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Jul 2023 DOI 10.14302/issn.2639-3166.jar-23-4648
Masoero GiorgioCorresponding author
The purpose of the trial was to check the effects of two grapevine treatments on the plant activity and on the bioactivity and biovariability of the soil. An alkaline complex of Soluble Biobased Substances (SBS) was used in soil at 30 g per plant in a single solution. Salicylic Acid (SA) was used on leaves at 150 mg l-1 every two weeks at 50 ml plant. The plants were examined for their foliar pH and NIR spectra. The soil bioactivity was monitored by means of hay-Litterbag-NIRS (LBN) in combination with the Teabag Index (TBI), using rooibos and green tea that had been buried for 60 days. The evolution of the TBI presented here concerns the TBI-NIRS spectroscopic method used for discriminant analysis. A new algorithm was used to estimate the soil microbiome from the green Teabag spectra. The obtained results showed that the plants and the soil responded to the treatments. In fact, SBS, but not SA, lowered the leaf pH by 5%, an unexpected and original result. Both treatments increased the variability of the leaf composition, with a lower discrimination, based on the NIR spectra, from the Control (75%) to 44% (SA) and 38% (SBS). The TBI method, which is based on weights, was less efficient (67%) than the TBI-NIRS of rooibos (96%) or the LBN of hay (80%), but it was like the TBI-NIRS of green tea (74%). The LBN analyses indicated that the mycorrhizal index had increased by 8% in SA but had reduced by 7% in SBS, while both treatments reduced the activity of the microbes, which did not affect the soil respiration rate. The mineral N in the soil was substantially raised by about 11÷69%. The Taxa profiles showed marked deviations from the Control. Moreover, the SBS treatment reduced the Glomeromycota by 35%, which matched to the reduction in the mycorrhizal index. The most favored Bacteria from the treatments were Proteobateriaand Actinobacteria, with Mortierellomycota being the most penalized. Neither treatment affected the production, but both delayed the technological maturity by 9-11%, while the SBS retarded the phenolic maturity by about 18%. It has been concluded that a simple treatment of vines can affect the bioactivity in the leaves and berries as well as the biovariability of the soil.
Dec 2020 DOI 10.14302/issn.2639-3166.jar-20-3639
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Via A. Doria 10, 10123 Torino (Italy).
An experiment on watercress (Lepidium sativum) 42 d days after sowing was set up to evaluate the effect of UVAB radiation on foliar pH and on NIR tomoscopy. The effect of 8 h of UV exposure (about 500 µWcm-2) was clear, causing a reduction in the foliar pH of 6.0%, compared to the contemporary control group (5.22 vs. 5.56). When the treated leaves were returned to white light, their pH rose by 1.7% (5.31), reaching the same level as leaves grown outdoors (5.33). On the basis of the NIR spectra, the leaves of the plants grown outdoors were recognized 100%, that is, more than the control leaves (87%) and the plants treated with UV on the day of measurement (81%). However, the effect of the UV marking on the leaves is not permanent as, after the UV treatment, the leaves returned to white light were classified at 61%, which is a greater value than the 37% of overlapping between the two groups. The foliar pH was highly correlated with the NIR spectra, with R2 0.43. These results corroborate the hypothesis of the influence of the solar cycle on the variation of the pH of leaves in plants, which we believe may have played a major role in past agricultural pandemics. These results call for the introduction of the pH test for the evaluation of resistance to pathogens. From the environmental point of view, the foliar pH could be enlisted as an in vivo long-time indicator of the response of plants to climate changes.
Dec 2019 DOI 10.14302/issn.2639-3166.jar-19-3116
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Italy
Foliar pH is a specific multifaceted parameter that is sensitive to a deficit in soil water and to temperature variations. It also represents a tool that can be used to rapidly phenotype the symbiosis induced in several crops by bio-fertilizers containing Arbuscular Mycorrhizal Fungi. Yearly decreases in foliar pH, which dropped from 3.73 in 2015 to 3.15 in 2017 and then stabilized at around 3.13, have been observed in an experimental vineyard near Torino (Italy) in six grapevine cultivars. In this paper, these curious, original results have been paired with the average sunspots of the 24th sun cycle, proximal to its endpoint. The paired values were highly correlated (r 0.95 P< 0.01), with close parabolic patterns. A lowering in foliar pH has been correlated with a modification of the leaf composition, as characterized by the higher hydration and reinforced wall. An increase in the circulating acidity of the plants has been hypothesized to interfere in a diminution in the general predisposition to block parasite attacks. From this perspective, the retrieval of several historic outbreaks and the long-term systematic monitoring of mud and Erwinia amylovora frequencies have suggested that the hypothesis that links the solar minima with dysfunctions of the plant-pest relationships cannot always be rejected. Cosmic influences pertaining to UV variations are poorly understood in plant physiopathology. Foliar pH appears to be a rapid and simple tool to unveil high-level mechanisms. It is this simple parameter that physiologists and geneticists, but also agronomists, are asked to consider.
Nov 2019 DOI 10.14302/issn.2639-3166.jar-19-3089
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Italy
The agronomic management of symbiotic (S) inoculations, by means of bio-fertilizers (BF), is aimed at inducing modifications of the plant rhizosphere and thereafter of the phenotype and yield of the crop. It is here shown that the yield response of maize to a symbiotic treatment may be correlated to six easy-to-calculate indicator variables on the basis of the raw foliar pH, NIR-Spectroscopy of leaves, and the NIRS of hay litter-bags from soils. It has been confirmed, in a set of thirteen pairwise comparisons of Symbiotic (S) soil inoculated by BF vs. Control (non-inoculated soil; C), that the inoculation on average acidified the leaves by -3.7% pH units (P<0.0001). The responses in yield ranged from +25.2% to -9.2% (av.ge +3.5%; P = 0.03), but with average null responses in two centers and a significant response (+11%) in a third center. NIR-Tomoscopy scans (No. 574) were also performed on the leaves, and in addition, hay-litter-bags that had previously been buried in fields were dug up after two months, and 431 NIR- scans were acquired. The effect-size on the yield was expressed as the logarithm of the response ratio, i.e. the mean of the inoculated Symbiotic treatment divided by the mean of the non-inoculated Control for each pairwise comparison. A multiple regression model was developed to predict the symbiotic response to the treatment using six independent variables, including the squared litter-bag fingerprints, and an R2adj. level of 0.78 (P=0.01) was reached, with a standard error of ±4%. Validation in one external maize field, with a positive response to bio-fertilizers, demonstrates the juxtaposition of the estimated and accomplished yield. In a second experiment, with 40 pairwise comparisons, the two tested maize varieties did not respond to five types of bio-fertilizer, and the negative results were predicted at 84% (P 0.0012). The soil biota is a key factor for the application of appropriate microbial inoculants in the field, but the genotype/genotype interactions between the microbial strain (s) and the crop cultivar (s) require prior screening to obtain the desired results.
Jan 2021 DOI 10.14302/issn.2639-3166.jar-20-3676
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Via A. Doria 10, 10123 Torino (Italy).
There is currently a lack of rapid indirect analysis methods for the assessment of the effects of soil microbiota on vine production. Fifteen clusters of two Nebbiolo and Erbaluce varieties were identified in five vineyards belonging to a cooperative of winemakers in North West Italy, according to the differences in the NDVI index, as monitored by the Crop Monitoring OES system. The vineyards were surveyed in 2019 and the experimental monitoring of 75 vines was conducted in 2020. The first indirect method (Litterbag-NIRS) involved examining hay litterbags with a smart SCiOTM device. The average litterbag-NIR spectra of the clusters, as far as the yield is concerned, were closely fitted with the measured production yield, with an R2 cross-validated value of 0.91 in the Nebbiolo vines and 0.67 in the Erbaluce vines. The results in yield were accounted for by considering a few dominant variables in both vines, namely the microbic respiration of the soil and the crude protein of the litterbag (positive), opposed to the soil NO3--N and litterbag ADF (negative). The pruning wood was also closely correlated to the litterbag spectra. A second rapid method, foliar pH coupled with the NIR spectroscopy of the leaves, was then performed. The overall results predicted from the foliar NIRS were 0.73 for yield and 0.79 for the Canopy Cover. However, the most interesting result concerned the yield regressions on the foliar pH, which were clearly negative in both vines and of a similar amount: -5.15 kg/pH in Nebbiolo (R2 0.68) and -5.63 kg/pH (R2 0.23) in Erbaluce. Litterbag-NIRS, which shows a high predictive capacity, and foliar pH - with or without foliar-NIRS - are indirect and frugal methods that can be recommended for a rational assessment of the microbial soil fertility of vineyards.
Mar 2020 DOI 10.14302/issn.2639-3166.jar-20-3260
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Via A. Doria 10, 10123 Torino (Italy).
The management of the inoculation of a plant’s roots, by means of biofertilizers (BF) containing arbuscular mycorrhizal (AM) fungi, is aimed at inducing modifications of the quality of the seeds. It is here shown that a seed-soil treatment can be elicited in the fingerprints of a symbiotic treatment using Near Infra Red (NIR)-SCiO NIR-SCiO spectra collections of single kernels: overall, a sensitivity of 73% and a specificity of 73% have been achieved, thus suggesting that it may be possible to assign the symbiotic origin of corn from just twenty kernels, provided that the dataset is adequately representative of the cultivar and AM. A global correlation study has shown a positive general trend (R2 0.45) of quality vs. quantity, in the sense that an increase in yield corresponded to an increase in the spectral differences between the symbiotic spectra and the control ones, but the inverse was also true, as a result of the parasitic behaviour of the BF treatments. The efficacy of the symbiosis can be back predicted from the NIR spectra; in fact, around 90% of the positive yield outcome results were discriminated from the negative ones. A reduction in the foliar pH (R2 0.37) and an increase in the foliar protein (R2 0.43) were observed as immediate phenotypic signs of a productive symbiosis. The commercial raw composition of the kernels appeared to only be affected slightly by the BF treatments; thus, till now uncharted secondary compounds of the maize kernels are involved, as supported by animal performances.
Aug 2018 DOI 10.14302/issn.2639-3166.jar-18-2264
Masoero GiorgioCorresponding author
Accademia di Agricoltura di Torino, Torino, Italy
The management of symbiotic Microbial Biota (MB) in the soil as agents that promote the yield and health of crops, is aimed at inducing modifications of the phenotype of plants, both over and under the ground. It is here shown, in Sorghumsudanensis plants, that: i) a simple response to MB inoculation is the result of the fall out of the raw pH; ii) the simple NIR scans of leaves can be considered to rapidly classify the outcomes; iii) the raw pH can be considered a key-variable of leaf modifications. An experiment was carried out on Sorghumsudanensis. The plants were seeded in pots and grown for 66 d, and then a control non-inoculated group (C) was compared with thirteen Arbuscular Mycorrhizae (AM) Glomus inoculated groups and with two commercial MB products. A total of 374 raw pH measurements conducted on the leaves showed that the 5.18 pH units in the C group were scaled by -1.9% (P<0.0336) in the MB group and by -3.4% in the AM group (P<0.0001), with a relevant diversity between groups. Direct discrimination of these three groups, by means of smart NIR-SCIO, showed a % reclassification of the C, MB and AM groups of 74%, 59% and 96% in the fresh leaves and of 65%, 51% and 94% in the dried ground leaves, respectively. The composition of the dried leaves, based on a set of 14 variables predicted via NIRS models, plus the total foliar dry weight and percentage, showed a typical increase in protein, ash and hemicellulose, and a typical decrease in the cellulose, dry matter, crude fiber and crop maturity index. These variables were related to the foliar pH, as a key-variable, by means of a PLS standard model (R2 0.81) in which a low pH steadily favored the dry mass weight and, to a lesser extent, the hemicellulose and the digestible NDF contents; on the other hand, a high pH increased the dry matter percentage and the cellulose content of the leaves. As expected, the leaves of the inoculated plants showed a more juvenile ontogenic status. The epigean botanical modifications can be considered harmonic expressions of a luxuriant symbiosis, as testified by the homologous NIR categorization. The outlook for a symbiotic agriculture, with mycorrhizal plants, should consider the raw pH as a multifaceted variable.