Influence of residual phosphate fertilizer on labile and extractable zinc in hawaii soils

Abstract

Zinc availability was studied using five soils from Hawaii which had histories of massive phosphorus applications. Heavy phosphate fertilization usually increased extractable Zn, irrespective of the extractant used. The extra extractable Zn associated with the added P probably came from Zn as an accessory element in the fertilizer. Treble superphosphate commonly used in Hawaii contains about 1400 ppm Zn. The Zn content of phosphate fertilizers must be considered before making statements about the effect of fertilizer P on Zn solubility and availability in soils.

Two solutions (0.1N HCl and 0.005M DTPA) were compared as Zn extractants for Hawaii soils. DTPA extracted less Zn than 0.1N HCl. Zinc extracted by repeated HCl treatment was more closely related to the labile Zn pool (E‐values and L‐values) than was DTPA‐extractable Zn. The results suggest that 0.1N HCl extractable Zn, Zn E‐value and Zn L‐value measured the quantity of a single fraction of soil Zn.

Repeated extraction of soil with 0.1N HCl seems to be a suitable procedure for evaluating the Zn status of acid, highly weathered soils of Hawaii.     

Zinc bioavailability in maize grains in response of phosphorous–zinc interaction

Phosphorous (P) and zinc (Zn) are plant nutrients that interact with each other in soil–plant systems. Such interactions may cause deficiency of one of the nutrients interacting with each other if interactions are antagonistic. In the present trial, a field experiment was conducted to investigate the interactive effect of Zn (0 and 16 kg ha^?1) and P (0 and 60 kg ha^?1) on growth, yield and grain Zn concentration of two maize (Zea mays L.) genotypes, i.e., Neelam (local) and DK‐6142 (hybrid). Growth and yield of both maize genotypes were increased by the application of Zn and P treatments compared with control, but Zn+P was more effective than their sole application. When compared to control, combined application of Zn+P increased grain Zn and P concentrations by 52% and 32%, respectively, averaged for the two genotypes. Single application of P decreased grain Zn concentration by 10% over control. Application of P and Zn particularly in combination decreased the grain [phytate] : [Zn] ratio and increased the estimated human Zn bioavailability in grains based on a trivariate model of Zn absorption in both maize genotypes. Conclusively, combined Zn+P application appeared more suitable for enhancing grain yield and agronomic Zn biofortification in maize grains. However, Zn fertilization aiming at increasing grain yield and grain Zn concentration should consider the genotypic variations and P rate.     

光照强度对伴矿景天生长和锌镉吸收性的影响

伴矿景天(Sedum plumbizincicola)是生长于浙江铅锌矿地区的一种景天科植物新种,具有超富集锌和镉的特性,是一种多年生草本植物,无性繁殖为主,与其他修复植物相比具有生长速率快、生物量较大的特点[1-2],可用来修复重金属污染土壤[3]。但对伴矿景天的生长习性鲜有研究,限制了其大规模的推广应用。因此,本文以Zn、Cd超积累植物伴矿景天为对象,探讨光照强度对其生物量与Zn、Cd浓度的影响,及可能的光合作用响应机制,旨在探明伴矿景天生长的适宜光照环境,为重金属污染土壤植物修复的农艺调控提供依据。1材料与方法1·1供试材料供试伴矿景天苗采自浙江淳安,将野外植株移至温室生长繁殖,通过株芽     

磷肥减施对玉米根系生长及根际土壤磷组分的影响

【目的】 我国农业过量和不合理施用磷肥现象普遍存在,导致磷资源的浪费,对环境也造成潜在威胁。研究减少磷肥用量对玉米产量、根系形态及根际中磷转化特征的影响,为集约化农业生产体系中磷肥合理施用提供技术基础。 【方法】 在河北省衡水小麦玉米轮作体系下连续三年进行了田间试验,在冬小麦季设置4个P₂O₅用量处理:0、112.5、150.0、187.5 kg/hm2,收获后在原处理小区免耕播种夏玉米。利用WinRHIZO根系分析系统分析获取根长、直径等数据,测定玉米籽粒产量、生物量和地上部磷含量及根际土壤中磷形态等指标。 【结果】 与农民习惯磷肥用量(P₂O₅187.5 kg/hm2)相比,3年磷肥用量减施20%~40%处理(P₂O₅150和112.5 kg/hm2),玉米籽粒产量、根系长度与直径和土壤有效磷含量尚未发生明显变化。但3年不施磷处理,根际土壤有效形态磷含量和玉米籽粒产量开始出现下降趋势。2009年和2010年玉米收获期,不施磷肥处理根际土壤有机磷含量低于非根际土壤。2008年玉米苗期和收获期土壤有机磷分组中,中等活性有机磷含量最高;磷肥减施20%~40%处理苗期根际中中等活性有机磷含量显著低于非根际土壤。土壤无机磷形态分组研究发现:从玉米苗期到收获期,各磷肥处理根际和非根际土壤中Ca₂-P下降明显;而不同磷肥处理间土壤中Ca₁₀-P、Ca₈-P、O-P (闭蓄态磷)、Al-P和Fe-P含量差异不显著。减施磷肥处理2008年玉米苗期根际土壤微生物量P含量较非根际土壤高;与习惯施肥量相比,磷肥减施未明显降低根际土壤微生物量磷。 【结论】 在华北小麦玉米轮作种植体系下,在土壤肥力水平较高地区,连续3年将小麦季磷肥的习惯用量减少20%~40%,对夏玉米产量、根系形态以及根际土壤无机磷、有机磷、微生物量磷含量影响尚不明显,因此,该地区磷肥施用量可从习惯用量的P₂O₅180 kg/hm2减至112.5 kg/hm2。     

Use of plants to evaluate the difference in available cadmium between soils

Abstract

A new method was proposed for assessing the difference in the capacity of soils to supply Cd to plants. The relation of tissue (tc) to soil (sc) Cd concentrations can be expressed as; log(tc) = α+βlog(sc), where α and β are the regression coefficients. When the same plant is grown on another soil, the equation will change to; log(tc) = α'+β'log(sc’). Based on both equations, the relationship between sc‘and sc becomes; log(sc’) = (α‐α')/β’ + (β/β') log(sc). Set p = (α‐α')/β’ and q = β/β’, then the difference of Cd availability between two soils can be evaluated according to the values of p and q. The p and q values were determined among four treatments in which radish was grown on a sand soil and a silty loam soil at two pH levels. The values showed that the Cd present in the sand soil (pH 5.6) and the metal in the silty loam soil (pH 7.5) were the most and least available, respectively. It was therefore considered that the parameters p and q could be used as criteria for selecting an ideal extractant capable of removing the actually available Cd from soils.     

Transformation of added phosphorus to acid upland soils with different soil properties in Indonesia

Abstract

The transformation of added phosphorus (P) to soil and the effect of soil properties on P transformations were investigated for 15 acid upland soils with different physicochemical properties from Indonesia. Based on oxide-related factor scores (aluminum (Al) plus 1/2 iron (Fe) (by ammonium oxalate), crystalline Al and Fe oxides, cation exchange capacity, and clay content) obtained from previous principal component analyses, soils were divided into two groups, namely Group 1 for soils with positive factor scores and Group 2 for those with negative factor scores. The amounts of soil P in different fractions were determined by: (i) resin strip in bicarbonate form in 30 mL distilled water followed by extraction with 0.5 mol L^?1 HCl (resin-P inorganic (P_i) that is readily available to plant), (ii) 0.5 mol L^?1 NaHCO₃ extracting P_{i and} P organic (P_o) (P which is strongly related to P uptake by plants and microbes and bound to mineral surface or precipitated Ca-P and Mg forms), (iii) 0.1 mol L^?1 NaOH extracting P_i and P_o (P which is more strongly held by chemisorption to Fe and Al components of soil surface) and (iv) 1 mol L^?1 HCl extracting P_i (Ca-P of low solubility). The transformation of added P (300 mg P kg^?1) into other fractions was studied by the recovery of P fractions after 1, 7, 30, and 90 d incubation. After 90 d incubation, most of the added P was transformed into NaOH-P_i fraction for soils of Group 1, while for soils of Group 2, it was transformed into resin-P_i, NaHCO₃-P_i and NaOH-P_i fractions in comparable amounts. The equilibrium of added P transformation was reached in 30 d incubation for soils of Group 1, while for soils of Group 2 it needed a longer time. Oxide-related factor scores were positively correlated with the rate constant (k) of P transformation and the recovery of NaOH-P_i. Additionally, not only the amount of but also the type (kaolinitic) of clay were positively correlated with the k value and P accumulation into NaOH-P_i. Soils developed from andesite and volcanic ash exhibited significantly higher NaOH-P_i than soils developed from granite, volcanic sediments and sedimentary rocks. Soil properties summarized as oxides-related factor, parent material, and clay mineralogy were concluded very important in assessing P transformation and P accumulation in acid upland soils in Indonesia.     

氮锌配施对玉米干物质积累及产量效应的研究

采用盆栽试验,研究了氮锌配施对玉米干物质积累、生长性状及产量的影响,结果表明,氮肥和锌肥都能增加玉米的干物质积累、株高、穗长、穗粗、穗粒数、百粒重及产量,且除穗长外氮肥的作用大于锌肥;氮锌配施效应大于单施氮肥或锌肥,氮锌交互效应为正,N1Zn1是最佳处理组合;综合考虑玉米生物产量、子粒产量、经济效益及环境污染,以施N1...     

The effect of zinc (Zn) application on uptake of cadmium (Cd) in some cereal species

It is widely accepted that plants absorb more Cd when they suffer from Zn deficiency, as the Zn deficiency is a critical problem in the world. The effect of increased Cadmium (Cd) application (0 and 15 mg kg^-1 Cd) on growing and Cd concentration in some cereal species was investigated at the increasing rate of Zinc (Zn) applications (0 and 15 mg kg^-1 Zn). The experiment was carried out under greenhouse conditions using a Zn deficient soil. According to the results, that increased Cd applications severely reduced dry matter production of plants. Dry matter production decreased in the following order: bread wheat > oat > maize > barley. These decreases were determined to be statistically significant (P < 0.01). Cd concentration of cereal species increased with the application of increasing rate of Cd, with a similar trend to that of the dry matter. Dry matter production of plants increased and Cd concentrations of plants decreased with the application of increasing rate of Zn. These results show that Cd accumulation of plant increase in Zn deficient soils. Cd accumulation in plants is hindered with the application of Zn.     

An effective planting model to decrease cadmium accumulation in rice grains and plants: Intercropping rice with wetland plants

Cadmium (Cd) pollution affects plant growth and poses a serious threat to food safety and human health.Cadmium-contaminated rice is assumed to be the main source of Cd exposure to humans,with grave health risks.Phytoremediation is an efficient,cost-effective,and eco-friendly approach to minimize Cd accumulation in rice.However,research on the effect of rice intercropping with wetland plants that exhibit great capacity for phytoremediation in decreasing Cd concentrations in paddies is limited.A p...     

改良剂对镉污染酸性水稻土的修复效应与机理研究

为探明田间条件下施用石灰、钙镁磷肥、海泡石和腐殖酸等改良剂对Cd污染酸性水稻土的修复效应和作用机理, 通过在Cd污染区建立田间小区试验, 研究了改良剂单施和与石灰配施对Cd污染酸性水稻土中Cd作物有效性的影响。结果表明, 施用改良剂有效地改变了土壤中Cd的存在形态, 除腐殖酸外, 其他改良剂均使土壤酸提取态Cd不同程度地转化为可还原态Cd和残渣态Cd; 施用改良剂可使0.1 mol·L^-1 NaNO₃和 0.01 mol·L^-1CaCl₂提取态Cd 降低26%~97%, 降低效果为石灰+海泡石>海泡石>石灰+钙镁磷肥>钙镁磷肥>石灰>石灰+腐殖酸>腐殖酸; 改良剂使水稻地上部分的Cd吸收量降低6%~49%。试验结果还显示, 施用改良剂提高土壤pH是引起土壤中Cd作物有效性降低的主要原因之一。根据田间试验的结果, 海泡石可推荐作为Cd污染酸性水稻土的改良剂, 而腐殖酸则不宜使用。     

Influence of potassium and magnesium fertilizer application on the yield and nutrient accumulation of maize genotypes under field conditions

The use of maize (Zea mays L.) genotypes that are able to utilize nutrients efficiently is an important strategy in the management of plant nutritional status; it is of particular importance with regard to potassium (K) and magnesium (Mg), due to their high requirement and influence on plant growth. The influence of K and Mg fertilizers on certain growth parameters of maize genotypes TM.815 and KL.72.AA, including length, seed in ear, seed weight growth, and nutrient concentration, was determined under field conditions over two successive years. The aim of the experiment was to study the effect of different rates of K and Mg fertilizers on maize genotype plant growth parameters, grain yield, and nutrient accumulation under field conditions.

A split plot design with three replicates was used and each block contained three treatments of 0, 100, and 200 kg ha^?1 of K₂O and 0, 10, and 20 kg ha^?1 of Mg; K₂SO₄ was used to supply K, and MgSO₄ was used for Mg.

Plants that responded to the K fertilizer had an increase in height, yield, and the concentration of K in the leaves and seeds. The addition of K fertilizer increased the concentration of nitrogen (N), iron (Fe), zinc (Zn), manganese (Mn), and K in the plant leaves and increased seed K concentration. Mg fertilizer increased the concentration of N, Fe, copper, and Mn in the leaves; however, it exerted no significant influence on K concentration. The KL.72.AA maize genotype had a higher mean plant height, number of seeds in ear, yield, and N, K, Fe, and Zn concentrations compared to the TM.815 maize genotype. In the experiment, the K fertilizer exerted a statistically significant effect on the leaf and seed K concentration; however, on a statistical basis, the Mg fertilizer did not affect the Mg concentration.     

土壤酶活性评价镉锌铅复合污染的可行性研究

模拟试验研究表明在Cd、Zn、Pb复合污染处理土壤中,过氧化氢酶、脲酶活性与碱性磷酸酶或转化酶活性可构成综合评价体系,反映土壤Cd、Zn、Pb污染含量以及土壤Cd-Zn、Zn-Pb复合污染效应,用其评价土壤Cd、Zn、Pb复合污染具有一定可行性。     

Soil affects on the cadmium and zinc contents of Chinese cabbage in Yunnan Province,China

Chinese cabbage and surface soil samples (0–20 cm) from a periurban market garden in Yunnan Province (P.R. China) were collected to determine variations of cadmium (Cd) and zinc (Zn) contents in Chinese cabbage and the influence of soil factors. Mean Cd content was 0.49 mg kg^?1 dry materials (DM) in Chinese cabbage, ranging between 0.23 and 1.34 mg kg^?1 DM (n = 21 samples). Mean Zn content was 51.2 mg kg^?1 DM, ranging from 34.9 to 157.5 mg kg^?1 DM (n = 21 samples). The soil factors best predicting Chinese cabbage Cd and Zn contents were total and available Cd and Zn contents and cation exchange capacity (CEC). Soil samples and corresponding Chinese cabbage samples were divided into two groups: soils with low pH (<6.5, n = 10) and soils with high pH (>6.5, n = 11). Positive correlation between CEC with pH > 6.5 and Cd and Zn contents in Chinese cabbage were observed. Available trace element contents and CEC explained 77% and 69% of variation of Cd and Zn contents in Chinese cabbage, respectively. AEC (enrichment coefficient related to trace element availability) and BCF (bioaccumulation factors) could be used to understand Cd and Zn accumulation in Chinese cabbage.     

磷肥中腐植酸添加比例对玉米产量、磷素吸收及土壤速效磷含量的影响

【目的】 腐植酸可提高磷肥的肥效,对于其在磷肥中适宜添加量的研究可为我国磷肥的增效减量提供依据。【方法】 将腐植酸增效剂按1%、5%、10%和20%的比例添加到磷酸一铵中,制成四种腐植酸磷肥试验产品（HP1、HP2、HP3和HP4）,利用土柱栽培试验研究在等磷量（施P2O5量0.1g/kg干土）投入及等肥料重量（施磷肥实物量0.16g/kg干土,即施P2O5量分别减少1%、5%、10%、20%）投入情况下,腐植酸磷肥对玉米产量、磷素吸收利用及土壤速效磷含量的影响。【结果】 1）在等磷量施用情况下,与普通磷肥（P）相比,四种腐植酸磷肥处理玉米籽粒产量增加4.5%～13.6%,且腐植酸添加量越大产量越高,均显著高于普通磷肥处理;在等肥料重量施用下,随着腐植酸磷肥施入P2O5量的减少,玉米籽粒产量逐渐降低,当P2O5施用量减少20%时籽粒产量与普通磷肥处理相比仍未显著降低。2）腐植酸磷肥处理在等磷量施用下较普通磷肥处理可显著提高玉米籽粒磷吸收量和地上部吸磷总量,分别增加6.0%～15.4%和6.3%～14.0%,但秸秆磷吸收量无显著变化;当腐植酸磷肥施入P2O5量减少20%时籽粒磷吸收量和地上部磷吸收总量会显著低于普通磷肥处理。3）与普通磷肥处理相比,在等磷量施用下,腐植酸磷肥的表观利用率提高5.9～13.1个百分点,农学利用率、偏生产力分别提高26.5%～79.1%、4.5%～13.5%,且均达到显著水平。4）施入腐植酸后主要影响050cm土层的土壤速效磷含量,其中1530cm土层速效磷含量增加最为显著,与普通磷肥处理相比增加18.1%～36.6%。【结论】 腐植酸增效剂在1%～20%的添加比例范围内对磷肥均具有较好的增效作用,可提高玉米产量、磷素吸收量及磷肥利用效率,并可提高土壤中的速效磷含量,且腐植酸添加量越大效果越好;利用腐植酸的增效作用来减少磷肥施用量是可行的,在当前磷肥施用量的基础上可减少磷肥用量20%左右而保证玉米不减产。     

An examination of zinc uptake patterns by cultivars of sorghum and maize : Differences amongst hybrids and their parents

Zinc absorption and transport patterns were examined in sorghum and maize hybrids and their parent cultivars with a view to observe, if any, and relate the differences amongst them meaningfully to traits like hybrid vigor. Short term uptake by excised roots or intact seedlings, from different concentrations of ZnCl₂ or ZnEDDHA and also, time course from 50 μM ZnCl₂, were measured. The results showed significant differences in the Zn absorption patterns by excised roots of sorghum cultivars. The rate of Zn transport to shoot in CSH‐8 was found to be higher than in others. The amount of Zn transported from ZnEDDHA was also more than that from ZnCl₂ in all sorghum cultivars. Furthermore, significant hybrid vigor was observed in Zn transport from ZnEDDHA for the two hybrids CSH‐7 and CSH‐8. The resemblance of absorption and transport patterns of Zn in CSH‐8 to those of 36‐A strongly suggests that the trait is inherited from the female parent.

No heterosis was observed in the absorption and transport of Zn in maize hybrids. However, a linear and an exponential isotherms for Zn transport in Ganga‐5 and Ganga‐2 hybrids indicates some hybrid vigor.     

水磷互作对潮土玉米苗期生长及磷素积累的影响

利用温室盆栽试验研究了水磷互作对潮土玉米苗期生长及磷素积累的影响。结果表明,水、磷能显著影响玉米株高与叶面积状况。水分胁迫条件下,适度施磷处理比对照玉米株高和叶面积分别增加69.7%和33.6%;而适水条件下分别增加38.3%和48.0%。适度施磷条件下,水分胁迫促进了玉米根系发育,根干重与根冠比均高于适水处理。水磷配合能提高了玉米干物质积累量,表现出显著正交互效应。适度施磷范围内,适水处理能显著提高植株体磷素吸收积累总量,但对植株磷含量影响不大;适水处理下,过量施磷会导致植株对磷素奢侈吸收,而在水分胁迫下反而降低对磷素的吸收积累。水磷适度配合表现出较好的耦合效果,达到“以水促磷”与“以磷促水”的目的。     

Accumulation of cadmium,fluorine, magnesium,and zinc in soil after application of phosphate fertilizer for 31 years in a grazing trial

Phosphate fertilizers are recognized as a potential source of elements that could contribute to soil pollution. The objective of this study was to determine the extent to which use of phosphate fertilizer in the past had resulted in an increase in heavy‐metal content in Irish soils. Samples were taken from a long‐term replicated (six replicates of 0.18 ha each) plot experiment with grazing cattle. Phosphate as superphosphate had been applied at two rates, 0 and 930 kg ha^–1 total P, over a 31 y period. Phosphorus, pH, soil organic matter, Cd, F, Mg, and Zn were measured in 0–10 and 10–20 cm soil layers in addition to extractable P and Mg (Morgan's solution) and Zn (0.5M EDTA). Increases in the phosphate‐enriched soil were significant at p < 0.05 except for F at both soil layers and for Cd at the 10–20 cm layer (p < 0.1) Recoveries for P, Cd, and F were in fair agreement with application. High recoveries of total Mg and Zn were encountered which could not readily be explained. These increases were paralleled by increases in extractable‐soil‐test values for these elements. Accumulation in soil of P over the period was such as to now necessitate little application of this element to soil for the near future. At the same time, increase in soil Cd was small, little more than 0.05 mg kg^–1 in soil, although it amounted to a sizable proportion of Cd in the soil. Similarly, increases in other elements, although real, would not lead to major concerns at the present time.     

添加物对镉、锌、铅污染土壤上小白菜的生长和养分吸收的影响

A pot experiment was carried out to study the effects of two amendments, lime and calcium magnesium phosphate, on the growth and Cd,Pd,Zn,Cu,Mn,Fe,N,P and K uptake of pakchoi (Brassica chinensis) in a Cd,Pb and Zn polluted acid soil in the southern part of China. The growth of pakchoi was apparently improved by lime and calcium magnesium phosphate application, the uptake of Cd,Pb,Cu and Zn by pakchoi was significantly depressed and the symptom caused by heavy metals pollution was eliminated. Meanwhile, the absorption of N,K and Mn was also inhibited by these amendments. Soil pH was the main factor controlling the uptake of the heavy metals by pakchoi. This suggests that lime and calcium magnesium phosphate could be used as effective amendments for eliminating the toxicity of heavy metals to the vegetable and inhibiting their absorption by the crop.     

不同施肥措施对旱地玉米土壤硝态氮累积的影响

长期定位试验研究不同施肥措施对旱地玉米土壤(NO3--N)累积的影响结果表明,不同施肥和秸秆还田措施可不同程度造成0~500cm土层NO3--N的累积,且对0~300cm土层NO3--N的累积影响较大。秋施肥秸秆覆盖还田处理产量最高,且土壤NO3--N累积量较低,所造成的环境风险也小,为我国北方半湿润偏旱区适宜施肥措施。