Seasonal changes in chemical composition of heavily fertilized Kikuyu pasture and their potential effects on the mineral nutrition of grazing cattle

1979 ◽  
Vol 19 (97) ◽  
pp. 183 ◽  
Author(s):  
AS Awad ◽  
DG Edwards ◽  
DO Huett
Keyword(s):  
Nitrogen Concentration ◽  
Nutrient Content ◽  
Early Summer ◽  
Phosphorus Concentration ◽  
Late Winter ◽  
Grazing Cattle ◽  
Nitrogen Concentrations ◽  
One Year ◽  
High Level ◽  
Phosphorus Application

was sampled at two week intervals over a period of one year. The concentrations of calcium throughout the year (0.15-0.28%) and phosphorus from late winter to early summer (0.20-0.28%) were well below the values normally considered to be required by milking cows and some classes of beef cattle. The nitrogen concentrations reached minimal values of 1.8-2.2% in winter, which appear to be adequate for milk production. From summer through to the end of winter, the ratio of K/(Ca + Mg) was much higher, and the Ca/P ratio was much lower, than those values reported to be associated with the occurrence of grass tetany in grazing cattle. Very high nitrogen concentratians in early summer (up to 5.2% N where 672 kg N ha-1 year-1 was applied) were in the range that has been associated with grass tetany in cattle. Lime application increased the nitrogen, phosphorus and calcium concentrations in the herbage throughout the year. The effect of lime in increasing nitrogen concentration in the herbage was maximal in late autumn and winter, at which time fertilizer nitrogen had little or no effect. The increased nitrogen concentration in the herbage through application of lime was associated with the development of a naturalized white clover component in the sward. Lime also increased the phosphorus concentration in the herbage, particularly from mid-winter to early summer, over which period phosphorus application per se had minimal effect. The application of lime allied with 134 kg N ha-1 year-1 maintained a high level of dry matter production as well as a more adequate and better balanced nutrient content in the kikuyu pasture throughout the year, and particularly in winter, when cattle grazing kikuyu pastures suffer a serious feed gap.

scholarly journals Mehlich 3 extractant used for the evaluation of wheat-available phosphorus and zinc in calcareous soils

2018 ◽  
Vol 64 (No. 2) ◽  
pp. 53-57 ◽  
Author(s):  
Sedlář Ondřej ◽  
Balík Jiří ◽  
Kulhánek Martin ◽  
Černý Jindřich ◽  
Kos Milan
Keyword(s):  
Stem Elongation ◽  
Phosphorus Deficiency ◽  
Calcareous Soils ◽  
Phosphorus Nutrition ◽  
Shoot Biomass ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Nitrogen Concentrations ◽  
One Year ◽  
Index Ratio

Relation between wheat (Triticum aestivum) nutritional status determined at the beginning of stem elongation and during anthesis, respectively, and available content of phosphorus (P-M3) and zinc (Zn-M3) determined by the Mehlich 3 extractant was studied. Both one-year pot experiment with spring wheat and two-year on-farm trials with winter wheat were run on various calcareous soils (pH values of 7.18–7.94, median 7.80, P-M3 1–289 ppm, median 54, and Zn-M3 2–14 ppm, median 4), in the Czech Republic (Central Europe). Phosphorus nutrition index (ratio of phosphorus concentration in shoot biomass to critical phosphorus concentration – P<sub>c</sub>) was calculated using the Belanger et al.’s model: P<sub>c</sub> = –0.677 + 0.221N – 0.00292N(2), where both phosphorus and nitrogen concentrations were expressed in g/kg shoot dry matter. Unlike phosphorus concentration in shoot biomass, phosphorus nutrition index significantly correlated with P-M3 content in soil. Optimal values of the phosphorus nutrition index were recorded if P-M3 was 51–68 ppm. Zinc concentration in shoot biomass more strongly correlated with P:Zn ratio (M3) in soil compared to Zn-M3 content in soil. P:Zn ratio in shoot biomass of 130:1 did not lead to phosphorus deficiency and corresponded to P:Zn (M3) ratio in soil of 9.3:1–14.3:1.

Decomposition of aspen, spruce, and pine boles on two sites in Minnesota

1993 ◽  
Vol 23 (9) ◽  
pp. 1744-1749 ◽  
Author(s):  
David H. Alban ◽  
John Pastor
Keyword(s):  
Nutrient Content ◽  
Magnesium Content ◽  
Jack Pine ◽  
Red Pine ◽  
Phosphorus Concentration ◽  
Quaking Aspen ◽  
Nitrogen And Phosphorus ◽  
Nutrient Contents ◽  
Decomposition Constant ◽  
Nitrogen Concentrations

Boles of quaking aspen (Populustremuloides Michx.), white spruce (Piceaglauca (Moench) Voss), red pine (Pinusresinosa Ait.), and jack pine (Pinusbanksiana Lamb.) were sampled after decomposing for 11–17 years. Mass loss and changes in chemical composition were determined. Density decreased by 40–73%, and the decomposition constant (k) decreased in the order aspen > spruce > red pine > jack pine. Although the decomposition rate was strongly species dependent, it did not differ between the two sites. The decomposition constant was weakly related to lignin and phosphorus concentration in the original stems (r2 = 0.44 and 0.49, respectively) and not significantly related to original nitrogen concentrations. Nutrient concentration increased during decomposition, particularly for nitrogen and phosphorus. Nitrogen content increased during decomposition, and potassium content decreased. Calcium and magnesium content changed little during decomposition, whereas phosphorus content increased or decreased, depending on species. In general, species with the lowest initial nutrient contents had the greatest nutrient increases during decomposition. Nutrient content of boles of all species became similar during decomposition.

Effects of variation in density and phosphate application on growth and composition of Townsville stylo (Stylosanthes humilis)

1970 ◽  
Vol 10 (45) ◽  
pp. 442 ◽  
Author(s):  
KG Rickert ◽  
LR Humphreys
Keyword(s):  
Nitrogen Concentration ◽  
Phosphorus Concentration ◽  
Dihydrogen Phosphate ◽  
Positive Density ◽  
Nitrogen And Phosphorus ◽  
Area Index ◽  
Stylosanthes Humilis ◽  
Plant Densities ◽  
Townsville Stylo ◽  
Phosphorus Application

Townsville stylo (Stylosanthes humilis) was grown at Brisbane from February to June 1967 at initial densities of 10, 50, 250, 1250, and 6250 plants per m2 in boxes of sand which received basal nutrients and applications of 0, 10, and 50 kg P per hectare as calcium dihydrogen phosphate. Plots were irrigated frequently. Wide differences in dry matter yield between plant densities and a positive density phosphorus yield interaction persisted throughout the experiment. Peak yield was 1050 g per m2 with leaf area index (LAI) of 6.8. Intraspecific plant competition was evident in high densities 35 days after emergence, extending to the lower densities by 58 days. Plant mortality at the highest density was independent of phosphorus treatment. Maximum growth rates were reached earlier at high than at low plant densities ; the subsequent decreases in growth rate were expressed through drifts in both LA1 and NAR and were associated with progressively more unfavourable environmental conditions for growth. Nitrogen and phosphorus concentration of both shoots and roots decreased with increasing density. Phosphorus application did not affect nitrogen concentration. Exploitation of native soil phosphorus and recovery of applied phosphorus was greatest in high density swards. The data illustrate the loss in potential production which may occur in sparse swards of Townsville stylo and the limitations to efficient phosphorus response inherent in low density swards.

Effects of phosphorus and superphosphate on the growth of Urochloa species

1984 ◽  
Vol 24 (127) ◽  
pp. 571 ◽  
Author(s):  
JG McIvor
Keyword(s):  
Field Trial ◽  
Nitrogen Concentration ◽  
Phosphorus Concentration ◽  
Stylosanthes Hamata ◽  
Phosphorus Requirements ◽  
Phosphorus Application

Six Urochloa accessions (U. mosambicensis cv. Nixon, CPI 46876, CPI 47167; U. oligotricha CPI 45607, CPI 47122, CPI 47 124) were grown in pots of phosphorus-deficient soil with varying rates of added phosphorus and their phosphorus requirements and responses compared. The same six accessions were grown in swards at Lansdown near Townsville with Stylosanthes hamata cv. Verano and S. scabra cv. Seca and their responses to superphosphate measured over a five-year period. All accessions gave large responses, both to phosphorus in pots and superphosphate in the field, with only small differences between accessions in their phosphorus requirements. Phosphorus application increased phosphorus concentration in the tops, from 0.11 to 0.17% without phosphorus, to 0.56-0.70% at 200 kg P/ha, but had little effect on nitrogen concentration. In the final year of the field trial, superphosphate did not significantly affect yield of the sown legume but yields of Urochloa were significantly increased by superphosphate application. This resulted in the nil superphosphate plots being legume dominant (mainly S. hamata) and the high superphosphate plots being Urochloa dominant.

Effects of Supplementary Soil Nutrients on Hummock Grasses

1994 ◽  
Vol 42 (6) ◽  
pp. 687 ◽  
Author(s):  
BL Rice ◽  
M Westoby ◽  
GF Griffin ◽  
MH Friedel
Keyword(s):  
Soil Nutrients ◽  
Total Phosphorus ◽  
Soil Phosphorus ◽  
Nitrogen Concentration ◽  
Nutrient Content ◽  
Separate Experiment ◽  
Phosphorus Concentration ◽  
Absolute Amount ◽  
Available Soil Phosphorus ◽  
Fertiliser Application

Hummocks of Triodia basedowii E. Pritz, T. pungens R.Br. and Plectrachne schinzii Henr. were treated with ash and with standard and high applications of slow-release fertiliser. Following rain and the ensuing growth and flowering, the soils and the hummocks were sampled for biomass and for nutrient content, and compared to controls. In a similar but separate experiment, seed set in inflorescences was assessed for hummocks treated with standard fertiliser application, for hummocks treated by removal of neighbouring hummocks, and for controls. In the absence of nutrient addition, total topsoil nitrogen concentration was higher under hummocks than outside, whereas total topsoil phosphorus concentration was lower under hummocks than outside. The absolute amount of phosphorus in the hummock itself was insufficient to account for the depletion of phosphorus in topsoil under the hummock. Available soil phosphorus was about 1-4% of total phosphorus, and was generally highest towards the edge of hummocks. Additions of ash did not significantly affect soil nutrients, while addition of fertiliser produced substantial increases in total nitrogen and in available and total phosphorus. The increases did not extend to the area surrounding the hummock. The increases in soil nutrients did not result in significant increases in new green growth, or in inflorescence biomass or number. However, nutrients appear to have been taken up into the plants, including into old tissue, because there were increases in nutrient concentration in plant tissues, which sometimes were statistically significant and sometimes not. In the second experiment, neither increased soil nutrients nor removal of neighbours increased the number of inflorescences produced, or the proportion of florets that gave rise to filled grain.

scholarly journals Size compositions and reproductive biology of an important bycatch shark species (Heterodontus portusjacksoni) in south-western Australian waters

2008 ◽  
Vol 88 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Ashlee A. Jones ◽  
Norman G. Hall ◽  
Ian C. Potter
Keyword(s):  
Deviance Information Criterion ◽  
Information Criterion ◽  
Early Summer ◽  
Late Winter ◽  
Shark Species ◽  
Total Length ◽  
One Year ◽  
Longline Fisheries ◽  
Marine Embayment ◽  
Western Australian

Heterodontus portusjacksoniwas obtained from the catches of commercial trawl, gillnet and longline fisheries operating in south-western Australian waters, in which this shark is an abundant bycatch species. Ninety per cent of theH. portusjacksonicaught by commercial trawling in a marine embayment were <400 mm in total length, whereas 99 and 100%, respectively, of the individuals taken by commercial gillnet and longline outside that embayment were >400 mm. Although the differences between the size compositions in the catches obtained by trawling vs both gillnetting and longlining, which were similar, are partly attributable to gear selectivity, they also reflect a use by juvenileH. portusjacksoniof protected nearshore waters as nursery areas and a tendency for larger juveniles and adults to occupy reef/rock habitats in a range of water depths. The fact that all but one of the numerousH. portusjacksoni>800 mm were females is reflected in the ratio of females to males differing significantly from parity in the gillnet and longline samples. Yolked oocytes usually take one year to develop to ovulatory size. Ovulation occurs in late winter to early summer and hatching takes place a year later when the embryo is 180–220 mm. The claspers of males commence rapid growth at a total length of ~450 mm, coincident with the onset of clasper calcification and gonadal maturation. The rate of clasper growth relative to total length reached a maximum at ~570 mm and then declined precipitously as the claspers approached full calcification. Based on gonadal criteria, theL50at maturity for females (805 mm) was nearly 40% greater than that for males (593 mm). Values of the deviance information criterion and marked overlap in their 95% confidence intervals demonstrate that theL50of 581 mm derived for males using full clasper calcification as the index of maturity was equally valid as the aboveL50derived for males at maturity using gonadal criteria. The capture of substantial numbers of juveniles by trawling and of females <L50at maturity by gillnetting and longlining may be having localized effects on the population structure ofH. portusjacksoniin south-western Australian waters.

Lake Paranoá, Brasília, Brazil: Integrated Management Plan for its Restoration

1992 ◽  
Vol 27 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Sonia Paulino Mattos ◽  
Irene Guimarães Altafin ◽  
Hélio José de Freitas ◽  
Cristine Gobbato Brandão Cavalcanti ◽  
Vera Regina Estuqui Alves
Keyword(s):  
Total Phosphorus ◽  
Drainage Basin ◽  
Integrated Management ◽  
Algal Growth ◽  
Nutrient Content ◽  
Management Plan ◽  
Cylindrospermopsis Raciborskii ◽  
Phosphorus Concentration ◽  
Limiting Factor ◽  
Total Phosphorus Concentration

Abstract Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.

scholarly journals Efficiency of Recycled Biogas Digestates as Phosphorus Fertilizers for Maize

Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 553
Author(s):  
Inga-Mareike Bach ◽  
Lisa Essich ◽  
Torsten Müller
Keyword(s):  
Biomass Production ◽  
Plant Biomass ◽  
Nutrient Content ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Phosphorus Fertilizers ◽  
Future Supply ◽  
Application Techniques ◽  
Phosphorus Recycling ◽  
Fertilizing Effect

Despite phosphorus resources on Earth being limited, over fertilization in many agricultural situations causes significant resource consumption. Phosphorus-recycling within agricultural production can reduce global dilution into the environment and is thus essential to secure sustainable future supply. This study investigated the fertilization efficacy of phosphorus fertilizers recycled from biogas digestates in maize shoots grown under controlled greenhouse conditions, in two soils, in a pot experiment. Variables investigated were plant-available phosphorus in soil, plant biomass production, and concentration of phosphorus, calcium, and magnesium in shoots. Soils were treated with three different fertilizer fractions, separated from biogas digestates, at equivalent phosphorus concentrations, using different combinations and application techniques, isolated or in combination, and compared to triple superphosphate (TSP) as a reference. One of the fractions (P-Salt) had effects on biomass production and plant phosphorus concentration equivalent to TSP in agricultural surface soil. In the second soil (with less active soil life and nutrient content), equivalence to TSP was achieved with combinations of two recycled fractions (P-Salt and dried solids). The enhancement of the phosphorus fertilizing effect by the solids was synergistic, indicating that the solids had a soil conditioning effect. The results show that biogas digestates are a valuable source for phosphorus recycling of fractions that have equivalent or even superior fertilizing properties compared to TSP.

Nitrogen cycling in a Venezuelan tropical seasonally flooded forest: soil nitrogen mineralization and nitrification

1994 ◽  
Vol 10 (3) ◽  
pp. 399-416 ◽  
Author(s):  
Barrios E. ◽  
Herrera R.
Keyword(s):  
Soil Nitrogen ◽  
Nitrogen Availability ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Ammonium Nitrogen ◽  
Wet Season ◽  
Flooded Forest ◽  
Nitrogen Concentrations ◽  
Minimum Stress ◽  
Seasonally Flooded

ABSTRACTSeasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.The predominance of mineralization versus nitrification (56 and 5 μgsoil month−1respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.

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