest dynamics. In this context, a better knowledge of the distribution of exotic earthworms can help understand the likely changes in the ecosystems that they have colonized. Here we report the results of an exhaustive literature review of the presence of exotic earthworms in the Canadian boreal forest and taiga zones. We identified 230 sectors containing 14 earthworm species (11 exotic, 2 native and 1 putative native) in 6 provinces and 3 territories across Canada’s boreal forest and taiga zone. We also report 23 as-yet unpublished observations from the province of Quebec. We note the presence of earthworms in environments (acid soils, harsh climate) that were historically considered inadequate for their survival. This suggests that the portion of Canada’s boreal forests suitable for their presence or colonization is larger than what was previously believed. This study represents the first compilation of exotic earthworm presence in this large northern area. Factors that could affect their distribution and potential effects on boreal ecosystems are also discussed. Globally, several earthworm species seem to be overcoming the previously assumed limitation by temperature and pH.

Pengaruh priming terhadap vigor benih kedelai (Glycine max (L.) Merril.) yang dikecambahkan pada media dengan cekaman alumunium

Kandungan aluminium yang tinggi pada tanah Ultisol merupakan salah satu masalah utama dalam budidaya tanaman kedelai mulai dari fase perkecambahan hingga pertumbuhan tanaman. Perlakuan priming pada benih diyakini mampu memperbaiki perkecambahan pada lingkungan yang kurang menguntungkan. Penelitian dilakukan untuk mengetahui pengaruh priming pada perkecambahan benih kedelai yang dikecambahkan dalam media masam dan mengandung aluminium. Penelitian disusun dalam Rancangan Acak Lengkap (RAL) pola faktorial. Faktor pertama adalah jenis priming : tanpa priming, H2O (air), KNO3 1%, KNO3 2%, GA3 50 ppm, GA3 100 ppm, dan PEG 6000 7,5%. Faktor kedua adalah varietas kedelai yaitu: Anjasmoro, Burangrang, dan Grobogan. Data dianalisis sidik ragamnya dan dilanjutkan dengan uji Beda Nyata Jujur (BNJ) 5% menggunakan program statistika R Studio. Hasil penelitian menunjukkan priming PEG 7,5% dan varietas Burangrang secara mandiri merupakan perlakuan terbaik untuk meningkatkan vigor benih kedelai berdasarkan variabel waktu muncul kecambah, kecepatan perkecambahan, dan panjang hipokotil. Implikasi penelitian ini adalah PEG 7,5% dapat digunakan untuk perbaikan perkecambahan pada tanah masam dengan kandungan aluminium yang relatif tinggi. High aluminium content in Ultisol is the main problem in soybean cultivation from germination to planting growth phases.Priming treatment is believed to improve seed germination in a poor-growing environment. This study aimed to determine the effect of priming of soybean seeds germinated under acid medium and aluminium stress. The experimental design used was Completely Randomized Design (CRD) with factorial pattern. The first factor was priming type : no priming, H2O (water), 1% KNO3, 2% KNO3, 50 ppm GA3, 100 ppm GA3, and 7.5% PEG 6000. The second factor was soybean variety : Anjasmoro, Burangrang, and Grobogan. The data obtained were analyzed using the R Studio statistic program with a 5% HSD test. The study resulted that each PEG 7.5% priming and Burangrang variety independently was the best in increasing soybean seed vigor based on sprout time emergence, germination speed and hypocotyl length. This research implicates that PEG 7.5% can be used to improve seed germination on acid soils with high aluminium content.

Germination and vigor of lettuce seeds (Lactuca sativa L.) pelleted with homeopathic preparations Alumina and Calcarea carbonica subjected to toxic levels of aluminum.

Background: aluminum toxicity is the most important factor limiting the growth of plants in acid soils, whereas current treatments are unfeasible. For this reason, alternatives are sought for, among which homeopathic treatment. Aims: this study aimed at evaluating the influence of homeopathic preparations Alumina 6cH, Alumina 12cH, Calcarea carbonica 6cH and Calcarea carbonica 12cH on the germination and vigor of lettuce seeds subjected to toxic levels of aluminum in paper-solution. At the same time, it was sought to develop a new procedure to apply homeopathic preparations in plants (pelleting). Methods: the statistical design was entirely randomized (CRD) with 6 treatments and 4 repetitions. Treatments included: 1) pelleted seeds/talc + Alum 6 cH; 2) pelleted seeds/talc + Alum 12cH; 3) pelleted seed/talc + Calc 6cH; 4) pelleted seeds/talc + Calc 12cH; 5) pelleted seeds/talc + distilled water; 6) non pelleted seeds (control). Variables evaluated were: germination percentage (GP), germination speed index (GSI) and radicle length (RL). Results: there was significant difference in GSI and RL – variables that reflect the vigor of seeds - between the samples treated with homeopathic preparations and the controls Conclusions: homeopathic preparations Alumina 6cH and 12cH and Calcarea carbonica 6cH and 12cH had significant effect on the vigor of lettuce seeds subjected to stress conditions.

Pre-Harvest MeJA Application Counteracts the Deleterious Impact of Al and Mn Toxicity in Highbush Blueberry Grown in Acid Soils

Volcanic ash-derived soils are characterized by low pH (pH ≤ 5.5) with increased concentrations of aluminum (Al3+) and manganese (Mn2+), which decreases plant growth, fruit quality, and yield. Methyl jasmonate (MeJA) improves abiotic stress tolerance. Our work aimed to evaluate the application of MeJA’s impact on the growth, antioxidant defense, and fruit quality of highbush blueberry grown under Al and Mn toxicity. A field assay was conducted with four-year-old bushes of highbush blueberry cultivar Legacy under eight treatments (Control, Al (87% of Al saturation), Mn (240 mg kg−1), and Al–Mn with and without MeJA application). Physiological, biochemical, and fruit quality parameters were measured. Growth rate significantly decreased with Al (20%), Mn (45%), and Al–Mn (40%). MeJA application recovered the growth rate. Photosynthetic parameters were not affected. Antioxidant activity increased under all treatments compared with controls, being higher with MeJA application. Total phenols (TP) were decreased in plants under Al (43%) and Mn (20%) compared with controls. MeJA application increased TP in all treatments. Fruits of bushes under Al and Mn toxicity with MeJA applications exhibited an increase in fruit firmness and weight, maintaining suitable contents of soluble solids. Our results provide insights about the beneficial effect of MeJA application on growth, antioxidant properties, and fruit quality of highbush blueberry plants grown in acid soils under Al and Mn toxicity.

Rice Residue-Based Biochar Mitigates N2O Emission from Acid Red Soil

Biochar application is considered an effective approach to mitigating nitrous oxide (N2O) emissions from agricultural soils. However, the mechanisms of biochar to mitigate N2O emissions from acidic red soils are still unclear. Therefore, the present study aims to underpin mechanisms associated with rice residue-based biochar in mitigating N2O emissions from acid soils. Soil treated with different rates of biochar control, from 1%, 2%, and 3%, and different soil properties, including soil pH, microbial biomass carbon (MBC), NH4+-N, NO3−-N, genes abundance (nosZ, nirK, AOA, and AOB), and enzymatic activities ((nitrate reductase (NR) and urease (UR)) were studied. The application of 3% biochar increased the soil pH (5.21–6.48), MBC (565–685 mg/kg), NO3−-N contents (24.23–44.5 mg/kg), genes abundance (nosZ, nirK, AOA, and AOB) and UR activity. The highest N2O emission (43.60 μg kg−1) was recorded and compared with the application of 1% (26.3 μg kg−1), 2% (18.33 μg kg−1), and 3% biochar (8.13 μg kg−1). Applying 3% biochar effectively reduced the N2O emission due to increased soil pH, MBC, NO3−-N contents, genes abundance (nosZ, nirK, AOA, and AOB), and weakened NH4+-N and NR activities. Therefore, increasing soil pH, genes abundance, and weakened nitrification following the addition of rice residue-based biochar can effectively reduce the N2O emissions from acidic red soils.

Water Use, Leaf Cooling and Carbon Assimilation Efficiency of Heat Resistant Common Beans Evaluated in Western Amazonia

In our study, we analyzed 30years of climatological data revealing the bean production risks for Western Amazonia. Climatological profiling showed high daytime and nighttime temperatures combined with high relative humidity and low vapor pressure deficit. Our understanding of the target environment allows us to select trait combinations for reaching higher yields in Amazonian acid soils. Our research was conducted using 64 bean lines with different genetic backgrounds. In high temperatures, we identified three water use efficiency typologies in beans based on detailed data analysis on gasometric exchange. Profligate water spenders and not water conservative accessions showed leaf cooling, and effective photosynthate partitioning to seeds, and these attributes were found to be related to higher photosynthetic efficiency. Thus, water spenders and not savers were recognized as heat resistant in acid soil conditions in Western Amazonia. Genotypes such as BFS 10, SEN 52, SER 323, different SEFs (SEF 73, SEF 10, SEF 40, SEF 70), SCR 56, SMR 173, and SMN 99 presented less negative effects of heat stress on yield. These genotypes could be suitable as parental lines for improving dry seed production. The improved knowledge on water-use efficiency typologies can be used for bean crop improvement efforts as well as further studies aimed at a better understanding of the intrinsic mechanisms of heat resistance in legumes.

The Importance of Liming with an Appropriate Liming Material: Long-Term Experience with a Typic Palexerult

Aluminium phytotoxicity is considered the main limiting factor for crop productivity in agricultural acid soils. Liming is a common practice used to improve acidic soil properties, but an appropriate liming material is essential for both agricultural productivity and environmental sustainability. A long-term field experiment with two liming amendments (dolomitic limestone and limestone) was developed during 10 years to determine the changes in soil acidity and assess the effects on crop (rye) yields. Although the adverse effects of the soil acidity conditions were alleviated with both amendments tested, dolomitic limestone was the most effective in the short- and long-term period. In terms of the saturation of exchange complex, dolomitic limestone had a better efficiency, likely based on its rate of dissolution. No significant changes in soil organic matter and exchangeable potassium levels between the treatments tested were found. Both liming materials significantly increased the rye total biomass, but interestingly, significant correlations were showed between tissue levels of magnesium and biomass production, but not between the latter and calcium. The increases in rye biomass production compared with control soils at the end of the research were the following: dolomitic limestone, 47%, and limestone, 32%. A link between an increase in magnesium bioavailability and biomass production was found, as well as between magnesium rye content and total, spike and stem biomass. Hence, it could conceivably be hypothesized that since magnesium is crucial for the transport of assimilates from source leaves to sink organs, alleviating its deficiency leads to avoiding the reducing growth rate of sink organs. Although further investigations are needed to gain a better understanding of liming on the biological, chemical and physical soil properties in the long term, our research provides support for the conceptual premise that an appropriate selection of liming material is crucial for the productivity of acid soils.

Secretion of Gluconic Acid From Nguyenibacter sp. L1 Is Responsible for Solubilization of Aluminum Phosphate

Phosphorus (P) deficiency is one of the major factors limiting plant growth in acid soils, where most P is fixed by toxic aluminum (Al). Phosphate-solubilizing bacteria (PSBs) are important for the solubilization of fixed P in soils. Many PSBs have been isolated from neutral and calcareous soils, where calcium phosphate is the main P form, whereas PSBs in acid soils have received relatively little attention. In this study, we isolated a PSB strain from the rhizosphere of Lespedeza bicolor, a plant well adapted to acid soils. On the basis of its 16S rRNA gene sequence, this strain was identified as a Nguyenibacter species and named L1. After incubation of Nguyenibacter sp. L1 for 48 h in a culture medium containing AlPO4 as the sole P source, the concentration of available P increased from 10 to 225 mg L–1, and the pH decreased from 5.5 to 2.5. Nguyenibacter sp. L1 exhibited poor FePO4 solubilization ability. When the pH of non-PSB-inoculated medium was manually adjusted from 5.5 to 2.5, the concentration of available P only increased from 6 to 65 mg L–1, which indicates that growth medium acidification was not the main contributor to the solubilization of AlPO4 by Nguyenibacter sp. L1. In the presence of glucose, but not fructose, Nguyenibacter sp. L1 released large amounts of gluconic acid to solubilize AlPO4. Furthermore, external addition of gluconic acid enhanced AlPO4 solubilization and reduced Al toxicity to plants. We conclude that secretion of gluconic acid by Nguyenibacter sp. L1, which is dependent on glucose supply, is responsible for AlPO4 solubilization as well as the alleviation of Al phytotoxicity by this bacterial strain.

ESTIMATION OF INDUSTRIAL MATERIAL FLOW PRODUCED BY „DEVNYA CEMENT“AD FOR REMEDIATION OF ACID SPILS

The issues of acidity and liming of soils were raised in Bulgaria more than 60-70 years ago. „Devnya Cement“ produces the Restart product, as an integral part of the process in the installation of cement clinker in a dry way and contains a high amount of calcium oxide (lime material). The aim of the study is to establish the effect of the studied product RESTART and possibilities for its use as an ameliorant on acid soils. A vegetation experiment was performed with a test crops of corn with different percentages of ameliorant. The chemical and physico-mechanical parameters of the treated soil were studied and the changes in the degree of soil acidity were established. Preliminary consumption rates of the ameliorant have been determined, when it is used for amelioration of acid soils. The chemical characteristics of the plant samples show, that the values of the chemical elements are in optimal concentrations and cannot have a harmful effect, when used as animal feed. To correct the acidity of soils with similar acidic properties as in the Devnya region, it may be recommended to apply about 1-2t/daa of the studied ameliorant.