Spectroscopic and Foliar pH Model for Yield Prediction in a Symbiotic Corn Production

Abstract

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 R 2 adj. 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.

Arbuscular Mycorrhizal Biofertilizers Sources in the Potato (Solanum Tuberosum) Plant show Interactions with Cultivars on Yield and Litter-bags Spectral Features

“…According to Sakha et al 25 In this experiment, the litter-bag features were closely correlated with the yield, thus confirming the importance of the respiratory capacity of the control soil and above all the increment that is realized after the inoculation, as clearly outlined in Figure 2. In fact, a multivariate relationships on the averages of the eight sub-groups allowed a model with R 2 0.67, thus confirming the effectiveness of the holistic symbiotic models build in the previous experiments for Olive 13 and Corn 14 .…”

“…The main result of this experiment is that a possible AM * cultivar interaction, which had previously been shown for corn 14 , has been confirmed. Thus, the adaptation of AM strains to the genetics of potato cultivars can be considered a first step toward reducing chemical inputs, with benefits for the environment, but without an excessive reduction in yield.…”

Sunspots are Correlated with Foliar pH in Grapevines

“…Volpato et al [19], using a pH mycorrhizal model, outlined that some maize varieties did not respond by lowering their foliar pH after inoculation, i.e. were not responsive to symbiosis, as they were oriented toward a commensalism or to parasitism.…”

Spectroscopic Kernel Quality from a Symbiotic Corn Production

“…Three recently published rapid methods, namely the NIRS-litter-bag technique 13 , the raw foliar pH 14,15,16 and foliar NIR-Tomoscopy 17 , have been used together, in a holistic model, for a symbiotic corn yield production 4 . The aim of this study has been to investigate the quality of symbiotic corn.…”

“…Symbiotic Agriculture (SA) is a cultivation method that systematically integrates the use of biofertilizers in the management of all rotating crops. In the first part of this maize study 4 , we examined some critical points necessary to achieve successful yields using complex biofertilizers. Further knowledge was obtained concerning potato 5 .…”