Greater Concentrations Of Ca Research Articles

Geothermal ecosystems on Mt. Erebus, Antarctica, support diverse and taxonomically novel biota.

Mt. Erebus, Antarctica, is the southernmost active volcano in the world and harbors diverse geothermally unique ecosystems, including 'Subglacial' and 'Exposed' features, surrounded by a vast desert of ice and snow. Previous studies, while limited in scope, have highlighted the unique and potentially endemic biota of Mt. Erebus. Here, we provide an amplicon-based biodiversity study across all domains of life and all types of geothermal features, with physicochemical and biological data from 48 samples (39 Exposed and 9 Subglacial) collected through various field seasons. We found potentially high taxonomic novelty among prokaryotes and fungi, supporting past hypotheses of high endemism due to the distinctive and isolated environment; in particular, the large number of taxonomically divergent fungal sequences was surprising. We found that different site types had unique physicochemistry and biota; Exposed sites were warmer than Subglacial (median: 40 vs 10°C for Exposed and Subglacial, respectively) and tended to have more photosynthetic organisms (Cyanobacteria and Chlorophyta). Subglacial sites had more Actinobacteriota, correlated with greater concentrations of Ca and Mg present. Our results also suggest potential human impacts on these remote, highly significant sites, finding evidence for fungal taxa normally associated with wood decay. In this study, we provide a blueprint for future work aimed at better understanding the novel biota of Mt. Erebus.

Application of biostimulants to improve tomato yield in Florida

Biostimulants are shown to increase crop production. This study was conducted to investigate the effects of individual biostimulants on tomato ('Phoenix') growth and yield. Six different biostimulants: CP₁, CP₂, BS, CP₂+BS, Competitor, and Water (control) were foliar applied at three different stages: pre-blooming, fruit setting, and color changing. The concentration of calcium (Ca), potassium (K), magnesium (Mg), and phosphorus (P) in leaves and roots were also determined. The results showed that plants treated with biostimulants had greater concentrations of Ca, K, Mg, and P compared to those treated with water only. Competitor and CP₂+BS significantly increased yield, plant height, and stem diameter by 76% and 41%, 42% and 34%, and 29% and 24%. Likewise, leaf greenness, photosynthetic rate (PN), relative water content (RWC), nitrate level in petiole sap, and fruit quality (citric acid, malic acid, tartaric acid, soluble solid concentration, and fruit firmness) were also improved by Competitor. In addition, enzymatic activities of nitrate reductase (NR) and nitrite reductase (NiR) were significantly increased by biostimulants compared to the control. Statistically, Competitor and CP₂+BS showed the greatest augmentation in plant height, stem diameter, leaf greenness, PN, RWC, nitrate level in petiole sap, and fruit yield and quality. Similarly, Competitor-treated plants also increased NR, NiR, leaf Ca, leaf K, leaf Mg, and leaf P by 34%, 70%, 22%, 26%, 27%, and 45%, respectively. Based on the findings of this study, application of Competitor or CP₂+BS showed promising results and may be used as a BMP tool for tomato production in Florida.

Determinação da folha padrão para diagnóstico nutricional do Açaizeiro

Abstract Assai palm is the main palm tree grown in the Brazilian Amazon. Nutritional diagnosis has become an essential tool in management of the crop. The aim of this study was to determine the standard leaf for nutritional diagnosis of the assai palm tree through evaluation of leaf nutrient content and use of two methods of statistical analyses: traditional (univariate) and multivariate. The study was conducted in the municipality of Belém, with eight treatments: the phyllotaxic positions of the leaves (number 2 to 9), in a completely randomized design. The leaf concentration of nutrients (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn) was determined for performing descriptive analyses, analyses of variance, correlation analysis, and principal component analysis (PCA). Young leaves had greater concentrations of N, P, K, Mg, S, Cu, and Zn, whereas in the older leaves, there were greater concentrations of Ca, B, Fe, and Mn. The leaves that exhibited less variation in nutrient concentrations were from 2 to 5. PCA analysis indicated interaction of positive loads of N-P and Cu-Mg and interaction of negative loads of Ca-Mn. The index of nutrient distribution indicated leaf number 5 as having the lowest factor loading value. Thus, leaf number 5 is most recommended for nutritional diagnosis of assai palm plants through sampling of 25 plants.

Effect of timing of prepartum vaccination relative to pen change with an acidogenic diet on lying time and metabolic profile in Holstein dairy cows

The objective was to assess the effect of prepartum vaccination timing relative to pen change with an acidogenic diet at 28 or 21 d before expected parturition (dpp) on lying time (LT), prepartum serum energy status (glucose, IGF-1, and nonesterified fatty acids), urine pH, and serum Ca at calving in pregnant Holstein dairy cows. Pregnant multiparous Holstein cows (n = 308) from 1 large dairy herd were randomly allocated into 1 of 3 treatment groups at 35 ± 3 dpp as follows: (1) vaccination at 28 dpp and pen change at 21 dpp (V28PC21; n = 108), (2) vaccination and pen change at 28 dpp (V28PC28; n = 99), and (3) vaccination and pen change at 21 dpp (V21PC21; n = 101). When cows changed pens, an acidogenic diet was introduced. Every other week, a group of 43 to 53 animals were enrolled and electronic data loggers (IceQube, IceRobotics) were fitted to the hind leg of individual cows to assess their LT. Blood samples were collected at 28, 26, 21, 19, 14 dpp and at calving. Parity, body condition score, days dry, and gestation length were not different among groups. Overall, V28PC28 cows had 7 additional days in prepartum pens consuming an acidogenic diet compared with V28PC21 or V21PC21 cows. Regardless of treatment group, cows in the far-off pen had 43 min/d less LT (709 vs. 753 min/d) and increased day-to-day coefficient of variation of LT (0.21 vs. 0.10) compared with cows within the prepartum pen. On average, for the 7 d following vaccination alone (28 to 22 dpp period), V28PC21 cows had ~22 min/d less LT compared with V21PC21 cows. Serum concentrations of glucose, nonesterified fatty acids, and IGF-1 were altered following vaccination alone, pen change alone, or vaccination plus pen change with an acidogenic diet before calving. At calving, V28PC21 cows had greater glucose concentrations (6.45 mmol/L) compared with V21PC21 cows (5.76 mmol/L), with V28PC28 cows intermediate (6.11 mmol/L). The assessment of Ca status at calving revealed that V28PC21 cows had greater Ca concentration (2.34 mmol/L) with lower subclinical hypocalcemia (<2.0 mmol/L; 17.3%) compared with V21PC21 cows (2.17 mmol/L and 31.9%), with V28PC28 cows intermediate (2.28 mmol/L and 25.2%). Serum concentrations of IGF-1 at calving were also greater for V28PC21 (3.43 nmol/L) cows compared with V21PC21 (2.69 nmol/L), with V28PC28 cows intermediate (3.07 nmol/L). Overall, V28PC21 cows had greater serum glucose, IGF-1, and ~46% reduction in subclinical hypocalcemia (from 31.9 to 17.3%) compared with V21PC21 cows but did not differ from V28PC28 cows (25.2%). These findings provided evidence that vaccinating cows at 28 dpp, followed 7 d later by pen change with an acidogenic diet at 21 dpp, would be beneficial.

Influence of Annual Plant Diversity on Forage Productivity and Nutrition, Soil Chemistry, and Soil Microbial Communities

Forage cover crops are gaining in popularity on the Canadian prairies, where multi-species crop mixtures are grown for soil and ecosystem enhancing benefits, but also harvested for forage. As the use of these forage mixtures increases, more knowledge is needed to understand the impact these mixtures have on forage production systems. The objective of this study was to determine the effects of increasing plant species diversity on forage productivity, soil chemistry, and soil microbial communities. Field trials were conducted in 2016 and 2017 at two separate locations in the Canadian Prairie region that included four treatments: (1) oat monoculture, (2) 3 spp. mixture (1 grass, 1 legume, 1 brassica), (3) 6 spp. mixture (2 grasses, 2 legumes, 2 brassicas), and (4) 9 spp. mixture (3 grasses, 3 legumes, 3 brassicas). Soil and plant samples were collected at the mid and late growing season to assess soil chemistry, plant biomass and composition, forage nutrition and quality, and soil bacterial and fungal communities. Overall, the oat monoculture had the highest biomass productivity, while the 9 spp. mixture produced the lowest biomass among the treatments. All three mixtures had a better nutritional profile (i.e., greater concentrations of Ca, Cu, Fe, total Kjeldahl nitrogen (TKN), total phosphorus (TP) and total potassium (TK), and lower concentrations of acid detergent fiber (ADF) and neutral detergent fiber (NDF)) compared to the monoculture. Differences in forage nutrition were particularly heightened at the end of the growing season. Soil chemical properties did not differ greatly among the treatments with the exception of higher levels of soil nitrate availability in the mixtures compared to the monoculture. Early indicators of a shift in soil microbial diversity and fungal community composition, and an increased abundance of fungal pathotrophs in the mixtures compared to the oat monoculture, was observed at one of the field sites. This study indicates that increasing plant species diversity does not always lead to an increase in biomass production or significant changes or improvements in soil microbial communities. However, the inclusion of multiple plant species can improve the quality and nutritive value of forages over a monoculture forage crop.

Feeding supplemental 25-hydroxyvitamin D3 increases serum mineral concentrations and alters mammary immunity of lactating dairy cows

Objectives were to determine the effects of feeding supplemental 25-hydroxyvitamin D3 [25(OH)D3] on concentrations of vitamin D metabolites and minerals in serum, mammary immune status, and responses to intramammary bacterial infection in dairy cows. Sixty multiparous, pregnant lactating Holstein cows with somatic cell count <200,000/mL were blocked by days in milk and milk yield and randomly assigned to receive a daily top-dressed dietary supplement containing 1 or 3 mg of vitamin D3 (1mgD or 3mgD), or 1 or 3 mg 25(OH)D3 (1mg25D or 3mg25D) for 28 d (n = 15/treatment). Cows were kept in a freestall barn and fed a total mixed ration in individual feeding gates. Individual dry matter intake (DMI) and milk yield were recorded daily, and milk and blood samples were collected at 0, 7, 14, and 21 d relative to the start of treatment. At 21 d, cows fed 1mgD and 3mg25D received an intramammary challenge with Streptococcus uberis. Cows were observed for severity of mastitis, and blood and milk samples were collected every 12 h to measure inflammation. The 1mg25D and 3mg25D cows had greater serum 25(OH)D3 concentrations at 21 d compared with 1mgD and 3mgD cows (62 ± 7, 66 ± 8, 135 ± 15, and 232 ± 26 ng/mL for 1mgD, 3mgD, 1mg25D, and 3mg25D, respectively). The 3mg25D cows had greater concentrations of Ca and P in serum at 21 d compared with other treatments (Ca = 2.38, 2.4, 2.37, and 2.48 ± 0.02 mM, 1.87, 1.88, and 2.10 ± 0.08 mM for 1mgD, 3mgD, 1mg25D, and 3mg25D, respectively). Yields of milk and milk components, DMI, body weight, and concentrations of 1,25-dihydroxyvitamin D and Mg in serum did not differ among treatments. Abundance of mRNA transcripts for interleukin-1β (IL1B) and inducible nitric oxide synthase (iNOS) in milk somatic cells before S. uberis challenge were increased in cows fed 25(OH)D3 compared with cows fed vitamin D3. Furthermore, IL1B, iNOS, β-defensin 7, and β-defensin 10 in milk somatic cells increased as concentrations of 25(OH)D3 increased in serum. Cows fed 3mg25D had less severe mastitis at 60 and 72 h after challenge with S. uberis compared with cows fed 1mgD. Concentrations of bacteria, somatic cells, and serum albumin in milk after challenge did not differ between treatments; however, an interaction between treatment and day was detected for lactate dehydrogenase in milk. Expression of adhesion protein CD11b on milk neutrophils after the S. uberis challenge was greater among 3mg25D cows compared with 1mgD cows. Transcripts of CYP24A1 and iNOS in milk somatic cells during mastitis also were greater in 3mg25D cows compared with 1mgD cows. Feeding 25(OH)D3 increased serum 25(OH)D3 more effectively than supplemental vitamin D3, resulting in increased serum mineral concentrations, increased expression of vitamin D-responsive genes, and altered immune responses to intramammary bacterial challenge.

Different sources of calcium for starter pig diets

Abstract The study was conducted to determine the true Ca absorption coefficients and growth performance of piglets fed diets containing different sources of Ca. In the metabolism study, 30 piglets uncastrated, with initial weight averages of 20.52 ± 1.84 kg, were assigned to 5 treatments with 6 piglets per treatment in a randomized complete block design. A basal diet was formulated to meet the piglets nutritional requirements, except to Ca (0.09%), and was supplemented with different source of Ca (limestone, monodicalcium phosphate, calcined bone meal, and oyster meal) to provide 0.64% total Ca. A low-Ca diet (0.018%) and 6 additional piglets were used to estimate the endogenous Ca excretion in the feces. Total feces and urine were collected to determine the apparent and true absorption of Ca. After the adaptation period (7 d), the excreted feces were collected twice daily, weighed, stored in plastic bags in freezer (−18 °C) until the end of the collection period (5 d). The volume of the urine collected for 24 h was measured and a 20% aliquot was stored in glass containers in refrigerator (3 °C) until the end of the collection period (5 d). Experimental diets, feces and urine were analyzed for Ca. To determine the effect of different Ca sources on the growth performance, 160 piglets were assigned, to 2 sexes (males intact and females) and 4 sources of Ca (the same ones used in the metabolism study), in a 2 × 4 factorial arrangement and randomized complete block design with 4 pens per treatment and 5 intact males or 5 females per pen. At the end of the study (22 d), blood samples were collected of the all piglets and 5 piglets per treatment were selected randomly regardless of sex to collect samples of organs. All samples were stored at −18 °C. Response criteria were: weight gain, feed intake, feed efficiency, Ca deposition in organs, bone strength, weight and size of the third metatarsal bone, and serum in Ca. The sources of Ca and direct or indirect collection method did not affect the absorption coefficients. There was no interaction among the sources of Ca and sex of the piglets for the performance variables. The piglets growth performance was similar among treatments. Calcined bone meal and oyster meal resulted in a greater content of mineral matter in the kidney (P = 0.013). The bone meal resulted in a greater Ca concentration in the piglets hearts (P

Field trial of 2 calcium supplements on early lactation health and production in multiparous Holstein cows

Our objectives were to measure serum Ca concentrations in the first 48 h postpartum in cows supplemented with oral Ca or subcutaneous Ca and nonsupplemented cows and evaluate the effect of these treatments on the incidence of metritis, displaced abomasum, mastitis, and early lactation disease (any of the diseases milk fever, retained placenta, metritis, or displaced abomasum), removal from the herd, pregnancy to first insemination, and average daily milk yield for the first 10 wk of lactation. We conducted 2 experiments on 1 commercial herd in New York State. In experiment 1, multiparous Holstein cows (n = 30) were blocked by parity (2 and ≥3) and sequentially assigned at calving to nontreated control (CON, n = 10), subcutaneous administration of 500 mL 23% Ca gluconate at calving (SC, n = 10), or administration of an oral Ca bolus containing 43 g of calcium at calving and again 12 h later (OB, n = 10). Blood was collected before treatment and at 1, 2, 4, 8, 12, 24, and 48 h thereafter for measurement of serum total Ca concentration. In experiment 2, 1,478 multiparous Holstein cows were sequentially assigned by calving date to the same 3 treatments (CON, n = 523; SC, n = 480; OB, n = 475). In experiment 1, SC cows had greater Ca concentrations from 1 through 12 h post-treatment and OB cows had greater Ca concentrations at 1 and 24 h post-treatment compared with CON cows. We found no difference in risk of metritis, displaced abomasum, early lactation disease diagnosis, or pregnancy to first insemination among treatments. Treatment with SC or OB had no effect on average daily milk yield compared with CON cows (CON = 46.7 kg; SC = 47.1 kg; OB = 47.0 kg). Cows treated with SC or OB that had a high relative herd milk rank in the previous lactation were almost half as likely to be diagnosed with mastitis in the first 60 DIM compared with CON cows [risk ratio (RR)SC = 0.57, RROB = 0.54]; however, we found no difference in risk of mastitis among treatments for cows with low relative herd milk rank. Second-parity cows fed a negative prepartum dietary cation-anion difference ration and treated with SC or OB were more likely to be removed from the herd than CON cows (RRSC = 3.91, RROB = 4.72); this difference was not observed in second-parity cows fed a neutral prepartum dietary cation-anion difference ration or in parity ≥3 cows. Although Ca supplementation increased serum Ca, this effect did not greatly improve milk production or health and reproductive outcomes.

METEOROLOGICAL FACTORS AND CALCIUM CONCENTRATION ON BROWNING OF A ‘FUYU’ PERSIMMON FRUIT

Calyx-end browning in ‘Fuyu’ persimmon (Diospyros kaki Thumb.) fruits was investigated to learn how meteorological factors and calcium (Ca) concentrations in soil, fruiting shoot, and fruit were related to the symptom occurrences, how longitudinal sections in fruits and fruiting height contribute nutrient partitioning of fruits, and how Ca soaking into fruits affects the cell structure in the flesh. Low humidity with extended radiation reduced fruit browning. Fruiting shoots without browning fruits had greater Ca and lower potassium (K) concentrations than the shoots with browning fruits. Proximal flesh had a greater Ca concentration than middle and distal end parts in calyx-end browning fruits that had lower ratios of Ca:K, Ca:magnesium (Mg), and Ca:K+Mg. Nutrient concentrations were similar to the fruiting height within a canopy, except for manganese, and boron. Calcium dipping into fruit under a vacuum increased Ca concentration in flesh and core parts, which had apparent cell wall strength.

Soil Inorganic Phosphorus Fractionation and Availability under Greenhouse Subsurface Irrigation

Inorganic phosphorus (P) fractions and their availability under subsurface irrigation were investigated in a greenhouse planted for 5 years with tomato. Irrigation was applied when soil water conditions reached the predefined maximum allowable depletion (MAD) for different treatments, e.g., −10 kPa, −16 kPa, −25 kPa, −40 kPa, and −63 kPa. Concentrations of five inorganic P fractions, which include of soluble / loosely bound P, aluminum (Al) P, iron (Fe) P, calcium (Ca) P, and occluded P, were obtained by following a sequential chemical fractionation procedure. Results showed that the effect of subsurface irrigation and schedules on inorganic P fractions was more pronounced in topsoil layers than in deep soils. The concentrations of soluble / loosely bound P, Al P, and Fe P generally decreased with soil depth, having the largest values at the depths of 0–10 cm and 10–20 cm. In all the irrigation treatments, Al P and Fe P were the dominant fractions at the depths of 0–10 cm, 10–20 cm, and 20–30 cm, whereas Ca P and occluded P were most predominant at the depths of 30–40 cm and 40–60 cm. Soluble or loosely bound P, Al P, and Fe P were the main sources contributing to plant-available P, whereas Fe P and Al P were the two most important sources for contribution to plant-available P. Frequent irrigation with small amounts of water (e.g., irrigation with MAD of −16 kPa and −25 kPa) yielded larger concentrations of soluble / loosely bound P, Al P, and Fe P, which are the main sources of plant-available P. However, infrequent irrigation with larger amounts of water in each irrigation event led to greater concentrations of Ca P and occluded P, which are relatively less available to plants.

Alfalfa Responses to Combined Use of Lime and Limiting Nutrients on an Acidic Soil

An on-farm field experiment was conducted on an acidic soil to investigate the effects of combined use of lime and deficient nutrients on herbage yield of alfalfa (Medicago sativa L.). Omitting lime and limiting nutrients led to elevated concentrations of aluminium (Al), iron (Fe), and manganese (Mn) in alfalfa leaves and stems and caused severe reductions in herbage yield of alfalfa. Combined use of lime (2 t ha−1) and nutrients [phosphorus (P): 20 kg ha−1, sulfur (S): 20 kg ha−1, zinc (Zn): 4 kg ha−1, and boron (B): 2 kg ha−1] had the maximum increase in groundcover, root biomass, nodulation, leaf retention, leaf-to-stem ratio, herbage yield, crude protein, and nutrient composition of alfalfa. These beneficial effects were due to raised soil pH; improved calcium (Ca), P, S, Zn, and B nutrition; and reduced Al, Mn, and Fe toxicity. Aluminium and all the nutrients except copper (Cu) were more concentrated in alfalfa leaves than stems. Aluminum concentration was about three times greater in the lower leaves than in upper leaves. Lower leaves also had much greater concentrations of Ca, Mg, K, S, Fe, Mn, Cu, and B compared with upper leaves. In contrast, P and Zn concentrations were greater in the upper leaves than in lower leaves. Results suggest that the combined use of lime and all the limiting nutrients may realize potential beneficial effects of alfalfa on acidic soils where more than one essential nutrient is deficient. This may increase growth potential, nitrogen contributions, and groundcover by alfalfa and reduce soil erosion and runoff.

Use of Fura 2 Fluorescent Dyes as Indicator for Studying Calcium Distribution in Several Plant Tissues

Calcium (Ca) is an essential plant nutrient and is important in determining quality of fruits in storage. The analytical method presently known to determine Ca concentration in vegetables measures total Ca, and there is a need to develop methods that can determine the distribution of Ca within vegetable tissues. The objective of this study was to determine the ability of fluorescent probes to visualize Ca location and distribution in vegetable tissues. We examined three protocols using fluorescent dyes developed to detect Ca. The first tested Fura 2 acetoximetil (AM) probe in fresh cuts from grapes at different combinations of temperatures and incubation times. The second protocol was developed with the aim of lowering the natural autofluorescense. In the third protocol, the Fura 2 probe was used in tissues previously fixed in formalin, acetic acid, and alcohol solution (FAA). Tissues were observed under an epifluorescence microscope and, to compare and complement the observations, under a scanning electron microscope (SEM). No sign of fluorescence was observed in fixed and fresh tissue using the Fura 2 AM. In fresh cuts, there was autofluorescent interference, provoked mainly by chlorophyll, but also from the vascular system and tannins. The Fura 2 probe was introduced to vegetable tissues by utilizing a pH of 4.5, and a more intense signal was observed in tissues with greater Ca concentration. This signal was also associated with Ca crystals, which might have had some degree of hydrolysis at low pH. Under a SEM microscope, Ca oxalate crystals were clearly observed in those tissues. Our results show that Fura 2 probe can be used to detect Ca and its distribution in vegetable tissues.

Learned appetites for calcium, phosphorus, and sodium in sheep1,2

If supplemental minerals are needed to promote optimal animal performance, what is the best way of providing them: free choice or in the diet? We hypothesized that herbivores discriminate among feeds containing Na, P, and Ca and modify their choices as a function of need. One group of lambs was fed a basal diet low in P and high in Ca (low P-high Ca), whereas another group was fed a basal diet high in P and low in Ca (high P-low Ca). After 73 d of exposure to the unbalanced diets, the lambs were conditioned by offering flavored grape pomace containing NaCl, CaCO(3), or NaH(2)PO(4). Preference for pomace + minerals was determined when all lambs were fed a basal diet of alfalfa pellets and barley grain (initial preference) and during 4 phases. Phases 1 and 2 occurred after 40 and 67 d of feeding the unbalanced basal diets, phase 3 occurred after conditioning with NaCl, CaCO(3), or NaH(2)PO(4), and phase 4 occurred 22 d after the groups were moved to 2 new (separate) locations so the animals in the different groups could not eat dirt, urine, or feces from the other pen. Preference for pomace did not differ between the groups during the initial preference tests (P = 0.62); both groups preferred NaCl > CaCO(3) = NaH(2)PO(4) (P < 0.001). As the study progressed, and lambs fed low P-high Ca had lower P and greater Ca concentrations in serum than lambs fed high P-low Ca (P < 0.001), the preference between groups diverged. In phase 2, lambs in high P-low Ca continued to prefer NaCl (P < 0.001), but lambs in low P-high Ca preferred NaH(2)PO(4) (P < 0.05). After conditioning, both groups preferred NaCl = NaH(2)PO(4) > CaCO(3) (P < 0.01 to 0.11). After the groups were moved to different locations, lambs fed low P-high Ca showed the lowest concentration (3.7 mg/dL) of inorganic P in serum for all phases (P < 0.001), and they preferred NaH(2)PO(4) > NaCl = CaCO(3) (P < 0.001). In contrast, lambs in high P-low Ca avoided NaH(2)PO(4) (P < 0.05). Lambs offered high P-low Ca showed a greater preference for CaCO(3) (P = 0.12) and NaCl (P < 0.05) and a lower preference for NaH(2)PO(4) compared with lambs fed low P-high Ca (P < 0.001). In summary, lambs discriminated among different flavored feeds containing NaCl, CaCO(3), and NaH(2)PO(4) and displayed preferences as a function of the mineral imbalance in their basal diets. Thus, it may be possible to feed Ca and P supplements free choice, such that individual animals within a group can manifest preferences based on their specific needs.

Evaluation of Populus and Salix Continuously Irrigated with Landfill Leachate I. Genotype-Specific Elemental Phytoremediation

There is a need for the identification and selection of specific tree genotypes that can sequester elements from contaminated soils, with elevated rates of uptake. We irrigated Populus (DN17, DN182, DN34, NM2, NM6) and Salix (94003, 94012, S287, S566, SX61) genotypes planted in large soil-filled containers with landfill leachate or municipal water and tested for differences in inorganic element concentrations (P, K, Ca, Mg, S, Zn, B, Mn, Fe, Cu, Al, Na, and Cl) in the leaves, stems, and roots. Trees were irrigated with leachate or water during the final 12 wk of the 18-wk study. Genotype-specific uptake existed. For genera, tissue concentrations exhibited four responses. First, Populus had the greatest uptake of P, K, S, Cu, and Cl. Second, Salix exhibited the greatest uptake of Zn, B, Fe, and Al. Third, Salix had greater concentrations of Ca and Mg in leaves, while Populus had greater concentrations in stems and roots. Fourth, Populus had greater concentrations of Mn and Na in leaves and stems, while Salix had greater concentrations in roots. Populus deltoides × P. nigra clones exhibited better overall phytoremediation than the P. nigra × P. maximowiczii genotypes tested. Phytoremediation for S. purpurea clones 94003 and 94012 was generally less than for other Salix genotypes. Overall, concentrations of elements in the leaves, stems, and roots corroborated those in the plant–sciences literature. Uptake was dependent upon the specific genotype for most elements. Our results corroborated the need for further testing and selecting of specific clones for various phytoremediation needs, while providing a baseline for future researchers developing additional studies and resource managers conducting on-site remediation.

Nutritive Value of Desmanthus Associated With Kleingrass During the Establishment Year

Seasonal variation in production and quality of warm-season grasses is a limitation for livestock productivity. The use of high quality forage legumes to aid in overcoming this problem can be a management alternative. The objective of this study was to evaluate the nutrient content of kleingrass (Panicum coloratum L.)–bundleflower (Desmanthus sp.) mixtures during the establishment year. Plots were drilled at a 0.15 m row-spacing with kleingrass sown either alone or in association with Illinois bundleflower (Desmanthus illinoensis [Michx.] MacM.) or desmanthus (Desmanthus pubescens [L.] Willd), which was previously identified as Desmanthus virgatus. Spacings of 0.30, 0.60, and 0.90 m between rows of bundleflower were used. Plots were planted in April and nutritive value was determined on samples harvested at 60, 90, and 120 days after planting. Age reduced kleingrass crude protein (CP) and increased fiber concentration. The CP concentration of desmanthus leaves was greater than that of Illinois bundleflower; however, the CP on a whole-plant basis was greater in Illinois bundleflower. Associations had greater CP yield than did the kleingrass monoculture. The tannin content was higher in desmanthus than in Illinois bundleflower. In both legumes the leaves had the greatest tannin concentrations, with a mean of 2.1% and 1.69% in desmanthus and Illinois bundleflower, respectively. With the exception of calcium (Ca), mineral content declined with increased age in both legumes and the grass. Levels of potassium, sodium, copper, and manganese were greater in kleingrass than in the legumes, while the legumes had greater concentrations of Ca and magnesium (Mg). Phosphorus and zinc concentrations were similar for kleingrass and legumes. The legumes did not affect the nutrient content of kleingrass when established in association, and the high CP of both legumes and their high levels of Ca and Mg suggest that animals grazing kleingrass-desmanthus associations may benefit nutritionally.

Mineral Composition of Medicago minima and Erodium cicutarium Under Various Water Regimes

Medicago minima and Erodium cicutarium are two annual, naturalized species in semi-arid, temperate rangelands of central Argentina. A field study was conducted to determine the effects of different levels of soil water availability on concentrations and partitioning of sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) in various organs in these species. Aboveground plant parts and roots showed lower or similar, but not higher, Na concentrations under water stress than under irrigated conditions in both species and years. Concentrations of K, Ca, and Mg of aboveground plant parts and roots in both years for E. cicutarium and of Ca in 1989 for M. minima were greater under water stress than under irrigated conditions. Aboveground plant parts of both species had in general a lower Na and a greater K concentration than roots. Leaves and roots had similar Mg concentrations in M. minima. However, concentrations of this nutrient were greater or similar in roots than in leaves in E. cicutarium, and those of Ca were greater in leaves than roots in both species. Leaves and/or stems had greater Ca concentrations than fruits in both species and years under all water levels. The lowest concentrations of Na, Ca, K, and Mg among plant parts in both species were generally found in flowers. Aboveground plant parts of M. minima and E. cicutarium exceeded the Na, K, Ca, and Mg concentrations recommended for a balanced beef cattle diet under all water levels. Both species contained more Na, K, Ca, and Mg in shoots (all aboveground organs) than in roots in both years. Differences between species in the proportional allocation of whole plant Na, K, Ca, and Mg to the various aboveground and belowground organs under water stress, rainfed, and irrigated conditions are discussed.

Nutritive Value of Desmanthus Associated With Kleingrass During the Establishment Year

Seasonal variation in production and quality of warm-season grasses is a limitation for livestock productivity. The use of high quality forage legumes to aid in overcoming this problem can be a management alternative. The objective of this study was to evaluate the nutrient content of kleingrass (Panicum coloratum L.)-bundleflower (Desmanthus sp.) mixtures during the establishment year. Plots were drilled at a 0.15 m row-spacing with kleingrass sown either alone or in association with Illinois bundleflower (Desmanthus illinoensis [Michx.] MacM.) or desmanthus (Desmanthus pubescens [L.] Willd), which was previously identified as Desmanthus virgatus. Spacings of 0.30, 0.60, and 0.90 m between rows of bundleflower were used. Plots were planted in April and nutritive value was determined on samples harvested at 60, 90, and 120 days after planting. Age reduced kleingrass crude protein (CP) and increased fiber concentration. The CP concentration of desmanthus leaves was greater than that of Illinois bundleflower; however, the CP on a whole-plant basis was greater in Illinois bundleflower. Associations had greater CP yield than did the kleingrass monoculture. The tannin content was higher in desmanthus than in Illinois bundleflower. In both legumes the leaves had the greatest tannin concentrations, with a mean of 2.1% and 1.69% in desmanthus and Illinois bundleflower, respectively. With the exception of calcium (Ca), mineral content declined with increased age in both legumes and the grass. Levels of potassium, sodium, copper, and manganese were greater in kleingrass than in the legumes, while the legumes had greater concentrations of Ca and magnesium (Mg). Phosphorus and zinc concentrations were similar for kleingrass and legumes. The legumes did not affect the nutrient content of kleingrass when established in association, and the high CP of both legumes and their high levels of Ca and Mg suggest that animals grazing kleingrass-desmanthus associations may benefit nutritionally.

Variation in Nickel Content in the Nickel‐Hyperaccumulating Shrub Psychotria douarrei (Rubiaceae) from New Caledonia1

ABSTRACTPlants that hyperaccumulate Ni contain &gt; 1000 ppm (dry wt.) in their tissues. Variation of Ni content within hyperaccumulating plant species is poorly explored. Using the Ni‐hyperaccumulating shrub Psychotria douarrei, we documented variation of leaf Ni levels within individual shrubs, and variation with respect to plant size and leaf age. Plant size did not correlate significantly with leaf Ni content, and leaf Ni content did not correlate significantly with soil Ni content. Older leaves contained twice as much Ni as younger leaves. Older leaves also contained greater concentrations of Ca, Fe, and Cr but less K, P, and Cu. Five elements (Zn, Pb, Co, Mn, Mg) showed no significant variation due to leaf age. We also examined the effect of leaf age on epiphyll cover, finding increased epiphyll cover on the upper surface of older leaves. The dominant leafy liverwort epiphyll had a relatively high Ni content (400 ppm), suggesting that epiphylls of Ni hyperaccumulators obtain some Ni from host leaves. Individual shrubs differed in mean leaf Ni content almost two‐fold (14,900‐27,700 ppm). Variation among branches within individuals also ranged widely; however, this intraplant variability was not strongly correlated with the mean leaf Ni content of an individual shrub. We concluded that Ni contents in leaves of P. douarrei vary considerably due to leaf age, among individual shrubs, and among branches within a shrub.

Harvesting Effects on Long‐Term Changes in Nutrient Pools of Mixed Oak Forest

AbstractThe effects of sawlog harvesting (SAW) vs. whole‐tree harvesting (WTH) on C and nutrient budgets of a mixed oak forest near Oak Ridge, TN, were assessed by sampling soils and vegetation just prior to and 15 yr after harvesting. Fifteen years after harvest, large woody residues in the SAW treatment lost &gt;80% of their mass and nutrient content. Greater concentrations of Ca, K, and Mg were found in both foliage and soils in the SAW treatment than in the WTH treatment, but there were no signs of deficiency in these nutrients and no differences in growth due to treatment. There were nod eclines in exchangeable Ca2+ in the WTH treatment, and the increases in soil exchangeable Ca2+ pools in the SAW watersheds were approximately equal to the amount of Ca2+ released by decomposing residues. On the other hand, no treatment effects on soil C, vegetation biomass, species composition, vegetation N or P concentration, soil bulk density, or soil N were found 15 yr after treatment. Contrary to what has been speculated on regarding the basis of nutrient budgets, this study showed no detrimental effects of WTH on productivity or soil nutrient status (i.e., reductions from preharvest conditions). The results did show, however, that nutrients (especially Ca) from logging residues are largely retained in soils and reflected in elevated foliar nutrient concentrations.

Mineral Dynamics in Forages of the Northern Great Plains

Mineral concentrations of range grasses are often below that required by grazing livestock. Limited information is available on forage mineral concentrations for the Northern Great Plains and there is little data on factors influencing concentrations of forage minerals throughout the year. Therefore, a study was conducted to evaluate special and temporal variations in mineral concentrations of major forage species in the Northern Great Plains. Herbage was sampled from 4 replicates on each of 2 soils in July, August, and September 1991, April, June, July, August, and September 1992, and April 1993. Herbage was sorted by species grouping and by live and dead tissue classes. Analyses on herbage included Ca, P, Mg, K, Na, Zn, Cu, Mn, and Mo. For western wheatgrass [Pascopyrum smithii (Rydb.) Love] and annual bromes [Bromus spp.], Zn and all macrominerals except Na were greater in live than in dead tissue. Live tissues of all other species groupings contained greater amounts of P and K than did dead tissue. Live tissue Mg concentrations were greater than dead tissue concentrations for other cool-season and warm season grasses. Manganese concentrations were greater in live than dead annual brome tissues, while Cu was greater in dear than live tissue. Dead sedge tissue contained greater concentrations of Ca than live tissue. Soil type affected several nutrient but this was partially related to soil effects upon composition of species groupings and live:dead ratios. Minerals most likely to be found in quantities less than required for animal production were P, Na, K, Zn, and Cu.