Comparative Evaluation of Ground and Unground Pearl Millet and Sorghum Grain Samples for Determining Total Iron and Zinc

Rapid and effective methods are needed to analyze large numbers of grain samples for iron (Fe) and zinc (Zn) to select cultivars that are denser in these minerals. This study was conducted for the comparative evaluation of ground and unground grain samples for determining total Fe and Zn in pearl millet and sorghum cultivars with a range in seed size. In general, the results of the study with 50 pearl millet and 49 sorghum cultivars showed that grain Fe and Zn, in these relatively small-seeded crops, can be routinely determined using unground samples. Highly significant positive correlations were found between the values of Fe and Zn in grains of these crops determined using ground and ground samples.     

Comparative Effect of Phosphorus Sources for Grain Amaranth Production

Abstract

Phosphorus (P) is expensive to the sub‐Saharan African resource‐poor farmers; therefore, there is a need for investigation of locally available alternative P sources to enhance farmers' productivity. Optimum P rate was determined during the early and late rains of 1999. Using the optimum P rate, influences of three P sources ogun rock phosphate (ORP), sokoto rock phosphate (SRP), single super phosphate (SSP) and a control were evaluated on amaranth varieties in 2000 at the vegetable research plots of the National Horticultural Research Institute (NIHORT), Ibadan, Nigeria. In 1999, three grain amaranth varieties (NH84/452, NH84/445, and NH84/493) were combined factorially with four P rates: 0, 30, 60, and 90 kgP/ha. Application of P significantly increased plant height, number of branches, leaf dry weight, and grain yield (GY) per plant. Significant increase in GY was in the order NH/493>NH/445>NH/452. Optimum P rates across varieties for leaf dry‐matter yield was established at 51.8 kgP/ha and for grain yield production was 48.4 kgP/ha. The experiment in the following year, 2000, was a RCB design using the optimum P determined in 1999. Three P sources (ORP, SRP, SSP) and a control were factorially combined with the three amaranth varieties. In the 2000 experiment, grain yield was 21.3, 16.9, 16.0, and 7.8 g/plant, respectively, for SSP, SRP, ORP, and the control. Growth was ranked in the order SSP>ORP>SRP>control. It was concluded for fertilizer recommendation purposes that 50 kgP/ha is optimum for grain amaranth production and that amaranth productivity indices could be alternatively improved with indigenous P sources.     

Rapid Determination of Mercury in Plant and Soil Samples Using Inductively Coupled Plasma Atomic Emission Spectroscopy, a Comparative Study

The objectives of this study were to simplify sample preparation and validate mercury detection in soil and plant samples using inductively coupled plasma atomic emission spectroscopy (ICP-AES). A set of mercury contaminated and mercury free soil and plant samples were digested and analyzed by ICP-AES, inductively coupled plasma mass spectrometry (ICP-MS), and cold vapor atomic absorption spectroscopy (CVAAS). Results show that mercury measurements in soil and plant samples using ICP-AES were in agreement with those analyzed using ICP-MS and CVAAS. The concentrations of mercury in soils and plant tissues determined by ICP-AES were 92.2% and 90.5% of those determined by CVAAS and ICP-MS, respectively. Digestion of soil samples with 4 M HNO₃ and direct measurement by ICP-AES without reduction of Hg²⁺ to Hg⁰ gave a reasonable and acceptable recovery (92%) for determining Hg in soils. We conclude that ICP-AES with optimized conditions (addition of gold chloride, extension of washing time, linear working range, and selection of wavelength – 194 nm) resulted in reliable detection of mercury in environmental samples.     

Phosphorus in Morgan Soil Test Extracts Measured By Molybdate Colorimetric and Inductively Coupled Plasma Spectroscopy Methods

Colorimetric P determination mainly reflects inorganic P, whereas inductively coupled plasma spectroscopy (ICP) measures all P in solution. We compared Morgan extractable P for ICP (MP-ICP) and colorimetry (MP-Color) using dairy farm field samples (0 to 20 cm) across northern New York (n = 250) and hayfield transect samples (0–15, 15–30, 45–50 cm; n = 164). Soil organic matter, pH, and extractable cations were also measured. Mean ratio of MP-ICP: MP-Color was 1.46 and differed significantly among Morgan P categories, ranging from 1.89 for low to 1.06 for very high. The numeric difference between MP-ICP and MP-Color ranged from 0 to 12.9 mg kg^?1. Organic matter, Al, and pH jointly accounted for 55% of the variability between methods across samples. Fertilizer P recommendations differed based on the two methods, suggesting results from both methods should be reported, particularly in the responsive range.     

Determination of Total Iodine in Soils by Inductively Coupled Plasma Mass Spectrometry

A method for the determination of the total amount of iodine in soil by inductively coupled plasma mass spectrometry was developed. Iodine in soil was completely extracted by heating a mixture of 5 mL of 5% tetramethylammonium hydroxide solution and 100 mg of soil for 3 h in an oven at 70°C. Indium as an internal standard was added and the extract was diluted at least more than 10-fold. Iodine amount in the solution was determined by measuring the signal intensity of ¹²⁷I against that of ¹¹³In. When the method was tested by analyzing four reference soil samples (GSS-1, 4, 5, and 7), the iodine contents obtained were in good agreement with the certified values for the samples.     

中国粮食作物秸秆焚烧释放碳量的估算

生物质燃烧对全球大气环境和气候系统会产生重要的影响,根据1999—2008年中国的粮食产量、谷草比,估算了主要粮食作物的秸秆产量,结合秸秆露天焚烧比例计算了中国1999—2008年主要粮食作物秸秆露天焚烧量,进一步依据相关排放因子得出CO和CO2的排放量及碳排放总量。结果发现,中国主要粮食作物年平均秸秆产量达到4.9×108t,粮食秸秆露天焚烧量平均为0.94×108t,约占粮食作物秸秆总量的19,其中稻谷秸秆露天焚烧量占到粮食秸秆露天焚烧量的43.1;粮食作物秸秆露天焚烧排放的CO和CO2总量平均每年分别为9.19×106t和1.07×108t;排放的总碳量平均每年为3.32×107t,其中稻谷、小麦、玉米、豆类秸秆露天焚烧释放的总碳量分别为9.88×106、9.93×106、11.14×106、2.22×106t。     

Evaluation of Agro Services International Soil Test Method for Phosphorus and Potassium

Soil testing is widely adopted as an essential diagnostic tool for identifying soil nutrient factors that limit sustained crop production. A systematic approach for rapid soil testing and fertilizer recommendation has been introduced and widely used in China by Agro Services International (ASI), USA. To verify the usefulness and reliability of the ASI method in soil testing and fertilizer recommendation in comparison with other commonly used traditional soil testing methods, 294 soil samples from major agricultural regions and soil types in China with a wide range of soil pH, from 5.1 to 8.9, were taken and analyzed for available phosphorus (P) and potassium (K) by the ASI multielement extraction solution and selected traditional methods, Olsen extractant for P, ammonium acetate (NH₄OAc) extractant for K, and multielement extractant Mehlich 3 for P and K. Also, 46 soils were selected from northern China regions for a greenhouse trial with sorghum seedlings to determine if the soil testing values correlate well with plant response. Results indicated that the amount of soil P extracted by the ASI method (ASI P) was correlated to both soil extractable P tested by the Olsen extractant (Olsen P) and Mehlich 3 extractant (Mehlich 3 P). The correlation coefficient of ASI P with Mehlich 3 P (R² = 0.86) was greater than that of ASI P with Olsen P (R² = 0.74) across all selected soils. A good correlation was also found between the exchangeable K from the ASI method with the traditional ammonium acetate method (R² = 0.81) and the Mehlich 3 method (R² = 0.85). The results from the greenhouse trial showed that the extractable P and exchangeable K by the ASI multielement extraction solution could be used to represent the fertility status of soil P and K for the selected soils. Regression analysis indicated that the relative dry-matter yield of the sorghum plants can be predicted with either ASI P and ASI K values with the correlation coefficients (R²) values of 0.78 and 0.72 respectively and could be a good measure for soil testing and fertilizer recommendation in the selected soils and regions in China.     

Differential Growth Performance of 15 Wheat Genotypes for Grain Yield and Phosphorus Uptake on a Low Phosphorus Soil Without and With Applied Phosphorus Fertilizer

ABSTRACT

Two field experiments were conducted to compare 15 wheat genotypes at two phosphorus (P) levels (zero-P control or low P level—without application of P fertilizer on soil with 8 mg extractable P kg^?1, and adequate P level—with P fertilizer applied at 52 kg P ha^?1) for yield, P uptake, and P utilization efficiency (P efficiency ratio—PER, P harvest index—PHI, and P physiological efficiency index—PPEI). On the average of two experiments, substantial and significant differences were observed among wheat genotypes for both grain and straw yields at both P levels. Grain yields ranged from 2636 to 4455 kg ha^?1 in the zero-P control, and from 2915 to 4753 kg ha^?1 at adequate P level. Genotype 5039 produced the maximum grain yield, while 6529-11 had the minimum grain yield at both P levels. Relative reduction in grain yield due to P deficiency stress (PSF) ranged from none to 32%, indicating differential P requirements of genotypes. Genotypes 4943, Pasban 90, Inqlab 91, PB 85, Lu 26s, 4770, Chakwal 86, 4072, 6544-6, and 5039 had little or no response to P application. Phosphorus responsive genotypes included FSD 83, Kohinoor 83, Parvaz-94, Pak 81, and 6529-11. A non-significant correlation (r = ?0.466, P > 0.05) between grain and PSF in zero-P control treatment also indicated the least effect of P deficiency on some wheat genotypes. A wide range of PPEI (270–380 kg grain kg^?1 P absorbed in grain + straw at control P level, and 210–330 kg grain kg^?1 P absorbed in grain + straw at adequate P level) indicated differential utilization of absorbed P by the genotypes for grain production. This indicated that wheat genotypes differed considerably in their P requirement for growth and responsiveness to P application. The findings also suggested that PPEI was a better parameter for measuring P efficiency than other parameters, and can be used for selecting P efficient genotypes, because it relates to the internal concentration of a nutrient and genetic makeup of plant. It is concluded that genotypes having ability to produce relatively high grain yield, good command to tune P within plant and high PPEI are suited to low P soil conditions. Genotypes 4072, Inqlab 91, 4943, Pak 81 and 5039 were P efficient and had above mentioned abilities, while genotypes FSD 83, 6544-6, and 6529-11 were P inefficient. It should be noted that traits related to P efficiency are inheritable and can be used to improve P use efficiency of a genotype through back cross breeding programs.     

Response of Maize (Zea Mays L.) to Phosphorus Fertilizers in Two Alfisols with Contrasting Phosphorus Availabilities and Sorption Capacities

Increase in phosphorus (P) availability with fertilizer addition is influenced by soil properties such as P sorption capacity. We investigated P availability changes and response of maize (Zea mays L) to four P fertilizers rates (0, 20, 30 and 40 kg ha^?1) in a two-site field experiment, having soils of contrastingly different available P (2.9 and 22.1 mg kg^?1) and P sorption capacities (171.9 and 54.2 mg kg^?1). Increase in available P was significantly greater in the soil with higher available P but lower P sorption capacity, than in the other; however, yield responses were similar in the two soils. Fertilizer P rates of 30 and 40 kg ha^?1 gave significantly greater maize yields than the unfertilized treatment in both soils. Results suggest the need to account for the P sorption capacity when deciding rates of P fertilizers to increase available P in soils.     

稻-麦轮作条件下2种施肥模式作物产量和农田氮磷径流流失比较

稻-麦轮作是太湖流域典型的集约化粮食作物种植体系,化肥用量大,氮磷流失控制广为关注。采用大区田间对比试验,研究了习惯施肥(FP)和优化控制施肥(CM)2种施肥模式对作物产量及氮磷肥料偏生产力的影响,同时探讨了2种施肥模式下农田径流水中各形态氮、磷的特征和径流氮、磷损失的差异。结果表明:优化控制施肥水稻和小麦地上部总生物量、籽粒产量、植株地上各部位养分(氮磷钾)含量及积累量与习惯施肥差异不显著(P>0.05);优化控制施肥水稻和小麦的氮肥偏生产力显著大于习惯施肥(P<0.05),磷肥偏生产力也相似。稻季和麦季优化控制施肥径流水中各形态氮、磷浓度小于习惯施肥,甚至达到显著水平(P<0.05);稻季、麦季和完整轮作期优化控制施肥总氮、总磷的累积流失量显著小于习惯施肥(P<0.05)。优化控制施肥模式不仅能保持水稻和小麦的籽粒产量,而且能显著减少稻-麦轮作体系的氮磷流失,可以在实际农业生产中加以推广和利用。     

长期地膜覆盖与施肥对土壤磷素和玉米吸磷量的影响

利用比较法对长期连续覆膜(17年)后土壤磷素的变化以及玉米吸收量的变化进行了研究。结果表明:经过17年的耕作,无论是施有机肥还是磷肥均能显著增加土壤中速效磷以及全磷的含量;覆膜栽培与裸地栽培比较结果,覆膜对于土壤中速效磷以及全磷含量的变化影响不大;对植株的籽粒、轴、叶片、茎的全磷进行了测定后显示:覆膜可以促进籽粒、轴、茎对磷的吸收,抑制了叶片对磷养分的吸收;从成熟期地上部分累积磷的总量来看,覆膜可以明显提高作物对磷的吸收。     

稻-麦轮作条件下两种施肥模式对作物产量 和农田氮磷径流流失的比较研究

稻-麦轮作是太湖流域典型的集约化粮食作物种植体系,化肥用量大,氮磷流失控制广为关注。本文采用大区田间对比试验研究了习惯施肥（FP）和优化控制施肥（CM）两种施肥模式对作物产量及氮磷肥料偏生产力的影响,同时探讨了两种施肥模式下农田径流水中各形态氮、磷的特征和径流氮、磷损失的差异。结果表明优化控制施肥水稻和小麦地上部总生物量、籽粒产量、植株地上各部位养分（氮磷钾）含量及积累量与习惯施肥差异不显著（P>0.05）;优化控制施肥水稻和小麦的氮肥偏生产力显著大于习惯施肥（P<0.05）,磷肥偏生产力也相似。稻季和麦季优化控制施肥径流水中各形态氮、磷浓度小于习惯施肥,甚至达到显著水平（P<0.05）;稻季、麦季和完整轮作期优化控制施肥总氮、总磷的累积流失量显著小于习惯施肥（P<0.05）。优化控制施肥模式不仅能保持水稻和小麦的籽粒产量,而且能显著减少稻-麦轮作体系的氮磷流失,可以在实际农业生产中加以推广和利用。     

HPLC-ICP-MS法测定农业废水中有机砷与无机砷的方法研究

建立了应用高效液相色谱(HPLC)和电感耦合等离子质谱(ICP-MS)联用技术测定农业水环境样品中三价砷(AsⅢ)、一甲基砷(MMA)、二甲基砷(DMA)、五价砷(AsⅤ)4种砷形态的分析方法。试验表明,4种砷形态的线性范围宽(1~300μg·L-1),相关系数(r)均大于0.999 0,方法检出限低(0.7~0.9μg·L-1),精密度好,重复测定7次结果的RSD均小于5%。通过计算加标回收率验证方法的准确性,加标回收率为94%~112%。实际样品的测定结果显示,农田废水中砷的主要存在形态为As(Ⅴ),其次为As(Ⅲ)。     

Phosphorus Determination after Mehlich 3 Extraction and Anion Exchange Resin in an Agricultural Soil of Northwestern Spain

Differences in soil phosphorus (P) contents measured by various techniques may have implications for agronomic and environmental testing. Reduced-tillage systems combined with surface manure application increase the potential risk of nutrient losses by surface runoff. A field trial was conducted to evaluate the effect of livestock slurry on nutrient accumulation at the surface layer of an acidic soil rich in organic matter with excess P levels and loamy texture. Two reduced-tillage systems, no tillage (NT) and minimum tillage (MT), and four different fertilizer treatments were assessed. The amounts of P extracted by anion-exchange resin (AER) and by Mehlich 3 (M3) were compared; in addition, differences between two determination methods of P contents extracted by Mehlich 3, namely molybdic acid colorimetric standard procedure (M3-COL) and inductively coupled plasma–mass spectroscopy (M3-ICP), were evaluated. Ninety-six soil samples were taken from the 0- to 5-cm surface layer in three successive dates after increasing manure addition. Colorimetric Mehlich 3 P ranged from 49 to 431 mg dm^–3. The ranks of mean extractable soil P concentrations were AER < M3-COL < M3-ICP. The linear correlation coefficient between M3-COL and M3-ICP was highly significant (R² = 0.89; P < 0.01), but a two-straight-lines model or a quadratic relationship were more adequate for describing the dependence between the two determination procedures after M3 extraction. Relative and absolute differences between M3-COL and M3-ICP showed a tendency to increase as organic carbon content increased. Phosphorus content extracted by AER and M3-COL or M3-ICP reported a significant but much less predictable relationship with R² values of 0.27 and 0.21 (n = 96), respectively. The P in the surface layer accumulated more under NT than under MT.     

Evaluation of Phosphorus Pools and Fractions in an Acid Tropical Soil Recapitalized with Different Phosphorus Sources

Abstract

Bray 1 phosphorus (B1P) and sequential phosphorus (P) fractions were determined on soils treated with triple superphosphate (TSP), Gafsa (GPR), and Christmas Island phosphate rocks (CIPR), respectively, with and without manure. The fractions extracted in decreasing lability were iron oxide–impregnated paper strip P (Pi‐strip P), inorganic (Pi), and organic (Po) bicarbonate (NaHCO3‐Pi and ‐Po), hydroxide [sodium hydroxide (NaOH)‐Pi and ‐Po], hydrochloric acid (HCl) P, and residual (residue P). The magnitude of B1P was in the order TSP>GPR=CIPR. Average B1P from PRs was two‐fold the amount in TSP, whereas that of the fractions was NaOH‐P>Residue P<sodium bicarbonate (NaHCO₃) P<Pi‐strip P <HCl. Bray 1 extracted mainly the most labile fractions (Pi‐strip P and NaHCO3‐Pi), and plant P uptake was correlated mainly to NaOH‐Po and NaHCO₃‐Pi. Magnitude of various fractions differed between TSP and PRs. Both B1P and the fractions were equally correlated to P uptake (R²=0.38**). Nevertheless, sequential fractionation appears to be a powerful tool to identify the P status and availability in soil.     

Ultrasound Method for Extraction of Phosphorus in Soil

In the present work, an ultrasoundic procedure for the extraction of phosphorus (P) available in soil is described. The proposed method is based on extraction by 0.5 M sodium bicarbonate (NaHCO₃), following with sonication under different conditions. Phosphorus was determined by the Murphy and Riley method. Sonication time and soil–extractant relative quantities were optimized. A statistical analysis approach was used to find suitable conditions for the ultrasoundic extraction. The main advantages of the sonication method are the reduced times of extractions, which take 10 min in contrast to the 30 min required by a shaking method, and the possibility to reduce soil and extractant quantities from 5 g–100 mL to 2 g–40 mL. Performance of the method was evaluated, and the procedure was utilized to analyze soils from Santiago del Estero, Argentina.     

关于退耕还林还草监测评价体系的构想

实施退耕还林还草意义重大,对退耕还林还草项目进行全面、系统的监测评价,是确保退耕还林还草目标得以实现的重要措施。分析了退耕还林还草项目监测评价的目的和内容,构建了退耕还林还草监测评价过程的行为—反应滚动模型,对退耕监测评价执行系统、指标体系及技术体系的构建等提出了建议。     

Interaction Between Phosphorus Nutrition and Drought on Grain Yield,and Assimilation of Phosphorus and Nitrogen in Two Soybean Cultivars Differing in Protein Concentration in Grains

ABSTRACT

Drought affects many physiological and biochemical processes and thus reduces plant growth. Phosphorus (P) fertilization improves tolerance to drought stress in many plants. A greenhouse experiment examined the interactive effects of P nutrition and drought stress on P accumulation and translocation, yield, and protein concentration in grains of two cultivars of soybean [Glycine max (L.) Merr.]. Plants of cultivars ‘Heisheng 101’ (high protein in grains) and ‘Dongnong 464’ (low protein) were grown in a P-deficient soil supplied with 0–30 mg P kg^?1 soil. Drought stress was imposed at the initial flowering (R1) or the podding (R4) stage. Drought stress limited P accumulation and reduced P translocation to the seed. The addition of P enhanced the concentration and accumulation of nitrogen (N) and P in shoots and seeds of both cultivars. Drought stress decreased shoot biomass, grain yield, and P accumulation; the decrease was greater in ‘Dongnong 46’ than ‘Heisheng 101,’ and even more so if drought stress was imposed at R4 than at R1. In contrast, drought stress increased the concentration of N in shoot and protein in grains. The addition of P alleviated the effect of drought stress on plant growth, P accumulation, and grain yield in both cultivars but to a greater extent in ‘Dongnong 46’. The results suggest that application of P fertilizers could mitigate drought stress at the reproductive stage, resulting in less yield penalty and improvement of grain quality of soybean grown in P-deficient soils.     

ICP-MS及其联用技术在植物重金属分析中的应用研究进展

电感耦合等离子体(inductively coupled plasma,ICP)是20世纪80年代发展起来的无机元素分析技术,它具有高分辨率和灵敏度、低检出限、样品耗用少、可同时检测多元素等特点,被广泛地用于无机元素特别是金属元素的分析。ICP与质谱(mass spectrometry,MS)联用极大地促进了无机多元素分析技术的发展。本文综述了ICP-MS及其几种联用技术的原理与性能特点、排除光谱干扰的方法以及在植物重金属分析中的应用实例32篇,以期为植物重金属分析技术的研究提供有益参考。     

秦岭巴山耕作区土壤有效磷与磷肥试验相对产量关系研究

依托测土配方施肥土壤养分数据库以及大量"3414"田间肥效试验结果,分析了秦岭巴山耕作区近30 a间土壤有效磷的变化情况,评价了5种农作物磷肥试验相对产量与土壤有效磷之间的线性关系,结果显示:目前该区域土壤有效磷含量平均值为18.1 mg/kg,达到中等磷水平;小麦、玉米、水稻、油菜、马铃薯肥效试验平均相对产量分别为85.7%、85.5%、88.7%、84.3%、86.0%,说明该区域在目前土壤有效磷含量水平下,基本能满足农作物相对产量80%～85%的生长需求。基于土壤有效磷含量已达中等偏高水平及当前农作物磷肥相对产量值,参照磷肥在土壤中的固定机理以及作物吸磷特性,对于土壤有效磷含量低于15mg/kg,特别是低于10mg/kg的低肥力农田,建议全部磷肥分为基肥、追肥两次施用;对于土壤有效磷含量高于20mg/kg,特别是有效磷高于30mg/kg的高肥力农田,只追施部分或少量磷肥,充分利用土壤有效磷,开发活化被固定的磷素资源,提高磷肥利用率,避免农业资源浪费,改善农业生态环境。