Available Phosphorus

Chemical composition and nutrient concentrations of 39 relatively poorly known Patagonian lakes (38-501S and from 701 to 681W) are described and analysed using principal component analysis (PCA). The general relationships between nutrients (total phosphorus, bioavailable phosphorus and dissolved inorganic nitrogen) and plankton biomass are examined. We seek to demonstrate that the extreme oligotrophy characterising many lakes and reservoirs of the Argentine Patagonian region of South America owes more to nitrogen deficiency than to a shortage of available phosphorus. The data show a range of trophic conditions with variable water chemistry characteristics. The first two axes of the PCA ordination explain most of the variance (63%). The first component of the variance in the environmental data is a trophic gradient, with positive correlations with the concentrations of nutrients (TP, SRP, DIN) and electrical conductivity and a negative correlation with transparency. For all the reservoirs considered, the calculated annual, summer and winter chlorophyll-a carrying capacities of the available phosphorus were consistently and significantly (Po0.05) in excess of observations but maximum chlorophyll-a values correlate with DIN availability. Indeed the chlorophyll-a carrying capacities, as an index of the resource-sustainable maximum biomass, of the available nitrogen gives a better predictive yield relationship than does P. Our findings are remarkable in so far as the general expectation that dinitrogen-fixing phytoplankton should thrive in the absence of dissolved inorganic nitrogen, at least to the supportive limits of the available phosphorus, is unfulfilled.

Con el propósito de identificar la estructura de variación espacial de algunas propiedades del suelo y optimizar el muestreo para el monitoreo de los cambios en dichas propiedades por efecto del manejo se utilizaron datos provenientes de un muestreo sistemático en dos suelos de ...

Five age series stands of Alnus nepalensis D. Don monocultures have been selected from the Pankhasari range of the Kalimpong forest division in the Eastern tlimalayas. Chemical soil properties such as organic carbon, total nitrogen, C:N ratio, available phosphorus and exchangeable cations (Ca +2 , K + and Na +) were analysed in all these different ages of plantation stands from the surface to 1 m deep profiles to find out the long term effect of A. nepalensis on the soil quality of these erosion vulnerable slopes. Organic carbon, available phosphorus and total nitrogen content per-hectare increased with increasing plantation stand age. Analysis of variance for nutrients showed significant variation in depth (total nitrogen, P < 0.001 ; organic carbon, P < 0.001 ; available phosphorus, P < 0.05; exchangeable Ca +2 , P < 0.01; and exchangeable K +, P < 0.01) and between plantation stands (organic carbon, P < 0.05; and available phosphorus P < 0.05). High value of total nitrogen content (34.97t ha -~ ) was obtained in 46 yr old stand. Soil pH is low. It increased down the depth and in older plantations. These stands with high soil total nitrogen and organic carbon content show increased fertility of the stands. The cover of A. nepalensis in rocky, landslide and e:osion prone slopes of the Eastern Himalayas, serves to protect and improve soil quality.

Fusarium oxysporum f.sp. anacardi is a causal of Fusarium wilt of cashew in Tanzania. Considering high disease incidence and severity of Fusarium wilt of cashew, the present study was undertaken to develop a sustainable disease management approach which involves the soil amendment. In the experiment, four cover crops including soybean, mucuna, green gram and cowpea were used. The experiments were conducted on farmer’s fields in 2021/2022 and 2022/2023. Treated plots significantly reduced Fusarium oxysporum f.sp. anacardi load and disease severity compared to non-treated plots (P≤0.05). In the first cropping cycle (2021/2022), disease severity ranged from 9.0% to 39.42% compared to 57.12% in non-planted plots. In the second cropping cycle (2022/2023), disease reduction ranged from 7.0% to 33.50% compared to 62.50% in non-planted plots. Mucuna was the most effective crop with disease severity rates of 9.0% and 7.0%, followed by cowpea with 9.78% and 11.30% in 2021/2022 and 2022/2023, ...

The effect of phytase supplementation to a canola-meal-based diet on phosphorus utilisation in Atlantic salmon was studied in a two-by-two factorial design. Diets were prepared without phytase or inorganic phosphorus supplementation, with phytase, with supplemental inorganic phosphorus and with both phytase and supplemental inorganic phosphorus. Available phosphorus was set below requirement and the total phosphorus set to meet requirements for salmonids. After 12 weeks, there were no significant differences in survival, feed intake and weight gain between diets. There was an interaction effect between supplements on bone ash, bone phosphorus and whole-body phosphorus so that adding phytase, inorganic phosphorus, or both resulted in significantly ( Pb0.05) higher values for these parameters. An interaction effect was also observed for phosphorus digestibility, phosphorus retention efficiency and phosphorus load. Phosphorus digestibility and retention efficiency were significantly ( Pb0.05) higher, and phosphorus load was significantly ( Pb0.05) lower in fish fed the phytase supplemented diet compared with diets containing supplemental inorganic phosphorus. In conclusion, phytase increased phosphorus availability, therefore reducing

A field survey was conducted to investigate metal(loid) concentration in soils and native plants in the Baoshan mining area for potential application in phytoremediation. Total concentrations of arsenic (As), cadmium (Cd), lead (Pb), and zinc (Zn) in soil varied from 125 to 6656, 5.10 to 1061, 568 to 49294, and 241 to 17296 mg kg -1 , respectively, showing severe contamination. Among 20 species native to this area, Pteris ensiformis accumulated 1091 mg kg -1 As in the shoot, and its translocation factor (TF) was greater than 1, suggesting potential capacity for As phytoextraction. Boehmeria nivea, Aster prorerus, and Hydrocotyle sibthorpioides showed potential for phytoextraction of Cd due to their high accumulation of Cd in shoots (490.3, 175.4, and 128.5 mg kg -1 , respectively) and high TFs (92.0, 22.1, and 6.7, respectively). Eleusine indica and P. ensiformis were found to contain high concentrations of Pb (7474 mg kg -1 ) and Zn (1662 mg kg -1 ) in roots, but with low TFs for Pb (0.4) and Zn (0.2), suggesting potential capability for phytostabilization. There was a positive correlation (p < 0.01, N = 25) of TFs between the metal(loid)s, indicating a synergic interaction in the uptake of metal(loid)s by these plants. According to metal(loid) concentrations in shoots, bioconcentration factors (BFs), and TFs, as well as the botanical features such as wide occurrence, high biomass yield, and rapid growth of the plants, the five native species identified above have the potential for phytoremediation in the Baoshan mining area.

The availability of key plant nutrients may change with elevation in tropical mountains due to altitudinal gradients in temperature and moisture which affect pedogenesis and nutrient cycling. In a transect from upper lowland to montane forests in NE Ecuador, we tested the hypotheses that (1) the availability of P is low in low-elevation forests but increases upslope, while the availability of N is relatively high at low elevations but decreases with elevation, and (2) increasing amounts of calcium, magnesium and potassium are stored on top of the soil with progressive humus accumulation toward higher elevations, likely to improve nutrient availability. In each 20 plots in undisturbed natural forest at 500, 1000, 1500 and 2000 ma.s.l., we measured in situ N net mineralization and nitrification rate (N NM and N NI , buried bag method), plant-available phosphorus (P a , resin-bag method), and salt-exchangeable calcium, potassium and magnesium concentrations (Ca ex , K ex , Mg ex ) in the organic and mineral topsoils. N NM and N NI , and the Ca ex , K ex and Mg ex concentrations were much more variable at the plot level than across the four elevations, while P a varied equally at small and large spatial scales. P a increased more than 10fold from 500 to 2000 m. The net release of nitrate dominated over ammonium at all elevations. While mass-related N NM and N NI rates and also organic matter C/N ratio in the topsoil remained invariant along the slope, N NM and N NI rates per ground area decreased by about 40% from 500 to 2000 m. Thus, the N NM /P a ratio decreased markedly with elevation proving our first hypothesis. In support of the second hypothesis, the pools of Ca ex , Mg ex and K ex in the organic layers increased with elevation, demonstrating the key role that organic topsoil horizons are playing for forest nutrition at high elevations. We suggest that the large difference in N versus P availability of tropical (upper) lowland and montane forests is likely to be a key factor influencing the species composition and productivity along tropical mountain slopes.

Soil CO 2 emission (FCO2) has been related to soil properties that are strongly influenced by agricultural management. The objective of this work was to study FCO2 and its relation to soil properties in adjacent areas cropped with sugarcane managed with Slash-and-burn (SB) and Green (G) harvest. FCO2 was significantly higher (p < 0.01; 2.74 mmol m À2 s À1 in SB and 2.07 mmol m À2 s À1 in G) in SB. Total emission in the 70-day period after harvest was also higher in the SB plot (729 g CO 2 m À2 ) when compared to the G (557 g CO 2 m À2 ) plot. Organic matter content and carbon stock (0-25 cm) were 13% and 20% higher in SB, respectively, when compared to G. Other soil properties that presented significant difference between plots were pH, available phosphorus, sum of bases, cation exchange capacity, texture, and humification index of soil organic matter. The SB plot presented higher spatial variations in the majority of the soil properties, including FCO2, when compared to the G plot. Principal component analysis sustains the distinction of two groups, G soil samples and SB soil samples, separately. Regression analysis was able to explain up to 75% and 45% of the FCO2 spatial variability in SB and G harvested areas, respectively, and indicates that the humification index of soil organic matter, and its interaction with soil bulk density, is an important factor not just to differentiate emissions in each plot. Linear correlation between humification and FCO2 in each management system shows a positive correlation (p < 0.10) in the G area and negative correlation (p < 0.05) in the SB area. In addition, the interaction between humification index and bulk density relates better than others properties with soil CO 2 emission, with this property being the most important to understand the emission variability in the Slash-and-burn area.

A study (100 days duration) was conducted to evaluate the efficiency of an exotic earthworm species (epigeic—Eisenia foetida) for decomposition of different types of organic substrates (kitchen waste, agro-residues, institutional and industrial wastes including textile industry ...

It is generally assumed that phosphorus (P) availability for plant growth on highly weathered and P-deficient tropical soils may depend more on biologically mediated organic P (P o ) turnover processes than on the release of adsorbed inorganic P (P i ). However, experimental evidence showing the linkages between P o , microbial activity, P cycling and soil P availability is scarce. To test whether land-use systems with higher soil P o are characterized by greater soil biological activity and increased P mineralization, we analyzed the partitioning of P among various organic and inorganic P fractions in soils of contrasting agricultural land-use systems and related it to biological soil properties. Isotopic labeling was used to obtain information on the turnover of P held in the microbial biomass. Soil samples were taken from grass-legume pasture (GL), continuous rice (CR) and native savanna (SAV) which served as reference. In agreement with estimated P budgets (+277, +70 and 0 kg P ha -1 for CR, GL and SAV, respectively), available P estimated using Bray-2 and resin extraction declined in the order CR > GL > SAV. Increases in Bray-2 and resin P i were greater in CR than GL relative to total soil P increase. Organic P fractions were significantly less affected by P inputs than inorganic fractions, but were a more important sink in GL than CR soils. Extractable microbial P (P chl ) was slightly higher in GL (6.6 mg P kg -1 ) than SAV soils (5.4 mg P kg -1 ), and significantly lowest in CR (2.6 mg P kg -1 ). Two days after labeling the soil with carrier free 33 P, 25, 10 and 2% of the added 33 P were found in P chl in GL, SAV and CR soils, respectively, suggesting a high and rapid microbial P turnover that was highest in GL soils. Indicators of P mineralization were higher in GL than CR soils, suggesting a greater transformation potential to render P o available. Legume-based pastures (GL) can be considered as an important land-use option as they stimulate P cycling. However, it remains to be investigated whether crops planted in pasture-crop rotations could benefit from the enhanced P o cycling in grass-legume soils. Furthermore, there is need to develop and test a direct method to quantify P o mineralization in these systems.

Los objetivos principales del estudio fueron cuantificar el nivel óptimo de P y la forma de aplicación del fertilizante soluble superfosfato triple (SFT) y determinar la dinámica del P inorgánico (Pi) y orgánico (Po) en sus diferentes &quot;Pools&quot; en el suelo a través del tiempo, en la altillanura plana, en un suelo ácido altamente meteorizado (Oxisol) de baja fertilidad y alta capacidad de fijación de P, en un ensayo satélite al Ensayo Culticore, denominado P residual en un sistema de cultivo rotacional de maíz (primer semestre) y soya (segundo semestre), establecido en 1993 y hasta 1997. Se compararon aplicaciones anuales de P: 0, 20, 30 y 50 kg/ha contra una única aplicación realizada al inicio del establecimiento del ensayo. Las dosis evaluadas de P residual fueron 80, 120 y 200 kg/ha. Se utilizó la técnica del fraccionamiento secuencial de P modificada por l-ledley et al. (1982) y Tiessen y Moir (1993), en la diferenciación de los diferentes &quot;Pools&quot; de P en el su...

Symbiotic and asymbiotic nitrogen fixation (SNF and ANF), two forms of biological nitrogen (N) fixation, are the main pathways for external N inputs into natural terrestrial ecosystems. However, the regulatory mechanisms of SNF and ANF, particularly in response to changing environmental conditions, remain poorly understood. Here, we investigated changes in SNF and ANF rates along two altitudinal gradients in two subtropical forests on soils with granite and slate parent materials. Our results revealed distinct patterns for SNF and ANF rates. SNF rates consistently declined with increasing altitude, whereas ANF rates initially increased at lower altitudes but declined at higher altitudes. These contrasting trends were attributed to divergent regulatory mechanisms of SNF and ANF rates. Specifically, the decrease in SNF rates was primarily driven by increased soil N availability and decreased air temperature. However, the drivers of ANF rates shifted from soil properties (e.g., phosphorus, iron, and moisture) at lower altitudes to climatic factors (e.g., air temperature) at higher altitudes. We also observed opposite trends of SNF and ANF between forests on granite and slate, demonstrating that lithology is an important driver of both SNF and ANF. Collectively, our findings highlight the divergent mechanisms regulating SNF and ANF in subtropical forests, which contribute to improving the mechanistic representation of biological N fixation in Earth system models.

In August 2002 extreme floods affected Bohemia a part of the Czech Republic, along Vltava and Labe rivers. After the flood had culminated, soil samples of arable and meadow soil (flooded and control-non-flooded) have been collected in the surroundings of the cities of České Budějovice (CB, South Bohemia, the Vltava river, the upper flood stream) and Ústí nad Labem (UL, the Labe river, the lower flood stream). Different parameters of arable soils have been affected more significantly than those of meadow soils. Soil texture e.g. has been shifted from sandy loam to loam (CB) and clay loam (UL). Organic carbon, total phosphorus and nitrogen contents have been increased as well as the content of some hazardous elements such as arsenic. A shift of soil pH from 6.1 to 4.8 has been noticed in CB and an opposite one from 5.1 to 7.1 was measured in UL. Available phosphorus decreased in CB by 56% while a four-fold increase was measured in UL. Chlorinated organic pesticides level was significantly reduced, but that of polycyclic aromatic hydrocarbons (PAH) increased up to the maximum values of legal limits. The UL arable soil also became heavily contaminated by PAH. The CB arable soil demonstrated high microbial activity, while UL arable soil suffered under stress conditions in this respect. The flooded meadow soils became covered with a layer of drifted soil sediment, which retained enhanced content of the PAH's, different hazardous elements, and, in addition, the soil aeration was reduced.

Algal-available phosphorus (P aa ) in river water and wastewater entering the Gulf of Finland (a Baltic Sea sub-basin) was estimated by a fresh-water and a brackish-water modifi cation of the dual-culture algal assay. Th e assay results were further related to those obtained by routine chemical analyses. According to the brackish-water assay, an average of 44% (range, 9-88%) of total phosphorus (TP) in water samples from the Neva, Kymijoki, and Narva rivers consisted of P aa , whereas the mean value given by the fresh-water assay was 22% (range, 0-48%). Phaeodactylum tricornutum Bohlin, which was used as the test alga in the brackish-water assay, had higher phosphoesterase activity and P affi nity than did Pseudokirchneriella subcapitata Korschikov, which was used in the fresh-water assay. Th is diff erence may explain the higher values of P aa shown by the brackish-water assay. Of the analytical P forms, total dissolved P best approximated, yet underestimated, the P aa in river water samples. As for the biologically purifi ed wastewaters of the city of St. Petersburg, both assays suggested that about 80% of TP (range, 59-103%) was available. Th at the assays gave similar results was probably due to the fact that most of the P in the wastewater samples was in the form of readily available dissolved reactive P. In untreated urban wastewaters, the mean proportion of P aa in TP was 46% (range, 19-76%). Although the true P aa may not be obtained by any assay, our fi ndings corroborate the view that severe underestimation may occur if the test conditions are suboptimal for the release and uptake of P.

Struvite precipitation causes important operational problems during the sludge treatment process, especially when EBPR sludge is treated. Predicting struvite formation is critical to be able to design process alternative that best minimizes struvite precipitation. With this aim, phosphorus precipitation in an anaerobic digestion pilot plant was studied using experimental data and mass balance analysis. The results obtained showed significant phosphorus precipitation as struvite (58% of the fixed phosphorus) and a low precipitation of calcium phosphates (15%), forming mainly hydroxyapatite (HAP). The rest of the phosphorus fixed in the digester (27%) was attributed to adsorption processes on solid surfaces. The effect of pH and available phosphorus concentration on phosphorus fixation in the digester was also studied, indicating that a decrease of available PO4-P concentration in the digester can minimise phosphorus precipitation, reducing the maintenance problems associated with struvite deposits.

Secondary salinisation is the most harmful and extended phenomenon of the unfavourable effects of irrigation on the soil and environment. An attempt was made to study the impact of poor quality ground water on soils in terms of secondary salinisation and availability of soil nutrients in Faridkot district of Punjab of northern India. Based on physiographic analysis of IRS 1C LISS-III data and semi-detailed soil survey, the soil map was finalized on a 1:50,000 scale and digitized using Arc Info GIS. Georeferenced surface soil samples (0-0.15 m) from 231 sites were collected and analyzed for available phosphorus (P) and potassium (K).

In a 3-year field experiment, we aimed to investigate the factors which drive the stability of soil aggregates in greenhouse soil.  To explore the impact of organic fertilizer on soil aggregates, we established four treatments: no fertilization (CK); inorganic fertilizer (CF); organic fertilizer (OF); and combined application of inorganic and organic fertilizers (COF).  The application of organic fertilizer significantly enhanced the stability of aggregates, that is it enhanced the mean weight diameter, geometric mean diameter and aggregate content (%) of >0.25 mm aggregate fractions.  OF and COF treatments increased the concentration of SOC, especially the aliphatic-C, aromatic-C and polysaccharide-C components of SOC, particularly in >0.25 mm aggregates.  Organic fertilizer application significantly increased the content of free Fe (Fed), reactive Fe (Feo), and non-crystalline Fe in both bulk soil and aggregates.  Furthermore, non-crystalline Fe showed a positive correlation with SOC content in both bulk soil and aggregates.  Both non-crystalline Fe and SOC were significantly positively correlated with >2 mm mean weight diameter.  Overall, we believe that the increase of SOC, aromatic-C, and non-crystalline Fe concentrations in soil after the application of organic fertilizer is the reason for improving soil aggregate stability.

We investigated several forms of phosphorus (P) in dryland soils to examine the chemical and textural controls on P stabilization on a diverse set of substrates. We examined three P fractions including labile, moderately labile, and occluded as determined by a modified Hedley fractionation technique. The P fractions were compared to texture measurements and total elemental concentrations determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Labile P related to the absence of materials involved in P sorption. Moderately labile P was most strongly associated with high total Al & Fe content that we interpret to represent oxides and 1:1 clay minerals. The occluded P fraction was strongly associated with low total Al & Fe environments and interpreted to represent 2:1 clay minerals where ligand exchange tightly sequesters P. The results indicate that the controls on P fraction distribution are initially closely tied to the chemical and physical properties of the bedrock units that contribute to soil formation. Further, these results suggest that the progression of stabilized P forms in dryland areas differs from the progression observed in mesic environments. Soil development in dryland settings, such as the formation of pedogenic carbonates, may lead to differing controls on P availability and the proportional size of the moderately labile fraction.

Bu çal›flma kapsam›nda, Türkiye'de ticari boyutta yetifltirilen 15 nar çeflidine ait meyvelerin çekirdek oranlar›, çekirdeklerin baz› fiziksel ve kimyasal özellikleri ile baz› mineral madde içerikleri belirlenmifltir. Araflt›rma kapsam›nda incelenen nar çeflitlerinin çekirdek oranlar› %8.11 ile %15.11 ve çekirdeklerin bin dane a¤›rl›klar› 19.36 g ile 36.81 g aras›nda de¤iflim göstermifltir. Örneklerin çeflitlere göre ya¤, protein, kül ve toplam fenolik madde içerikleri s›ras›yla kurumadde üzerinden

Soil acidification affects at least 4 million hectares of agricultural land in Victoria, Australia. Low soil pH can inhibit plant growth through increased soluble aluminum (Al) concentrations and decreased available phosphorus (P). The addition of organic amendments may increase P availability through competition for P binding sites, solubilization of poorly soluble P pools, and increased solution pH. The effect of two organic amendments (lignite and compost) on P solubility in an acid soil was determined through controlled environment (incubation) studies. Three days after the addition of lignite and compost, both treatments increased orthophosphate and total P measured in soil solution, with the compost treatments having the greatest positive effect. Increased incubation time (26 days) increased soil solution P concentrations in both untreated and amended soils, with the greatest effect seen in total P concentrations. The measured differences in solution P concentrations between the lignite-and compost-amended treatments were likely caused by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment with lignite or compost also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. Based on the results presented, it is proposed that the measured increase in soil solution P with amendment addition was likely caused by both chemical and biological processes, including biotic and abiotic P solubilization reactions, and the formation of soluble organic-metal complexes.

Phosphorous is an essential nutrient in plants required for root establishment. In the soil, it is applied as DAP, TSP or phosphate rocks. In acid soils, aluminium and iron are dominant and tend to “fix” phosphorous, making it unavailable for plant uptake. Phosphorous deficiencies are monitored through soil chemical analysis. There are many methods for the extraction of available forms; however the choice is dependent on several factors among them soil pH. Forty soil samples were collected from three different acid soils in Western Kenya. The samples were air dried, sieved under 2.0 mm sieve and stored in sample bags for subsequent analysis. Phosphorous extraction of was carried out using a basic extractant (Olsen bicarbonate method) and acid extractant (double acid method). The extracts were measured colorimetricaly by the ascorbic acid method at 880 nm wavelength. The methods were compared in terms of extracting efficiency, correlations and soil critical levels. The soils had a pH...

China is currently experiencing a severe issue of excessive fertilization. Variable rate fertilization (VRF) technology is key to solving this issue in precision agriculture, and one way to implement VRF is through management zone (MZ) delineation. This study is aimed at evaluating the feasibility and potential benefits of VRF based on site-specific MZs in smallholder farm fields. This study determined the amounts of basal and top-dressing fertilizers in different spatial units, based on soil nutrient MZs and crop growth MZs, respectively. The potential agronomic, economic, and environmental advantages of spatial variable rate fertilization were further assessed by comparing the farmer's treatment, the expert's treatment, and the variable rate fertilization treatment based on management zones (VR-MZ). The results showed that VR-MZ reduced the use of nitrogen (N), phosphorus (P), and potassium (K) fertilizers by 22.90-43.95%, 59.11-100%, and 8.21-100%, respectively, and it also increased the use efficiency of N, P, and K by 12. 27-28.71, 89.64-176.85, and 5.48-266.89 kg/kg, respectively, without yield loss. The net incomes of VR-MZ were 15.5-449.61 USD ha -1 higher than that of traditional spatially uniform rate fertilization. Meanwhile, less nitrous oxide emission (23.50-45.81%), ammonia volatilization (19.38-51.60%), and nitrate ion leaching amounts (28.77-53.98%) were found in VR-MZ compared to those in uniform fertilization. The results suggest that the VR-MZ has great potential for saving fertilizers, significantly increasing farmers' net income, reducing environmental pollution, and promoting the sustainable use of resources. This study provides a theoretical basis and technical support for exploring a VRF suitable for village-scale farming.

Between 1996 and 1998 phytoplanktonic primary production and bacterioplankton production were measured monthly at five sampling stations in the lower Kis-Balaton reservoir. The open water area of the reservoir was rich in phytoplankton and had hypertrophic characteristics, but inside the reed stand (80% of the surface area) phytoplankton biomass and production were substantially (30-50 times) lower. The algal removal efficiency of the lower Kis-Balaton reservoir was 96%. The reservoir had a considerably smaller effect on bacterioplankton removal than on the phytoplankton. The decrease of biomass and production of bacterioplankton in the through-flowing water was approximately 60%. Inside the reed stand the biomass and the production of planktonic bacteria exceeded that of the phytoplankton by several times, suggesting that the release of biodegradable dissolved organic (humic) substances from macrophytes stimulated the metabolism of bacterioplankton. The significant reduction of phytoplankton inside the dense reed stand was primarily the result of the shading effect of the reeds. In the open water area a shading experiment demonstrated that a 1-week residence period for planktonic algae in the reed-covered area was sufficient for their complete elimination. The decomposition of planktonic algae, reed material and the lack of primary production inside the reed stand created oxygen-deficient and phosphorus-rich conditions during the vegetative period. These results suggest that reed-covered water bodies can effectively retain suspended solids and planktonic algae, but because of decomposition processes they cannot retain biologically-available phosphorus.

Between 1996 and 1998 phytoplanktonic primary production and bacterioplankton production were measured monthly at five sampling stations in the lower Kis-Balaton reservoir. The open water area of the reservoir was rich in phytoplankton and had hypertrophic characteristics, but inside the reed stand (80% of the surface area) phytoplankton biomass and production were substantially (30-50 times) lower. The algal removal efficiency of the lower Kis-Balaton reservoir was 96%. The reservoir had a considerably smaller effect on bacterioplankton removal than on the phytoplankton. The decrease of biomass and production of bacterioplankton in the through-flowing water was approximately 60%. Inside the reed stand the biomass and the production of planktonic bacteria exceeded that of the phytoplankton by several times, suggesting that the release of biodegradable dissolved organic (humic) substances from macrophytes stimulated the metabolism of bacterioplankton. The significant reduction of phytoplankton inside the dense reed stand was primarily the result of the shading effect of the reeds. In the open water area a shading experiment demonstrated that a 1-week residence period for planktonic algae in the reed-covered area was sufficient for their complete elimination. The decomposition of planktonic algae, reed material and the lack of primary production inside the reed stand created oxygen-deficient and phosphorus-rich conditions during the vegetative period. These results suggest that reed-covered water bodies can effectively retain suspended solids and planktonic algae, but because of decomposition processes they cannot retain biologically-available phosphorus.

Bu cal ma, Ala ehir ilcesi Tepekoy mevkiinde bulunan Sultani Cekirdeksiz (Vitis vinifera L.) uzum ba nda ciftci ko ullar nda yurutulmu tur. Bu cal mam zda de i ik cinko gubrelerinin farkl dozlar uygulanm t r. Zn lu gubrenin I. formu olan ZnSO4.7H2O (%20) ; II. formu olan Zn elat (DISSOLVINE %15 Zn) dan %0.25-%0.50 olmak uzere iki dozu yapraktan uygulama eklinde yap lm t r. Denemede ya uzum verimi (kg/parsel), suda cozunebilir kuru madde miktar(%), titre edilebilir asitlik (g/100ml), olgunluk indisi , pH, 100 tane a rlsertli i (g) belirlenmi tir. Sonucta tum uygulamalar n incelenen kalite ozellikleri uzerine istatistiki olarak etkili oldu u ve ya uzum verimi ac s ndan en yuksek de erlerin Zn gubrelerinin elat formunun %0.50 lik ve ZnSO4.7HO formunda %0.25 lik doz seviyelerinde ula ld

The effects of phosphate solubilizing bacterium (Bacillus FS-3) application on phosphorus contents of tomato (Lycopersicon esculentum L.) plant, growing performance and phosphorus forms in soil were evaluated under greenhouse condition. Five different phosphorus fertilizer treatments (normal superphosphate, triple superphosphate, di-ammonium phosphate, phosphoric acid, and rock phosphate) with and without bacterium (Bacillus FS-3) were applied in pots as 344 kg P/ha. Basal fertilizers were applied to all the pots as 180 kg N/ha (NH 4 NO 3 33% N), 100 kg K/ha (K 2 SO 4 50% K 2 O). The results obtained showed that phosphorus availability from soil increased with phosphate solubilizing bacterium (PSB) application. The amount of plant available form of soil phosphorus fraction (resin-Pi + NaHCO 3 -Pi + NaHCO 3 -Po + NaOH-Pi + NaOH-Po) increased with PSB application. In all fertilizer types, bacteria application converted approximately 20% of less available phosphorus into labile forms. Statistically significant differences were obtained in shoot and root dry weight of tomato plants treated with PSB application. In all of the fertilizers, plant shoot and root weight and P uptake were greater with PSB applications than without PSB. The highest shoot-root dry weight and P uptake of plant were determined in triple superphosphate (TSP) with PSB application treatment. The data in the present study suggest that the application of PSB (FS-3) may increase the availability of soluble phosphate by dissolving the inorganic forms of phosphate and that bacterial strain tested in this study has a potential to be used as a bio-fertilizer in sustainable and organic agriculture.

The study was conducted to investigate the effects of Alphamune G fed to growing pullets on their performance during laying. A total of one hundred and forty four (144) commercial black Harco pullet chickens made up of seventy-two (72) each of age 19 weeks old (group A) as well as age 15 weeks old (group B) were fed four graded levels of Alphamune G (0.00, 0.04, 0.05 and 0.06 % inclusion level). A factorial arrangement of four levels of dietary Alphamune G and two age groups were the treatments in a Complete Randomized Design. The study was conducted for 17 weeks, when the birds of each of group A and B attained age 36 weeks and 32 weeks, respectively. Laying pullets fed the control diet 0.00% had the highest value of egg weight, shell thickness and feed intake. Highest values for feed to gain ratio, feed per dozen eggs and feed cost per dozen eggs were observed in laying pullets fed 0.04% inclusion level of Alphamune G. The haugh unit, yolk index and weight gain were observed to have the highest value in layers fed 0.05%. Highest values was observed for % hen day production for laying hens fed 0.06% inclusion level of Alphamune G. In conclusion, among laying hens fed dietary levels of Alphamune G, birds fed inclusion levels of 0.06% performed the best in terms of production characteristics, egg quality and economic value compared to 0.04% and 0.05%.

Sediment may act as a sink and source of phosphorus to water. The sediment phosphorus release is seasonal, being influenced by temperature and microbial activity. In the present investigation role of sediment microbial electron transport system activity (ETSA) and alkaline phosphatase for phosphorus regeneration were studied in peak summer in top 0-2 cm sediments from seven inland water bodies. Microbial oxidation was high and typically influenced by organic matter deposition. Sediments were highly mineralised and bacteria were possibly starved of directly utilizable carbon. Oxic mineralization was the dominating process for phosphorus release at least in sewage fed ponds, beel and two freshwater ponds. At least 50% variations in sediment soluble reactive phosphorus could be explained by phosphatase activity. Study suggests that alkaline phosphatase and microbial oxidation are closely coupled processes in both carbon and phosphorus mineralization.

En la actualidad, la aplicación generalizada y uniforme de prácticas de manejo a toda un área bajo cultivo viene siendo discutida, porque, en ocasiones ese procedimiento no ha mostrado el uso de insumos más efi ciente y más favorable al ambiente y al hombre. El siguiente trabajo tiene el propósito de sugerir alternativas para el manejo efectivo del cultivo de café, en la zona media de la cuenca del rio Castán, Municipio Trujillo, Estado Trujillo, mediante el empleo de herramientas de Sistemas de Información Geográfi co (SIG) y técnicas de Agricultura de Precisión (AP) se defi nen espacios pequeños o microparcelas con Manejo de Sitio Especifi co (MSE), dentro de una unidad de mayor tamaño (parcela cultivada), tomando como factor de defi nición de esos sitios de manejo, a la variabilidad espacial de algunos parámetros de suelo. Es decir, se maneja una microparcela como unidad específi ca, a la cual se le aplicarán los insumos con un manejo controlado, según las necesidades particulares de cada sección o bloque de terreno. El trabajo se realizó, en dos parcelas cultivadas con café, de aproximadamente 1,5 hectáreas. Para cada parcela se defi nió una cuadrícula con 123 puntos de muestreo y en cada uno se colectaron muestras de suelo hasta 15 cm de profundidad. Los puntos de muestreo fueron georeferenciados en un sistema de proyección en coordenadas rectangulares UTM. Los resultados del análisis de los parámetros de suelo: pH, Al, CE, contenido de MO, N, P, K, Ca, Mg y Textura fueron procesados con los Software Surf 8 y VA R IOWIN, lo cual permitió la obtención y construcción de semivariogramas omnidireccionales y mapas de contorno, para cada parámetro con la visualización de la variabilidad y rango de dependencia espacial que presentan. Entre los resultados de mayor relevancia, se aprecia que los valores de pH, determinan suelos extremadamente ácidos, lo cual es atribuible al lavado de los suelos de montaña, los bajos contenidos de materia orgánica y signifi cativa presencia de aluminio soluble. Esta situación, conduce a defi nir que el encalado es la primera práctica a efectuar, de acuerdo a los requerimientos por unidad o sitio de manejo, lo cual repercute en la disminución del efecto del aluminio y en el incremento en la absorción de otros nutrientes, facilitando la mejora de las condiciones de suelo y en consecuencia la productividad del cultivo. Palabras clave: SIG, Agricultura de precisión, geoestadística, manejo de sitio específi co Abstract Nowadays, widespread and uniform crop fi eld management practices across an area under cultivation are being discussed. Sometimes, those procedures have not proved the most effi cient and the most favorable use of inputs to the environment and man. The following approach suggests alternatives for effective coffee crop cultural practices, in the central zone of the Castán River Basin, Municipality

We analyzed 144 composite sediment samples to appraise the seasonal variation in select major nutrients in the bed sediments of Keoladeo National Park (KNP), Bharatpur, a subtropical monsoonal wetland system in India, from September 2003 to July 2005. Total organic carbon (TOC, %) and total nitrogen (TN, %) in the sediments were in the range of 0.61-14.01 and 0.26-0.68, respectively. The total available phosphorus (TAP, %) and total available sulphur (TAS, %) ranged from 0.001 to 0.034 and from 0.001 to 0.012, respectively. While C:N ratio was within a narrow range (1.38-13.56), C:P ratios varied widely (18.81-5995.83). Similar wide variations were seen in C:S ratio (352.2-3929.5) as well as N:P ratio (9.34-56.6). All the parameters except TAS showed depth-wise declines along the sediment profile. In contrast, the pH gradually increased along the depth. Most of the parameters significantly varied across months and sediment layers. A positive correlation (Two-tailed, P \ 0.05) existed between TOC and all the nutrients and their ratios except TAP and N:P. TAP was positively correlated with electrical conductivity (EC) and water soluble substances (WSS), suggesting the contribution of phosphate to the dissolved salts. During certain months elements such as P were comparatively low in concentration, in spite of input through agricultural runoff and large scale bird droppings, probably due to its higher uptake by macrophytes growing luxuriantly in the wetland. Organic materials appear to decay at a faster rate during the drier periods as indicated by the fall in TOC and the rise in TN. Principal Component Analysis (PCA) shows that three components contributed to 68.9% of the total variance. The first component that accounted for 26.4% of the total variance reflects the importance of total organic carbon in wetland sediments and the ratio of carbon to other nutrients. The second one accounting for 23.7% of the variance correlated with water soluble substances (EC, WSS and TAS). The third component accounting for 18.7% of the variance reflects the influence of two major nutrients, nitrogen and phosphorus, in sediments those affect the biogeochemical processes in wetlands. Thus, the three PCA components can be characterized as 'sediment organic carbon and its ratios with other elements', 'WSS, TAS' and 'the limiting nutrients such as N and P', respectively.

Liquid feeding systems for swine have been widely used in Western Europe and are gaining popularity in North America. For example, in Ontario, Canada, about 20% of growing-finishing pigs are raised on liquid feeding systems. Liquid feeding has many potential benefits over conventional dry feeding of pigs, such as use of inexpensive co-products from the alcohol industry, and benefits of growth performance, health and environment. The objective of this study was to determine the effects of liquid feeding using byproducts from ethanol production with corn as fermentation substrate, including distillers dried grains with solubles (DOGS), wet distillers grains with solubles (WDGS), wet distillers grains (WDG), thin stillage (wet distillers solubles, WDS), and dry thin stillage (freeze-dried distillers solubles, DDS) on the performance of wean-finish pigs in comparison to feeding conventional dry corn soybean meal.

Nematodes cause damages to many plants directly by sucking plants content or indirectly by transmitting some viruses or by providing the enterance to other plant disease agents to the root tissues. Nematode species belonging to the families of Xiphinematidae, Longidoridae, Trichodoridae and Paratrichodoridae particularly play an important role as vectors of plant viruses. In this work, the studies related to the nematodes as vectors of virus diseases, the process of the acquisition, retention and release of viruses by vector nematodes utilization of knowledge in plant protection area were rewieved.

Spatial distribution of selected metals (Al, Fe, Mn, Zn, Cu, and Co) in surface sediments in the EEZ of the east coast of Peninsular Malaysia was investigated. The aim of this paper is to determine the distribution pattern and pollution status of heavy metals in tropical shelf sediments since limited information is available. Heavy metal concentrations ranged between 207.58 and 491.33 µg·g−1 for Mn, 36.13 and 125.93 µg·g−1 for Zn, 14.49 and 22.33 µg·g−1 for Cu, 2.00 and 11.12 µg·g−1 for Co, 6.20 and 8.95% for Fe, and 0.94 and 6.62% for Al. The mean concentrations of heavy metals are in decreasing order as follows: Fe &gt; Al &gt; Mn &gt; Zn &gt; Cu &gt; Co. Most metals registered low concentrations at the nearshore areas. Pearson correlation indicates that most of the metals are derived from the miscellaneous sources. Based on the EFs and Igeo, it is implied that the surface sediment trace metal levels in the study area might be enriched by anthropogenic sources. However, the PLI su...

Three different forms of casts are produced by earthworm species of rubber plantation. These are tower-like casts (Metaphire houlleti, Eutyphoeus gammiei, Eutyphoeus gigas, Eutyphoeus scutarius, Eutyphoeus assamensis, Eutyphoeus callosus, Eutyphoeus comillahnus, Eutyphoeus turaensis, Eutyphoeus sp.), composite irregular casts (Pontoscolex corethrurus, Drawida papillifer papillifer) and large globoid mounds (Kanchuria sp.1). Although the annual cast production in the rubber plantation (24 tonnes ha ) was higher than that in the mixed forest (21.3 tonnes ha ), the difference was not significant 1 1 (p>0.05). Cast production increased significantly (p<0.05) during monsoon in the mixed forest and during both summer and monsoon in the rubber plantation compared to the winter season. Organic matter content, available phosphorus and potassium, pH, electrical conductivity and water holding capacity of casts increased significantly (p<0.01) compared to the non-ingested surrounding soil in majority of the earthworm species studied. Cast production by earthworms showed significant (p<0.01) positive correlation with soil temperature, soil moisture and rainfall and week correlation with both pH and organic matter content of the soil.

Oxidic soils are phosphorus drains in soil; hence, P availability is a limiting factor in tropical, weathered Oxidic soils. It has been shown that some brachiarias grown as cover crops may increase soil available P to subsequent crops. The objective of this study was to evaluate soil P cycling and availability, as well as the response of soybean to soluble and natural reactive phosphates as affected by ruzi grass (Urochloa ruziziensis, R. Germ. and C.M. Evrard, Crin) grown as a cover crop in a no-till system. Experimental treatments consisted of the presence or absence of ruzi grass in combination with a control (0.0 P) and soluble and reactive rock phosphate broadcast on the soil surface in the winter (80 kg ha -1 P 2 O 5 ), plus three rates of P applied to soybean furrows (0, 30, and 60 kg ha -1 of P 2 O 5 ) at planting, in the form of triple superphosphate. Soybean was cropped in two seasons: 2010/2011 and 2011/2012. Soil samples were taken before soybean planting (after desiccation of Brachiaria) at 0.00-0.05 and 0.05-0.10 m for soil available P. Total weight of dry matter and P accumulated in ruzi grass were determined, as well as soybean yields, P in soybean grains, and P use efficiency (PUE). The use of natural phosphate increased soil P availability. The highest yields were obtained with higher application rates of triple superphosphate in the planting furrow combined with broadcast rock phosphate. Broadcast application of Arad reactive phosphate increases and maintains soil available P, and this practice, associated with ruzi grass grown as a cover crop and the use of triple superphosphate applied to soybean furrows, results in higher use of P by soybeans.

Quantification of changes in soil properties (particularly organic carbon and total nitrogen) due to natural and anthropogenic influences is essential in understanding carbon fluxes between land and atmosphere. This thesis examines the effects of topographic aspect, vegetation community and land use on physical and chemical properties of soils in southeastern Ethiopia. Soil samples were collected under three vegetation communities, Schefflera abyssinica/Hagenia abyssinica (SHaD), Hypericum revoltum/Erica arborea/Schefflera volkensii (HESD) and shrub-sized Erica arborea (EAD), at four topographic aspects (north/south/east/west-facing). Soil samples were also collected from three land use types (native forest, cropland, grazing) between 3000-3150 m altitude. The soil properties examined generally exhibited significant variations with respect to vegetation and aspect. Sand, silt and clay content was high under EAD, HESD and SHaD respectively. Soil bulk density was lower in A-than B-horizons for all vegetation types and aspects. Available P was high under all south-facing communities and in east-facing Ahorizon soils under SHaD. Soil pH was high in both horizons under SHaD. Base cation adsorption in soil followed the trend Ca 2+ >Mg 2+ >K + >Na + for all communities and aspects. CEC was high under south-and east-facing SHaD and EAD. Overall, percentage base saturation was high under SHaD across all aspects. Soil organic carbon (SOC) and total nitrogen (N) stocks to 1.0 m depth were highest under EAD (46.03 kg C m-2 , 3.61 kg N m-2) and southern aspect (44.97 kg C m-2 , 3.75 kg N m-2). Mean annual temperature was important for variations in SOC and total N stocks along vegetation gradients across all aspects. About 45% of SOC was held in the upper 0.3 m, indicating that large amounts of CO 2 can be released to the atmosphere if the vegetation communities are cleared for arable/grazing land. Conversion of native forest into cropland significantly increased soil bulk density and pH while reducing SOC, total N and CEC concentrations by 31, 32 and 38%, respectively (1.0 m layer). Protecting remnant afroalpine/afromontane vegetation communities or improving existing cropping systems could mitigate nutrient losses while enhancing organic carbon sequestration for sustainable agriculture, ecosystem functioning and climate change mitigation.

Approximately two-thirds of phosphorus in various grains is present as phytate, which is not well-utilized by fish and other monogastric species. Besides its low availability of phosphorus, phytate is reported to reduce the availability of other dietary nutrients to animals. Single-gene, Ž .

The study reports the effects of irrigation of a sodic soil with post methanation effluent (PME) of a distillery. Impact of long term effluent irrigation in the field (10 years) and short term effluent irrigation using different doses of PME in the laboratory (30 days) was studied in combination with three bioamendments i.e. farmyard manure, brassica residues and rice husk. Impact on various soil properties like EC, pH, total organic carbon (TOC), total Kjeldahl nitrogen (TKN), available phosphorus, exchangeable K, Na, Ca, Cl, microbial population and soil enzyme activities were studied. Long term application of PME proved useful in significantly increasing TOC, TKN, K, P and soil enzymatic activities in the soil but tended to build up harmful concentration of Na, that could be chelated by bioamendments. In short terms studies, application of 50% PME along with bioamendments proved to be the most useful in improving the properties of sodic soil and also favoured successful germination and improved seedling growth of pearl millet.

O objetivo deste trabalho foi identificar e estimar a diversidade de comunidades de fungos micorrízicos arbusculares (FMAs) autóctones associados ao amendoim forrageiro (Arachis pintoi), em monocultivo e consorciado com outras forrageiras. A amostragem foi realizada em sete áreas, em Rio Branco, AC, sendo coletadas quatro amostras de solo em cada área, na profundidade de 0-10 cm, nas estações seca (junho de 2004) e chuvosa (janeiro de 2005). As áreas cultivadas com A. pintoi foram: monocultivo, consórcio com pastagens de gramíneas e outras leguminosas e como cobertura do solo em cafeeiro, além de capoeira e mata adjacentes como testemunhas. Foi verificada a ocorrência de 21 espécies de FMAs nas duas estações, sendo 18 espécies no período seco e 16 no chuvoso. As espécies foram distribuídas em cinco gêneros: Acaulospora, Entrophospora, Gigaspora, Glomus e Scutellospora. A densidade de esporos foi maior no consórcio A. pintoi x Brachiaria brizantha x Pueraria phaseoloides e a menor na...

fundamental para el desarrollo de las plantas. Para superar esta dificultad de orden natural y mitigar la demanda de fósforo del suelo, últimamente se adicionan microorganismos solubilizadores de fosfatos (MSF). En esta investigación, se estudiaron los microorganismos Kocuria sp., B. subtilis, S. diversispora y P. ochrochloron y el efecto que tienen sobre la disponibilidad de fósforo, en el desarrollo de plántulas de café, bajo condiciones de invernadero, con 23 tratamientos y 10 repeticiones, en diseño estadístico, completamente al azar. Los experimentos se desarrollaron en un suelo Typic Melanudand con pulpa de café descompuesta Recibido para evaluación: 4 de Mayo de 2016. Aprobado para publicación: 13 de Septiembre de 2016.

The project aims to develop a survey designed for the representative assessment of copper contents in vineyard soils. The method development for the sampling of adequate monitoring areas is based on a preliminary survey of load distribution as well as on exposure assessment on selected areas of some typical vinery sites in Rheinland-Pfalz, differently managed and with different use history. Additionally to the sampling of selected areas, which reflects the spectrum of the load situation in viticulture, chemical quantitative analysis of soil samples collected from areas of known mode of cultivation and history followed by biological standard tests will be conducted. Obtained findings will serve for further method development, for preselection of adequate monitoring areas and for first indications of hazard potential. The project is a prerequisite for the performance of the long-term study "Development of current data of effects of copper contents in organic soils in viticulture, pomiculture and hopculture on soil life in terms of the strategy paper concerning further copper application in agriculture, especially in organic farming."

One hundred ninety two swine were used in a trial to assess the relative bioavailability of phosphorus (RBP) in six phosphate sources. Phosphates were three feed grade phosphates (FP), two made in Brasil, and one USA made, and three rock phosphate samples (RP) originated from two mines sites in Brasil, and one mine site in Israel. Levels of calcium, phosphorus and fluorine in RP were 29, 12 and 1.7% (RP source 1), 33, 14 and 1.4% (RP source 2), and 30, 14 and 3.6% (RP source 3), respectively. Pigs were fed a corn-soybean meal basal diet (18% CP, 0.95% Lys, 0.75% Ca, 0.37% P) or the basal diet with 0.15% P from a standard purified grade calcium phosphate (SP), or with 0.15% P from experimental FP or RP. Each diet was fed to six pen replicates of four pigs per pen for 35 days (14.4 to 39.9 kg). Weight gain (WG), feed/gain (FG), plasma P (PP), bone ash (BA), and breaking strength of metacarpals and metatarsals (BS-MM) and femurs (BS-F) were improved by phosphorus addition. However, per...

Neste trabalho efeitos do manejo tradicional da cultura de cana-de-acucar foram comparados com area de vegetacao nativa (Cerrado), no municipio de Mineiros ? GO, regiao em expansao dessa cultura, quanto ao teor de fosforo disponivel de perfis de Solos Frageis. Estes solos, por suas caracteristicas intrinsecas e ou posicao na paisagem, tem baixa resiliencia e elevada suscetibilidade a degradacao fisica, quimica e biologica quando submetidos a acao antropica, exigindo estrategias especiais para o seu manejo sustentavel. Neste experimento foram utilizadas, como tratamentos, areas adjacentes, sendo duas com os solos Latossolo de textura media e Neossolo Quartzarenico, com cultivo de cana-de-acucar e uma, de Neossolo Quartzarenico com fitofisionomia de Cerrado (testemunha). Amostras de solo foram coletadas em transecto, com 10 pontos georreferenciados e equidistantes entre si, ao longo do comprimento de rampa, em cada tratamento. Amostras compostas foram retiradas das camadas 0-20, 20-40...

Three fungal isolates (phosphate-dissolvers), Aspergillus niger, A. fumigatus and Penicillium pinophilum were isolated from the rhizosphere of different plants grown in Ismailia and South Sinai Governorates. They effectively solubilized rock phosphate or tricalcium phosphate in Pikovskaya's liquid medium. In pot and column experiments, they significantly reduced pH and increased available phosphorus in the soil treated with either rock phosphate or superphosphate. The yield components of wheat and faba bean plants increased as a result of soil inoculation with the isolated fungi. Penicillium pinophilum was the most efficient isolate. It increased the yield of wheat grains by 28.9 and 32.8% in the soil treated with rock phosphate and superphosphate, respectively. Similarly, it increased the production of faba bean seeds by 14.7 and 29.4% with the same treatments. The uptake of phosphorus by both crops significantly increased due to inoculation of the soil with the tested fungi.

Previous research demonstrated that phosphorus (P) fertilization of tall fescue (Festuca arundinacea Schreb.) pastures on acidic soils increased leaf P, magnesium (Mg), and calcium (Ca) concentrations and reduced the risk of grass tetany. It has been suggested that liming could have a similar effect by increasing soil pH and remobilizing sorbed P. To investigate this option, calcitic or dolomitic limestone was applied to stockpiled tall fescue plots on two acidic soils, a fragipan and a claypan. As expected, increasing rates of limestone were correlated with higher soil pH s. Contrary to predictions, limestone applications had very little effect on soil or plant P. However, both types of limestone at both locations altered leaf macronutrient concentrations in a manner that improved the grass tetany equivalent ratio: increased Ca and/or Mg and decreased K concentrations, thus lowered the likelihood of grass tetany in grazing beef cattle.