Luciano Cavani

Identification of organic matter from peat, leonardite and lignite fertilisers using humification parameters and electrofocusing

The organic matter extracted from peats (P), leonardites (Le) and lignites (Li) was characterised by humification parameters and electrofocusing (EF). The degree of humification and the humification index might be used to distinguish P from Le and Li, but not Le from Li because they showed overlapped values, while the humification rate could be used only for the identification of Le and EF profiles of P, Le and Li fertilisers revealed different band patterns: P samples did not show bands in the region with isoelectric point, pI > 4.4; Le samples showed very intense bands in the region with pI > 4.4; Li samples showed a very different band pattern with poorly resolved bands in the region with pI > 3.8. P, Le and Li samples can be distinguished by combining humification parameters and EF.

Determination of free L- and D-alanine in hydrolysed protein fertilisers by capillary electrophoresis.

of racemisation of hydrolysed protein fertilisers (HPFs) using an The objective of this study was to determine the degree inexpensive and easy to handle analytical method for qualitative control of the products. Using a polyacrylamide coated capillary and a run buffer containing 0.1 M Tris-borate+2.5 mM EDTA-Na2+0.1% sodium dodecylsulfate+10 mM beta-cyclodextrin a quantitative separation of D- and L-alanine (Ala) was made from an not treated HPF sample derivatised with dansyl chlorine by capillary electrophoresis. The D-Ala:[D-Ala+L-Ala] ratio, called degree of racemisation (RD), was calculated. The analysis of ten commercial HPFs has shown that more than 60% of HPFs have an RD > or = 40%. while only one product has shown an RD <5%. These results showed that most of the HPFs on the market are obtained with strong hydrolytic processes and high contents of D-amino acids are probably less effective as plant nutrients or even potentially dangerous to plants.

Capillary zone electrophoresis of soil humic acid fractions obtained by coupling size-exclusion chromatography and polyacrylamide gel electrophoresis

Capillary zone electrophoresis (CZE) was used for characterisation of soil humic acid (HA) fractions obtained by coupling size-exclusion chromatography with polyacrylamide gel electrophoresis, on the basis of their molecular size and electrophoretic mobility. CZE was conducted using several low alkaline buffers as background electrolyte (BGE): 50 mM carbonate, pH 9.0; 50 mM phosphate, pH 8.5; 50 mM borate, pH 8.3; 50 mM Tris-borate+1 mM EDTA+7 M urea+0.1% sodium dodecyl sulphate (SDS), pH 8.3. Independently of BGE conditions, the effective electrophoretic mobility of HA fractions were in good agreement with their molecular size. The better resolution of HA were obtained in Tris-borate-EDTA buffer with urea and SDS. This results indicated that CZE, mostly with BGE-contained disaggregating agents, is useful for separating HAs in fractions with different molecular sizes.

Relationships between stability, maturity, water-extractable organic matter of municipal sewage sludge composts and soil functionality

Compost capability of restoring or enhancing soil quality depends on several parameters, such as soil characteristics, compost carbon, nitrogen and other nutrient content, heavy metal occurrence, stability and maturity. This study investigated the possibility of relating compost stability and maturity to water-extractable organic matter (WEOM) properties and amendment effect on soil quality. Three composts from municipal sewage sludge and rice husk (AN, from anaerobic wastewater treatment plants; AE, from aerobic ones; MIX, from both anaerobic and aerobic ones) have been analysed and compared to a traditional green waste compost (GM, from green manure, solid waste and urban sewage sludge). To this aim, WEOMs were characterized through chemical analysis; furthermore, compost stability was evaluated through oxygen uptake rate calculation and maturity was estimated through germination index determination, whereas compost impact on soil fertility was studied, in a lab-scale experiment, through indicators as inorganic nitrogen release, soil microbial biomass carbon, basal respiration rate and fluorescein di-acetate hydrolysis. The obtained results indicated that WEOM characterization could be useful to investigate compost stability (which is related to protein and phenol concentrations) and maturity (related to nitrate/ammonium ratio and degree of aromaticity) and then compost impact on soil functionality. Indeed, compost stability resulted inversely related to soil microbial biomass, basal respiration rate and fluorescein di-acetate hydrolysis when the products were applied to the soil.

Effect of compost application on the dynamics of carbon in a nectarine orchard ecosystem

The aim of the present study was to compare the quantity and the type of carbon (C) stored during the 14-year lifetime of a commercial nectarine orchard ecosystem fertilized with mineral or organic fertilizers. The study was carried out in the Po valley, Italy, in a nectarine orchard of the variety Stark RedGold, grafted on GF677 hybrid peach × almond. Since orchard planting in August 2001, the following treatments were applied in a randomized complete block design with four replicates per block and compared: 1. unfertilized control; 2. mineral fertilization (including P and K at planting and N applied as NO3NH4 yearly at the rate of 70-130 kg ha-1); 3. compost application at a rate of 5 Mg DW ha-1 yr-1; 4. compost application at a rate of 10 Mg DW ha-1 yr-1. Compost was obtained from domestic organic wastes mixed with pruning material from urban ornamental trees and garden management after a 3-month stabilization period. Application of compost at the highest rate increased C in the soil; the amount of C sequestered was approximately 60% from amendment source and 40% from the net primary production of trees and grasses with a net increase of C compared to mineral fertilization. Compost application was found to be a win-win strategy to increase C storage in soil and, at the same time, to promote plant growth and yield to levels similar to those obtained with mineral fertilization. The rate of C application is crucial, indicated by the fact that compost supply at the rate of 10 Mg ha-1 yr-1 was the only fertilization strategy of the ones tested that resulted in higher C sequestration. This shows that compost amendment may stimulate an increase in the net primary production of plants.

Indirect effect of glyphosate on wine fermentation studied by microcalorimetry

The use of herbicide such as glyphosate is a common practice in viticulture to limit nutrients and water competition between vine/weed plants. However, the impact of such herbicide on the resulting grapes juice quality and, later, on wine fermentation has not yet been proven. In this work, grapes of Vitis vinifera L. cv Gewürztraminer harvested from plants subjected to the weed control with glyphosate were analysed for their fermenting capacity by isothermal microcalorimetry after inoculation with Saccharomyces cerevisae. The resulting heat flow traces were fitted by two additive Gompertz functions and used to describe the yeast growth rate. The comparison of the fitting parameters showed that glyphosate decreased the heat generated by yeast growth. This effect was consistent with a change in the amino acids and sugars contents in grapes. However, the results also show that the impact of the herbicide on yeast fermentation can be partly overcome with an additional N fertilization (i.e. urea) in the vine. Microcalorimetry has revealed for the first time these effects on the fermenting process of grapes.

Interactions of organic and inorganic chromium species with Ca-polygalacturonate

This study investigated the interactions of CrIII and CrVI present as free metal ions or as organic CrIII (Cr-L) with a Ca-polygalacturonate (Ca-PG) network. Ca-PG networks were treated with solutions of chromium (CrIII and CrVI) at different concentrations at three different pH values. The Cr-L complex were obtained by water extraction of hydrolysed leather. The CrVI had almost no interaction with the Ca-PG networks, whereas CrIII as a free metallic ion was strongly retained by the network. The calculated Langmuir adsorption isotherms showed a twofold increase in maximum CrIII adsorption but a decrease in the affinity of the metal with the Ca-PG networks. This would indicate that the different chromium species, i.e. CrIII and its hydrolytic species, interact in a different way with the polygalacturonate chains. In addition, thermal analysis showed that CrIII sorption modified the structure of the network. These modifications were reduced, and thermal stability increased if Ca-PG adsorbed Cr-L or L. Furthermore, the treatment of Ca-PG with hydrolysed leather water extract-reduced CrIII sorption by 94%. The hydrolysed leather fraction immobilized onto the Ca-PG networks probably consisted of peptides and could therefore represent an important source of organic N.

Rhizodeposition of Zea mays L. as affected by heterosis

Abstract The objective of the present work was to investigate in a field experiment the quantity and quality of rhizodeposits of different parental inbred lines (Lo1016 and Lo964, B73 and H99) and hybrids of Zea mays L. Rhizosphere soil was collected after 40 days and several properties were determined: pH, organic carbon, total nitrogen, acid and alkaline phosphatases, organic acids, bioavailable phosphorous, α-amino nitrogen, total phenols, total root-derived rhizodeposits. The results showed that heterosis induced more qualitative differences within the genotypes as δ13C, TOC and TN did not show any significant differences. The two groups of genotypes enhance phosphorous availability adopting two different strategies. In the first group, B73 × H99 shows the best phenological performance as well as the highest concentration of bioavailable P, result which is correlated with a high organic acid concentration (in particular succinic and acetic acid), total phenols, α-amino nitrogen and acid phosphatase activity. There is thus a strict relationship between the phenological superiority of this particular hybrid and its ability to modify the chemistry of its rhizosphere whereas the second hybrid (Lo1016 × Lo964) seems to have developed different strategies as for example changing the root morphology, stimulating microbial biomass or favouring mycorrhizal symbiosis.

Vantagens energéticas e ambientais do uso de adubo em couro

No Brasil, a industria de curtimento gera grandes quantidades de residuos. Este pais ocupa uma posicao significativa como produtor de pele - especialmente couro bovino. Os residuos solidos sao muitas vezes descartados no ambiente sem tratamento, o que implica problemas ambientais e desperdicio de energia. Normalmente, o controle e o gerenciamento industrial de residuos solidos no pais sao caracterizados pela falta de estudos sobre o assunto, quantidade e qualidade dos residuos gerados, alem da falta de unidades compativeis de tratamento final e descarte em algumas regioes. O couro e bronzeado com sais de cromio. Este processo visa obter um melhor acabamento, aumentando a resistencia ao desgaste e a corrosao. O bronzeamento com os sais de cromo (III) os torna mais flexiveis e macios. Assim, este estudo pretende verificar um modelo matematico do comportamento da mineralizacao de nitrogenio potencial e do comportamento do sal de cromo (III) em solos apos aplicacao de fertilizante feito de hidrolisado de couro bovino. O modelo matematico sera aplicado de acordo com os dados obtidos, e apos a aplicacao da metodologia estabelecida.

Estudo experimental do impacto do cromo a partir de fertilizantes altamente energeticamente eficientes no solo

A legislacao ambiental brasileira sobre os efeitos de alguns elementos quimicos descartados no solo ainda e muito recente, especialmente no que diz respeito as varias transformacoes de diferentes tipos de cromo que podem ser usados em conjunto com fertilizantes feitos de restos de couro. Este fato e principalmente devido a falta de dados experimentais que mostram claramente as varias modificacoes sofridas pelos varios tipos de cromo liberados na crosta terrestre, associados a fertilizantes. Este fato nao ocorre em muitos paises desenvolvidos, como a Italia, por exemplo, onde ja existem varios estudos sobre os efeitos de varios tipos de cromo, que sao usados em conjunto com fertilizantes de couro. Este trabalho apresenta um estudo experimental sobre o comportamento do cromo (III) em solo aravel, utilizando fertilizante de couro hidratado como fertilizante eficiente em energia.