Tillage,lime, and poultry litter effects on plant concentrations of zinc,manganese, and copper

Minimum tillage cropping systems and the use of animal manures on cropland are becoming more prevalent. An experiment was initiated to determine the effects of tillage and lime/gypsum variables on uptake of zinc (Zn), manganese (Mn), and copper (Cu) by corn (Zea mays L.) and to show correlations between plant uptake of these metals and soil pH and Mehlich 1‐extractable soil metals where poultry litter was used as a nitrogen (N) source. Surface soil samples were taken in the spring and fall for two years from a long‐term tillage experiment that had been in place for nine years. There were two tillage treatments [conventional (CT) and no‐tillage (NT)] and six lime/gypsum treatments (control, 8,960 kg gypsum ha^‐1 every fourth year, 4,480 kg lime ha^‐1 every fourth year, and three treatments of 8,960 kg lime ha^‐1 in a four‐year period divided by application times into 1, 2, and 4 treatments). Poultry litter was applied each year of the two‐year experiment at a rate of 8.96 Mg ha^‐1 on a dry weight basis. Soil samples were analyzed for pH and Mehlich 1‐extractable Zn, Mn, and Cu, and plant tissue (small plant, ear leaf, stalk, and grain) was analyzed for Zn, Mn, and Cu concentrations. Lime treatments resulted in lower Zn in the small plant and ear leaf for CT, but not for NT. Plant Mn was decreased by lime and gypsum rates for small plant, ear leaf, stalk and grain for both years for CT and NT. Correlations for plant Zn versus soil pH were generally non‐significant, except for one year for ear leaf Zn (R=‐0.413**). Correlations for soil pH and plant tissue Cu were all nonsignificant. Correlations for plant Mn and soil pH were strong with R values over 0.80. Plant Mn response to treatments was found at a pH range of 4.2 to 5.8 for ear leaf and pH 5.2 to 6.2 for stalks. Plant Mn and Zn versus Mehlich 1‐extractable soil Mn and Zn, respectively, were negative. This response was possibly due to oxidation‐reduction and non‐incorporation of the lime for Mn and non‐incorporation of the lime for Zn. Also, the poultry litter was high in Zn (447 mg kg^‐1), which could have masked pH effects. It was concluded that soil sampling for plant micronutrients for NT, especially where a waste material high in micronutrients is applied, can give erratic and even erroneous results. However, lime and tillage treatments had a predictable effect on micronutrient uptake as related to soil pH.     

Effects of lime,phosphorus, manganese,copper, and zinc on plant mineral composition,yield of itarley,and level of extractable nutrients for an acid Swedish mineral soil

Abstract

A pot experiment was performed during the 1992 growing season on an acid, sandy topsoil taken from a Swedish liming experiment. A central composite experimental design was used in order to study the effects of supply of phosphorus (P) and micronutrients at different liming levels on yield of barley (Hordeum vulgare L. c.v. Golf), mineral content in plant, straw, and grain, and level of soil extractable nutrients. The results showed no increase of yield due to liming despite the fact that lime increased the yield significantly in the field experiment. The soil appeared initially to have a good balance between the nutrients included in the experimental design with the exception of P. An excessive supply of manganese (Mn) decreased the yield. The contents of calcium (Ca) and aluminum (Al) in the plant were hardly affected by the treatments, while the contents of P, Mn, copper (Cu), and zinc (Zn) more than doubled compared to no supply. The contents of P, Cu, and Zn were mainly influenced by the supply of the actual element, while the content of Mn was more closely related to the supply of lime. Soil pH(H₂0) and CaCl₂‐extractable P, Mn, Cu, and Zn were highly related to the supplies of lime, P, Mn, Cu and Zn, respectively. Only a few interactions were observed.     

Tillage effects on soil degradation, soil resilience, soil quality, and sustainability

Soil degradation, decrease in soil's actual and potential productivity owing to land misuse, is a major threat to agricultural sustainability and environmental quality. The problem is particularly severe in the tropics and sub-tropics as a result of high demographic pressure, shortage of prime agricultural land, harsh environments, and resource poor farmers who presumably cannot afford science based recommended inputs. Tillage methods and soil surface management affect sustainable use of soil resources through their influence on soil stability, soil resilience, and soil quality. Soil stability refers to the susceptibility of soil to change under natural or anthropogenic perturbations. In comparison, soil resilience refers to soil's ability to restore its life support processes after being stressed. The term soil quality refers to the soil's capacity to perform its three principal functions e.g. economic productivity, environment regulation, and aesthetic and cultural values. There is a need to develop precise objective and quantitative indices of assessing these attributes of the soil. These indices can only be developed from the data obtained from well designed and properly implemented long-term soil management experiments conducted on major soils in principal ecoregions.     

土壤锌、铁、铜、锰形态的分布及其与植物有效性的关系

The distribution of various fractions of Zn,Fe,Cu and Mn in 15 types of soils in China and its relationship with plant availability were studied.Fractions of various elements were found to have some similar characterstic distribution regularities in various types of soils,but various soil types differed to varying degrees in the distribution of each fraction.Soil physico-chemical properties,such as pH,CEC and the contents of OM,CaCO3,free Fe,free Mn and P2O5,were significantly correlated with the distribution of elemental fractions,and a significant correlation also existed between the distribution and plant availability of elemental fractions.Various fractions of each element were divided into two groups based on their plant availability.The correlation between the distribution of combination fractions and plat availability indicated a significantly or an extremely significantly positive correlation for Group I but a significantly or an extremely significantly negative correlation for Group II.Therefore,the fractions in Goup I were primary pools of available nutrients,while those in Group II could hardly provide available nutrients for plants.Decreasing the transformation of corresponding elements into fractions of Group II and increasing the storage capacity of various fractions of Group I were an important direction for regulation and controlling of soil nutrients.However,some Particular soils with too high contents of Zn,Fe,Cu and Mn should be regulated and controlled adversely.     

Soil compaction and poultry litter effects on factors affecting nitrogen availability in a claypan soil

Soil compaction may affect N mineralization and the subsequent fate of N in agroecosystems. Laboratory incubation and field experiments were conducted to determine the effects of surface soil compaction on soil N mineralization in a claypan soil amended with poultry litter (i.e., Turkey excrement mixed with pine shavings as bedding). In a laboratory study, soil from the surface horizon of a Mexico silt loam soil was compacted to four bulk density levels (1.2, 1.4, 1.6 and 1.8 Mg m⁻³) with and without poultry litter and incubated at 25 °C for 42 days. A field trial planted to corn (Zea mays L.) was also conducted in 2002 on a Mexico silt loam claypan soil in North Central Missouri. Soil was amended with litter (0 and 19 Mg ha⁻¹) and left uncompacted or uniformly compacted. Soil compaction decreased soil inorganic N by a maximum of 1.8 times in the laboratory study; this effect was also observed at all depths of the field trial. Compacted soil with a litter amendment accumulated NH₄⁺-N up to 7.2 times higher than the noncompacted, litter-amended soil until Day 28 of the laboratory incubation and in the beginning of the growing season of the field study. Ammonium accumulation may have been due to decreased soil aeration under compacted conditions. Application of litter increased soil N mineralization throughout the growing season. In the laboratory study, soil inorganic N in unamended soil was negatively correlated with soil bulk density and the proportion of soil micropores, but was positively related with soil total porosity and the proportion of soil macropores. These results indicate that soil compaction, litter application and climate are interrelated in their influences on soil N mineralization in agroecosystems.     

Soil compaction and poultry litter effects on factors affecting nitrogen availability in a claypan soil

Soil compaction may affect N mineralization and the subsequent fate of N in agroecosystems. Laboratory incubation and field experiments were conducted to determine the effects of surface soil compaction on soil N mineralization in a claypan soil amended with poultry litter (i.e., Turkey excrement mixed with pine shavings as bedding). In a laboratory study, soil from the surface horizon of a Mexico silt loam soil was compacted to four bulk density levels (1.2, 1.4, 1.6 and 1.8 Mg m⁻³) with and without poultry litter and incubated at 25 °C for 42 days. A field trial planted to corn (Zea mays L.) was also conducted in 2002 on a Mexico silt loam claypan soil in North Central Missouri. Soil was amended with litter (0 and 19 Mg ha⁻¹) and left uncompacted or uniformly compacted. Soil compaction decreased soil inorganic N by a maximum of 1.8 times in the laboratory study; this effect was also observed at all depths of the field trial. Compacted soil with a litter amendment accumulated NH₄⁺-N up to 7.2 times higher than the noncompacted, litter-amended soil until Day 28 of the laboratory incubation and in the beginning of the growing season of the field study. Ammonium accumulation may have been due to decreased soil aeration under compacted conditions. Application of litter increased soil N mineralization throughout the growing season. In the laboratory study, soil inorganic N in unamended soil was negatively correlated with soil bulk density and the proportion of soil micropores, but was positively related with soil total porosity and the proportion of soil macropores. These results indicate that soil compaction, litter application and climate are interrelated in their influences on soil N mineralization in agroecosystems.     

Influence of farm yard manure,poultry manure and forest litter on copper solubility in soil and uptake by Phaseolus vulgaris

Long term and intensive use of copper‐based fungicides on coffee farms may contaminate soils with copper. The legacy of copper pollution may pose the risk of contaminating food crops cultivated on these soils. A randomized block design field experiment at Kilimanjaro, Tanzania was designed to investigate the effects of different application rates of cattle manure, poultry manure and forest litter on aqua regia, EDTA and CaCl₂ extractable copper in soils and copper uptake by bean plants grown on this long‐term copper‐contaminated soil (more than 50 yr of copper application). It was important to examine the potential of the organic amendments in mobilizing or immobilizing copper and assess the risks of contaminating bean crops at a farm, where the application of organic amendments was common practice. At harvest, rhizosphere soils were collected and analysed. The soils were found to have large concentrations of copper, greatly exceeding international standard levels. Poultry manure applied at 40 tons/ha significantly increased CaCl₂ extractable copper compared with the control treatment. Organic carbon, cation exchange capacity, EDTA extractable copper, aqua regia extractable copper and copper concentrations in bean seeds or leaves were not significantly changed by the organic matter treatments. The concentration of copper was significantly less in bean seeds than in bean leaves (P < 0.01). The bean plants did not take up excessive quantities of copper, and therefore, the risk of copper contamination of bean crops in this farm appears to be small.     

Long-term effects of tillage on the availability of iron, copper, manganese, and zinc in a Spanish Vertisol

Organic matter accumulation and increased microbial activity under no-till can affect the dynamics of some essential micronutrients for plants. The main purpose of this work was to study the long-term effect of tillage on the availability of Fe, Mn, Cu, and Zn in a calcareous soil from Southern Spain. To this end, nutrient availability in surface soil (0–5-cm depth) subjected to a long-term tillage experiment (21 years) was evaluated via pot experiments and chemical tests involving DTPA extraction (as availability index) and sequential chemical fractionation of Mn and Fe.Soil organic matter (SOM) content and microbial activity (estimated by the β-glucosidase method) were found to be significantly higher under no-till (NT) than under conventional (CT) or minimum tillage (MT). Also, DTPA extractable Mn, Cu, and Zn, and citrate–bicarbonate extractable Mn (Mn_cb), were all higher under NT than under CT and MT, the differences being related to the increase in SOM as revealed by the correlation of Mn, Cu, and Zn extractable with DTPA and SOM (r = 0.87, P < 0.001; r = 0.8, P < 0.01, and r = 0.86, P < 0.001, respectively), and that between Mn_cb and SOM (r = 0.87, P < 0.001). However, the increased extractability resulted in no increased concentrations of these nutrients in plants. Moreover, the Mn concentration in the last expanded leaf was significantly lower with NT than with CT, which can be ascribed at least partly to an increased microbial activity under NT as revealed by the negative correlation between Mn in plants and β-glucosidase activity in soil (r = −0.71, P < 0.01). The Fe concentration in plants was not affected by soil tillage; also, it was only related to citrate–ascorbate extractable Fe (r = 0.69, P < 0.05), which exposes the contribution of poorly crystalline Fe oxides in soil to Fe nutrition in plants.     

Effects of solid phase from pig slurry on iron,copper, zinc,and manganese content of soil and wheat plants

A two‐year lysimeter experiment was conducted using winter wheat plants on two texturally contrasting soils (soil A and soil B). The main objective of this study was to evaluate the influence of increasing doses (5, 10, 15, 20, and 251 ha^‐1) of solid phase from pig slurry (SP) on soil extractable copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) and on wheat micronutrients composition and uptake. As the control, a basic dressing of NPK fertilizer was applied. Results showed that increasing additions of SP significantly enhanced extractable Cu, Zn, Fe, and Mn content on the topsoil for both soils tested. In addition, a significant increase was detected for extractable Cu, Zn, and Mn content with increasing application rates of SP for subsoil A, but no significant differences were detected for subsoil B. A significant increase in the contents of Fe, Mn, and Zn in the plants as well as total uptakes were observed from increasing doses of SP. Copper content in the plants was not significantly affected. Finally, a strong pH effect was exerted in the Mn and Zn uptake by the plants.     

Tillage effects on soil strength and solute transport

To study the effect of different soil tillage practices and the consequences of soil deformation on the functioning of the pore system, we performed unsaturated leaching experiments (by applying a suction of −10 kPa) on undisturbed soil columns from the Ap-horizon of a luvisol derived from glacial till (agricultural site at Hohenschulen, North Germany). We compared two different tillage practices (conventionally tilled to 30 cm depth, and conservational chiselled to a depth of 8 cm-Horsch system) with respect to soil strength, pore connectivity and their effect on the fate of surface-applied fertilisers. The soil strength was measured by determining the precompression stress value (PCV). The conventionally tilled topsoil had a PCV of 21 kPa at a pore water potential of −6 kPa, while the conservation treatment resulted in a slightly higher PCV of 28 kPa, suggesting a slowly increasing soil strength induced by the formation of aggregates under reduced tillage practice.

The leaching experiments were modelled using the convection dispersion equation (CDE) and a modified version of the mobile–immobile approach (MIM), which included three water fractions: mobile, immobile and totally immobile water. From the CDE mobile water fractions (θ_m) ranging from 47 to 67% were found, and θ_m was slightly higher in the ploughed seedbed compared to the conservation-tilled one. This could be due to higher aggregation in the latter one. Dispersivities were relatively large, ranging from 44 to 360 mm, but no difference was found for the treatments. The MIM could simulate the drop in concentration when leaching was interrupted, but overall did not improve the simulation, despite the larger number of fitting parameters.

Compacting the soil with loads of 70 kPa prior to the leaching experiment did not affect solute transport in the conservational tilled soil. In the conventional-tilled soil, however, the dispersivity decreased and the mobile water content increased compared to the non-compacted soil, suggesting that the former one is less prone to deformation by mechanical loads.     

Effects of moist storage and different drying temperatures on the extractability of iron,copper, manganese,and zinc in soil samples

Abstract

The objective of this study was to investigate the effect of different pretreatments on the extraction of cationic micronutrients [iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn)] from four different soils. Samples were either stored in the field‐moist state for seven days before drying or dried immediately. Three drying treatments were used: air‐dried (72 hours), oven‐dried at 40°C (48 hours), or oven‐dried at 105°C (24 hours). Micronutrients were then extracted with 0.1N HC1 or diethenetriamine‐pentacetic acid (DTPA). Storage, drying temperature, extractant, and soil type all influenced micronutrient extractability. In general, a higher temperature increased the level of micronutrient extracted. However, the reverse effect was also observed. The effect of storage was variable and probably depended on the sample moisture content. We conclude that the results from routine analysis and experimentally determined indices can only be compared if soil samples are subjected to the same pretreatments. Hence, rigorous standardization of the sample preparations is imperative for accurate determination of plant‐available micronutrients.     

Tillage effects on near-surface soil hydraulic properties

The processes for the formation of porosity are thought to differ between tilled and non-tilled cropping systems. The pores are created primarily by the tillage tool in the tilled systems and by biological processes in non-tilled systems. Because of the different methods of pore formation, the pore size distribution, pore continuity and hydraulic conductivity functions would be expected to differ among tillage systems. The objective of this study was to determine effects of three tillage systems — mold-board plow (MP), chisel plow (CP), and no-till (NT) — on hydraulic properties of soils from eight long-term tillage and rotation experiments. Tillage effects on saturated and unsaturated hydraulic conductivity, pore size distribution, and moisture retention characteristics were more apparent for soils with a continuous corn (CC) rotation than for either a corn-soybean (CS) rotation or a corn-oats-alfalfa (COA) rotation. Pore size distributions were similar among tillage systems for each soil except for three soils with a CC rotation. The MP system increased volume of pores >150 μm radius by 23% to 91% compared with the NT system on two of the soils, but the NT system increased the volume of the same radius pore by 50% on one other soil. The NT system had 30 to 180% greater saturated hydraulic conductivity than either the CP or MP systems. The NT system with a CC rotation showed a greater slope of the log unsaturated hydraulic conductivity; log volumetric water content relationship on two of the soils indicating greater water movement through a few relatively large pores for this system than for either the CP or MP systems.     

重金属Cu、Zn在施入畜禽粪的菜园土中的淋溶研究

The leaching characteristics of a garden soil may be greatly affected by application of poultry and livestock manures from intensive farming. Packed soil columns of a garden soil （CK） and the soils after respectively receiving 2% pig manure （PM）, chicken manure （CM）, and commercial organic manure （OM） were leached with 0.05 mol L^-1 Ca（NO3）2 and 0.01 mol L 1 EDTA solutions. The leachate EC （electric conductivity） values gradually increased at the beginning and then reached a stable value when the soil columns were leached with 0.05 mol L^-1 Ca（NO3）2 solution. The leachate EC values showed a peak-shape when leached with 0.01 mol L^-1 EDTA solution. In all the soil columns, the pH values of the leachates decreased with increase of displacement volumes when the Ca（NO3）2 solution was used. The total amounts of Cu and Zn eluted from the four soil columns were significantly correlated with the extracted soil Cu and Zn concentrations by 1.0 mol L^-1 NH4NO3, but were not correlated with the leachate dissolved organic carbon （DOC） contents. The Zn concentration in the leachate of the PM-treated soil column with 0.05 mol L^-1 Ca（NO3）2 solution was above the Quality Standard III for Ground Water of China （GB/T 14848-93, Zn 〈 1.0 mg L^-1）. When compared with 0.05 mol L^-1 Ca（NO3）2, the EDTA solution significantly accelerated Cu and Zn elutions in the manure-treated columns. This suggested that applying poultry and livestock manures from intensive farming to farmland might pose a threat to the groundwater quality.     

Excess trace metal effects on cotton: 2. Copper,zinc, cobalt and manganese in Yolo loam soil

Abstract

Two cultivars of cotton (Gossypium spp.) were grown in Yolo loam soil (soil pH about 6) in pots in a glasshouse to determine phytotoxic effects of excesses of Cu, Zn, Co, and Mn. Leaf yields of cv. Acala SJ‐2 were depressed 35% by 400 μg Cu/g soil, 54% by 400 μg Zn/g soil, 98% by 400 μg Co/g soil, and 84% by 2000 μg Mn/g soil. Leaf metal concentrations at these application levels in μg/g leaf were 12.0 Cu, 520 Zn, 243 Co, and 14780 Ma, respectively. Plants were tolerant of in / dry leaves of 10 Cu, 157 Zn and 444 Mn. The concentration for Co could not be ascertained. Leaf yields of cv. Giza 70 were depressed 53% by 400 μg Cu/g soil, 25% by 400 μg Zn/g soil, 92% by 400 μg Co/g soil and 90% by 2000 μg Mn/g soil. This cv. was more tolerant of Zn than Acala SJ‐2. Leaf metal concentrations at these application levels in μg/g leaf were 11.8 Cu, 312 Zn, 224 Co, and 18300 Mn respectively. Gradients of these four elements existed from leaves to stems. Many interactions with other elements were observed.     

The influence of soil properties,total copper,iron, manganese,and zinc on the yield of oat,carrot, onion and lettuce

Abstract

As part of a series of studies for evolving useful soil tests for Cu, Fe, Mn and Zn in cultivated organic soils, 55 such soils from eastern Canada were used in a greenhouse study. Oat, carrot, onion, and all three followed by lettuce were grown in a greenhouse in 2 L pots containing 1.8 L of soil. The moisture, fertilization and temperature conditions provided were known to be non‐Hmiting. And yet, yields of crops, on per kg soil basis, generally correlated negatively with certain soil properties. The more decomposed and denser soils tended to be less productive, even though more soil, but not significantly less water, was accessible to the roots in such soils than in the case of less decomposed, more open soils. In contrast, crop yield per unit soil volume (1.8 L) basis showed a negative effect of water holding capacity on yield of oat, and positive effect of pH on carrot yield. No other correlations were significant. The results thus corroborated the practice of basing soil tests and fertilizer reconmendations on volume rather than weight of organic soils; indicated that the quality of organic soils, in terms of ability to store and cycle water, oxygen and nutrients, declines with length of cultivation, even before nutritional and water management problems arise, probably due to poor soil aeration; and suggested that the effect of soil quality on potential productivity be examined to derive factors that would help refine fertilizer recommendations.     

Tillage effects on soil properties and wheat cultivars traits

Information regarding the evaluation of tillage effects on soil properties and rainfed wheat (Triticum aestivum L.) cultivars of Iranian fields is not available. Therefore, this research was conducted in Sanandaj (west of Iran) using a randomized complete block design in a split-plot arrangement. Three types of tillage including conventional tillage (moldboard plow to soil depth of 30 cm plus disk harrow twice), minimum tillage (chisel plow to soil depth of 15 cm plus disk harrow once) and no-tillage are assigned to the main plots. Wheat cultivars (Sardari and Azar2) were randomly distributed within the subplots in each tillage system. Results showed that the greatest bulk density and cone index were found in the minimum tillage and no tillage systems. The highest rate of grain yield was obtained in the minimum tillage system. The grain yield of Sardari cultivar (1624.1 kg ha^?1) was significantly greater than that of Azar2 (1572 kg ha^?1). Minimum tillage improved soil physical properties and wheat growth compared with the other tillage systems. No tillage increased microbial biomass carbon and bacteria number in soil compared with the other tillage systems. We conclude that using minimum tillage for Sardari cultivar will be more effective compared with other treatments.     

Phosphatase activities in soil after repeated untreated and alum-treated poultry litter applications

Repeated additions of untreated and aluminum sulfate (alum)-treated poultry litter to soil affect ecology and consequent nutrient dynamics. The objective of this study was to determine how repeated annual poultry litter additions affected phosphatase activities in concert with changes in soil phosphorus (P). Field plots were amended annually since 1995 with either 2.24 or 8.96 Mg ha⁻¹ alum-treated (AL-1 or AL-4, respectively) or untreated poultry litter (PL-1 or PL-4, respectively) or equivalent rates by N content of ammonium nitrate (AN-1 or AN-4, respectively). Soil pH, total C (C_Tot), microbial biomass C, double-stranded deoxyribonucleic acid (dsDNA), Mehlich-III P (M3P), water-soluble P (WSP), and acid and alkaline phosphatase activities were measured before and 10 days, 1 month, and 6 months after fertilizer applications in 2003 and 2004. M3P and acid phosphatase activities were higher in AL-4 soil than in all other treatments. Higher WSP in the untreated compared to the alum-treated litter resulted in higher WSP in the soil amended with untreated litter. At the same time, alkaline phosphatase activities were significantly higher in PL-4 compared to AL-4. In contrast, alkaline phosphatase activities were significantly lower in AN-4, the treatment with the lowest pH. Additionally, alkaline phosphatase activities expressed per unit C_Tot or dsDNA remained significantly greater in PL-4 and significantly lower in AN-4, than all other treatments. Thus, some factor beyond an increase in soil C or microbial biomass contributed to elevated alkaline phosphatase activities in PL-4, despite increased WSP in the treatment receiving the high rate of untreated litter.     

Uptake of iron,zinc, manganese,and copper by seedlings of hybrid and traditional rice cultivars from different soil types 1

In pot experiments, uptake of zinc (Zn), copper (Cu), iron (Fe), and manganese (Mn) by hybrid rice from different soil types was compared with a traditional rice (Oryza sativa L.) cultivar. The concentration and total uptake of Fe in the shoots of hybrid rice grown in Oxisol and Ultisol were lower than those of the traditional cultivar. The concentration and total uptake of Zn in the shoots of hybrid rice grown in the Inceptisol (calcareous) were significantly higher than those of the traditional cultivar. Higher ratios of Zn and Fe in upper leaves (UL) to the lower leaves (LL) were found in hybrid rice grown in the calcareous Zn‐deficiency soil. The results indicated that hybrid rice root avoided absorbing excess Fe from Fe‐toxic soils due to its higher oxidizing power, and was more efficient in absorbing Zn from calcareous Zn‐deficient soils than the traditional cultivar.     

Sorption of manganese,cobalt, zinc,strontium, and cesium onto agricultural soils: Statistical analysis on effects of soil properties

In this study, distribution coefficients (K _d s) of five radionuclides (⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn, ⁸⁵Sr, ¹³⁷Cs) were measured by a batch technique for 36 agricultural soils (paddy and upland soils) collected in Japan. Twelve properties of the soils and measured K _d ss were examined for their probability distributions. Soil properties showed log-normal type distributions, except pH(H₂O), and total calcium and potassium contents for which distributions were normal. The K _d s distributions were also lognormal types except for ⁵⁴Mn-K _d s? No significant difference in soil K _d s was found between upland and paddy soils. The K _d s were analyzed for correlations with each soil property. The combinations showing the highest correlation were: the exchangeable calcium for ⁵⁴Mn and ⁶⁰Co; the water content for ⁶⁵Zn; the cation exchange capacity for ⁸⁵Sr; and the exchangeable potassium for ¹³⁷Cs, For ⁵⁴Mn and ⁶⁰Co, their K _d s also correlated with supernatant pH. Only ⁸⁵Sr-K _d s showed an adequate correlation with the value if the CEC divided by the supernatant EC. For the other four nuclides, some other mechanisms besides ion exchange seemed to be working.     

Tillage effects on compaction, earthworms and other soil quality indicators in Hungary

The philosophy toward tillage throughout the last century in Hungary can be characterized as a fight against extreme climatic and economic situations. The ‘Hungarian reasonable tillage’ approach that was promoted by Cserháti at the end of the 1800s was aimed at reducing tillage without increasing the risk of crop failure in arable fields. Recently, new tillage trends and systems have been introduced because of the rise in energy prices and because of the need to cut production costs, conserve soil and water resources and protect the environment. In Hungarian relation, the rationalized plowing, loosening and mulching systems are counted to the new tillage solutions. There are new steps in the sowing methods too, such as seedbed preparation and plant in one pass, till and plant, mulch-till and plant and direct drilling, which are environment capable, throughout improving soil condition and avoiding the environment harms. The applicability of various soil conservation tillage methods is currently being tested in research projects and discussed in workshops throughout the country. In this paper, soil quality problems such as compaction, trends in soil tillage, and factors affecting soil quality or condition as well as improvement and maintenance are summarized. The data show that annual disking and plowing causes subsoil compaction at the depth of tillage within 3 years and that the compacted layer expanded both in surface and deeper layers after the 5th year. Soil quality deterioration by tillage-pans was improved by subsoiling and maintained by direct drilling and planting soil-loosening catch crops. Within a loam and a sandy loam soil there were close correlations between earthworm activity and soil quality. Earthworm numbers increased on undisturbed but noncompacted soils and soils that included stubble residues remaining on the surface, but did not increase on soils that were deteriorated by tillage-pans or left bare by the absence of mulch. Our goal for the new millennium, is to use only enough tillage to create and maintain harmony between soil conservation, soil quality and crop production.