•The biochar obviously decreased the concentration of phenolic acids in soil.•The addition of biochar significantly increased the seedlings growth.•The biochar improved the antioxidant enzyme ...activities, and reduced the lipid peroxidation.•The application of biochar to replant soil can alleviate the ARD.
The purpose of this study was to investigate the mechanisms and effects of biochar on the plant growth of Malus hupehensis Rehd. seedlings under replant conditions. Before the M. hupehensis Rehd. seedlings were planted in pots, biochar was added to pots filled with replant soil at four rates: 0, 5, 20, 80gkg−1. The growth of seedlings was monitored with plant height and photosynthesis. The antioxidant enzyme activities, lipid peroxidation and osmotic regulation substance contents in seedlings leaves were also measured. The phenolic compounds in the four soil treatments were detected too. The results showed that the addition of biochar significantly decreased the contents of phenolic acids in replant soil through the sorption of biochar. In comparison with the control, biochar applied to replant soil at 80gkg−1 enhanced the plant height, fresh weight, and photosynthetic parameters. Furthermore, seedlings in soil treated with biochar, particularly at 80gkg−1, exhibited higher activity of antioxidant enzymes including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase. With the addition of biochar, the contents of malondialdehyde, O2•− and H2O2 significantly decreased, and the osmotic substances accumulation in leaves also declined. These results suggested that the addition of biochar can alleviate apple replant disease by activating antioxidant enzymes, decreasing lipid peroxidation, and significantly reducing the phenolic acids content of replant soil through the sorption of biochar.
•The addition of biochar-compost mixtures to replant soil failed to improve apple tree growth.•Biochar-compost treatment of the planting hole did not increase nutrient supply of the leaves under ...replant conditions.•Fertility and fruit quality were not affected by the application of biochar-compost mixtures.
In fruit growing areas, the new establishment of apple orchards on soils previous planted with apple trees is problematic, because plant vitality, yield, and fruit quality of the new planted trees are suppressed through specific apple replant diseases. We hypothesized that the addition of biochar mixed with compost could help to combat the negative impact of replant disease by improving soil fertility and by altering microbial composition of the fatigue soil. To test this, we applied 3kg of two biochar-compost substrates containing 15% and 30% of biochar into the planting holes prior replanting of apple trees (Malus domestica; c.v. ‘Braeburn’ trees on M9). We then evaluated plant growth, nutrient content of the leaves as well as fruit yield and quality in comparison to a fertilized and untreated control trial. However, apart from some even negative effects on plant growth, the other investigated parameters did not respond to the application of biochar-compost substrates. Hence, both biochar compost additions as well as the granular fertilizer did not suppress apple replant diseases and thus failed to improve the overall performance of the apple trees over the three years of investigation.
Repeated apple cultivation in the same area leads to apple replant disease (ARD), which can probably be reduced by the use of organic supplements and selected rootstock/variety combinations. Soils at ...two conventionally and one organically farmed site in north-eastern Germany were tested for ARD in pot trials. In subsequent field trials, the effects of champost, microbially carbonised compost, and coniferous wood shavings piled up like a dam (‘Müncheberger Damm’ (M)-dam) and of rootstock/variety combinations were tested. On the organic site, only leonardite and champost were tested. The pot trials indicated for all sites that the soil is affected by ARD. After five years, the growth increase in trunks in the M-dam was 20–40% higher than in controls and other treatments, depending on the site. On one site, the yield over four years was a 15.7% increase for M-dam and also for champost compared to controls, on the other site, it was 11.7% and 3.0%, respectively. The M.9 rootstock with the Gala variety had a higher, but insignificant, yield compared to G.11/Gala by 6.7 or 2.6%, depending on the site. No difference in trunk growth or yield with Topaz was observed at the organic farmed site. Further research on M-dam and champost is supported, as both are promising in terms of yield.
The fruit quality of ‘Redhaven’ peach
Prunus persica (L.) Basch. grafted on 11 (Adesoto, Julior, GF 677, Monegro, Barrier 1, Cadaman, MrS 2/5, Ishtara, Penta, Tetra and peach seedling) experimental ...rootstocks was evaluated in 2008 under replant orchard conditions. Several quality indices weight, flesh firmness (FF), ground colour measurements, and soluble solids content (SSC) were measured, and HPLC analysis were performed for numerous chemical parameters (quantification of individual sugars, organic acids, phenolic compounds in skin and in pulp). Total phenolic content and antioxidant capacity in skin and in pulp were also measured. Julior had the heaviest fruit, while Barrier 1 and GF 677 produced fruit lighter in weight. Rootstocks influenced harvest maturity. Monegro produced the least ripe fruit, characterised by high FF, phenolic compounds in the skin and low SSC. Adesoto rootstock resulted in the best overall fruit quality (high values of SSC, individual and total sugar content levels, individual and total organic acids and phenolic compounds in pulp) as well as high total yield. Julior rootstock also produced good quality peach (high values of SSC, individual and total sugars). Cadaman and peach seedling rootstock produced ‘Redhaven’ fruit of the lowest quality, indicated by low values of sugars, organic acids, phenolic compounds in pulp and in skin.
Both mycorrhizal and Trichoderma spp. fungi are known for antagonistic effects against certain biological pathogens causing apple replant disease (ARD). The aim of this study was to assess the ...effectiveness of the bioinoculants based on endomycorrhizal and Trichoderma spp. fungi on the biological properties of soil as well as the parameters of the apple tree growths in a fruit tree nursery under replantation conditions. A two-year experiment was conducted on Jonagold apple trees grafted on to M.9 rootstock in western Poland. The trees were planted in the replant soil—from areas used for the production of apple trees, and in the crop rotation soil, that had not been used for nursery purposes before. A mycorrhizal inoculum and preparations containing Trichoderma spp. fungi were applied to the replant soil. Biological properties of the soil and the growth of the aerial and underground parts of the apple trees were assessed. The enzymatic (dehydrogenases and protease) and respiratory activity of the replant soil was significantly lower than that of the crop rotation soil. The apple trees grew worse when exposed to the ARD conditions. The effectiveness of applied bioinoculants in mitigating the effects of replantation in the nursery were shown. Both the treatment mycorrhization and the application of bioinoculants containing Trichoderma spp. increased the respiratory and enzymatic activity of the replant soil. The growth of the root system and the aerial parts of the trees (including leaves) was much better after the combined use of both types of fungi than in the replant soil that had not received the fungal treatment.
Apple replant disease (ARD) impacts the economic yield of orchards by physiological and morphological suppression of apple trees on replanted soils. The complexity of replant disease caused by a ...plethora of biological interactions and physical properties of the soil requires complex management strategies to mitigate these effects. Based on expert recommendations, we selected two management strategies linked to agroecological principles of (a) organic fertilisation with a specific mulch composition (MDK) and (b) biofertilisation with arbuscular mycorrhizal and bacterial strains (AMFbac), applied by a composition of existing products. For both management strategies we provide a proof-of-concept, by pot and field experiments. Both treatments have the potential to mitigate ARD effects on plant vigour. ARD effect was fully mitigated by MDK treatment in the short-term (one year) and was mitigated by up to 29% after seven years of MDK treatment (long-term). MDK provides an additional substrate for root growth. AMFbac has the potential to mitigate ARD effects on plant vigour but with non-replicable plant-beneficial effects in its current form of application. Thereby our results show a principal potential to mitigate economic effects but not to overcome replant disease inducing effects. While the MDK treatment is found resource intensive but reliable, the AMFbac treatment was found more user-friendly.
The effect of pre-inoculation with arbuscular mycorrhizal fungi (AMF) on post-transplant growth of peach seedlings in replant and non-replant soils was studied for two successive seasons. Seedlings ...raised in sterile media and pre-inoculated with soil-based
Gigaspora margarita inoculum were transplanted in replant and non-replant field soils alongside non-inoculated controls. Pre-inoculated seedlings transplanted in non-replant soils showed greater initial growth in the first year. Plant height, and lateral shoot length and number was highest in non-replant soils irrespective of mycorrhizal pre-inoculation. Similarly, biomass yield was significantly higher in seedlings in non-replant soils, though there were no significant differences in shoot/root ratios, and in tissue mineral content between and within treatments. Seedling infection by indigenous AMF was high in both replant and non-replant soils, and even non-inoculated seedlings recorded high infection levels after the first season. Generally, mycorrhizal activity was lower, and spore populations higher in replant soils, while the opposite was true in non-replant soils. It seems that soil sickness has a negative impact on plant metabolism and limits the capacity of the plant host to support the mycorrhizal symbiosis.
Apple seedlings cv. Antonovka were grown in soil taken from an orchard with a distinctive specific apple replant disease. The influence of the different available soil phosphorus (P) level (0, 20, 40 ...and 80 mg P dm ⁻³ of soil) and arbuscular mycorrhizae fungi (AMF) inoculation on the vegetative growth, chlorophyll fluorescence, and the frequency of mycorrhizae were assessed. Moreover, leaf and root mineral composition was ascertained by means of the inductively coupled plasma mass spectrometry (ICP-MS) method. The inoculation with AMF influenced seedlings growth as well as the biomass production and partitioning. The method of inoculation (granular, quick root dip or irrigation) had a great impact on the frequency of mycorrhizae (83.3, 98.8 and 100%, respectively) as well as on the abundance of arbuscules (36.4, 62.9 and 67.3%) as compared to the control (11.7%). The beneficial effect of AMF on leaf PSII efficiency was established. AMF inoculated plants had a significantly higher content of nitrogen, potassium, phosphorus and boron (N, K, P and B) in the shoots and a higher content of nitrogen, sulfur, copper, iron, manganese, molybdenum and titanium (N, S, Cu, Fe, Mn, Mo and Ti) in the roots. Although roots showed a higher concentration of aluminium, barium, lithium, cadmium, lead and vanadium (Al, Ba, Li, Cd, Pb, and V) but upon AMF inoculation, the concentration of these cations was much lower.
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