Amelioration of Al toxicity and P deficiency in acid soils by additions of organic residues: a critical review of the phenomenon and the mechanisms involved
01 Jan 2001-Nutrient Cycling in Agroecosystems (Kluwer Academic Publishers)-Vol. 59, Iss: 1, pp 47-63
TL;DR: In this paper, an integrated overview of the probable mechanisms responsible and their implications is presented and discussed, and the practical implication of the processes discussed is that organic residues could be used as a strategic tool to reduce the rates of lime and fertilizer P required for optimum crop production on acidic, P-fixing soils.
Abstract: High rates of lime and fertilizer-P are characteristically required to obtain high crop yields on highly weathered acid soils. Much of the agriculture in the southern tropical belt, where acid soils predominate, is carried out by resource-poor, semi-subsistence farmers who are unable to purchase large quantities of lime and fertilizer. There are, however, a number of reports that additions of organic residues to acid soils can reduce Al toxicity (thus lowering the lime requirement) and improve P availability. The literature regarding these effects is sparse and disjointed and an integrated overview of the probable mechanisms responsible and their implications is presented and discussed. During decomposition of organic residues, a wide range of organic compounds are released from the residues and/or are synthesized by the decomposer microflora. The two most important groups in relation to Al toxicity and P availability are soluble humic molecules and low molecular weight aliphatic organic acids. Both these groups of substances can complex with phytotoxic monomeric Al in soil solution thus detoxifying it and they can also be adsorbed to Al and Fe oxide surfaces consequently blocking P adsorption sites. During residue decomposition, there is often a transitory increase in soil pH and this induces a decrease in exchangeable and soil solution Al through their precipitation as insoluble hydroxy-Al compounds. It also confers a greater negative charge on oxide surfaces and thus tends to decrease P adsorption. The increase in pH has been attributed to a number of causes including oxidation of organic acid anions present in decomposing residues, ammonification of residue N, specific adsorption of organic molecules produced during decomposition and reduction reactions induced by anaerobiosis. There are also mechanisms specific to either Al detoxification or improved soil P status. For example, regular applications of organic residues will induce a long-term increase in soil organic matter content. Complexation of Al by the newly-formed organic matter will tend to reduce the concentrations of exchangeable and soluble Al present. As organic residues decompose, P is released and this can become adsorbed to oxide surfaces. This will, in turn, reduce the extent of adsorption of subsequently added P thus increasing P availability. The practical implication of the processes discussed is that organic residues could be used as a strategic tool to reduce the rates of lime and fertilizer P required for optimum crop production on acidic, P-fixing soils. Further research is, therefore, warranted to investigate the use of organic residues in the management of acid soils.
Citations
More filters
TL;DR: In this paper, a statistical meta-analysis was performed with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass) with an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%.
1,762 citations
TL;DR: In this paper, the authors considered the sensitivity of individual organic matter fractions to changes in soil management and have specific effects on soil properties and processes, and concluded that individual organics are sensitive to changes and have a specific effect on soil function.
Abstract: Total soil organic matter content is a key attribute of soil quality since it has far-reaching effects on soil physical, chemical, and biological properties. However, changes in contents of organic carbon (C) and total nitrogen (N) occur only slowly and do not provide an adequate indication of important short-term changes in soil organic matter quality that may be occurring. Labile organic matter pools can be considered as fine indicators of soil quality that influence soil function in specific ways and that are much more sensitive to changes in soil management practice. Particulate organic matter consists of partially decomposed plant litter, and it acts as a substrate and center for soil microbial activity, a short-term reservoir of nutrients, a food source for soil fauna and loci for formation of water stable macroaggregates. Dissolved (soluble) organic matter consists of organic compounds present in soil solution. This pool acts as a substrate for microbial activity, a primary source of mineralizable N, sulfur (S), and phosphorus (P), and its leaching greatly influences the nutrient and organic matter content and pH of groundwater. Various extractable organic matter fractions have also been suggested to be important, including hot water-extractable and dilute acid-extractable carbohydrates, which are involved in stabilization of soil aggregates, and permanganate-oxidizable C. Measurement of potentially mineralizable C and N represents a bioassay of labile organic matter using the indigenous microbial community to release labile organic fractions of C and N. Mineralizable N is also an important indicator of the capacity of the soil to supply N for crops. It is concluded that individual labile organic matter fractions are sensitive to changes in soil management and have specific effects on soil function. Together they reflect the diverse but central effects that organic matter has on soil properties and processes. (c) 2005 Elsevier Inc.
826 citations
TL;DR: In this paper, it was shown that the reported decreases in P sorption are not related to competition from the decomposition products of organic matter breakdown, but are the result of P release from the OM that was not accounted for when calculating the reduction in P-sorption.
Abstract: The incorporation of organic matter ( OM) in soils that are able to rapidly sorb applied phosphorus ( P) fertiliser reportedly increases P availability to plants. This effect has commonly been ascribed to competition between the decomposition products of OM and P for soil sorption sites resulting in increased soil solution P concentrations. The evidence for competitive inhibition of P sorption by dissolved organic carbon compounds, derived from the breakdown of OM, includes studies on the competition between P and (i) low molecular weight organic acids (LOAs), (ii) humic and fulvic acids, and (iii) OM leachates in soils with a high P sorption capacity. These studies, however, have often used LOAs at 1 - 100 mM, concentrations much higher than those in soils ( generally < 0.05 mM). The transience of LOAs in biologically active soils further suggests that neither their concentration nor their persistence would have a practical benefit in increasing P phytoavailability. Higher molecular weight compounds such as humic and fulvic acids also competitively inhibit P sorption; however, little consideration has been given to the potential of these compounds to increase the amount of P sorbed through metal - chelate linkages. We suggest that the magnitude of the inhibition of P sorption by the decomposition products of OM leachate is negligible at rates equivalent to those of OM applied in the field. Incubation of OM in soil has also commonly been reported as reducing P sorption in soil. However, we consider that the reported decreases in P sorption ( as measured by P in the soil solution) are not related to competition from the decomposition products of OM breakdown, but are the result of P release from the OM that was not accounted for when calculating the reduction in P sorption.
538 citations
TL;DR: In this article, the authors proposed the integration of plant nutrition research with plant genetics and molecular biology is indispensable in developing plant genotypes with high genetic ability to adapt to nutrient deficient and toxic soil conditions and allocate more micronutrients into edible plant products such as cereal grains.
Abstract: The world population is expanding rapidly and will likely be 10 billion by the year 2050. Limited availability of additional arable land and water resources, and the declining trend in crop yields globally make food security a major challenge in the 21st century. According to the projections, food production on presently used land must be doubled in the next two decades to meet food demand of the growing world population. To achieve the required massive increase in food production, large enhancements in application of fertilizers and improvements of soil fertility are indispensable approaches. Presently, in many developing countries, poor soil fertility, low levels of available mineral nutrients in soil, improper nutrient management, along with the lack of plant genotypes having high tolerance to nutrient deficiencies or toxicities are major constraints contributing to food insecurity, malnutrition (i.e., micronutrient deficiencies) and ecosystem degradation. Plant nutrition research provides invaluable information highly useful in elimination of these constraints, and thus, sustaining food security and well-being of humans without harming the environment. The fact that at least 60% of cultivated soils have growth-limiting problems with mineral-nutrient deficiencies and toxicities, and about 50% of the world population suffers from micronutrient deficiencies make plant nutrition research a major promising area in meeting the global demand for sufficient food production with enhanced nutritional value in this millennium. Integration of plant nutrition research with plant genetics and molecular biology is indispensable in developing plant genotypes with high genetic ability to adapt to nutrient deficient and toxic soil conditions and to allocate more micronutrients into edible plant products such as cereal grains.
504 citations
TL;DR: In this paper, the authors reviewed crop residue management practices, mainly surface retention, incorporation or removal, describing their advantages and limitations in cereal-based agroecosystems in developing countries.
374 citations
References
More filters
Book•
01 Jan 1982
TL;DR: In this paper, the authors present an analysis of organic matter in soil using NMR Spectroscopy and analytical pyrolysis, showing that organic matter is composed of nitrogen and ammonium.
Abstract: Partial table of contents: Organic Matter in Soils: Pools, Distribution, Transformations, and Function. Extraction, Fractionation, and General Chemical Composition of Soil Organic Matter. Organic Forms of Soil Nitrogen. Native Fixed Ammonium and Chemical Reactions of Organic Matter with Ammonia and Nitrite. Organic Phosphorus and Sulfur Compounds. Soil Carbohydrates. Soil Lipids. Biochemistry of the Formation of Humic Substances. Reactive Functional Groups. Structural Components of Humic and Fulvic Acids as Revealed by Degradation Methods. Characterization of Soil Organic Matter by NMR Spectroscopy and Analytical Pyrolysis. Structural Basis of Humic Substances. Spectroscopic Approaches. Colloidal Properties of Humic Substances. Electrochemical and Ion-Exchange Properties of Humic Substances. Organic Matter Reactions Involving Pesticides in Soil. Index.
5,658 citations
"Amelioration of Al toxicity and P d..." refers background in this paper
...Humic substances, which make up 70–80% of the soil organic matter (SOM) content of most mineral soils, are complex systems of high molecular weight organic molecules made up of a core of phenolic polymers produced from the products of biological degradation of plant and animal residues and the synthetic activity of microorganisms (Stevenson, 1994)....
[...]
...Physical (Van der Waals) forces will also be involved in the interaction of humic molecules with oxide surfaces (Stevenson, 1994)....
[...]
...Waals) forces will also be involved in the interaction of humic molecules with oxide surfaces (Stevenson, 1994)....
[...]
...Negatively charged, high-molecular-weight, humic polymers can form strong bonds with metal hydrous oxide surfaces through both electrostatic bonding (anion exchange) and specific adsorption i.e. ligand exchange (Stevenson, 1994)....
[...]
...…organic matter (SOM) content of most mineral soils, are complex systems of high molecular weight organic molecules made up of a core of phenolic polymers produced from the products of biological degradation of plant and animal residues and the synthetic activity of microorganisms (Stevenson, 1994)....
[...]
TL;DR: In this paper, the chemistry of submerged soils is discussed and the role of lake, estuarine, and ocean sediments as reservoirs of nutrients for aquatic plants and as sinks for terrestrial wastes.
Abstract: Publisher Summary This chapter discusses the chemistry of submerged soils. The chemical changes in the submerged materials influence: (a) the character of the sediment or soil that forms, (b) the suitability of wet soils for crops, (c) the distribution of plant species around lakes and streams and in estuaries, deltas, and marine flood plains, (d) the quality and quantity of aquatic life, and (e) the capacity of lakes and seas to serve as sinks for terrestrial wastes. The single electrochemical property that serves to distinguish a submerged soil from a well-drained soil is its redox potential. The redox potential of a soil or sediment provides a quick, useful, semiquantitative measure of its oxidation–reduction status. Two recent developments have stimulated interest in the chemistry of submerged soils: the breeding of lowland rice varieties, with a high yield potential, and the pollution of streams, lakes, and seas, by domestic, agricultural, and industrial wastes. The chemistry of submerged soils is valuable: (a) in understanding the soil problems, limiting the performance of high-yielding rice varieties, and (b) in assessing the role of lake, estuarine, and ocean sediments as reservoirs of nutrients for aquatic plants and as sinks for terrestrial wastes.
2,651 citations
"Amelioration of Al toxicity and P d..." refers background in this paper
...Such reactions characteristically occur under anaerobic conditions (Ponnamperuma, 1972) and lead to a rise in soil pH: MnO2+ 2H+ + 2e− Mn2+ + 2OH− FeO(OH)+ e− +H2O Fe2+ + 3OH−...
[...]
...Such reactions characteristically occur under anaerobic conditions (Ponnamperuma, 1972) and lead to a rise in soil pH: MnO2+ 2H+ + 2e− Mn2+ + 2OH− FeO(OH)+ e− +H2O Fe2+ + 3OH− Hue & Amien (1989) suggested that localized anaerobic conditions could develop around rapidly decomposing pieces of organic…...
[...]
01 Jan 1995
1,690 citations
"Amelioration of Al toxicity and P d..." refers background in this paper
...Inhibition of root growth occurs through impedance of both cell elongation and cell division (Kochian, 1995)....
[...]
...Aluminium in a form complexed to soluble OM is not toxic to plants (Kinraide, 1991; Suthipradit et al., 1990) and complexation of Al by OM appears to be a very important mechanism of detoxification of soil solution Al (Kochian, 1995; Ritchie, 1989)....
[...]
...Aluminium toxicity also interferes directly with active ion uptake processes functioning across the root-cell plasma membrane (Kochian, 1995; Wright, 1989)....
[...]
..., 1990) and complexation of Al by OM appears to be a very important mechanism of detoxification of soil solution Al (Kochian, 1995; Ritchie, 1989)....
[...]
...The reason for this is thought to be that at low pH (where Al3+ predominates) the presence of H+ partially alleviates the phytotoxic effect of Al3+ by competing with Al3+ at the root cell plasma membrane (Kochian, 1995)....
[...]
TL;DR: Acid soils occupy approximately 30% or 3950 m ha of the world's ice free land area and occur mainly in two global belts where they have developed under udic or ustic moisture regimes as mentioned in this paper.
Abstract: Acid soils occupy approximately 30% or 3950 m ha of the world’s ice free land area and occur mainly in two global belts where they have developed under udic or ustic moisture regimes. The northern belt (cold and temperate climate) is dominated by Spodosols, Alfisols, Inceptisols and Histosols and the southern tropical belt consists largely of Ultisols and Oxisols.
1,271 citations
"Amelioration of Al toxicity and P d..." refers background in this paper
...Acid soils occupy about 30% of the world’s icefree land area and occur in two main global regions; the northern cold temperate belt and the southern tropical belt (Von Uexküll & Mutert, 1995)....
[...]
...Acid soil infertility is a major limitation to crop production on highly weathered and leached soils in both tropical and temperate regions of the world (Sanchez, 1976; Von Uexküll & Mutert, 1995)....
[...]
...Acid soils occupy about 30% of the world’s icefree land area and occur in two main global regions; the northern cold temperate belt and the southern tropical belt ( Von Uexkull & Mutert, 1995 )....
[...]
...Acid soil infertility is a major limitation to crop production on highly weathered and leached soils in both tropical and temperate regions of the world (Sanchez, 1976; Von Uexkull & Mutert, 1995 )....
[...]
TL;DR: Recent progress that has been made in the understanding of Al toxicity and the mechanisms of Al tolerance in plants are reviewed.
Abstract: Aluminum (Al) is the most abundant metal in the earth's crust, comprising about 7% of its mass. Since many plant species are sensitive to micromolar concentrations of Al, the potential for soils to be Al toxic is considerable. Fortunately, most of the Al is bound by ligands or occurs in other nonphytotoxic forms such as aluminosilicates and precipitates. However, solubilization of this Al is enhanced by low pH and Al toxicity is a major factor limiting plant production on acid soils. Soil acidification can develop naturally when basic cations are leached from soils, but it can be accelerated by some farming practices and by acid rain (Kennedy, 1986). Strategies to maintain production on these soils include the application of lime to raise the soil pH and the use of plants that are tolerant of acid soils. Although Al toxicity has been identified as a problem of acid soils for over 70 years, our knowledge about the primary sites of toxicity and the chain of events that finally affects plant growth remains largely speculative. In this paper we review recent progress that has been made in our understanding of Al toxicity and the mechanisms of Al tolerance in plants.
1,242 citations
"Amelioration of Al toxicity and P d..." refers background in this paper
...Malic acid release from root tips appears to be a mechanism of Al resistance for wheat genotypes, whilst citric acid release is apparently related to Al resistance in maize and snapbean genotypes (Delhaize & Ryan, 1995; Miyasaka et al., 1991; Pellet et al., 1994)....
[...]