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Annual Application (annual + application)

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Earth and Environmental Science100%

Selected Abstracts

Cadmium leaching from some New Zealand pasture soils

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2003
C. W. Gray
Summary Cadmium (Cd) inputs and losses from agricultural soils are of great importance because of the potential adverse effects Cd can pose to food quality, soil health and the environment in general. One important pathway for Cd losses from soil systems is by leaching. We investigated loss of Cd from a range of contrasting New Zealand pasture soils that had received Cd predominantly from repeated applications of phosphate fertilizer. Annual leaching losses of Cd ranged between 0.27 and 0.86 g ha,l, which are less than most losses recorded elsewhere. These losses equate to between 5 and 15% of the Cd added to soil through a typical annual application of single superphosphate, which in New Zealand contains on average 280 mg Cd kg,1 P. It appears that Cd added to soil from phosphate fertilizer is fairly immobile and Cd tends to accumulate in the topsoil. The pH of the leachate and the total volume of drainage to some extent control the amount of Cd leached. Additional factors, such as the soil sorption capacity, are also important in controlling Cd movement in these pasture soils. The prediction of the amount of Cd leached using the measured concentrations of Cd in the soil solution and rainfall data resulted in an overestimation of Cd losses. Cadmium concentrations in drainage water are substantially less than the current maximum acceptable value of 3 µg l,1 for drinking water in New Zealand set by the Ministry of Health. [source]

Relationship between the isotopically exchangeable and resin-extractable phosphate of deficient to heavily fertilized soil

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2000
A. Schneider
Summary The rate and extent of soil,solution transfer of orthophosphate ions (Pi) depend both on soil solution Pi concentration and on time. This is so both in experiments on sorption,desorption and in those on isotopic exchange. Because the two methods are based on different principles, it is questionable whether they give a similar quantification of Pi transfer. The amount of isotopically exchangeable Pi, E, was determined over periods of 100 minutes and described as a function of both time and Pi concentration in solution for three soil samples taken from field plots having different P fertilizer histories over 26 years of annual application. In separate experiments, amounts of Pi, Qd, were extracted from soil suspensions using three levels of anion exchange resin strips for periods ranging from 10 minutes to 7 days. Both initial and final solution Pi concentrations were measured. These concentrations and periods of resin-contact were used to predict the difference in E, ,E, between the initial and final states of the suspension,resin system using extrapolations of the equations fitted to the exchange data. Under conditions in which the solution concentration of Pi decreased during extraction the ,E values and the resin-extracted Pi values, Qd, were equal. It is thus possible, using the description of E, to predict the amount of Pi released from soil suspension knowing the initial and final solution Pi concentrations and the time it took for the system to pass from the initial to the final state. For the soil studied, identical amounts of mobile Pi, i.e. the Pi which participates in the soil,solution dynamics, may therefore be assessed by either isotopic exchange or desorption. [source]

Copper, zinc, and cadmium accumulation in two prairie soils and crops as influenced by repeated applications of manure,

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2007
Sarah L. Lipoth
Abstract A study was conducted to determine the effect of repeated (5,7 y) annual application of liquid swine or solid cattle manure on the plant availability of copper (Cu), zinc (Zn), and cadmium (Cd) at two field sites in the W-central and E-central agricultural regions of Saskatchewan, Canada. Soil samples, plant-straw and grain samples from the 2003 growing season were collected and analyzed for total Cu, Zn, and Cd concentrations using nitric acid microwave digestion followed by atomic-absorption spectroscopy. An ammonium bicarbonate diethylenetriaminepentaacetic acid (AB-DTPA) extraction was performed on the soil samples as a measure of the plant-available fraction. Crop plants that were tested included wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). The results of this study indicated that long-term repeated applications of manure fertilizer sometimes resulted in increased plant availability of Cu, Zn, and Cd, as reflected in increased concentrations of the plant-available metal observed both in the soil and plant tissue. In the case of Cu and Zn, these increases were related to the rate of application, as the manure is a source of Cu and Zn. Changes in soil conditions from repeated manure application, including a decrease in pH and stimulated plant-root growth can explain the effect that both manure and urea-fertilizer application had on increasing the Cd concentration in the plant. Overall, there does not appear to be any concern about soil metal loading and plant accumulation in these soils after 5,7 y of manure application, as soil and plant concentrations were well below the allowable limits. [source]

Glycosidases in soils as affected by cropping systems

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2005
Daniel E. Dodor
Abstract Glycosidases are a group of soil enzymes that play a major role in degradation of carbohydrates. This study was conducted to assess the impact of crop rotation and N fertilization on the activities of ,- and ,-glucosidases and ,- and ,-galactosidases in plots of two long-term field experiments at the Clarion-Webster Research Center (CWRC) and Northeast Research Center (NERC) in Iowa. Surface-soil (0,15 cm) samples were taken in 1996 and 1997 in corn (Zeamays L.), soybean (Glycinemax (L.) Merr.), oats (Avenasativa L.), or meadow (alfalfa) (Medicago sativa L.) plots that received 0 or 180,kg N ha,1, applied as urea before corn, and an annual application of 20,kg P ha,1 and 56,kg K ha,1. Activities of the four glycosidases were significantly affected by crop rotations in both years at the two sites but not by nitrogen application. In general, higher activities were observed in plots under meadow or oat and the lowest in continuous corn (CWRC) and soybean (NERC). Four-year rotation showed the highest activity, followed by 2-year rotation and monocropping systems. Linear-regression analyses indicated that, in general, the activities of the glycosidases were significantly correlated with microbial-biomass C (r > 0.302, p , 0.05) and microbial-biomass N (r > 0.321, p , 0.05), organic-C (r > 0.332, p , 0.05) and organic-N (r > 0.399, p , 0.01) contents of the soils. Results of this work suggest that multicropping stimulated the activities of the glycosidases. The specific activities of the glycosidases in soils of the two sites studied, expressed as g p -nitrophenol released per,kg of organic C, differed among the four enzymes. The lowest values were obtained for ,-galactosidase and ,-glucosidase, followed by ,-galactosidase and ,-glucosidase. Glycosidasen in Böden unter dem Einfluss von Bewirtschaftungssystemen Glycosidasen stellen eine Gruppe von Bodenenzymen dar, welche eine entscheidende Rolle im Abbau von Kohlenhydraten spielen. Ziel dieser Untersuchungen war die Erfassung des Einflusses von Fruchtfolge und N-Düngung auf die Aktivitäten von ,- und ,-Glucosidasen und ,- und ,-Galactosidasen in zwei Langzeitfeldversuchen, dem Clarion-Webster-Versuchsfeld (CWRC) und dem Northeast-Versuchsfeld (NERC) in Iowa. In den Jahren 1996 und 1997 wurden Oberbodenproben (0,15 cm) von Parzellen unter Mais (Zeamays L.), Sojabohne (Glycine max (L.) Merr.), Hafer (Avena sativa L.) oder Luzerne (Medicago sativa L.) entnommen, welche vor Mais 0 oder 180,kg N ha,1 in Form von Harnstoff sowie jährliche Düngergaben in Höhe von 20,kg P ha,1 und 56,kg K ha,1 erhielten. Über zwei Jahre wurden die Aktivitäten der vier Glycosidasen in beiden Feldversuchen signifikant von der Bewirtschaftung beeinflusst, jedoch nicht von der N-Düngung. Im allgemeinen wurden höhere Enzymaktivitäten in Parzellen unter Luzerne oder Hafer festgestellt und die geringsten unter Maismonokultur (CWRC) bzw. Sojabohne (NERC). Vierjährige Fruchtfolgen zeigten die höchsten Aktivitäten, gefolgt von zweijährigen Fruchtfolgen und Monokulturen. Analysen mittels linearer Regression weisen auf eine Korrelation zwischen Glycosidaseaktivitäten und C (r > 0.332, p , 0.05) und N der mikrobiellen Biomasse (r > 0.321, p , 0.05) sowie den Gehalten an org. C (r > 0.332, p , 0.05) und N (r > 0.399, p , 0.01) hin. Die Ergebnisse dieser Untersuchungen deuten darauf hin, dass die Aktivitäten von Glycosidasen durch mehrjährige Fruchtfolgen stimuliert wurden. Die spezifischen Glycosidaseaktivitäten in den Böden der zwei Feldversuche, berechnet als freigesetztes p -Nitrophenol (g (kg org. C),1), variierten zwischen den vier Enzymen. Die geringsten Werte wurden für ,-Galactosidase und ,-Glucosidase festgestellt, gefolgt von ,-Galactosidase und ,-Glucosidase. [source]

Long-term effects of imidacloprid on the abundance of surface- and soil-active nontarget fauna in turf

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2009
Daniel C. Peck
Abstract 1Outbreaks of root-feeding scarab larvae in turfgrass are widely managed through preventive applications of imidacloprid. Long-residual activity and application before feasible scouting probably lead to its overuse and overexposure. 2Recent investigations revealed a selective impact of imidacloprid (not trichlorfon or halofenozide) on certain nontarget turf arthropods, motivating the present study on the persistence of abundance effects over 6 years of annual applications. 3Arthropods were sampled monthly (July to October) in replicated plots using soil core heat extraction and pitfall traps to quantify soil- and surface-active arthropods. Captures were identified to class, order or family. The most represented taxa were analysed to test for cumulative effects and their change over season and year. 4Imidacloprid had no impact on pitfall captures, although the abundance of Hemiptera, Thysanoptera, Coleoptera and Collembola was suppressed in soil core captures. Among beetles, impact was expressed in adults (not larvae), and in Carabidae and Staphylinidae (not Chrysomelidae or Curculionidae). Among springtails, impact was expressed in Entomobryomorpha (not Poduromorpha or Symphypleona). Impact did not diminish with year but there was variable recovery between applications. 5There may therefore be a diverging response of soil- and surface-active fauna to the nontarget impacts of imidacloprid. The suppression of predaceous (not phytophagous) beetles indicates an indirect effect mediated through declines in prey populations. 6The magnitude of abundance effects confirms that the balance between target and nontarget impact should be explicitly examined. Implications are discussed with respect to functional relevance for nutrient cycling and the natural regulation of pests. [source]