Phosphate eesoeption isotherms in four selected tropical soils and one temperate soil

Abstract

Some problem areas connected with soil testing and with reporting soil test and plant analysis results are explored, A uniform system for reporting soil test results is suggested as a step towards further standardization of soil test methods within and among states. Four categories are suggested as a common terminology for soil test and plant analysis results. These are: deficient, probable response, adequate and excessive.     

The distribution of zinc in selected soils in Louisiana

Abstract

The zinc (Zn) content of ten selected soils in Louisiana was partitioned into the following fractions: water‐soluble, exchangeable, chelated, organic and residual. In seven of the soils, water‐soluble > exchangeable < chelated < organic < residual Zn. In three of the soils, water‐soluble < exchangeable < chelated < organic < residual Zn.

The ten soils contained an average of 1.7, 0.9, 2.6, 4.4 and 86.4 per cent of the total in the water‐soluble, exchangeable, chelated, organic and residual mineral Zn fractions respectively.     

The effect of various nitrogen fertilizers on zinc (zn) availability in non calcic brown forest soils

In this article the effect of different nitrogen fertilizer application on the availability of zinc (Zn) content in non calcic brown forest soil was investigated. For this purpose increasing rates of NH₄Cl, (NH₄)₂S0₄; NH₄N0₃ and Ca(N0₃)₂.4H₂0 fertilizers were applied for having different physical and chemical properties in two soil samples. An incubation experiment was carried out over 4 months. The available Zn content of the soils was determined each month. According to the results the highest available Zn content of the soils was obtained from NH₄Cl applied to the soils followed by (NH₄)₂S0₄; NH₄N0₃ and Ca(N0₃)₂.4H₂0 application to soil. At the end of the experiment the average available Zn content of non calcic brown forest soils for NH₄Cl, (NH₄)₂S0₄; NH₄N0₃ and Ca(N0₃)₂.4H₂0 fertilizers are 0.93, 0.91, 0.88 and 0.77 mg kg^?1, respectively.     

The zinc status of some Nova Scotia soils and crops

Abstract

Ranges for total, 0.1N HCl and EDTA‐(NH₄)₂CO₃ extractable Zn in 69 samples of surface soil (0–15 cm), representing nine soil series, were 14–108, 0.9–10.5 and 0.5–8.0 ppm respectively. Total Zn in barley (Hordeum vulgare), carrot (Daucus carata sativa), corn (Zea mays L), grape (Vitis spp.), onion (Allium cepa), pea (Pisum sativum, strawberry (Fragaria spp.), and wheat (Triticum spp.) leaves and in barley and wheat grain ranged from 13.5 to 80.6 ppm.

The results suggest that, with the possible exception of corn leaf samples from one location, Zn levels in plant tissue were adequate. However, the results also indicate that liming strongly acid sandy soils reduces Zn availability and may induce a deficiency in Zn sensitive crops.     

Influence of soil pH and application of zinc on the yield and uptake of selected nutrient elements by rice

Abstract

Rice grown on a recently water‐leveled Crowley silt loam that contained less than 1.8 μg g^‐1 of 0.1 N HCl‐extractable Zn with pH levels ranging from 6.8 to 7.7, responded to Zn application. Each kg ha of applied Zn as Zn chelate, 14.2 % Zn, resulted in increases of +673, +477, and +2026 kg rice ha^‐1 at pH 6.8, 7.3, and 7.7, respectively. There was a critically low concentration of Zn in rice plants at the midtillering, first joint, and panicle differentiation stages of plant development when no Zn was applied. A yield response to applied Zn was obtained when the concentration of Zn in rice tissue was less than 15 μg g^‐1.

Application of Zn resulted in a significant increase in the uptake of N by rice plants at each of the three stages of plant development. Application of Zn also resulted in relatively large and significant increases in the uptake of Zn from the soil irrespective of soil pH. The uptake of Zn by rice plants at each of the growth stages showed a two‐ to three‐fold increase following Zn application when soil pH was 6.8 and 7.3. Also, the uptake of Zn by rice plants following Zn application showed a four‐fold increase at midtillering, a five‐fold increase at first joint, and a six‐fold increase at panicle differentiation, respectively, when soil pH was 7.7.     

Effect of tillage treatments upon soil tests for soil acidity,soil phosphorus and soil potassium at three soil depths

Abstract

Soil samples were obtained at 0–3, 3–6, 6–9 and 0–9 inch depths from experimental plots receiving five tillage treatments. Each of two samplers composited approximately six one‐inch cores from each plot. Soil samples were analyzed for acidity, P and K using routine analysis procedures in the University of Illinois Soil Testing Laboratory.

Few significant differences were attributed to sampler and it was concluded that samplers using similar sampling techniques were obtaining soil samples from the same population.

No significant differences in soil acidity at different depths were observed. The different tillage methods did significantly affect soil P at the 0–3 inch depth, but had no significant effect on soil P at deeper depths. Different tillage methods also significantly affected soil K values at different depths.     

The influence of acid soil factors on the growth of snapbeans in major appalachian soils

Abstract

Acid soil limitations to plant growth were assessed In 55 horizons of 14 major Appalachian hill land soils. Aluminum sensitive “Romano” and Al‐tolerant “Dade” snapbeans (Phaseolus vulgaris L.) were grown for 5 weeks in limed and unlimed treatments of the 55 horizons. Shoot and root growth was depressed >20% in unlimed relative to limed treatments in approximately 2/3 of the horizons. Dade snapbeans were generally more tolerant of the acid soil conditions and had higher Ca concentrations in the shoots than Romano snapbeans. However, the sensitive‐tolerant snapbean pair could not consistently be used to identify horizons with soil Al problems. Growth of both snapbeans was generally best in A horizons and worst in E horizons. The E horizons in this study were characterized by low Ca saturation (exchangeable Ca x 100/cation exchange capacity) and high Al saturation (exchangeable Al x 100/cation exchange capacity). Exchangeable Ca, soil Ca saturation and total soil solution Ca were positively correlated (p<0.01) with snapbean root and shoot growth. Soil Al saturation, total soil solution Al and soil solution Al reacting in 15 seconds with 8‐hydroxyquinoline were negatively correlated (p<0.01) with growth. The ratio of Ca/Al in soil solution was more closely related to snapbean growth than the soil solution concentration of any individual element. Soil and soil solution Mn were, in general, not significantly correlated with snapbean growth. Many of the horizons in this study had both Al toxicity and Ca deficiency problems and interaction between Ca and Al affected both snapbean growth and Ca uptake. These findings confirm the importance of considering Ca as well as Al when investigating Al phytotoxicity.     

Effect of fertilization and irrigation upon NPK composition of corn leaves,on corn yields,and available k in soil

Abstract

Corn (Zea mays L.) was grown for three consecutive years on Congaree loam to measure the effects of rates of N, P, and K fertilization and irrigation on the nutrient concentration of leaves, the level of available K in the soil, and on the yield of corn. Plant nutrients consisting of 0, 56, 140, 224, and 280 kg N/ha; 0, 15, 37.5, 60, and 75 kg P/ha, and 0, 28, 70, 112, and 140 kg K/ha were applied in a central composite rotatable design in each of the three years. All plant residue was removed each year when the corn was harvested, and the plots remained fallow during the winter months. One half of the experiment was irrigated when there was a 50% depletion of available soil moisture in the 0‐ to 46‐cm soil depth.

Leaf composition was affected by fertilization and irrigation. A rapid decrease in available soil K in the 0‐ to 15‐cm depth was evident the first year with all rates of added K. The decline in available soil K was unaffected by irrigation and levels of applied N and P.

There were consistent yield responses each year to added N, no response to added P, and a response to added K only during the second year.     

Spatial and temporal variation in the elemental composition of soil solution from gleyic peaty-podzolic soils

The behavior of different elements in solutions from gleyic peaty-podzolic soils was described by four types of fluctuations (from weak to strong ones). With account for the spatial and temporal variation, chemical elements were divided into groups with stable (Si, Al, Na, and C_wso) and variable (Co, Mo, Ni, Sb, and Pb) concentration levels. The spatial variation component of the solution composition was lower than its time dynamics. The intratype variability of the composition of the solutions was insignificant within a season, but it was significantly affected by the contrasting climatic conditions of different years. The solutions from the upper soil horizons had different specific features. The F, H, and AE horizons were similar in their solution composition, and the solutions from the E horizon and litter differed in the concentrations of most macro-and microelements and their pH values.     

Resistance and resilience of zinc tolerant nitrifying communities is unaffected in long-term zinc contaminated soils

Zinc (Zn) tolerant nitrifying communities were previously identified in soil samples of a long-term Zn contaminated transect towards a galvanised pylon. We questioned whether Zn tolerance increased the vulnerability of the nitrifying communities to stressors. The influence of pesticide addition, freeze-thaw or dry-wet cycles on the soil nitrification (‘functional stability’) was assessed in a series of these soils representing a Zn contamination and Zn tolerance gradient. The immediate effect of the stressors to the nitrification (‘resistance’) and the residual effect after 3 weeks incubation (‘resilience’) were determined. Our results show that neither resistance nor resilience to these stressors was affected by adaptation of the nitrifying communities to elevated Zn concentrations in the long-term contaminated soils.     

The effect of two endogeic earthworm species on zinc distribution and availability in artificial soil columns

The objective of this study was to determine the impact of earthworm bioturbation on the distribution and availability of zinc in the soil profile.Experiments were carried out with Allolobophora chlorotica and Aporrectodea caliginosa in 24 perspex columns (∅ 10 cm), filled with 20-23 cm non-polluted soil (OM 2%, clay 2.9%, pH 0.01 M CaCl₂ 6.4), that was covered by a 3-5 cm layer of aged zinc spiked soil (500 mg Zn/kg dry soil) and another 2 cm non-polluted soil on top. After 80 and 175 days, columns were sacrificed and each cm from the top down to a depth of 15 cm was sampled. Earthworm casts, placed on top of the soil, were collected. Each sample was analyzed for total and CaCl₂-exchangeable zinc concentrations.Effects of earthworm bioturbation were most pronounced after 175 days. For A. chlorotica, total and CaCl₂-exchangeable zinc concentrations in the polluted layers were lower with than without earthworms. Total zinc concentrations in the non-polluted layers were higher in columns with earthworms. Casts of A. chlorotica collected on the soil surface showed slightly higher total zinc concentrations than non-polluted soil. Casts were found throughout the whole column. For A. caliginosa there were no differences in total zinc concentration between columns with and without earthworms. CaCl₂-exchangeable zinc concentrations in the polluted layers were lower for columns with earthworms. Casts were mainly placed on top of the soil and contained total zinc concentrations intermediate between those in non-polluted and polluted soil layers.This study shows that different endogeic earthworm species have different effects on zinc distribution and availability in soils. A. chlorotica transfers soil throughout the whole column, effectively mixing it, while A. caliginosa decreases metal availability and transfers polluted soil to the soil surface.     

The elemental composition and amphiphilic properties of humic acids in southern taiga soils

This paper gives the characteristics of the elemental composition and amphiphilic properties of humic acids (HAs) extracted from different horizons of the most typical soils in the Central Forest Biosphere Reserve (CFBR, the Tver Oblast). An attempt at characterizing some properties of the structure of HAs is made based on the data of the elemental composition. The data on amphiphilic properties enable one to reveal whether components that are capable of migration are present.     

Characterization of zinc adsorption sites in two mineral soils

The adsorption of Zn, as compared with Mg, on two mineral soils, which differed in their major cation-exchange materials and with and without Ca-saturation, was measured in the presence of free CaCl₂.

The adsorption of Zn as well as Mg occurred on cation-exchange sites. The Zn adsorption data conformed to a two-term Langmuir equation. The presence of two kinds of adsorption sites and their numbers and bonding energies were deduced. However, the Langmuir approach was not adopted on the basis of comparison between the total number of the adsorption sites for Zn deduced and the CEC of the soils.

As an alternative approach, the selectivity coefficient as defined by the equation:

was calculated for each adsorption equilibrium and plotted against the amount of Zn adsorbed. This [Zn]_soil plot was used to estimate the capacities of the soil to adsorb Zn with specified affinities. The value varied between 1 and 1,000, whereas the corresponding value varied only between 0.5 and 1. The value was dependent upon the amount of Zn adsorbed, the status of exchangeable cations, and the major cation-exchange materials (montmorillonite VS. allophane-imogolite) in the soils. The importance of surface OH groups in allophane-imogolite as specific adsorption sites for Zn was suggested.     

The determination of cadmium in soils,plants and fertilizers by dithizone extraction and atomic absorption spectroscopy

Abstract

Methods are proposed for the determination of cadmium in soils, plants and fertilizers.

Soil is first dissolved by treatment with hydrofluoric and hydrochloric acids and plant material is digested with nitric‐perchloric‐sulphuric acids. The cadmium is then extracted from the resulting solutions as the dithizone complex. After destruction of the dithizone the cadmium is dissolved in dilute hydrochloric acid and determined by atomic absorption spectroscopy. Cadmium in phosphatic fertilizers is determined directly by atomic absorption measurement on hydrochloric acid digests of the fertilizer.

The proposed methods have precision adequate for the study of cadmium in soil‐plant systems, the limits of detection being: plant material, 0.004 ppm Cd; soils, 0.02 ppm; and phosphatic fertilizers, 1 ppm.     

Selective determination and formation of elemental selenium in soils

A selective method for the determination of elemental selenium in soil was developed and was applied to the study of elemental selenium in soil. (1) Elemental selenium extracted with carbon disulfide from soil was selectively transformed into selenocyanate ion by reacting with potassium cyanide in carbon disulfide. The selenocyanate ion formed was recovered into an aqueous solution and the amount of selenium in the aqueous solution was determined. This method was specific to elemental selenium and did not interfere with the other selenium compounds and soil components. The method was also highly sensitive and enable to determine more than 0.1 μg kg^-1 of elemental selenium in soil. (2) The formation of elemental selenium was confirmed, when a soil was submerged and the redox potential of the soil decreased. The amount of elemental selenium formed was proportional to the selenite content of the soil, indicating that elemental selenium is transformed from selenite upon its reduction.     

The determination of boron in soil extracts,plant materials,composts, manures,water and nutrient solutions

Abstract

A rapid colorimetric method for the determination of boron in soil extracts, plant materials, composts, manures, water and nutrient solution is proposed. The method is rapid, reliable and carried out in aqueous solution. A marked advantage is that boron can be determined in the same soil extract or plant material digest used for determination of other elements.     

Effect of Mg And Zn fertilization on soil test levels,ear leaf composition,and yields of corn in northern West Virginia

Abstract

A corn fertility study was conducted at two locations in northern West Virginia to determine the response of corn (Zea mays L.) to applied Mg and Zn on two soils testing low in Mg by the ammonium acetate and Baker tests and low in Zn by the Baker test. The study consisted of three rates of Mg (0, 112, and 224 kg/ha) and three rates of Zn (0, 3.36, and 6.72 kg/ha) applied in a factorial design. The soil at the Morgantown location was medium textured with a CEC of 22.4, and the soil at the Reedsville location was coarse textured with a CEC of 15.8. Yield responses to applied Mg were obtained only on the coarse textured soil at the Reedsville location where exchangeable Mg was less than 5% of the CEC and equilibrium Mg was less than 9.0 10 ^‐4M. No yield response to Zn was obtained at either location.     

The residual phosphorus,potassium, chlorides and other salts in soils following five years of fertility studies

Abstract

Soil samples were taken from six experimental sites (3 in phosphorus and 3 in the potassium rate studies) to depths of 60 or 90 cm. Phosphorus from the various rates of applied P was found to have accumulated in the surface soil except where mechanical mixing was suspected. Potassium from the various rates of applied K was found accumulated in soil depths of 0 to 20 cm. However, the accumulated amounts of P and K were small in comparison to the rates applied. In the potassium studies, chlorides accumulated in the subsoils of the two sites that had restricted soil layers.     

Crop production impacts on soil phosphorus removal and soil test levels

An 8-year field study documented the impact of tillage, crop rotations, and crop residue management on agronomic and soil parameters at Brookings, South Dakota. The greatest annual proportion of above-ground biomass phosphorus (P) removed was from the grain (78–87% of total) although crop residue removed some P as well. Greater above-ground total biomass P (grain P + crop residue P) was removed from corn than from soybean and spring wheat crops mainly due to the greater corn grain biomass harvested. Cumulative above-ground biomass P removal was greatest for the corn-soybean rotation (214 kg P ha^?1), while it was lowest for the soybean-wheat rotation (157 kg P ha^?1). Tillage treatments within crop rotation or residue management treatments did not influence annual or cumulative P removal rates. Olsen extractable soil orthophosphate-P levels declined consistently through time from a mean of 40 µg g^?1 (2004) to 26 µg g^?1 (2011). Biomass P removal was calculated to be 15.7 ha^?1 yr^?1 to decrease Olsen extractable soil orthophosphate-P levels by 1 µg g^?1 yr^?1 over 8 years of the study.     

The use of sewage sludge as soil amendment. The need for an ecotoxicological evaluation

Background, aim, and scope  Sewage sludge use in agriculture should be limited by the presence of metals and other persistent environmental pollutants. The present study aims to contribute for the definition of a test battery of ecotoxicological assays that allows a proper ecotoxicological characterization of sludges, providing information on their potential hazard and identified “safe” application levels. Materials and methods  Three sludges from distinct sources (urban, olive-processing, and electroplating industries) were tested using avoidance and reproduction tests with earthworms (Eisenia andrei) and springtails (Folsomia candida) and plant growth tests with turnips (Brassica rapa) and oats (Avena sativa). Different soil–sludge mixture concentrations mimicking recommended/realistic field dosages were tested. Results  Only the sludge from the electroplating industry induced an avoidance response from the earthworms (EC₅₀ = 0.4 t/ha) and collembolans (no observed effect concentration (NOEC) = 15 t/ha). This sludge was the only sludge responsible for any effect on the reproductive output of the earthworms (EC₅₀ = 7.74 t/ha). Regarding collembolans, none of the sludges tested caused any significant decrease in reproduction. In higher plant tests, the two industrial sludges were toxic, causing a decrease growth in both species. The EC₂₀ values determined for B. rapa were 20.3 and 24.2 t/ha and for A. sativa 14.7 and 16.2 t/ha for sludges from olive-processing and electroplating industries, respectively. Discussion  The metal loadings of the different test sludges could partially explain the results obtained. The toxicity of the test sludge from electroplating industry observed on the tested invertebrates and plants could be explained by the high amount of total chromium from which 22.3% was in the most toxic oxidation state—Cr(VI). However, the toxicity caused by the sludge from the olive-processing industry in the test plants could be attributed to the presence of other compounds (not measured in this study) since the metal content was not high enough to induce such an effect. The absence of toxicity showed by the urban test sludge was in agreement with its low levels of metals. Conclusions  The response of the different test organisms and end points varied according to the sludge type. The urban sludge was non-toxic whereas the sludge from the electroplating industry caused a toxic effect on almost all parameters measured (avoidance behavior of both test organisms, reproduction of earthworms, and growth of both plant species). Sludge from the olive-processing industry only caused a toxic effect on growth of both plant species. By analyzing the sensitivity of the different parameters for the most toxic sludge, it was found that avoidance and reproduction were more sensitive than plant growth, whereas plant seed germination was not sensitive at all. Recommendations and perspectives  The ecotoxicological evaluation of wastes can be used as an environmental safety control of sludge use in agriculture. A tiered approach could be adopted for this purpose, incorporating avoidance tests in the first tier (screening level) and reproduction and plant growth tests in a second tier. But more evidence aiming to define the most suitable ecotoxicological test battery for specific sludges with a different contamination profile is still needed.