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.     

Interrelation of Inorganic Phosphorus Fractions and Sorghum‐Available Phosphorus in Calcareous Soils of Southern Khorasan

The objectives of this research were to determine inorganic phosphorus (P) fractions in calcareous soils of southern Khorasan and find their relationship with sorghum‐available P. Eighty soil samples were obtained and analyzed for some physical and chemical characteristics, among them 24 samples that varied in plant‐available P and soil properties were used for soil testing. From 24, 8 samples were selected for P fractionation as well. Five extraction procedures were used for soil testing. Results indicate that the extracted plant‐available P by the Olsen et al. (1954 Olsen, S. R., Cole, C. V., Watanabe, F. S. and Dean, L. A. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate (USDA Circ. 939), Washington, D.C.: U.S. Government Printing Office.  [Google Scholar]) and Paauw (1971 Paauw, F. V. 1971. An effective water extraction method for the determination of plant available phosphorus.. Plant and Soil, 34: 497–481.  [Google Scholar]) methods show the greatest correlation coefficients with plant P uptake and sorghum dry matter. The sequential inorganic P extraction analyzing indicated that the abundance of various inorganic fractions was in the order Ca₁₀‐P > Al‐P > Ca₈‐P > Ca₂‐P > Oc‐P > Fe‐P. The results also indicate Olsen P correlates positively and significantly with Ca₂‐P and Fe‐P fractions and positively but not significantly with the Al‐P fraction.     

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.     

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.     

Correction and standardization of critical limit of zinc for maize (Zea mays L.) crop: Bangladesh perspective

Abstract

Critical limit (CL) determination of zinc (Zn) is very important for predicting response of maize crop to its application in soils and for the crop’s actual fertilizer requirement. This study was conducted at Bangladesh Agricultural Research Institute, Gazipur, to determine the CL of Zn for maize grown in 20 soils collected from the five Agro–Ecological Zones during January to March, and April to June of 2017. The available Zn content of soils and maize biomass were estimated utilizing the extraction method with 0.005?M diethylene triamine pentaacetic acid (DTPA). During January to March and April to June 2017, the amount of DTPA extractable Zn in different soils ranged from 0.60–3.25?mg?kg^?1 and 0.50–1.68?mg?kg^?1, respectively. During both periods of crop growth (January to March and April to June, 2017), the soil available zinc was negatively significantly correlated with soil pH, available P, exchangeable Ca, exchangeable Mg and positively significantly correlated with relative dry matter (DM) yield. Soil Zn also positively significantly correlated with maize tissue Zn content (r?=?0.521*). However, the CL of Zn were estimated to be 0.84?mg kg^?1 in soils and 26.1?mg kg^?1 in maize tissue for maize cropping as determined by Cate and Nelson’s (1965 Cate, R. B., and L. A. Nelson. 1965. A rapid method for correlation of soil test analysis with plant response data. International soil testing series technical Bulletin No. I North Caroline State University, Agricultural Experiment Statistics, Releigh, USA, pp. 135–136. [Google Scholar]) graphical procedure. Maize crop may respond to Zn application in soils containing Zn at/below the above level. This data may be used for predicting plant response to Zn fertilizer and development of crop Zn nutrition guide for maximum production.     

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.     

Die Anwendung der Ertragskurvenberechnung nach von Boguslawski und Schneider bei der Auswertung aktueller N-Steigerungsversuchsserien

Abstract

Yield curve calculation according to von BOGUSLAWSKI and SCHNEIDER as well as the EDP calculating programme, derived from it by Horst and Heyn (1988 Horst H Heyn J 1988 Ein PC-Programm zur Errechnung von Ertragskurven nach der dritten Annäherung an das Ertragsgesetz von v. Boguslawski und Schneider LUFA Kassel, hausintern  [Google Scholar]) and later also Kowert (2001 Kowert A 2001 Erstellung eines PC-Programmes zur Ermittlung von Ertragskurven bei Düngungsversuchen Diplomarbeit FH Osnabrück, FB Agrarwissenschaften, Studiengang Landwirtschaft  [Google Scholar]), are described. With the version at hand objective and reproducible results can be calculated in a fast and user-friendly way.

This program enables an exact definition of the maximum yield and the best fertilisation required; also every yield value on the basis of a given amount of nutriment can be deduced. Thereby results of tests and series with differing variations can be offset against each other together. Like this wide research series with accordingly high significance can be evaluated. Of course other parameters can be calculated in addition to the yield, too.

This yield curve calculation is particularly suitable for the evaluation of research on N-increase. Considering Hessian research on winter wheat, winter barley, winter rye, rape seed and sugar beet as example, the effects of increasing mineral N-fertilisation on the yield, the adapted financial gross earning and the N-removal with the main product of a crop are indicated.

The N-fertilisation aiming at the greatest natural yield of the tested fruit winter wheat, winter barley, winter rye, rape seed and sugar beet, requires an amount of about 145 to 225 kg N/ha. The economical optimisation of the N fertilisation is about 30 to 40 kg/ha lower with cereals compared to about 90 kg/ha lower with rape and sugar beet.

The optimisation of the N-fertilisation as to the financial gross earning leads to a significant increase of the supply-removal-account into an uncritical range for all fruits. The amount of the N-fertilisation should not be fixed on the natural yield, but on parameters of cost-effectiveness. This leads to economical and ecological advantages.     

Short-Term Ion Uptake by Phalaenopsis as Affected by Concentration of the Solution

ABSTRACT

Nutrient uptake over a 72 h culture period by clonal micropropagules of Phalaenopsis Tanigawa × Yukimai Dream ‘KS 370’ and ‘KS 352’ were surveyed by Ichihashi's (1997) Ichihashi, S. 1997. “Orchid production and research in Japan”. In Orchid Biology, Reviews and Prospectives, Edited by: Arditti, J. and Pridgeon, A. M. 171–212. Dordrecht, , The Netherlands: Kluwer.  [Google Scholar] nutrient solution at the original ion strength and its half and quarter. Uptake of major anions [nitrate (NO₃ ^?), phosphate (H₂PO₄ ^?), and sulfate (SO₄ ^2?)] and cations [ammonium (NH₄ ⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺)] measured with an ion chromatograph increased as the ionic strength of the solution increased in both cultivars. The final uptake rates of nutrients were 0.8, 2.0, 2.1, 1.2, 3.0, 2.0, and 1.6 me L^?1, respectively in the order of ions mentioned above. The ratios of the uptake rates between cations (mono or bivalent) were almost in proportion to the ratio of their initial ion strength. Therefore, no antagonistical absorption of cations was found in that ion strength. Leaf content of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and copper (Cu) increased as the ionic strength of the solution increased, but concentrations of iron (Fe), manganese (Mn), and zinc (Zn) were not affected significantly. Nitrogen (N) content of leaves in ‘KS 370’ after 72 h culture increased significantly by increasing the ionic strength of the solution. Root concentrations of P, K, Ca, Mg, and Fe increased as the ionic strength of the solution increased in both cultivars. The N concentrations of roots in either ‘KS 370’ or ‘KS 352’ had positive correlations with an increasing ionic strength of the solution, although they were constantly greater in ‘KS 370’ than in ‘KS 352’. The greatest fresh weight was obtained when the plants were cultured in a half strength solution. Whereas dry weight decreased in all treatments as the ionic strength of the solution decreased. These findings show that increased ion absorption affected plant dry weight. The obtained findings provide fundamental information for the closed hydroponic system of phalaenopsis cultivation.     

Evaluation of Chemical Extractants for the Determination of Available Potassium

Abstract

Evaluation of nutrient status in soil is important for nutritional, environmental, and economical aspects. This research was carried out to determine the potassium (K) available to corn (Zea mays) in 15 soils from the Hamedan province in the west of Iran. The treatments included two K levels [0 and 200 mg K kg^?1 as potassium sulfate (K₂So₄)] and 15 soils in a factorial experiment in a randomized block design with three replications. The results indicated that K application increased yield, K concentration, and K uptake of corn. According to the mechanism of the extraction, these extractants can be classified into four groups. The first group of extractants, acidic extractants, includes 0.02 M strontium chloride (SrCl₂)+0.05 M citric acid, 0.1 M hydrochloric acid (HCl), and Mehlich 1. The second group includes 0.1 M barium chloride (BaCl₂), 0.01 M calcium chloride (CaCl₂), and 1 M sodium acetate (NaOAc). The third group includes 1 M ammonium acetate (NH₄OAc), ammonium bicarbonate–diethylenetriamine tetraacetic acid (AB‐DTPA), and finally distilled water. The results showed that correlation between extractants in each groups were significantly high. Correlation studies showed that NH₄OAc and AB‐DTPA cannot be used as available K extractants. The correlation of other extractants with relative yield, plant response, and K uptake were significantly high. Therefore, these extracting solutions can be used as available K extractants.

Potassium critical levels by extractants were also determined using the method by Cate and Nelson (1971) Cate, R. B. and Nelson, L. A. 1971. A simple statistical procedure for partitioning soil test correlation into two classes. Soil Science Society of America Proceeding, 35: 658–660. [Crossref], [Web of Science ®] , [Google Scholar]. Potassium critical levels for 90% relative yield were 29, 27, 82, 84, 45, 145, and 272 mg kg^?1 for 0.002 M SrCl₂, distilled water, 0.02 M SrCl₂+0.05 M citric acid, 0.1 M HCl, Mehlich 1, 1 M NaOAC, and 0.1 M BaCl₂, respectively.     

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.     

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.     

Evaluation of different methods for the determination of saturated hydraulic conductivity for simulation of water table depth and drainage discharge using the DRAINMOD computer simulation model

The purpose of this study was to investigate application of the DRAINMOD computer simulation model for estimation of water table depth (W) and drainage discharge (q) by using different values of saturated hydraulic conductivity (K _s) in a subsurface drainage system in Kooshkak area in Fars province. These values of K _s were obtained from the drainage system, a direct measurement of K _s calculated from drainage data (K _s1), Porchet method with saturated inverse hole (K _s2), ordinary Porchet method (K _s3) and saturated Porchet obtained using an empirical equation presented by Sepaskhah and Rezaee (K _s4) (Sepaskhah AR, Rezaee A. 1998. Hydraulic conductivity measurement for subsurface drainage system. Iran Agr Res. 17:139–150). The results indicated that saturated Porchet and saturated Porchet calculated using Equation (17) are reliable for determination of K _s because their values are close to that obtained from the direct method. Furthermore, the results indicated that W fluctuations and q are estimated properly by the DRAINMOD model, as shown by an index of agreement of 0.90–1.0 and 0.99 for W and q, respectively. However, q estimations were more accurate than W fluctuations, as shown by a mean absolute error of 0.045–0.243 and 1.73–25.44 for q and W, respectively. Using different values of K _s in the model caused tangible differences between the results, especially in W fluctuations, and showed that the model is sensitive to this parameter. Among the indirect methods of K _s determination, using the measured K _s obtained by the saturated Porchet method (K _s2) resulted in more accurate W and q. It was determined that the saturated Porchet method is more difficult and time-consuming than the ordinary Porchet method. Therefore, a relationship between these two tests has been developed in the study area [similar to the equation that was presented by Sepaskhah and Rezaee (1998 Sepaskhah, A R and Rezaee, A. 1998. Hydraulic conductivity measurement for subsurface drainage system. Iran Agr Res, 17: 139–150.  [Google Scholar])] and estimation of K _s from ordinary Porchet method can then be converted to saturated Porchet method for use in DRAINMOD model.     

Forms of phosphorus in soils of Rajasthan

Phosphorus in soils is found to be present in organic combinations, inorganic form or in adsorted form on clay complex. Different forms of soil phosphorus have different solubilities and consequent availability in soils. A knowledge about the content and types of soil phosphorus enables one to understand the organic behaviour and predict the response of added phosphatic material to crops (Parker 1953). The form in which phosphorus is present in soil is directly related to pH and CaCO₃ in the soil as well as the intensity of the development of the soil. Williams (1950) has found that in calcareous soils of South Australja most of the phosphorus was in combination with calcium, whereas in acid soils it forms compounds with alumina and iron. Hibbard (1931) concluded that in alkaline and calcareous soils, phosphorus exists mostly in the form of hydroxyapatite, chloroapatite, and the like. Kanwar and Grewal (1959) studied fractionation of phosphorus in Punjab soils and reported that differences in the nature and amounts of the phosphorus present in acid and alkaline soils of the State explain the causes of different phosphatic fertilizer responses to the crops. A similar report has been given by Goel and Agarwal (1959) who studied the fractionation of phosphorus in Kanpur soils and concluded that the mature soils are rich in iron and aluminium bound phosphorus and respond better to phosphatic fertilizer than the immature soils rich in Ca²⁺ and Mg²⁺ bound phosphorus. Chai Moo Cnoo and Caldwell (1959) reported that Fe³⁺ and Al³⁺ bound phosphorus was abundant in acid soils while Ca²⁺ and Mg²⁺ bound phosphorus content in alkaline soils, and organic phosphorus agreed, in general, with the content of organic matter, with some deviations.     

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.     

Influence of Catchment Characteristics and Flood Type on Relationship Between Streamwater Chemistry and Streamflow: Case Study from Carpathian Foothills in Poland

The study aimed to determine the influence of catchment characteristics and flood type on the relationship between streamflow and a number of chemical characteristics of streamwater. These were specific electrical conductivity (SC), pH, the concentrations of main ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO ₃ ^? , SO ₄ ^2? , and Cl^?), and nutrients (NH ₄ ⁺ , NO ₂ ^? , NO ₃ ^? , and PO ₄ ^3? ). These relationships were studied in three small catchments with different geological structure and land use. Several flood types were distinguished based on the factors that initiate flooding and specific conditions during events. Geological factors led to a lower SC and main ion concentrations at a given specific runoff in catchments built of resistant sandstone versus those built of less resistant sediments. A lower concentration of nutrients was detected in the semi-natural woodland catchment versus agricultural and mixed-use catchments, which are strongly impacted by human activity. The strongest correlation between streamflow and the chemical characteristics of water was found in the woodland catchment. Different types of floods were characterized by different ion concentrations. In the woodland catchment, higher SC and higher concentrations of most main ions were noted during storm-induced floods than during floods induced by prolonged rainfall. The opposite was true for the agricultural and mixed-use catchments. During snowmelt floods, SC, NO ₃ ^? , and most main ion concentrations were higher when the soil was unfrozen in the agricultural and mixed-use catchments versus when the soil was frozen. In the case of the remaining nutrients, lower concentrations of NH ₄ ⁺ were detected during rain-induced floods than during snowmelt floods. The opposite was true of PO ₄ ^3? .     

Influence of sea salts on the soil metabolism

Abstract

Microbial metabolism in reduction process of waterlogged paddy soils has been studied by Takai, Koyama, and Kamura (1, 2, 3, 4, 5, 6), Koyama (7, 8, 9, 10, 11, 12), and others. The results indicated that microbial metabolism in waterlogged soils takes place according to the following steps: (1) In the early stage of the incubation period, dissolved O₂, is consumed and the redox potential drops rapidly. (2) NO₂? and NO₂? are reduced to N₂. (3) Mn⁴⁺ is reduced to Mn²⁺. (4) Fe³⁺ is reduced to Fe²⁺. (5) SO₄ ²? is reduced to S^2?. (6) H₂ and CH₄ are produced. Takai and Chiang (13) reported that NH₄₊ and PO₄ ³⁺ in waterlogged paddy soils increase with the incubation period. Chiang and Takai (14) indicated that carbohydrates in the soil solutions almost remain constant throughout the incubation period, however, organic acids change similarly to those reported previously (5, 6).     

Study of Pedo Genesis of soils of Bundi district (Rajasthan)

The soils of Rajasthan vary from desert sand to heavy clay with all intermediate stages like sandy loam, loam and clay loam. The last two textural groups are more prevalant on the eastern, northeastern and southeastern part of the Aravallies which run almost in the middle of the State from southeast to northeast. The latter groups of soils have more potential from the point of agricultural development in the State. These soils are widely termed as alluvial soils which is a general term to indicate the nontaxonomic group of soils that have parent material of alluvial origin, Riecken ¹⁷, Kelloog ⁸ has referred to the soils developed from the alluvium as classified under variety of world soil groups. In our country many of the alluvial soils have not yet been studied from the soil genesis point of view as a measure to classify the soils under taxonomic groups. Ray Chawdhary and Mukerji ¹⁵, concluded that the alluvial soil groups of our country are ill defined and the classification of these soils need more study. Basu ³ was able to distinguish the genetic characteristics of the soils of Deccan. Agrawal and Mukherji ¹⁾ established that distinct genetic soil types have come into expression under Gangetic alluvium. Agarwal ² has concluded about the three types of soils in the toposequence with precipitated calcium throughout, zone of calcium accumulation in the bottom of the profile and soils free of calcium, and suggests that the soils of Gangetic plain be called as derived from alluvium. A process of reclassifying the alluvial soil series into taxonomic groups is a common trend in the United States since the last two decades.     

Ion mass budgets for small forested catchments in Finland

Ion mass and H⁺ budgets were calculated for three pristine forested catchments using bulk deposition, throughfall and runoff data. The catchments have different soil and forest type characteristics. A forest canopy filtering factor for each catchment was estimated for base cations, H⁺, Cl^? and SO ₄ ^2? by taking into account the specific filtering abilities of different stands based on the throughfall quality and the distribution of forest types. Output fluxes from the catchments were calculated from the quality and quantity of the runoff water. Deposition, weathering, ion exchange, retention and biological accumulation processes were taken into account to calculate catchment H⁺ budgets, and the ratio between external (anthropogenic) and internal H⁺ sources. In general, output exceeded input for Na⁺, K⁺, Ca²⁺, Mg²⁺, HCO ₃ ^? (if present) and A^? (organic anions), whereas retention was observed in the case of H⁺, NH ₄ ⁺ , NO ₃ ^? and SO ₄ ^2? . The range in the annual input of H⁺ was 22.8–26.3 meq m^?2 yr^?1, and in the annual output, 0.3–3.9 meq m^?2 yr^?1. Compared with some forested sites located in high acid deposition areas in southern Scandinavia, Scotland and Canada, the catchments receive rather moderate loads of acidic deposition. The consumption of H⁺ was dominated by base cation exchange plus weathering reactions (41–79 %), and by the retention of SO ₄ ^2? (17–49 %). The maximum net retention of SO ₄ ^2? was 87% in the HietajÄrvi 2 catchment, having the highest proportion of peatlands. Nitrogen transformations played a rather minor role in the H⁺ budgets. The ratio between external and internal H⁺ sources (excluding net base cation uptake by forests) varied between 0.74 and 2.62, depending on catchment characteristics and acidic deposition loads. The impact of the acidic deposition was most evident for the southern Valkeakotinen catchment, where the anthropogenic acidification has been documented also by palaeolimnological methods.     

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.     

Humus composition of mountain soils in Central Japan with special reference to the distribution of P type humic acid

The central districts of Japan are mountainous areas rising to 3,000 metres which are predominantly covered with forest vegetation. A comprehensive and systematic classification of the soils in this region has not yet been made, but the following soil types have been reported to occur: - 1. 1. Brown forest soils, podzolic soils, black soils and red soils. [Described by OHMASA (14)]

2. 2. Alpine grassland soils and alpine meadow soils. [Described by KUMADA et al. (9)]

3. 3. A series of randzina-like soils with a very restricted distribution. These are derived mainly from limestone and show various degrees of maturity. [Described by KUMADA et al. (8)]

4. 4. Red-yellow soils. These sometimes show a close resemblance to OHMASA's red soils and are found on diluvial plateaux and hills. [Described by KANNO (1)]

5. 5. Paddy soils.