Effect of Chromium and Lead on Yield,Chemical Composition of Essential Oil,and Accumulation of Heavy Metals of Mint Species

A pot culture experiment was conducted to investigate the effect of increasing levels (30.0 and 60.0 mg kg^?1 soil) of chromium and lead on the yield, chemical composition of essential oil, and phytoaccumulation of heavy metals of three mint species (Mentha arvensis, M. piperita, and M. citrata). The fresh herbage yield of M. arvensis was not significantly affected by the application of chromium and lead, but its essential oil yield was significantly decreased by the application of chromium and lead as compared to the control. The fresh herbage, root yield, and essential oil yield of M. piperita were significantly increased and those of M. citrata were decreased by the increase in the levels of chromium and lead applications. The levels of α-pinene, β-pinene, sabinene, β-myrcene, limonene, menthone, and isomenthone in M. arvensis and M. piperita oil and of sabinene, pinene, and linalyl acetate in M. citrata oil were considerably affected by the application of chromium and lead to soils as compared to control plants. The concentrations of chromium in shoots and roots of mint species significantly increased as the levels of chromium in soil increased. The increases in the levels of lead in soil enhanced the concentrations of lead in the shoots and roots of mint species as compared to the control. The accumulations of chromium and lead were greater in the roots than in the shoots in all the three species of mint. Mentha piperita was found to be the most suitable crop for cultivation in the chromium- and lead-contaminated soils, followed by M. arvensis and M. citrata.     

Fate of Carbon in Water-Stable Aggregates during Decomposition of 13C-Labeled Corn Straw

Fundamental knowledge about decomposition, fate of crop residue, and allocation of residue-derived carbon (C) in soil aggregates is essential to understand the C dynamics in soil. The incorporation of C derived from corn residue in water-stable aggregate fractions, particulate organic C (POC), and mineral-associated C (MAC) in soil were examined using the ¹³C tracer technique. Soil was treated with corn straw at the rate of 1% dry mass of soil brought to 66% of field capacity and incubated for 70 days at 25 °C. Samples were taken at 20, 35, and 70 days and analyzed for water-stable aggregates. Values for POC and MAC were analyzed for total C and ¹³C enrichment. The addition of corn straw caused a shift in the distribution of recoverable particles with significant decreases in <53-μm silts and clays, microaggregrates (53–250 μm), and smaller macroaggegates (250–2000 μm); however, the large macroaggegates (>2000 μm) increased significantly. Macroaggregates contained greater amount of C than microaggregates. The proportion of ¹³C recovered in the fractions <53 μm (silt and clay), 53–250 μm, and 250–2000 μm increased during decomposition of corn straw, whereas there was no significant change in >2000-μm fraction. Most (70–76%) of the soil organic C was affiliated with MAC (<53 μm). Carbon (¹³C) derived from corn straw decreased in POC but increased in MAC as decomposition proceeded. In the long term, microaggregate fraction appears to be involved in storage and stabilization of the C derived from corn straw and is important for soil quality and soil C sequestration point of view.     

Analyzing the Relation between Loss-on-Ignition and Other Methods of Soil Organic Carbon Determination in a Tropical Cloud Forest (Mexico)

The objective of this study was to analyze the relationship between soil organic carbon content, determined by dry combustion (%OC_LECO) and the Walkley–Black method (%OC_WB), and loss on ignition (LOI). Soil samples were collected from noncalcareous O and A1 horizons within a tropical cloud forest. Linear regression equations were developed to estimate organic carbon from LOI. The applicability of the predictive equations was evaluated by comparison of measured and predicted organic carbon data for independent soil samples. The results showed that the LOI method produced a better linear relationship with the %OC_LECO (R ² = 0.96, P < 0.001) than with the %OC_WB (R ² = 0.88, P <0.001) method. These results also showed that %OC_WB and %OC_LECO prediction equations underestimate and overestimate soil organic carbon by 0.74% and 0.56%, respectively. This study suggests that LOI may be a good estimator of soil organic carbon for noncalcareous O and A1 horizons in a tropical cloud forest.     

Effects of Lead Forms and Organic Acids on the Growth and Uptake of Lead in Hydroponically Grown Wheat

This study investigated the effects of lead (Pb) form (free or complexed) and type and concentration of chelants [citric acid and ethylenediaminetetraacetic acid (EDTA)] on the growth and ability of wheat to accumulate Pb. Wheat variety Auqab-2000 was exposed to four levels of EDTA and citric acid (0, 500, 1000, and 1500 μM) in the presence of Pb (1000 μM). Both the free Pb (1000 μM) and high concentration (1500 μM) of EDTA and citric acid reduced the plant biomass. Without the addition of chelants, only a little Pb was accumulated by wheat shoots. This demonstrates that organic acids used in enhanced phytoextraction applications do not merely serve to increase metal mobility and plant availability but also can help to increase translocation rates of metals absorbed by the plant roots. Greater translocation of Pb from roots to shoots was observed with EDTA than that with citric acid.     

Commercial Extract of Ascophyllum nodosum Improves Root Colonization of Alfalfa by Its Bacterial Symbiont Sinorhizobium meliloti

The soil bacterium Sinorhizobium meliloti forms a symbiotic relationship with alfalfa (Medicago sativa) roots, which results in the formation of intracellular root nodules. This symbiosis increases nitrogen (N) in the soil; however, to establish such a synergistic relationship, a complex communication system is required between the bacterium and its legume host. Rhizobacteria are known to respond to plant root exudates and produce signal molecules known as “Nod” factors. Research suggests that the brown seaweed (Ascophyllum nodosum) extract (ANE) stimulates both root nodulation and growth of alfalfa (Khan et al. 2011 Khan, W., Palanisamy, R., Critchley, A. T., Smith, D. L., Papadopoulos, Y. and Prithiviraj, B. 2011. Ascophyllum nodosum (brown seaweed) extract and its organic fractions stimulate root nodulation and growth of alfalfa (Medicago sativa). Communications in Soil Science and Plant Analysis (Accepted),  [Google Scholar]). To elucidate the mechanism of action, the effects of ANE on the early stages of root–rhizobia interactions were examined. A. nodosum extract (ANE) and its organic fractions were prepared and alfalfa roots were treated. After 2 days, the treated roots were inoculated with S. meliloti. The roots from treated plants were excised and observed for colony-forming units. To verify whether ANE elicited the synthesis and secretion of factors similar to those induced by luteolin, S. meliloti cultures were treated with ANE and the bacterial components were analyzed by high-pressure liquid chromatography (HPLC). To study Nod factor induction by S. meliloti due to ANE treatment, a root hair deformation assay was performed. A translational fusion of S. meliloti NodC:LacZ (strain JM57) was used to observe the effect of ANE on bacterial gene expression. When S. meliloti culture medium was supplemented with ANE, no effect on bacterial growth was observed. However, it was observed that the attachment of S. meliloti to the root hairs was improved. Similarly in vitro ANE root treatments, followed by S. meliloti inoculation, increased bacterial colonies. HPLC profiles and a root hair deformation assay suggested that ANE elicits production of compounds similar to the Nod factor, which are normally induced by the plant signaling molecule luteolin. The results suggest that ANE may contain compound(s) that promote the legume–rhizobia symbiotic relationship and plant signaling.     

Fertilizer application in aid of plantation establishment in the savanna areas of Nigeria

Fertilizer trials were conducted to stimulate tree establishment and growth in the savanna region of Nigeria. The main nutrients investigated were N, P, K and B while the tree species included Azadirachta indica (Neem), Acacia auriculiformis, Eucalyptus spp., and Pinus spp. Borate application reduced the incidence of die-back of eucalypts and it also increased height growth. There was positive response to phosphate application by all species; phosphate reduced mortality considerably in pines on some sites. Response to N fertilizer by the species varied and related to type of N fertilizer. Urea was often found injurious to pines. There was strong interaction between N and P and usually response to N was not obtained on P-deficient sites. In all the cases where it was applied, there was no response to K. On more arid sites with poorly buffered soils, mineral fertilizers alone were insufficient to produce satisfactory tree growth. Application of animal manure on such sites increased survival and growth of Azadirachta indica, E. camaldulensis and A. auriculiformis.     

Analysis and use of cumulative nutrient uptake formulas in plant nutrition and the temporal-weight-averaged influx

A generalized cumulative uptake formula of nutrient uptake by roots following our previous formula (Reginato-Tarzia, Comm. Soil Sci. and Plant., 33 (2002 Reginato, J. C., and D. A. Tarzia. 2002. An alternative formula to compute the nutrient uptake for roots. Communications in Soil Science and Plant Analysis 33 (5&;6):821–30.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), 821-830) is developed. Cumulative nutrient uptake obtained by this formula is compared with the simulated results obtained by the Claassen and Barber (Claassen and Barber, Agronomy J., 68 (1976 Claassen, N., and S. A. Barber. 1976. Simulation model for nutrient uptake from soil by a growing plant root system. Agronomy Journal 68:961–64.[Crossref], [Web of Science ®] , [Google Scholar]) 961–964) and Cushman (Cushman, Soil Sci. Soc., 43 (1979 Cushman, J. H. 1979. An analytical solution to solute transport near root surfaces for low initial concentrations: I. Equation development. Soil Science Society of America Journal 43:1087–90.[Crossref], [Web of Science ®] , [Google Scholar]) 1087–1090) formulas. A mass balance is analyzed for the three formulas of cumulative nutrient uptake in order to decide which of them is correct. Moreover, the mass balance is also verified through a computational algorithm using data obtained from literature, and we compute the potassium (K) uptake for maize for low and high soil concentrations using the three mentioned formulas. The theoretical analysis shows that Claassen and Barber, and Cushman formulas do not verify, in general, the mass balance condition. The Claassen and Barber formula only verifies this condition when the influx is constant and root grows linearly. The Cushman formula verifies the mass balance when the influx is constant regardless of the law of root growth. Reginato and Tarzia formula always verifies the mass balance whatever be the representative functions for the influx and the law of root growth. Moreover, we propose a redefinition of the averaged influx from which the Williams formula (Williams, J. Scientific Res., 1 (1948 Williams, R. F. 1948. The effect of phosphorus supply on the rates of intake of phosphorus and nitrogen upon certain aspects of phosphorus metabolism in gramineous plants. Australian Journal of Scientific Research 1:333–61. [Google Scholar]) 333–361) can be deduced. We remark that Williams formula is a consequence of our definition of temporal-weight-averaged influx for all root growth law expressions. Also, we present a comparison of influx and cumulative uptake of cadmium (Cd) with data extracted from literature. Cumulative uptake is obtained through the Barber–Cushman model and our moving boundary model by using the redefinition of averaged influx on root surface and the correct cumulative uptake formula presented in this paper.     

Fertilizer application in aid of plantation establishment in the savanna areas of Nigeria

Fertilizer trials were conducted to stimulate tree establishment and growth in the savanna region of Nigeria. The main nutrients investigated were N, P, K and B while the tree species includedAzadirachta indica (Neem),Acacia auriculiformis, Eucalyptus spp., andPinus spp. Borate application reduced the incidence of die-back of eucalypts and it also increased height growth. There was positive response to phosphate application by all species; phosphate reduced mortality considerably in pines on some sites. Response to N fertilizer by the species varied and related to type of N fertilizer. Urea was often found injurious to pines. There was strong interaction between N and P and usually response to N was not obtained on P-deficient sites. In all the cases where it was applied, there was no response to K. On more arid sites with poorly buffered soils, mineral fertilizers alone were insufficient to produce satisfactory tree growth. Application of animal manure on such sites increased survival and growth ofAzadirachta indica, E. camaldulensis andA. auriculiformis.     

Effect of Long-Term Fertilizer Management and Crop Rotations on Accumulation and Downward Movement of Phosphorus in Semi-Arid Subtropical Irrigated Soils

Crop species and their varieties vary in phosphorus (P) requirements for optimum production and response to P application. As crop recovery of added P often ranges from 10 to 40%, the rest accumulates in soil and may create potential for P leaching, depending upon the soil characteristics, duration of P applications, and cropping systems. Accumulation and distribution of Olsen P (plant-available labile P), total inorganic P, and total organic P were investigated in soil profiles of three field experiments differing in rate (9–44 kg P ha^–1), frequency (applied once or twice annually), and duration (4–34 years) of fertilizer P applications, crop rotations, soil characteristics, and irrigation pattern (upland irrigated and flooded-rice crop) in a subtropical region. Profile samples were collected from soil depths of 0–15, 15–30, 30–60, 60–90, 90–120, and 120–150 cm of different treatments in these experiments and analyzed for different forms of P and soil characteristics. The results revealed that (i) annual applications of fertilizer P either to one crop (alternative-applied P) or to both crops (cumulative) led to the accumulation of residual fertilizer P in the form of Olsen P, varying from 44 to 148 kg P ha^–1, and the magnitude of accumulation was proportional to applied fertilizer P rate, frequency, and duration; (ii) majority of residual fertilizer P accumulated as inorganic P (74–89%) followed by organic P (11–26%) and Olsen P (9–19%), illustrating that the inorganic P pool is a major sink for fertilizer P; (iii) application of fertilizer nitrogen (N) and potassium (K) alone or in combination with fertilizer P did not affect residual fertilizer P accumulation in soil profile; (iv) incorporation of farmyard manure enhanced the P enrichment of soil profile; (v) irrigation pattern, soil pH (7.1–7.7), and calcium carbonate (CaCO₃) (trace–0.33%) did not influence P movement to deeper soil layers; silt, clay, and soil organic C (SOC) showed strong relationships with Olsen P (r = 0.827, 0.938, and 0.464, P < 0.01) and enhanced the retention of labile P in the plow layer; and (vi) only 6–29% total residual P moved beyond 30 cm deep in fine-textured soils under 22-year rice (Oryza sativa L.)–wheat (Triticum aestivum L.) and 34-year maize (Zea maize L.)–wheat rotations, whereas 41, 27, 20, 9, and 3% were located in soil layers 0–30, 30–60, 60–90, 90–120, and 120–150 cm deep, respectively, in coarse-textured soil profile under 4-year peanut (Arachis hypogaea L.)–sunflower (Helianthus annuus L.) field. These findings confirmed that interplay between the fertilizer P management (alternative vis-à-vis cumulative P application and optimal vis-à-vis excessive rates of fertilizer P in different crop rotations), amount of labile P accumulated in soil profile, and soil characteristics (silt, clay, and SOC) largely controlled the downward movement and resultant potential for P leaching in subtropical irrigated soils.     

Formulation of humic substances coated fertilizer and its use to enhance K fertilizer use efficiency for tomato under greenhouse conditions

A greenhouse experiment was conducted at Land Resources Research Institute, NARC, Islamabad to examine the impact of humic substances (HSs) coating on potassium fertilizers use efficiency. Tomato variety “Rio Grande” was used. The treatments applied were T1= Control (N, P at 250 and100?mg kg^?1 respectively), T2?=?N, P?+?K at 200?mg kg^?1 as SOP, T3?=?N, P?+?K at 200?mg kg^?1 as NPK blend, T4?=?N, P?+?K at 200?mg kg^?1 HSs coated SOP) and T5?=?N, P?+?K at 200?mg kg^?1 HSs coated NPK blend. Results indicated a positive impact of sole and HSs coated products on agronomic traits, nutrient concentration, fruit quality traits, flower number, fruit umber, fruit weight, chlorophyll contents, fresh and dry biomass, tissue water contents, diameter and fruit mineral composition. The response of afore said traits to applied treatment varied.     

Dynamics of Forms of Inorganic Phosphorus in Soil under Coffee Plants as a Function of Successive Annual Additions of the Nutrient

Phosphorus (P) dynamics and availability in soils are influenced by P fertilization. This paper aimed to evaluate inorganic P fractions bonded to calcium (Ca), iron (Fe), and aluminum (Al), associating them with soil mineralogy. The experiment was carried out using an acidic kaolinitic–oxidic soil, located in an irrigated area cultivated with coffee plants (Coffee arabica L.), submitted to successive annual fertilizations with triple superphosphate doses of 0, 50, 100 200, and 400 kg ha^?1 phosphorus pentoxide (P₂O₅) in randomized blocks with three replications. Phosphorus fractions were determined in soil samples collected at two depths, 0–10 and 10–20 cm, according to the methodology used by Chang and Jackson (1957 Chang, S. C. and Jackson, M. L. 1957. Fractionation of soil phosphorus. Soil Science, 84: 133–144. [Crossref] , [Google Scholar]). The inorganic P fractions presented the following sequence: P-Al > P-Fe > P-Ca. The dynamics of forms of inorganic P showed that P-Al is controlling the P bioavailability as a result of an acidic pH and a very simple and thermodynamically stable clay mineralogy, typical of very weathered and old tropical soils.     

Interaction effect of nitrogen,phosphorus, and zinc fertilization on growth,yield, and nutrient contents of aromatic rice varieties

Abstract

Studies on nutrient interactions in aromatic rice are needed for proper understanding of impact of imbalanced use of nutrients in the era of multi and micro-nutrient deficiencies. A pot experiment was conducted during the rainy/wet season (June–October) of 2013 at New Delhi, to study the interaction effects of two levels each of nitrogen (N) (0 and 120?kg?ha^?1), phosphorus (P; 0 and 25.8?kg?ha^?1), and zinc (Zn; 0 and 5?kg?ha^?1) in two aromatic rice (Oryza sativa L.) varieties, viz. Pusa Rice Hybrid 10 and Pusa Basmati 1121. Application of N, P, and Zn resulted in increase of dry matter (0.91, 0.32, and 0.24?g plant^?1, respectively) 60?days after sowing (DAS) and grain yield of rice (3.68, 1.67, and 1.17?g plant^?1). The increase in yield of rice owing to N application was relatively higher by 0.98, 0.22, and 1.05?g plant^?1, respectively, when either P or Zn or both were applied with N than alone application of N, indicating synergetic effect of P and Zn application with N. The higher concentration and uptake of K in grain (0.25% vs 0.10%) and straw (1.32% vs 0.94%) were observed in the treatment received N than no N, though K was applied uniformly in all the treatments. It indicates positive interaction of N and K. The higher uptake of P in grain and straw was observed when P was applied with N and Zn (3.34 and 2.15?mg plant^?1), or with N (3.26 and 2.11?mg plant^?1) signifying positive effect of N on P uptake in rice.     

Phosphorus Fertility Assessment of Intensively Farmed Areas of Catchments Draining to the Great Barrier Reef World Heritage Area; 2: Potential of Soils to Release Soluble Phosphorus

Abstract

The potential of fertilized cropping soils (sugarcane, vegetables, fruit trees) in river catchments that drain to the Great Barrier Reef World Heritage Area in northeastern Australia to release soluble phosphorus (P) was assessed using soil chemical tests on typical soils (0–10 cm) collected in 2003. Tests included total P, diagnostic soil P tests, estimates of P buffering, and soluble and redox sensitive soil P. Routine soil P tests proved poor predictors of CaCl₂ P (0.005 M). Values≥0.20 for the Mehlich‐3 P saturation ratio separated (P<0.01) lower from higher concentrations of CaCl₂ P. The ratio of Mehlich‐3 Fe to [Mehlich‐3 Fe+Mehlich‐3 Al] is offered as a possible simple index of redox sensitive P. Part 1 (Rayment and Bloesch 2006 Rayment, G. E. and Bloesch, P. M. 2006. Phosphorus fertility assessment of intensively farmed areas of catchments draining to the Great Barrier Reef World Heritage Area, 1: Soil phosphorus status. Communications in Soil Science and Plant Analysis, : 37 [Google Scholar]) describes the soil survey in more detail.     

Characteristic Variation of Concentration and Chemical Form in Sulfur, Nitrate, Ammonium, and Chloride Species Observed at Urban and Rural Sites of Japan

A field survey on the concentration of chemical species in particulate matter and gaseous compounds at two monitoring sites with different site classifications (urban and rural) was conducted over three years. Total (particulate matter + gaseous compounds) concentrations at the rural site were significantly lower than those at the urban site for all species (sulfur $\left( {{\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} {\left( {\text{p}} \right)}} \right.$ and SO₂(g)), nitrate ${\text{(NO}}_{{{\text{3}}^{{\text{ - }}} }} {\left( {\text{p}} \right)}$ and HNO₃(g)), ammonium ${\text{(NH}}_{{{\text{4}}^{{\text{ + }}} }} {\text{(p)}})$ and ammonia (NH₃(g)), and chloride (Cl^? (p) and HCl (g))), which is thought to reflect classification of the site. The difference in the sulfur concentration at the urban and rural sites was characterized by the difference in SO₂ (g) concentration. Further, a clear seasonality was observed for the nitrate species. The HNO₃ (g) concentration was high in the summer compared with other seasons at both the urban and rural sites. The ${\text{NH}}_4^ + \left( {\text{p}} \right)$ concentration levels were approximately the same as those of NH₃ (g) at both sites. The molar ratios of the particulate matter concentration to the total concentration showed different characteristics; the nitrate, ammonium and ammonia, and chloride species showed a clear seasonal variation: low in summer and high in winter and the values were similar regardless of the site. On the other hand, the sulfur species showed constant values at both the urban and rural sites, however the concentrations were significantly different for the two sites. Ammonium accounted for the largest proportion of cations in the particulate matter, regardless of the site classification. In contrast, ${\text{SO}}_4^{2 - } \left( {\text{p}} \right)$ accounted for the largest proportion of anions at the rural site, whereas ${\text{NO}}_3^ - \left( {\text{p}} \right)$ was comparable to ${\text{SO}}_4^{2 - } \left( {\text{p}} \right)$ at the urban site. Ammonia accounted for the largest proportion of all chemical species at both sites. Seasonal analysis of the proportional distribution in particulate matter and gaseous compounds provides information on atmospheric conditions.     

Phosphorus Fertility Assessment of Intensively Farmed Areas of Catchments Draining to the Great Barrier Reef World Heritage Area; 1: Soil Phosphorus Status

Abstract

Australia's reef water quality protection plan has a key objective: “reduce the load of pollutants from diffuse sources in the water entering the Reef.” This article reports on a survey to assess the contemporary phosphorus (P) status of fertilized cropping soils across 21 catchments in coastal Queensland, Australia. The survey focused on surface soils from cane farms, vegetable and subtropical/tropical fruit tree sites. There were sampling depth effects on P levels in sugar and fruit tree sites (lower with depth). Importantly, 84% of 105 sugarcane sites were excessively fertile and only 3% rated low (P deficient). Some 75% of 16 vegetable sites and 38% of 8 fruit tree sites had excess ratings for extractable soil P fertility. Highest total P levels (0–10 cm) occurred in fruit tree sites, followed by vegetable and sugarcane soils. There are regional differences in P soil fertility, and the recycling of mill by‐products needs attention. Part 2 (Bloesch and Rayment 2006 Bloesch, P. M. and Rayment, G. E. 2006. “Phosphorus fertility assessment of intensively farmed areas of catchments draining to the Great Barrier Reef World Heritage Area, 2: Potential of soils to release soluble phosphorus”. In Communications in Soil Science and Plant Analysis 37 [Google Scholar]) examines the potential of these soils to release soluble P in a nutrient‐sensitive area.     

MONITORING NITROGEN POLLUTION FROM SUGARCANE RUNOFF USING 15N ANALYSIS

In many forested wetlands of Louisiana, surface water quality is being deteriorated by nutrient input from adjacent agricultural production areas. This field study assesses the input of fertilizer N, applied to sugarcane fields, to forested wetlands. The potential use of natural abundance variations in ¹⁵N¹⁴N ratios for identification and tracing surface water N sources (NH ₄ ⁺ - and NO₃ ^--N) was evaluated. Runoff and surface water samples were collected from sugarcane fields and bordering forested wetlands (6 stations) over a 16 month period and analyzed for NH ₄ ⁺ -N, NO ₃ ^- -N, and associated NH ₄ ⁺ -δ¹⁵N and NO ₃ ^- -δ¹⁵N ratios. Fertilizer N draining into adjacent forested wetland was estimated to be only a small fraction of the amount applied. Concentrations of NH ₄ ⁺ - and NO ₃ ^- -N in the collected water samples were low and ranged from 0.02 to 1.79 mg L^-1. Isotopic analysis revealed NH ₄ ⁺ -δ¹⁵N and NO ₃ ^- -δ¹⁵N means were distinctive and may have the potential to be used as tracers of N contamination. The mean NH ₄ ⁺ -δ¹⁵N value was +18.6 ± 7.1‰ and the NO ₃ ^- -δ¹⁵N mean was +8.3 ± 3.1‰. Anomalously high NO ₃ ^- -δ¹⁵N values (>30‰) were attributed to denitrification.