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1.
Salt-affected soils in arid and semi-arid tracts of the Indian Punjab are prone to deficiency of micronutrients. Nine profiles from alluvial terraces, sand dunes and palaeochannels in the southwestern Punjab were investigated for total and diethylenetriamine-penta-acetic acid (DTPA) extractable Zn, Cu, Mn and Fe. Soil physiography exerted significant influence on the spatial distribution of micronutrients. Total contents varied from 20–78 for Zn, 8–32 for Cu, and 88–466 mg kg?1 for Mn and 0.82–2.53% for Fe. DTPA-extractable contents varied from 0.10–0.98 for Zn, 0.14–1.02 for Cu, 0.54–13.02 for Fe and 0.82–9.4 mg kg?1 for Mn. Total contents were higher in fine-textured soil than in coarse-textured soils. Concentration of micronutrients in the surface layer was low and there occurred more accumulation in the Cambic horizon. Organic carbon, pH, clay, silt and calcium carbonate exerted strong influence on the distribution of micronutrients. DTPA extractable Zn, Cu, Mn and Fe increased with increasing organic carbon but decreased with increase in pH and calcium carbonate content. Total micronutrient contents increased with increase in clay, silt and calcium carbonate contents and decreased with increase in sand content.  相似文献   

2.
Modern agricultural systems have to provide enough micronutrient output to meet all the nutritional needs of people. Accordingly, knowledge on micronutrient status in soil and crop edible tissues is necessary. This study was carried out to investigate zinc (Zn), iron (Fe), manganese (Mn), and copper (Cu) concentration of calcareous paddy soil and the relative rice grain. Rice crops (straw, hull, and grain) and associated surface soils (0–25 cm) were collected from 136 fields and analyzed for total and diethylene triamine pentaacetic acid (DTPA) available Zn, Fe, Mn, and Cu. The DTPA-Zn concentration in more than 50% of paddy soils was less than its critical deficiency concentration (2 mg kg−1), while the concentrations of DTPA Fe, Mn, and Cu were sufficient. The grain Zn concentration of more than 54% of the rice samples was less than 20 mg kg−1. About 55% and 49% of the rice samples were deficient in Mn and Cu, respectively, while the Fe concentration in rice grains was sufficient. A significant negative correlation was found between the CaCO3 content and soil DTPA-extractable Zn, Fe, Mn, and Cu. There were significant relationships between the total soil phosphorus and DTPA-extractable micronutrient concentrations. By considering the average daily rice consumption of 110 g per capita, the Zn, Fe, Mn, and Cu intake from rice consumption was estimated to be 2.4, 7.7, 1.6, and 0.7 mg for adults, respectively.  相似文献   

3.
Desilication and leaching are processes that accompany plinthilization, leading to nutrient depletion. Soils from 12 profiles in a plinthitic landscape were analyzed for extractable micronutrients [iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu)]. Soils of the landscape from crestal to lower‐slope position contain plinthite in the profile, whereas those of the valley floor are devoid of plinthite. The micronutrients were extracted using diethylenetriaminepentaacetic acid (DTPA) and 0.1 M hydrochloric acid (HCl). The results showed that 0.1 M HCl extracted more of the micronutrients than DTPA. The DTPA‐extractable Fe, Zn, Mn, and Cu in all the soils ranged from 1.15 to 12.44 (mean, 3.69); 0.71 to 2.75 (mean, 1.86); trace 12.44 (mean, 3.35), and trace 3.76 (mean, 0.63) mg kg?1, respectively. The DTPA‐extractable micronutrient contents were generally greater than the critical available level (4.5 mg kg?1 for Fe, 0.8 mg kg?1 for Zn, 1.0 mg kg?1 for Mn, and 0.2 mg kg?1 for Cu). The 0.1 M HCl‐extractable micronutrients in the landscape ranged from 8.00 to 30.40 (mean, 15.19); 0.30 to 6.49 (mean, 1.35); 1.00 to 27.20 (mean, 7.74); and 0.26 to 15.0 (mean, 2.77) mg kg?1 for Fe, Zn, Mn, and Cu, respectively. Both DTPA‐ and 0.1 M HCl‐extractable micronutrients were generally lower in the plinthitic horizons than in the nonplinthitic horizons and higher in the Ap than the subsoil horizons. Correlation analysis showed a significant relationship between DTPA‐Fe and DTPA‐Mn, Cu, and organic carbon (r = 0.913**, 0.411**, and 0.385**). There was a significant and positive relationship between 0.1 M HCl‐extractable Mn and organic carbon (C), total nitrogen (N), and available phosphorus (P) (r = 0.413**, 0.337**, and 0.350**, respectively).  相似文献   

4.
Lowland or flooded rice is mainly responsible for about 76% of total rice production at global level, yet information on micronutrient requirements for this crop is limited. Six greenhouse experiments were conducted at the National Rice and Bean Research Center of EMBRAPA, Santo Antônio de Goiás, Brazil, to determine requirements of zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), manganese (Mn), and iron (Fe) for lowland rice grown on a Brazilian Inceptisol. The levels of micronutrients used were Zn (0, 10 20, 40, and 80 mg kg?1), Cu (0, 5, 10, 20, and 40 mg kg?1), B (0, 5, 10, 20, and 40 mg kg?1), Mo (0, 2, 4, 8, and 16 mg kg?1), Mn (0, 50, 100, 300, and 600 mg kg?1), and Fe (0, 250, 500, 1000, and 2000 mg kg?1). Grain yield was significantly increased in a quadratic fashion with the addition of Zn, Cu, B, Mo, Mn, and Fe. The adequate rates of micronutrients for maximum grain yield were Zn 33 mg kg?1, Cu 25 mg kg?1, B 26 mg kg?1, Mo 10 mg kg?1, Mn 250 mg kg?1, and Fe 1269 mg kg?1. In addition to grain yield, plant height, straw yield, panicle density, and root growth of lowland rice were also improved with the addition of most of these micronutrients. Improvement in root growth has special significance in improving nutrient-use efficiency under nutrient-stress conditions. Micronutrient-use efficiency (grain yield per unit nutrient applied) was in the order of Cu > Zn > Mn > Fe > Mo > B.  相似文献   

5.
Available micronutrient status of zinc, copper, manganese, and iron (Zn, Cu, Mn, and Fe) in surface soil samples under a rice–wheat system collected from farmers' fields in 40 districts representing different agroclimatic zones of the Indo‐Gangetic Plain (IGP) were determined. The selection of farmers, villages, blocks, and districts within an agroclimatic zone was made on the basis of a multistage statistical approach. In Trans‐Gangetic Plains, the diethylenetriaminepentaacetic acid (DTPA)–extractable Zn ranged from 0.11 to 5.08, Cu ranged from 0.22 to 4.72, Mn ranged from 2.9 to 101.2, and Fe ranged from 1.05 to 97.9 mg kg?1. In the Upper Gangetic Plains, the DTPA‐extractable Zn ranged from 0.04 to 2.53, Cu ranged from 0.06 to 4.32, Mn ranged from 11.1 to 421.0, and Fe ranged from 3.48 to 90.2 mg kg?1. In the Middle Gangetic Plains, the DTPA‐extractable Zn ranged from 0.17 to 8.60, Cu ranged from 0.09 to 7.80, Mn ranged from 3.0 to 155.1, and Fe ranged from 9.22 to 256.7 mg kg?1. In the Lower Gangetic Plains, the DTPA‐extractable Zn ranged from 0.04 to 3.46, Cu ranged from 0.21 to 4.38, Mn ranged from 9.54 to 252.2, and Fe ranged from 3.60 to 182.5 mg kg?1. The intensively cultivated Trans‐Gangetic transect representing the midplain and Siwalik had more available micronutrients than the arid plain. Midplain and arid plain showed 17 to 20% of soil samples were low to medium in Zn and 5 and 8% were low in Fe. In the Upper Gangetic Plains, only 25% samples were deficient in Zn, especially in central and southwest plains. In the Middle Gangetic Plains, 20 to 30% of samples were deficient in Zn, and very few samples were deficient in other micronutrients. In the Lower Gangetic Plains, a majority of the samples were medium to high in micronutrients except in Barind and Rarh Plains where 30% of samples were deficient in Zn. In the Lower Gangetic Plains, the available micronutrients were plentiful. Available micronutrients increased with increase in organic C content and decreased with increase in sand content, pH, and calcium carbonate. These soils are alluvial in nature, and there was no definite pattern of micronutrient distribution with depth in the profile. However, there was more accumulation in the Ap horizon than in the B horizon.  相似文献   

6.
长期施肥对潮土耕层土壤和作物籽粒微量元素动态的影响   总被引：4，自引：0，他引：4  
Micronutrient status in soils can be affected by long-term fertilization and intensive cropping.A 19-year experiment (1990-2008) was carried out to investigate the influence of different fertilization regimes on micronutrients in an Aquic Inceptisol and maize and wheat grains in Zhengzhou,China.The results showed that soil total Cu and Zn markedly declined after 19 years with application of N fertilizer alone.Soil total Fe and Mn were significantly increased mainly due to atmospheric deposition.Applications...  相似文献   

7.
稻草与生石灰对设施土壤微量元素含量和番茄产量的影响   总被引：3，自引：0，他引：3  
为了探究设施内添加稻草与生石灰对土壤微量元素含量和番茄产量的影响,以长期施肥定位试验为依托,比较了施用鸡粪(M)的基础上,添加稻草(MR)、生石灰(MCa)、稻草与生石灰同时添加(MRCa)各处理全土及各粒级团聚体中有效态Fe、Mn、Cu、Zn含量和番茄产量的变化。结果表明:(1)添加稻草可增加土壤中有效态Fe、Mn、Zn含量,MR处理较M处理分别增加3.2%,80.9%,15.1%,对有效态Cu含量无显著影响;添加生石灰也可增加土壤中微量元素含量,其中Mn含量增加显著。土壤中有效态Fe、Mn、Cn、Zn含量与pH呈极显著负相关(P<0.01),与有机质含量呈极显著正相关(P<0.01)。(2)随着土壤团聚体粒级的减小,有效态微量元素含量呈下降趋势。添加稻草和生石灰可增加1~0.25mm粒级中有效态Mn含量,MRCa处理较其他处理增加6.6%~46.6%;添加稻草可增加<0.25mm粒级中有效态Zn含量。土壤中有效态Fe含量与<1mm粒级中含量呈显著正相关(P<0.01);土壤中有效态Mn、Zn含量分别与各粒级中含量呈显著正相关(P<0.01);土壤中有效态Cu含量与1~0.25mm粒级中含量呈显著正相关(P<0.01)。(3)施入稻草或生石灰可增加番茄产量,且稻草和生石灰同时施入产量最高,MRCa处理较MCa、MR处理分别增加12.6%,33.8%。土壤有效态Fe、Cu含量与产量正相关,其中有效态Fe含量对产量具有直接作用,决策系数最高,土壤有效态Cu含量对产量具有间接作用。因此,可以通过长期添加稻草和适量生石灰缓解设施土壤微量元素短缺的现状,且可获得最高作物产量,为设施内土壤可持续利用和设施农业可持续发展提供保障。  相似文献   

8.
The Mehlich 3 method for the extraction of available micronutrients, such as copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), is more advantageous compared to the diethylene triamine pentaacetic acid (DTPA) method, because it can also be used for the extraction of macronutrients. The aim of this study was to compare the Mehlich 3 and DTPA methods for 172 soils in Greece having different levels of pH and calcium carbonate. Single and multiple regression analyses were employed to evaluate the relationship between Mehlich 3 and DTPA tests. Mehlich 3 results correlated well with DTPA-extractable Cu and Zn, but the correlation was poor for DTPA-extractable Mn. Also, a high correlation was found between Mehlich 3 and DTPA-extractable Fe for calcareous soils (R2 = 0.89), while a moderate relationship was found for noncalcareous soils (R2 = 0.65), which was improved to 0.78 when the pH was taken into account in multiple regression analysis.  相似文献   

9.
稻米和土壤微量元素的空间变异   总被引：1，自引：0，他引：1  
Consumption of rice is the main source of micronutrients to human in Asia. A paddy field with unknown anthropogenic contamination in Deqing County, Zhejiang Province, China was selected to characterize the spatial variability and distribution of micronutrients in rice grain and soil. A total of 96 paired soil and rice grain samples were collected at harvest. The micronutrients in the soil samples were extracted by diethylenetriamine pentaacetic acid (DTPA). The mean micronutrient concentrations in rice grain were 3.85 μg Cu g-1, 11.6 μg Fe g-1, 39.7 μg Mn g-1, and 26.0 μg Zn g-1. The mean concentrations were 2.54 μg g-1 for DTPA-Cu, 133.5 μg g-1 for DTPA-Fe, 30.6 μg g-1 for DTPA-Mn, and 0.84 μg g-1 for DTPA-Zn. Semivariograms showed that measured micronutrients in rice grain were moderately dependent, with a range distance of about 110 m. The concentrations of the DTPA-extractable micronutrients all displayed strong spatial dependency, with a range distance of about 60 m. There was some resemblance of spatial structure between soil pH and the grain Cu, Fe, Mn, and Zn. By analogy, similar spatial variation was observed between soil organic matter (SOM) and DTPA-extractable micronutrients in the soil. Kriging estimated maps of the attributes showed the spatial distributions of the variables in the field, which is beneficial for better understanding the spatial variation of micronutrients and for potentially refining agricultural management practices at a field scale.  相似文献   

10.
A total of 400 surface soil(0–15 cm) samples were collected from cultivated soils representing four soil series,namely,Hariharapur,Debatoli,Rajpora and Neeleswaram in Orissa,Jharkhand,Himachal Pradesh and Kerala states of India,respectively,and were analyzed to measure the contents of total and extractable Mn and Fe,to establish the relationship among total and extractable Mn and Fe and soil properties,and to characterize the spatial distribution pattern of Mn and Fe in some cultivated acid soils of India. The contents of total as well as extractable Mn and Fe varied widely with extractants and soil series. However,the amounts of Mn or Fe extracted by diethylene triamine penta-acetic acid(DTPA),Mehlich 1,Mehlich 3,0.1 mol L-1 HCl and ammonium bicarbonate DTPA(ABDTPA) were significantly correlated with each other(P 0.01). Based on the DTPA-extractable contents and the critical limits(2 mg Mn kg-1soil and 4.5 mg Fe kg-1 soil) published in the literature,Mn and Fe deficiencies were observed in 7%–23% and 1%–3% of the soil samples,respectively. The content of soil organic carbon(SOC) had greater influence on total and DTPA-extractable Fe than did soil pH. Geostatistical analysis revealed that total and DTPA-extractable Mn and Fe contents in the acid soils were influenced by soil pH,SOC content,and exchangeable cations like potassium,calcium and magnesium. Spatial distribution maps of total and DTPA-extractable Mn and Fe in soil indicated different distribution patterns.  相似文献   

11.
Micronutrient status in soils and crops can be affected by different fertilization practices during a long-term field experiment. This paper investigated the effects of different fertilization treatments on total and DTPA-extractable micronutrients in soils and micronutrients in crops after 16 year fertilization experiments in Fengqiu County, Henan Province, China. The treatments of the long-term experiment included combinations of various rates of N, P and K in addition to two rates of organic fertilizer (OF) treatments. Winter wheat and summer maize were planted annually. Soil macro- and micronutrients along with pH and organic matter (OM) were analyzed. Grains and above ground parts of both crops in the final year were harvested and analyzed for Cu, Zn, Fe and Mn. The results showed that soil Cu, Zn, Fe and Mn concentrations did not change among the different treatments to a significant level, except for a slight decrease of soil Zn in the CK (no fertilizer application) compared to the OF treatment. The DTPA-extractable soil Zn, Fe and Mn concentrations increased from 0.41 to 1.08 mg kg−1, from 10.3 to 17.7 mg kg−1, and from 9.7 to 11.8 mg kg−1, respectively, with increasing soil OM content, thus showing the importance of soil OM in micronutrient availability for crops. The NPK treatment also had higher DTPA-extractable micronutrient concentrations in soil. Deficiency of N or P resulted in a low yield but high micronutrient concentrations in crops except Cu in maize stalks. Higher available soil P significantly decreased crop micronutrients, possibly because of their precipitation as metal phosphates. Maize stalks contained higher concentrations of micronutrients than those of wheat straw, whereas wheat grain had higher micronutrients than those of corn grain. The transfer coefficients (TCs) of micronutrients from straw to grain were significantly different between winter wheat (1.63–2.52 for Cu; 2.31–3.82 for Zn; no change for Fe; 0.55–0.84 for Mn) and summer maize (0.24–0.50 for Cu; 0.50–1.21 for Zn; 0.02–0.04 for Fe; 0.07–0.10 for Mn). In conclusion, application of organic matter significantly increased the DTPA-extractable concentrations of Zn, Fe and Mn compared to the CK, grain and vegetative tissue in the CK and NK had higher micronutrient concentrations than those in other treatments.  相似文献   

12.
In the present study, a laboratory experiment was designed to compare the 0.01 M calcium chloride (CaCl2) and diethylenetriaminepentaacetic acid (DTPA) extraction methods for their ability to predict cadmium (Cd), copper (Cu), iron (Fe), Manganese (Mn), nickel (Ni), and zinc (Zn) availability and mobility in five calcareous soils. The soils were spiked with different amounts of metals (0, 50, 100, 200, and 400 mg kg?1) both in binary (Cu and Zn; Ni and Cd; Fe and Mn) and in multi-systems (Cd, Cu, Fe, Mn, Ni, and Zn) and incubated for 1 months at field capacity. In metal-spiked soils, both extraction methods showed a linear relationship of extractable to total metals for all soils. The fraction of total metals extracted by DTPA was much higher than the fraction extracted by CaCl2, which was attributed to the formation of soluble metal-complexes in the complexing extracts calculated by the Visual Minteq program. DTPA extraction method showed higher selectivity for Cu over other metals both in binary and in multi-systems. Different order of metals extractability was found in binary and multi-systems for both extraction methods. Solid/solution distribution coefficient (Kd) was calculated by the ratio of the solid phase to soil solution concentration of metals extracted by CaCl2 or DTPA extraction methods. Both in binary and in multi-systems, the average Kd (l kg?1) of metals by soils were in the order of Mn (5398) > Fe (4413) > Zn (3376) > Cu (2520) > Ni (969) > Cd (350) in the CaCl2-extractable metals and Fe (35) ≥ Ni (34) > Zn (18) > Mn (11.2) > Cu (6.3) > Cd (4) in the DTPA-extractable metals. Results showed that among the six studied metals, Cd had the lowest Kd, implying a relative higher mobility in these calcareous soils. The Visual Minteq indicated that in the CaCl2-extraction method and in both binary and multi-systems the dominant species for Cu, Mn, Ni, and Zn were Cu2+, Mn2+, Ni2+ and Zn2+, respectively, while for Cd and Fe, the dominant species were CdCl+ and Fe(OH)2+, respectively.  相似文献   

13.
Abstract

Three extracting reagents were evaluated by correlation analyses to provide the best index of Zn, Cu, Mn and Fe availability to wheat (Triticum aestivum L.) plants growing under open field conditions. Twenty one soils were selected to obtain the widest range in properties of soils of the land wheat cultivated. The magnitude of the extractive power varied in the following order: 6NHCl ? EDTA + NH4OAC, pH4.65 > DTPA‐TEA, pH 7.3. The mild extractants, EDTA and DTPA, gave the same order of removal of micronutrients being Zn < Cu < Fe < Mn. The acid extractant was on the contrast more effective on Cu and Fe with respect to Zn and Mn, respectively. Wheat concentrations of Zn, Mn and Fe were significantly correlated to soil micronutrients. Highly significant relationships were found for Zn extracted by DTPA solution (r = 0.737***) and for Mn and Fe extracted by EDTA solution (r = 0.710*** and r = 0.564**). Plant Zn and Mn were also well predicted by the acid extraction. The absence of correlation for plant Cu vs. soil Cu occurred probably because of wheat concentrations almost constant, ranging from 5.0 to 8.0 mg/kg.  相似文献   

14.
Heavy metal uptake, translocation and partitioning differ greatly among plant cultivars and plant parts. A pot experiment was conducted to determine the effect of cadmium (Cd) levels (0, 45 and 90 mg kg?1 soil) on dry matter yield, and concentration, uptake and translocation of Cd, Fe, Zn, Mn and Cu in seven rice cultivars. Application of 45 mg Cd kg?1 soil decreased root and shoot dry weight. On average, shoot and root Cd concentrations and uptake increased in all cultivars, but micronutrients uptake decreased following the application of 45 mg Cd kg?1. No significant differences were observed between 45 and 90 mg kg?1 Cd levels. On average, Cd treatments resulted in a decrease in Zn, Fe and Mn concentrations in shoots and Zn, Cu and Mn concentrations in roots. Differences were observed in Cd and micronutrient concentrations and uptake among rice cultivars. Translocation factor, defined as the shoot/root concentration ratio indicated that Cu and Fe contents in roots were higher than in shoots. The Mn concentration was much higher in shoots. Zinc concentrations were almost similar in the two organs of rice at 0 and 45 mg Cd kg?1. A higher Cd level, however, led to a decrease in the Zn concentration in shoots.  相似文献   

15.
Abstract

Alfisols, Vertisols, Inceptisols, Aridisols, Mollisols, and Entisols were sampled (0–30 cm) from 32 locations across Ethiopia. The soils were analyzed for copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) contents using 0.005 M diethylene triamine pentaacetic acid (DTPA), 0.05 M hydrochloric acid (HC1), and 0.02 M ethylene diamine tetraacetic acid (EDTA) extractants. EDTA extracted more of each micronutrient than DTPA, which extracted greater amounts than HC1. The quantities of EDTA and DTPA‐extractable micronutrients were significantly correlated, and were in the order: Mn>Fe>Cu>Zn. The order of HCl‐extractable micronutrients was Mn>Fe>Zn>Cu. Micronutrient contents of Mollisols, Vertisols, and Alfisols were usually greater than those of the other soils, and Entisols usually had the lowest micronutrient contents. The contents were mostly positively correlated with clay and Fe2O3 contents, but negatively correlated with soil pH and A12O3contents. While comparison of DTPA‐ and EDTA‐extractable micronutrients with critical levels showed that most soils had adequate amounts of the micronutrients for crops, the amounts extracted by HC1 were below critical levels in most soils. Since the critical levels that were used in the comparisons were not established in Ethiopia, calibration of the soil contents of these micronutrients with crops grown in Ethiopia is required to identify the most suitable extractant(s).  相似文献   

16.
Zinc (Zn) deficiency in soils and field crops is widespread across the world, including India, resulting in severe reduction in yield. Hence, soil application of Zn fertilizers is recommended for ameliorating Zn deficiency in soil and for obtaining higher crop yield and better crop quality. Zinc sulfate is commonly used Zn fertilizer in India because of its solubility and less cost. However, good quality and adequate quantity of zinc sulfate is not available in the market round the year for farmers' use. Field experiments were therefore conducted during rainy season of 2010 and 2011 at research farm of Indian Institute of Soil Science, Bhopal, India to assess the influence of Zn application through zinc sulfate monohydrate (33% Zn), zinc polyphosphate (21% Zn) and Zn ethylenediaminetetraacetate (EDTA) (12% Zn) on yield and micronutrient concentration and uptake by maize (Zea mays L.). In both the years, grain and vegetative tissue (stover) yield of maize increased significantly with successive application of Zn up to 1 kg ha?1 added through zinc sulfate monohydrate and zinc polyphosphate. Addition of 2.5 kg Zn ha?1 did not increase yield further but resulted in highest stover Zn concentration. Zinc, copper (Cu), manganese (Mn), and iron (Fe) concentration in maize grain varied from 22.2 to 27.6, 1.6 to 2.5, 3.5 to 4.7 and 19.9 to 24.5 mg kg?1 respectively in both the years. Maize stover had 25.9 to 36.2, 7.9 to 9.8, 36.7 to 44.9 and 174 to 212 mg kg?1 Zn, Cu, Mn, and Fe, respectively. Zinc application did not influence Cu, Mn and Fe concentration in both grain and stover of maize. Transfer coefficients (TCs) of micronutrients varied from 0.72 to 0.95, 0.18 to 0.30, 0.08 to 0.13 and 0.10 to 0.15 for Zn, Cu, Mn, and Fe respectively. Total Zn uptake significantly increased with Zn application from 0.5 to 2.5 kg ha?1 supplied through zinc sulfate monohydrate and zinc polyphosphate. Recovery efficiency of Zn declined with increased Zn rates.  相似文献   

17.
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 soil mapping units and eleven drainage districts were sampled. Soil pH, OC and DTPA‐extractable Cu, Mn, and Zn were determined on each sample. AU collected data were analyzed with the GLM procedure of SAS and quartile reference was used to separate the data. Manganese availability was negatively correlated with pH and OC. Significant correlations were also found between Cu and soil pH, and Zn and OC. The pH x OC interaction significantly affected both Mn and Zn availability. Soil pH, OC, and DTPA‐extractable Cu, Mn, and Zn were used to categorize soil mapping units and drainage districts into low, medium, and high tendencies for micronutrient availability. This categorization can be used as a tool for growers and consultants for soil micronutrient management  相似文献   

18.
Abstract

Vertisols of India are developed over isohyets of 600 to 1500 mm, and their chemical cycles are set by drainage, landforms, and particle size, which results in variable pedogenic development within the otherwise homogeneous soils. The purpose of this study was to identify pedogenic processes in the distribution of total and DTPA‐extractable zinc (Zn), copper (Cu), manganese (Mn), and iron (Fe). The soils are developed over basaltic parent material of Cretaceous age. Soil samples were drawn from genetic horizons of the 13 benchmark profiles and analyzed by using HF–HClO4 acid for total and DTPA extraction. Correlation coefficients were calculated taking all samples together. The total concentration varied from 24 to 102 mg kg?1 for Zn, 21 to 148 mg kg?1 for Cu, 387 to 1396 mg kg?1 for Mn, and 2.36 to 9.50% for Fe. Their variability was proisotropic and haplodized, and their concentrations increased with advancing isohyets. Within the isohyets, hindrance in drainage caused retention of Zn and Cu but loss of Fe. The piedmont soils had more Fe than alluvium soils. The spatial distribution of total contents of Zn, Cu, and Fe was influenced by the pedogenic processes associated with Haplusterts but not with provenance materials. Surface concentrations of the elements by biotic lifting and/or harvest removal were negated by the pedoturbation that further contributed to the irregular distribution of the elements in the profiles. Total Zn and total Cu had positive coefficients of correlations with coarse clay, whereas total Mn and total Fe were positively correlated with fine clay. The DTPA‐extractable forms were functions of isohyets and drainage and showed association with organic carbon content and coarse clay.  相似文献   

19.
Profiles of semi-arid-zone soils in Punjab, northwestern India, were investigated for different forms of copper (Cu), including total Cu, diethylenetriaminepentaacetic acid (DTPA)–extractable Cu, soil solution plus exchangeable Cu, Cu adsorbed onto inorganic sites, Cu bound by organic sites, and Cu adsorbed onto oxide surfaces. When all soils were considered, total Cu content ranged from 7 to 37 mg kg?1, while DTPA-extractable and soil solution plus exchangeable Cu contents ranged from 0.30 to 3.26 mg kg?1 and from 0.02 to 0.43 mg kg?1, respectively. Copper adsorbed onto inorganic sites ranged from 0.62 to 2.6 mg kg?1 and that onto oxide surfaces ranged from 2.0 to 13.2 mg kg?1. The Cu bound by organic sites ranged from 1.2 to 12.2 mg kg?1. The magnitudes of different forms of Cu in soils did not exhibit any consistent pattern of distribution. Organic matter and size fractions (clay and silt) had a strong influence on the distribution of different forms of Cu. The content of all forms of Cu was generally greater in the fine-textured Alfisols and Inceptisols than coarse-textured Entisols. Soil solution plus exchangeable Cu, Cu held onto organic sites, and and Cu adsorbed onto inorganic sites (crystalline) had significant positive correlations with organic carbon and silt contents.The DTPA Cu was positively correlated with organic carbon, silt, and clay contents. Total Cu content strongly correlated with silt and clay contents of soils. Among the forms, Cu held on the organic site, water soluble + exchangeable Cu, and Cu adsorbed onto oxide surface were positively correlated with DTPA-extractable Cu. The DTPA-extractable Cu and soil solution plus exchangeable Cu seems to be good indices of Cu availability in soils and can be used for correction of Cu deficiency in the soils of the region. The uptake of Cu was greater in fine-textured Inceptisols and Alfisols than coarse-textured Entisols. Among the different forms only DTPA-extractable Cu was positively correlated with total uptake of Cu.  相似文献   

20.
A pot experiment was conducted in a greenhouse to evaluate the effects of different levels of cadmium (Cd) on Cd accumulation and their effects on uptake of micronutrients in Indian mustard [Brassica juncea (L.) Czern.]. Cadmium accumulation in shoots and interactions among other metals [manganese (Mn), iron (Fe), copper (Cu), and zinc (Zn)] were investigated. Ten levels of Cd ranging from 0 to 200 mg kg–1 soil were tested. The crop was grown for 60 days in a loamy sand soil with adequate basal fertilization of nitrogen (N), phosphorus (P), and potassium (K), and dry-matter yield (DMY) was recorded. The plants were analyzed for total Cd and micronutrients, and the soil was analyzed for diethylenetriaminepentaacetic acid (DTPA)–extractable Cd. Experimental results showed that the DTPA-extractable Cd in the soil increased consistently and significantly with increase in rates of Cd application up to 200 mg Cd kg–1 soil. Significant reduction in the DMY of Indian mustard occurred with application of 5 mg Cd kg–1 soil and greater. The content as well as uptake of Cd by Indian mustard increased significantly over the control at all rates of its application. It increased from 5.95 μg pot–1 in the control to 150.6 μg pot–1 at Cd application of 200 mg kg–1 soil. Application of Cd to soil though decreased the content of micronutrients in plants, but significant reduction occurred only for Fe at rates beyond 50 mg Cd kg–1 soil. However, the total removal of Fe, Zn, and Cu registered a significant decline over the control at and above Cd application of 10 mg kg–1 and that of Mn beyond 10 mg kg–1. In loamy sand soil, a DTPA-extractable Cd level of 3.8 mg kg–1 soil and in plant content of 28.0 μg Cd g–1 DMY was found to be the upper threshold levels of Cd for Indian mustard. Considerable residual content in the soil suggests that once the soil is contaminated by Cd it remains available in the soil for decades, and food crops grown on these soils may be a significant source of Cd toxicity to both humans and grazing animals.  相似文献   

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