Effects Of Soil Chemical Properties Research Articles

Diversity patterns of indigenous arbuscular mycorrhizal fungi associated with rhizosphere of cowpea (Vigna unguiculata (L.) Walp.) in Benin, West Africa

Assessment of diversity and understanding factors underlying species distribution are fundamental themes in ecology. However, the diversity of native arbuscular mycorrhizal fungi (AMF) species in African tropical agro-ecosystems remains weakly known. This research was carried out to assess the morphological diversity of indigenous AMF species associated with rhizosphere of cowpea (Vigna unguiculata (L.) Walp.) in different agro-ecological zones (AEZ) of Benin and to examine the effects of soil chemical properties, climatic factors and agricultural practices on this diversity. Results showed that, in Benin, cowpea was grown by farmers in very exhausted soils, where available phosphorus and potassium were deficient. The indigenous AMF spore density was on average 202 spores per 100 g dry soil and there was no difference in the density among the agro-ecological zones (P = 0.56). Fifteen AMF morphospecies belonging to eight genera (Gigaspora, Scutellospora, Racocetra, Acaulospora, Funneliformis, Rhizophagus, Glomus and Claroideoglomus) were detected. The computed species richness estimators indicated that a limited number of additional undetected morphospecies are probably present in cowpea fields. According to analysis of similarity (ANOSIM), the arbuscular mycorrhizas community composition of the Sudanian zone and Guinean zone were not significantly different (r = −0.01; P = 0.517). The diversity of AMF morphospecies in the fields was weak with prevalence of Glomeraceae (92%). Furthermore, AMF diversity and evenness indices were negatively correlated with annual rainfall (P < 0.01) and with available phosphorus (P < 0.05). However, no significant correlation was observed between AMF diversity indices and soil organic carbon. Ultimately, this study tends to confirm that soil management practices (tillage, soil disturbance) have negative effect on AMF diversity.

Effect of soil depth and increasing fertilization rate on yield and its components of two durum wheat varieties

Agronomic practices, climatic variables, and soil conditions are key factors in crop productivity. Although the effects of soil chemical properties and water and agronomic crop management are known, there is little information about effective soil depth and its influence on crop productivity. Since most crop fertilization systems are based on the productive potential associated with climatic conditions and chemical properties of the first 20 cm of soil depth, the objective of this study was to determine the importance of effective depth in terms of increasing fertilization rates on durum wheat ( Triticum turgidum L. var. durum) productivity. Two experiments were conducted in the 2006-2007 season in the Santa Rosa Experimental Station (71°54’ S, 36°31’ W, 220 m a.s.l.) of the Instituto de Investigaciones Agropecuarias (INIA) located in south central Chile. We used the hard wheat cvs. Llareta-INIA and Corcolen-INIA because both respond differently to soil physicochemical properties. Each cultivar was sown in sectors with different depths: 1) 0.45 m depth, silt loam on river material and 2) 1.0 m depth, loam on deep sediments. Fertilization was: 1) control without fertilization, 2) basal fertilization (BF) based on P, K, Ca, Mg, S, B, and Zn plus 90 kg N ha-1, and 3) BF plus 210 kg N ha-1. Grain yield, plant height, and number of stems m-2 were positively affected by increasing depth of soil profile. The increasing fertilization rate affected grain yield and plant height. Grain yield for cv. Corcolen-INIA had a greater response than cv. Llareta-INIA when soil depth was increased.

Influence of soil chemical properties on relative abundance of arbuscular mycorrhiza in forested soils in Malaysia

The effect of soil chemical properties on the diversity and colonization of arbuscular mycorrhiza (AM) varies among ecosystems. This study was conducted to assess and compare the abundance of AM in a rehabilitated forest and a logged-over forest soil using the most probable number and spore number methods. Glomus (71.7%-82.1%) and Acaulospora (17.4%-19.5%) were found to be abundant in both sites, while Gigaspora was found only in the logged-over forest. The abundance of AM in the rehabilitated forest based on the spore count was significantly higher than in the logged-over forest by a 6-fold difference. Furthermore, root colonization in the rehabilitated forest was found to be almost 9-fold higher than in the logged-over forest. Such differences are linked to the soil chemical properties. The addition of organic matter during forest rehabilitation activity had created favorable conditions for AM sporulation. Soil P in both forests was positively related to the spore count (r > 0.68, P < 0.001) while the most probable number (MPN) was negatively influenced by soil K (r = -0.632, P < 0.01). In conclusion, this study showed that soil chemical properties have a direct effect on the abundance of AM.

Effect of soil chemical properties on growth, foliation and nutrition of Norway spruce stand affected by yellowing in the Bohemian Forest Mts., Czech Republic

In 1998, a fertilizer experiment aiming to investigate the effects of slow-release N, P, K and Mg fertilizer (SILVAMIX Mg NPK®) on a 60-year-old spruce stand with symptoms of yellowing was established. In this paper, trees were selected to investigate the relation between annual diameter increment, yellowing, foliation, needle and soil chemical properties: ten from the fertilized treatment (F), ten green trees from the control (CG) and ten yellow trees from the control (CY). CG and CY trees were growing in close proximity at a distance of only several meters apart under the same soil conditions. In treatment F, increased annual diameter increment, improved foliation, needle Mg concentration, plant-available Mg and P concentrations in the soil and absence of yellow trees were recorded 7 years after a single application of the fertilizer. During the last 15 years, annual growth increment and foliation of CY trees have continuously decreased while relatively stable values were recorded for CG trees and increased for F trees. In 2006, CG and CY trees differed significantly in Mg concentration in needles, foliation, yellowing and annual diameter increment. Although differences in soil chemical properties between CG and CY treatments were not significant, lower concentrations of plant-available Mg2+ and higher concentrations of H+ and Al3+ were found in soils under CY trees. There was a negative correlation between soil concentration of Mg and yellowing, but this correlation was relatively weak, indicating that there is no simple relation between soil and needle concentrations of Mg. In the investigated locality, the “new type” of yellow tree decline has been a long-term gradual process.

Plant species and functional group effects on abiotic and microbial soil properties and plant–soil feedback responses in two grasslands

Summary Plant species differ in their capacity to influence soil organic matter, soil nutrient availability and the composition of soil microbial communities. Their influences on soil properties result in net positive or negative feedback effects, which influence plant performance and plant community composition. For two grassland systems, one on a sandy soil in the Netherlands and one on a chalk soil in the United Kingdom, we investigated how individual plant species grown in monocultures changed abiotic and biotic soil conditions. Then, we determined feedback effects of these soils to plants of the same or different species. Feedback effects were analysed at the level of plant species and plant taxonomic groups (grasses vs. forbs). In the sandy soils, plant species differed in their effects on soil chemical properties, in particular potassium levels, but PLFA (phospholipid fatty acid) signatures of the soil microbial community did not differ between plant species. The effects of soil chemical properties were even greater when grasses and forbs were compared, especially because potassium levels were lower in grass monocultures. In the chalk soil, there were no effects of plant species on soil chemical properties, but PLFA profiles differed significantly between soils from different monocultures. PLFA profiles differed between species, rather than between grasses and forbs. In the feedback experiment, all plant species in sandy soils grew less vigorously in soils conditioned by grasses than in soils conditioned by forbs. These effects correlated significantly with soil chemical properties. None of the seven plant species showed significant differences between performance in soil conditioned by the same vs. other plant species. In the chalk soil, Sanguisorba minor and in particular Briza media performed best in soil collected from conspecifics, while Bromus erectus performed best in soil from heterospecifics. There was no distinctive pattern between soils collected from forb and grass monocultures, and plant performance could not be related to soil chemical properties or PLFA signatures. Our study shows that mechanisms of plant–soil feedback can depend on plant species, plant taxonomic (or functional) groups and site‐specific differences in abiotic and biotic soil properties. Understanding how plant species can influence their rhizosphere, and how other plant species respond to these changes, will greatly enhance our understanding of the functioning and stability of ecosystems.

Effect of soil chemical properties on the remediation of phenanthrene-contaminated soil by electrokinetic-Fenton process

The electrokinetic-Fenton (EK-Fenton) remediation of soil contaminated with phenanthrene was studied. Two different soils were chosen to investigate the effects of chemical properties, such as Fe oxide contents and acid soil buffer capacity. The H 2O 2 concentrations in pore water, the electrical potential distributions and the electrical currents were monitored to assess the electrochemical effect in relation to the soil properties. Hadong caly had high acid buffer capacity, and thus the amount of electroosmotic flow was lager in the experiment with Hadong clay than with EPK kaolin. The major mechanism of phenanthrene removal was a degradation in the experiment with EPK Kaolin, while it was a simple transport away from the system in experiment with Hadong clay. It was mainly because of the lower acid buffering capacity and better H 2O 2 stability in case with EPK Kaolin than with Hadong clay.

Soil seed bank variation patterns according to environmental factors in a natural grassland

This research aimed to determine the soil seed bank and its relationship with environmental factors that have an influence in the distribution of the vegetation above the ground in an excluded area of natural grassland in the South of Brazil. Most of the 122 identified species in the seed bank were perennials. Data analysis indicated three distinct community groups, according to the size and composition of the soil seed bank in lowlands with permanent wet soils, in lowlands and in other areas. In general, lowlands were characterized by low-fertility soils, high moisture and aluminum contents, being spatially homogeneous habitats and, therefore, more restricted to vegetation heterogeneity than other parts of the relief. Environmental factors most associated with soil seed bank size and composition were relief position and their co-related soil variables such as: soil moisture content, potassium content, organic matter, basic saturation of cation exchange soil capacity, exchangeable basics sum of the soil and clay soil content. According to that, relief position, associated with combined effects of soil chemical properties related to it, determines the observed variation pattern of the soil seed bank, as a reflection of the vegetation above the area.

Dissolution of iron by mugineic acid from soils and comparison with DTPA soil test

Mugineic acid (MA), which is a multidentate phytosiderophore, is exuded to the rhizosphere by the roots of graminaceous plants (e.g. barley) growing under Fe-deficient conditions, resulting in the dissolution of Fe as a form of MA-Fe111 complex (MAFe). To clarify the effects of soil chemical properties on the amount of Fe dissolved by MA, an experiment to study the reaction of MA using 38 soil samples was conducted, and the concentrations of free MA (uncomplexed and non-adsorbed MA) and MAFe in solution and the amounts of MA adsorbed on the soils were determined after the reaction. Soil pH value was a good indicator to predict the behavior of MA in soils. A large proportion of added MA was adsorbed on soils or formed MAFe in solution in acidic soils, whereas it did not react with soils and occurred as free MA in alkaline soils. These features were in good agreement with the interaction of MA with Fe (hydr)oxides, as reported in previous papers. Other soil chemical properties, such as soil organic carbon (SOC) content and the amount of amorphous (hydr)oxide components, also affected the behavior of MA in the soils. The Fe dissolution ability of MA was compared with that of diethylenetriaminepentaacetic acid (DTPA) soil test. Although the amounts of extractable Fe were similar between the MA extraction and DTPA soil test, factors influencing the amount of Fe dissolved (formation constant with Fe111, reaction pH, rate constant, etc.) were different between both chelating compounds.

Micronutrients in the Kootenai river valley of Northern Idaho. I. Effect of soil chemical properties on micronutrient availability

Abstract Crops grown on soils of the Kootenai River Valley of northern Idaho are showing an increasing tendency for micronutrient deficiencies. These soils are generally high in organic carbon (OC) and slightly alkaline. Soil pH has been increasing at the rate of 0.2 units every 10 years for the last 30 years. Normal soil sampling and testing procedures have failed to identify potential deficiencies of micronutrients prior to planting crops. Consequently, a different way to predict the tendency of micronutrient deficiencies is desired. The objectives of this study were to: (1) evaluate the effects of soil pH and OC on DTPA‐extractable Cu, Mn, and Zn, (2) establish relationships between pH, OC, Cu, Mn, and Zn and soil mapping units and geographic areas (drainage districts), and (3) predict tendencies for deficiencies or sufficiencies of evaluated micronutrients. One hundred fifty‐four soil samples were collected from the surface 30 cm of fields in the Kootenai River floodplain during 1989 and 1990. Six soi...

Zinc diffusion and extractability as affected by zinc carrier and soil chemical properties

This work was carried out to evaluate the effect of soil chemical properties, Zn carrier and time elapsed after fertilizer application on the diffusion and extractability of Zn. A soil block technique was used to study zinc diffusion and DTPA extractability from ZnEDTA and ZnSO4 fertilizers in three soils that varied in texture, CaCO3 content, organic matter content, and pH using Zn65 tracer. ZnEDTA diffused readily in all soils, moving 20–25 mm from the fertilizer layer after three days. The rate of Zn diffusion and the extractability of Zn, however, varied among the soils and were lowest in Baha soil with the highest clay content, organic matter, and CEC despite its lower pH. The high pH and CaCO3 content in Dirab soil did not restrict the diffusion or reduce the extractability of ZnEDTA in this soil. On the other hand, the diffusion of Zn from ZnSO4 fertilizer was largely restricted in all soils and was confined to 5 mm from the fertilizer layer after 13 d. The extractability of ZnSO4 fertilizer was largely affected by soil pH and CaCO3 content and was lowest in Dirab calcareous soil. Organic matter amendment at 5% (as alfalfa) considerably reduced the diffusion and the extractability of ZnSO4 in both Dirab calcareous and Bakyria noncalcareous soils. The application of 1% (w/w) elemental S reduced soil pH and increased Zn diffusion from ZnSO4 fertilizer in Bakyria soil but had slight effect on Dirab calcareous soil.

Comparative growth responses of N2-fixing and N-fertilized subterranean clover on acid soils

Effects of soil chemical properties on biological N2-fixation (BNF) byTrifolium subterraneum L. ‘Mt. Barker’ —Rhizobium trifolii strain 162×95 were studied on thirteen soils in a greenhouse experiment. Dry matter production of inoculated/+N plants indicated three groups of soils. Mean soil solution activities of Al3+ were 29.4, 9.8 and 0.1 μM for groups of soils with no BNF, limited BNF, and unlimited BNF, respectively. Using easily measurable soil chemical properties, the following equation related relative dry matter production to pH and soil Al saturation: Inoculated/+N×100=−140+46.83 (soil solution pH) −0.31 (Al concentration ×100/CEC) (r2=0.66).