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The effect of nitrogen on the development and photosynthetic activity of digitaria eriantha steud. subsp. eriantha
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: MaureenM. Wolfson --- Department of Botany, C.F. Cresswell --- Department of Botany,Digitaria eriantha Steud. subsp. eriantha, plants were grown under controlled conditions and treated with different concentrations and forms of nitrogen. The plants showed a preference for nitrate nitrogen, as opposed to ammonium nitrogen, with greater total dry matter production and... -
Long term nitrogen and phosphorus application to veld
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: C.H. Donaldson --- , G. Rootman --- , D. Grossman --- Department of Agriculture,The long term effects of a 5N x 3P factorial fertilizer application trial on hay yields, botanical composition and soil properties of veld are presented. Significant increases in hay yields were recorded during most years. There was a strong correlation... -
The influence of different forms and concentrations of nitrogen on the growth and metabolism of digitaria eriantha and chloris Gayana grown under saline conditions
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: J M Brauer --- Department of Botany, MaureenM Wolfson --- Department of Botany,Chloris gayana and Digitaria eriantha plants were watered with nutrient media containing a high concentration of sodium chloride (150 mM) and either high (200 mg/l) or low (25 mg/l) concentrations of nitrate nitrogen and ammonium nitrogen. Dry mass and leaf... -
The effect of form and level of nitrogen fertlization on the yield of Digitaria eriantha Steud*
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: N.F.G. Rethman --- Department of Plant Production,On dryland Digitaria eriantha ammonium sulphate and limestone ammonium nitrate were superior to potassium nitrate and urea. With reference to the level of nitrogen fertilization it was found that levels in excess of 300 kg N/ha, and up to 400... -
The influence of nitrate and ammonium forms of nitrogen fertilizer on the growth and osmoregulation of digitaria eriantha and Chloris gayana grown under saline conditions
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: LesleyJ. Gray --- Department of Botany, MaureenM. Wolfson --- Department of Botany,Digltaria eriantha and Chloris gayana were grown under controlled conditions for three months and were treated with a nutrient solution containing 150 mMol NaCl and the following nitrogen sources: 25 or 200 mg/l NH4 +‐N or NO3 −‐N or no... -
The effect of source of nitrogen on the dry matter yield, nitrogen and nitrate‐N content of Lolium multiflorum
Item type: Journal Article • Journal: Journal of the Grassland Society of Southern Africa • Authors: R.J. Eckard --- Department of Agriculture and Water Supply (Natal Region), Republic of South AfricaThree sources of N fertilizer (urea, limestone ammonium nitrate (LAN) and ammonium sulphate) showed no consistent significant trends in terms of the dry matter yield and nitrogen or nitrate‐N content of midmar ryegrass. Ammonium sulphate was found to acidify the... -
Die rol wat nitraat: ammoniumverhoudings speel in die effektiewe benutting van stikstof by Zea mays L.
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F.G. Adriaanse --- , J.J. Human --- Departement Agronomie,Die invloed van verskillende nitraat: ammoniumverhoudings by sub- en supra-optimale stikstofkonsentrasies op die opname en benutting van stikstof is ondersoek. Effektiewe stikstofbenutting is in terme van saadopbrengs per eenheid opgeneemde stikstof gemeet. Die beste nitraat: ammoniumverhouding was 3:1 by 100... -
Movement of ammonia plus ammonium from nitrogen fertilizers band placed in alkaline soils
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.C. du Preez --- Department of Soil Science, Republic of South Africa R. du T. Burger --- Department of Soil Science, Republic of South AfricaMovement of NH3 plus NH4 + from nitrogen fertilizers, band placed either as crystals or as granules in alkaline soils, was determined. The pH values of these soils, whereof the clay contents ranged from 7,6 to 49,9%, were adjusted to... -
Invloed van nitraat:ammoniumverhoudings op die ontwikkeling van Zea mays L.
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F.G. Adriaanse --- , Republiek van Suid-Afrika J.J. Human --- Departement Agronomie en Hortologie, Republiek van Suid-AfrikaDie invloed van drie nitraat:ammoniumverhoudings by twee stikstofkonsentrasies op planteienskappe is met blomtyd en na fisiologiese volwassenheid vir suiwerlyne gemeet. 'n Kwartssandkultuur is as groeimedium in 'n glashuis gebruik. Toenemende NH4 +-verhoudings het planthoogtes, blaaroppervlaktes en droëmateriaalproduksie van verskillende plantkomponente... -
Die relatiewe belang van die vorm en konsentrasie van stikstof in die wortelsone op die ontwikkeling van Zea mays L.
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F.G. Adriaanse --- , Republiek van Suid-Afrika J.J. Human --- Departement Agronomie en Hortologie, Republiek van Suid-AfrikaDie invloed van ses nitraat:ammoniumverhoudings by 200 mg N l1 in een proef en twee ander verhoudings by 50, 100 en 200 mg N l1 in 'n tweede proef is op droëmateriaalproduksie en stikstofinhoud ondersoek. Die algehele beste behandeling was... -
A vacuum filtration and leaching method for the colorimetric determination of ammonium and nitrate nitrogen in soils
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A. D.P. Botha --- , Republic of South Africa J.C. Johnson --- , Republic of South AfricaThe extracting solution and soil were separated by using vacuum filtration, followed by continuous leaching. The procedure was evaluated by spiking five different topsoil samples (having a wide range of physical and chemical properties) with ammonium nitrate and determining the... -
A comparison of the utilization of initially-applied labelled ammonium and nitrate nitrogen by wheat grown in a pot experiment
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A. D.P. Botha --- , Republic of South Africa D.C. Pretorius --- , Republic of South AfricaThe utilization of initially-applied 15N-labelled ammonium and nitrate nitrogen by wheat plants grown in soil was investigated in a pot experiment under controlled growth chamber conditions. The application rate was approximately 140 kg N ha−1) and the treatments consisted of... -
Utilization of initially-applied labelled ammonium nitrate by three successive crops
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A. D.P. Botha --- , Republic of South Africa D.C. Pretorius --- , Republic of South Africa J.C. Johnson --- , Republic of South Africa M.V. Kidson --- , Republic of South AfricaThe aim of the study was to compare N uptake from initially-applied NH4 + and NO3- ions and to compile a balance sheet for applied fertilizer N. In a pot experiment, maize, sorghum and sunflower plants were grown in succession,... -
The effect of oven-drying on residual inorganic nitrogen in soils
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: G.H. Wiltshire --- Department of Soil Science, Republic of South Africa C.C. du Preez --- Department of Soil Science, Republic of South AfricaResidual ammonium nitrogen in soils which were dried in an oven increased, whereas residual nitrate nitrogen remained almost constant. This observation led to experiments which help to explain the accumulation of ammonium nitrogen in oven-dried soils. It was found that... -
Response of maize to ammonium nitrate, urea and cogranulated urea-urea phosphate
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: O.A. Yerokun --- Department of Soil Science, ZambiaUrea fertilizers may lose N by ammonia volatilization when applied in the field. In order to reduce this loss, modified urea compounds are being used. Not all of them reduce ammonia loss and improve crop yields. A field study was... -
Ammonia volatilization from ammonium nitrate, urea and urea phosphate fertilizers applied to alkaline soils
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: O.A. Yerokun --- Department of Soil Science, ZambiaThe volatilization of ammonia following applications of urea fertilizers to soils may release significant amounts of N into the atmosphere and reduce the plant available N. This study compared ammonia loss from urea phosphate (170 g N kg−1, 190 g... -
Optimizing MCPA (K-salt) activity with adjuvants
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: B.L. de Villiers --- , Republic of South Africa H.A. Smit --- , Republic of South Africa R.C. Lindeque --- , Republic of South Africa J.J. Smit --- , Republic of South AfricaMCPA [2-methyl-4-chloro phenoxy acetic acid] is applied with various water sources containing antagonistic salts. It is applied without an adjuvant but is often mixed with bromoxynil for a broader spectrum of weeds. MCPA (K-salt) was applied in carriers containing calcium... -
Rind texture and juice acid content of Citrus spp. as affected by foliar sprays of mono-potassium phosphate (MKP), urea ammonium phosphate (UAP) and mono-ammonium phosphate (MAP)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: F.N. Mudau --- Department of Plant Production, Republic of South Africa K.I. Theron --- Department of Horticultural Science, Republic of South Africa E. Rabe --- Department of Horticultural Science, Republic of South AfricaRind coarseness of fruit of Citrus spp. is a general problem in the Citrusdal region of South Africa (Western Cape Province), often limiting the percentage of exportable fruit. Acid content of the juice of Citrus fruit is an important determinant... -
Water and nutrient retention by Aquasoil® and Stockosorb® polymers
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: M.G. Ghebru --- Department of Plant Production and Soil SCience, South Africa E.S. du Toit --- Department of Plant Production and Soil SCience, South Africa J.M. Steyn --- Department of Plant Production and Soil SCience, South AfricaWater retention and hydration rate of Aquasoil and Stockosorb polymers, the effects of these polymers on the water, ammonium and nitrate retention of a pine bark growth medium and the response of the polymers to fertilizer solutions were investigated. Aquasoil... -
The effects of N-source, shading and root zone cooling on two Disa hybrids
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: D. Pienaar --- Department of Agronomy, Republic of South Africa N. J.J. Combrink --- Department of Agronomy, Republic of South AfricaAlthough the Disa genus contains more than 130 species, the most commonly grown is Disa unifiora and its hybrids. The evergreen Disas are indigenous to South Africa and have great potential for marketing as cut flowers or pot plants but... -
Effect of tillage systems and nitrogen application rates on selected physical and biological properties of a clay loam soil in KwaZulu-Natal, South Africa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: TS Taylor --- Soil Science, School of Environmental Sciences, South Africa LW Titshall --- Soil Science, School of Environmental Sciences, South Africa JC Hughes --- Soil Science, School of Environmental Sciences, South Africa GR Thibaud --- Soil and Analytical Services Division, Department of Agriculture, South AfricaThe effects of agricultural management practices on soil physical and biological parameters provide fundamental information for assessing sustainability. Tillage (annual conventional tillage and no-till) and nitrogen fertiliser (limestone ammonium nitrate at rates of 0, 100 and 200 kg N ha−1)... -
Dynamics of a cyanobacterial bloom in a hypereutrophic reservoir, Lake Chivero, Zimbabwe
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: L Mhlanga --- Department of Biological Sciences, Zimbabwe W Mhlanga --- Department of Environmental Science, ZimbabweBlooming and non-blooming periods between 2004 and 2006 in a hypereutrophic reservoir, where cyanobacterial blooms have previously been reported to be permanent, presented an opportunity to characterise factors that may favour cyanobacterial dominance. As a bloom developed in May 2004,... -
Uptake and accumulation of ammonium by Alexandrium catenella during nutrient pulses
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: Y Collos M Lespilette A Vaquer M Laabir A PastoureaudField observations in Thau Lagoon, southern France, indicate that the growth of natural populations of Alexandrium catenella during blooms is limited by nitrogen and exhibits a storage rather than a growth response to an ammonium pulse. Therefore, ammonium uptake and... -
Optimisation of nitrogen and potassium for Aloe vera (L.) Burm.f. in a soilless culture system
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Jamal-Ali Olfati --- Horticultural Department, Iran Mohammad Saadatian --- Department of General Science, Faculty of Education, Iraq Eshaq Moqbeli --- Horticultural Department, IranAloe vera (L.) Burm.f. is highly appreciated due to its short growth period and high economic value among all Aloe species, and is used in pharmaceuticals, folk medicine, healthcare, cosmetic products and food products. Hydroponic systems have the potential to... -
Differences in nitrogen cycling and soil mineralisation between a eucalypt plantation and a mixed eucalypt and Acacia mangium plantation on a sandy tropical soil
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Sogni Viviane Tchichelle --- Centre de Recherche sur la Durabilité et la Productivité des Plantations Industrielles, Republic of the Congo Daniel Epron --- Centre de Recherche sur la Durabilité et la Productivité des Plantations Industrielles, Republic of the Congo Fidèle Mialoundama --- Université Marien NGouabi, Republic of the Congo Lydie Stella Koutika --- Centre de Recherche sur la Durabilité et la Productivité des Plantations Industrielles, Republic of the Congo Jean-Michel Harmand --- CIRAD, France Jean-Pierre Bouillet --- CIRAD, France Louis Mareschal --- Centre de Recherche sur la Durabilité et la Productivité des Plantations Industrielles, Republic of the CongoSustainable wood production requires appropriate management of commercial forest plantations. Establishment of industrial eucalypt plantations on poor sandy soils leads to a high loss of nutrients including nitrogen (N) after wood harvesting. An ecological intensification of eucalypt plantations was tested... -
Effect of soil- and foliar-applied nitrogen fertiliser on growth, yield and protein content of spring wheat (Triticum aestivum L.) under glasshouse conditions
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Mongezi M Mbangcolo --- Dohne Agricultural Development Institute, South Africa Petrus J Pieterse --- AgriSciences, Department of Agronomy, South AfricaFoliar application of nitrogen (N) can be essential in improving yield and grain protein content of wheat. Limestone ammonium nitrate and calcium nitrate solution were used as two N top-dressing treatments applied at three growth stages to evaluate their effect... -
Wintertime rates of net primary production and nitrate and ammonium uptake in the southern Benguela upwelling system
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: RF Flynn --- Department of Oceanography, South Africa JM Burger --- Department of Oceanography, South Africa K Pillay --- Branch: Oceans and Coasts, Department of Environmental Affairs (DEA), South Africa SE Fawcett --- Department of Oceanography, South AfricaThe elevated levels of primary productivity associated with eastern boundary currents are driven by nutrient- rich waters upwelled from depth, such that these regions are typically characterised by high rates of nitrate-fuelled phytoplankton growth. Production studies from the southern Benguela... -
Comparison of single vs composite soil electrical apparent conductivity-directed samples of irrigated soils for inorganic nitrogen estimation with electromagnetic induction sensors
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: --- University of the Free State, South Africa --- University of the Free State, South Africa --- University of the Free State, South Africa --- University of the Free State, South AfricaThe management of soil can be improved by precision agriculture. A way to achieve this is by quantifying NH4+–N and NO3−–N in soil. The sampling of soil for quantifying these N species is a laborious task. Electromagnetic induction (EMI) sensors... -
Are inorganic nitrogen concentrations in potassium chloride and saturated paste extracts of irrigated soils comparable?
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: D Steenekamp --- University of the Free State, South Africa LD van Rensburg --- University of the Free State, South Africa JH Barnard --- University of the Free State, South Africa CC du Preez --- University of the Free State, South AfricaPrecision agriculture is gaining momentum in irrigation through the assessment of soil salinity variability, often facilitated by electromagnetic induction (EMI) sensors. This study aimed to evaluate whether saturated paste extracts (SATe) could serve as a substitute for the standard 2... -
Pelargonic acid for the management of firebreak tracer-lines: results from four trials implemented in South Africa
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: Keith M Little --- Nelson Mandela University, South AfricaMost South African planted forests occur in high wildfire risk regions, with firebreaks used to minimise the risk of run-away fires. Desiccant herbicides together with burning are used for firebreak preparation in a stepwise manner. In late summer, 1–2 m...