Soil solid and solution phase changes and mung bean response during amelioration of aluminium toxicity with organic matter

Abstract

A soil incubation and short-term root growth experiment was conducted to investigate the effects of organic matter application on AI toxicity alleviation in a highly weathered acid soil. Ground leaves of a tree legume (Calliandra calothyrsus Meissn.), ground barley (Hordeum vulgare L.) straw, or CaCO 3 were mixed at various rates with A-horizon soil of a red podzolic soil (Epiaquic Haplustult) and incubated at 90% of field capacity for 4 or 10 weeks. After the incubation, a short term (48 h) root growth test was conducted using mung bean (Vigna radiata (L.) Wilczek), followed by the analysis of the solution and solid phases of the post-harvest soil.Adding either CaCO 3 or organic matter increased root length in mung bean largely by decreasing the activity of monomeric AI in the soil solution. With organic matter, the major mechanisms of this decrease were presumed to be precipitation of soluble AI and the formation of Al-organic matter complexes. The former effect was predicted from the pH increase accompanying the organic matter addition, the increase being larger with legume leaves which had the higher exchangeable and soluble Ca and Mg contents. The concentration of A1 complexed with soluble organic matter also was shown to increase with increasing rate of organic matter addition, the effect again being larger with legume leaves.The sum of monomeric AI species activity and A13+ ~ctivity was negatively correlated with relative root length for the organic matter and CaCO 3 treatments. However, indices which took into account the possible alleviation effects of basic cations in soil solution on A1 toxicity provided an improvement in correlation with relative root length.The efficiency of the two organic amendments relative to CaCO 3 in decreasing A1 toxicity was assessed by comparing the rates required to reduce A13+ activity below 10/xM, the value found to be associated with 90% relative root length for mung bean. The rates of CaCO3, legume leaf and barley straw required to reach this critical value were 0.75, 14, and 42 t ha -1 respectively.

Soil conditions and evolution of aluminium resistance among cultivated and wild plant species on the Island of Madeira

“…In the presence of organic matter the toxicity of Al in soils was considerably reduced presumably due to the detoxifying effect of organic acids or via the formation of Al-organic complexes (Bessho andBell 1992, Haynes andMokolobate 2001). Analysis of effect of soil organic matter on Al resistance among the wild and cultivated species revealed an interesting phenomenon.…”

Yield, Quality and Micronutrients Uptake of Carrot (Daucus carota L.) and some Soil Properties as Affected by Organic Fertilizers and Elemental Sulphur Application

“…This increase in soil pH with chicken manure, were also reported in other studies (Pitman and Singh, 1993). The mechanism responsible for this increase in soil pH was due to ion exchange reactions which occur when terminal OH -of Al or Fe 2+ hydroxyl oxides are replaced by organic anions which are decomposed products of the manure such as malate, citrate and tartrate (Eshoo and Bell, 1992, Pocknee and Summer, 1997and Hue & Amiens, 1989. The ability of chicken manure to increase soil pH was also attributable to the presence of basic cations in the chicken manure released upon microbial decarboxylation (Natsher and Schwetnmann, 1991).…”

Dinâmica de íons em solo ácido lixiviado com extratos de resíduos de adubos verdes e soluções puras de ácidos orgânicos

“…Efeitos benéficos do manejo orgânico de solos ácidos têm sido observados em diversos sistemas agrícolas, cujas principais alterações químicas na camada de 0 a 20 cm de profundidade são: elevações do pH e do teor de Ca em detrimento do Al (Sanchez et al, 1982;Hue & Amien, 1989;Bessho & Bell, 1992). Em alguns casos, esses efeitos se estendem à subsuperfície do solo (Watt et al, 1991;Pavan, 1994;Liu & Hue, 1996;Oliveira & Pavan, 1996).…”