Ordinary Superphosphate Research Articles

Phosphate availability in calcareous Vertisols and Inceptisols in relation to fertilizer type and soil properties

The availability to plants of fertilizer phosphorus (P) applied to soil, as measured by chemical extraction, is used to estimate P fertilizer needs. We studied the availability of P, applied as monocalcium phosphate (MCP) powder, ordinary superphosphate (OSP) granules and diammonium phosphate (DAP) granules in 24 calcareous Vertisols and Inceptisols of Andalusia, Spain, by using laboratory incubation techniques. The soils differed widely in their P adsorption- and Ca-phosphate precipitation-related properties. For MCP, availability (defined as the proportion of added P that is recovered by extraction with NaHCO3 or is isotopically exchangeable) decreased markedly with incubation time and increasing addition rate. The mean recoveries after 180 d of incubation at field capacity at a rate of 246 mg P kg−1 soil were 17% for Olsen P, 38% for Colwell P, and 16% for isotopically exchangeable P (IEP). Increasing the application rate to 2460 mg kg−1 resulted in recoveries of 6% for Olsen P, 25% for Colwell P, and 4% for IEP. While IEP-based recovery was not significantly correlated to any soil property, that based on Olsen P (and, to a lesser extent, Colwell P) decreased sharply with increase in the ratio of clay (or Fe oxides) to total (or active) calcium carbonate equivalent. Accordingly, Olsen P might overestimate P availability in those soils relatively rich in carbonate and poor in clay and Fe oxides. On the other hand, recovery of applied P from soils containing more clay and Fe oxides, by a sequential extraction (with H2O, two 0.5M NaHCO3 treatments, 0.5M HCl), was lower than 100%, thereby suggesting phosphate occlusion by Fe oxides or clay.

Comportamento de extratores em solo tratado com fontes diversas de fósforo

Em condições de casa-de-vegetação foram feitos sete cultivos sucessivos para avaliar o efeito direto e residual do superfosfato simples granulado e do termofosfato magnesiano (Yoorin) fornecidos em quatro doses (O, 50,100 e 200 ppm). O fósforo disponível foi determinado depois do terceiro, quarto e último cultivos usando-se os extratores de Mehlich 1, Bray 1, resina e a técnica de diluição isotópica (valor E). De um modo geral, os coeficientes de correlação mais altos entre P disponível e matéria seca ou fósforo total absorvido, foram encontrados com os dados obtidos com resina e Mehlich 1, seguindo-se os obtidos com Bray 1 e, em último lugar, os com o valor E.

Effectiveness of two partially acidulated rock phosphates, coastal superphosphate and Ecophos, compared with North Carolina reactive rock phosphate and superphosphate

The effectiveness of coastal superphosphate, a partially acidulated rock phosphate (PARP) made from apatite, and Ecophos, a PARP made from calcium iron aluminium (crandallite millisite) rock phosphate, was compared in pot experiments with the effectiveness of ordinary superphosphate (OSP) and North Carolina reactive apatite rock phosphate (NCRP). There were three experiments using different lateritic soils collected in Western Australia. Fertilizer effectiveness was measured using yield of dried wheat (Triticum aestivum) tops grown for 28 days. Three successive crops were grown. The phosphorous (P) fertilizers were applied and mixed with the soils before sowing the first crop. In addition, OSP was added to extra pots before sowing crops 2 and 3 in order to measure the effectiveness of the original P fertilizers relative to freshly-applied OSP for these crops.

Long‐Term Effects of Forest Fertilization on Site Organic Matter and Nutrients

AbstractThe long‐term effects of time‐of‐planting fertilization on the accumulation and distribution of above‐ and belowground organic matter and nutrients are largely unknown for intensively managed southern pine (Pinus spp.) stands in the U.S. lower Coastal Plain. These effects were investigated using a 25‐yr‐old slash pine (P. elliottii Engelm. var. elliottii) plantation in north Florida. The experiment was conducted on a poorly drained, P‐deficient Rutlege soil (sandy, siliceous, thermic Typic Humaquept) using a randomized complete block design. The experimental treatments included: (i) control, (ii) NPK (112, 39, and 45 kg ha−1 using ordinary superphosphate [OSP] + N and K) and (iii) P (314 kg P ha−1 using ground rock phosphate [GRP]). Fertilization significantly increased total aboveground organic matter accumulation, with levels for the OSP + NK and GRP treatments being 2.5 and 1.8 times greater than the control, respectively. Levels of soil organic matter measured to a depth of 91 cm did not vary, however. Treatment effects were found for P, K, and Ca levels in the fertilized slash pine biomass components and surface soil. Long‐term differences in extractable soil P were most pronounced for the GRP treatment, with concentrations in the surface 15 cm being 2.6 times greater than the control; only the high P treatment sustained foliar P levels within the published critical range for slash pine. While field trials are required to confirm actual fertilizer carryover effects, results from this experiment suggest that sites previously fertilized with operational P rates (40–80 kg ha−1) will again require treatment when establishing the next pine rotation.

Residual value of superphosphate and queensland rock phosphate measured using yields of serradella, burr medic and subterranean clover grown in rotation with wheat and bicarbonate‐extractable soil phosphorus

Abstract The residual value of ordinary (single) superphosphate (SP) and Queensland (Duchess) apatite rock phosphate was measured in a pot experiment using yields of three legume species (serradella, Ornithopus compressus; medic, Medicago polymorpha var. brevispina; clover, Trifolium subterraneum) fertilized with mineral nitrogen (N) grown in rotation with wheat (Triticum aestivum). The plants were grown in a glasshouse in a sandy soil (pH in CaCl2 ‐ 5.8) for 30 to 34 days. There were four crops: legume, wheat, legume, and wheat. The phosphate (P) requirement of the plant species was determined from the amount of P required to produce 90% of the maximum yield. Soil samples were taken before sowing each crop to measure bicarbonate‐extractable soil P (soil test P) which was related to the yields of that crop. Relative to freshly‐applied (FSP), the residual value of SP declined by about 60% between the first and second crop, and by a further 25% by the fourth crop. For crop 3, the residual value of SP varied...

Interaction between Plant Nutrients: IV. Interaction between Calcium and Phosphate

Abstract The interaction between calcium and phosphate is complex because these ions both support and counteract each other. The supporting effect is due to a simultaneous uptake and translocation of calcium and phosphate. The counteracting effect is caused by precipitation of less soluble calcium phosphates at the vicinity of nutrient-absorbing roots. At high activity ratios between potassium and calcium the risk of calcium deficiency is obvious. The capability of plants to absorb calcium ions is then increased by application of soluble phosphate fertilizers. In a field experiment, application of potassium chloride decreased the uptake of phosphorus and crop yield. Application of ammonium phosphate increased the content of water-soluble phosphate in a soil extract and the early uptake of phosphorus and calcium. Application of ordinary superphosphate had less effect than ammonium phosphate on the solubility of phosphate in the soil, whereas the calcium ion activity and crop yield increased considerably. E...

Efeito da adubação com superfosfato simples em características agronômicas e propriedades tecnológicas da fibra das variedades de algodoeiro IAC 13-1, IAC 16 e IAC 17

Utilizando-se dados de ensaio de longa duração, instalado com as variedades IAC 13-1, IAC 16 e IAC 17 em latossolo roxo de baixa fertilidade, avaliou-se o efeito de sucessivas aplicações de superfosfato simples sobre características agronômicas e propriedades tecnológicas da fibra do algodoeiro. O esquema adotado foi de parcelas subdivididas, sendo os tratamentos das parcelas distribuídos em blocos ao acaso, com quatro repetições. As parcelas foram ocupadas pelas doses anuais de 0, 225, 450 e 675kg/ha de superfosfato simples e as subparcelas, pelas variedades. A gleba experimental recebeu calagem antes do primeiro plantio e adubações anuais de nitrogênio e potássio nas doses fixas de 50 e 75kg/ha de N e K(2)0 respectivamente. As variedades IAC 13-1, IAC 16 e IAC 17 reagiram de maneira semelhante à aplicação de superfosfato simples, para todas as características estudadas. No entanto, as duas primeiras demonstraram maior aproveitamento do adubo, refletindo em acréscimos significativos no comprimento da fibra, o que não ocorreu com a IAC 17.0 uso do superfosfato simples concorreu para aumentar a tenacidade da fibra, o peso de cem sementes e o peso de um capulho, independentemente da variedade utilizada, enquanto a uniformidade de comprimento, o índice Micronaire e a porcentagem de fibras não foram beneficiados pelo adubo.

RESIDUAL PHOSPHORUS SOLUBILITY FOR AN ACID, CLAYEY, FORESTED SOIL IN THE PRESENCE OF OXALATE AND CITRATE

A highly weathered, clayey soil was sampled 14 yr after a Pinus radiata stand was broadcast fertilized with 0, 50 and 200 kg P ha−1 as ordinary superphosphate. Incremental loadings of oxalate and citrate anions from 10 to 100 μmol of anion g−1 soil were evaluated for increased soluble, reactive P (SRP) and soluble, nonreactive (SNP) P. Sorption isotherms were compared to evaluate the effect of the previous fertilization on P sorption by the soil material sampled, and also to measure SNP displacement by orthophosphate-P. A portion of the SNP pool was more readily released than SRP and orthophosphate displaced a significant amount of SNP. After 14 yr the effect of fertilization was still obvious in the sampled soil material. Much of the organic anion-soluble P was in the SRP form. Key words: Citrate, organic P, orthophosphate, oxalate, Pinus radiata, residual P

Phosphate Rock Fertilization in Tilled and No‐Till Low‐Input Systems in the Humid Tropics

AbstractApplication of phosphate rock is of interest to low‐input systems in the humid tropics, because phosphate rock is less expensive than ordinary superphosphate and releases P quickly in acid soils. However, the lack of incorporation in zero‐tillage systems may result in low availability of surface‐applied P. This study was directed toward determining the effects of these two P sources under no‐till and rotovation tillage systems on crop production in a fine‐loamy siliceous, isohyperthermic Typic Paleudult of Yurimaguas, Peru. A rotation of Al‐tolerant cultivars of rice (Oryza sativa L.)‐rice‐cowpea (Vigna unguiculata) was followed for seven consecutive harvests. Grain yields increased with rotovation in the first crop, were not affected by tillage methods during the second and third crops, but decreased with rotovation from the third to the seventh crops. Sechura phosphate rock at a soil pH of 4.5 was as effective as superphosphate in supplying available P. A total of 13.9 Mg ha−1 of rice and 2.5 Mg ha−1 of cowpea grain was produced in seven harvests in newly cleared fields without lime or P application. There were significant responses to P fertilization in one rice crop and in both cowpea crops. On the average, however, rice yield did not respond to P. A single application of 22 kg P ha‐' was sufficient to produce 85% of the maximum yield of cowpea for 2 yr. The results with cowpea indicate that broadcast phosphate rock is a good source of P for low‐input systems on acid soils where acid‐tolerant cultivars are used.

Phosphorus leaching in sandy soils .I. Short-term effects of fertilizer applications and environmental conditions

The consequences of previous as well as current environmental conditions and management practices on the potential for phosphorus (P) to be lost by drainage from sandy soils in the short term (< 1 year) were studied in the laboratory and the field. The potential for P losses by drainage was estimated by measuring soil solution P levels and rapidly released P. Rapidly released P was measured by determining the concentration of dissolved inorganic P contained in filtered (<0.45 pm) soil solutions after incubating soil at saturation for 15 min at ambient temperature. In the laboratory, sandy soils were incubated with ordinary superphosphate, coastal superphosphate (a granulated mixture of equal parts of superphospate, rock phosphate and elemental sulfur) or lime-superphosphate (a lime-reverted superphosphate with 18% kiln dust) and sequentially desorbed with deionized water. The effects of the extent of leaching, fertilizer type, application rate and the time of contact with the soil on soil solution P levels were investigated. The influence of annual pasture death and summer rainfall on rapidly released P in soils that had been pre-treated by leaching were also investigated. Phosphorus concentrations decreased logarithmically in the successive supernatants of the sequentially desorbed soils. More P was desorbed from soils incubated with superphosphate and lime-superphosphate than soil incubated with coastal superphosphate. At each level of pre-leaching, the P concentrations in the soil solution increased with increasing time. The level, to which the P concentration in the soil solution increased at each time, decreased with increased extent of pre-leaching. The addition of P fertilizers increased the concentration of P in the soil solution. The concentrations increased with increasing application rate and were much higher for superphosphate than for coastal superphosphate; however, there was little effect of contact time on soil solution P levels. Rapidly released P levels after leaching increased during a period of no further leaching. Additional moisture or plant material during this period of no further leaching increased the rate and extent to which rapidly released P increased. Monitoring of rapidly released P in the 0-2, 2-5, 5-10 and 10-20 cm layers of field plots, with and without applications of superphosphate, showed that sampling depth, water flow path, fertilizer management, rainfall pattern and background P levels would affect the estimate of short-term P losses. Rapidly released P in the 0-2 cm layer varied markedly with time and was higher (P < 0.05) than that in lower soil layers. Rapidly released P increased after the winter and spring rains diminished and then decreased after the rains commenced again at the end of the summer. A possible annual cycle of P in sandy soils in a mediterranean climate is postulated by considering the laboratory and field data in combination.

Efeitos de três adubos fosfatados sobre a acidez de dois solos do município de Piracicaba

Foi realizado um ensaio em vasos para se estudar os efeitos dos fertilizantes fosfatados (Superfosfato simples, Termofosfato e Fosforita de Olinda) sobre o pH e o teor de Al3+ trocável de dois solos (Orthic Haplacrox e Orthic Hapludent) do município de Piracicaba-SP. O Termofosfato reduziu tanto a acidez ativa quanto a acidez trocável em ambos os solos. A fosforita de Olinda e o Superfosfato simples reduziram a acidez de troca mas afetaram muito pouco o pH dos dois solos.

Phosphorus leaching in sandy soils .II. Laboratory studies of the long-term effects of the phosphorus source

Long-term phosphorus (P) losses and gains in sandy soils continuously fertilized with either ordinary superphosphate or coastal superphosphate (a granulated mixture of superphosphate, rock phosphate and elemental sulfur) or previously fertilized with superphosphate were investigated under leaching conditions in columns in the laboratory. The soils were subjected to 10 consecutive cycles designed to simulate the mediterranean weather conditions in the Harvey region of the Coastal Plain of Western Australia. Each cycle consisted of a wet phase during which the equivalent of 850 mm of rainfall was leached through the soil and a drier phase during which the soil was incubated in the presence of moisture equivalent to summer rainfall (150 mm). Dissolved inorganic P in the leachate was used as a measure of P loss. A sequential fractionation procedure (a resin extraction followed by 0.5 M sodium bicarbonate, 0.1 M sodium hydroxide and 0.1 M sulfuric acid extractions) and total inorganic and organic P were used to measure changes in P levels in the soils. Phosphorus losses from the previously fertilized soils decreased logarithmically with increasing number of cycles. Total inorganic P and resin-extractable P were able to explain >94% of the variation in P losses. Addition of either fertilizer increased the amount of P leached from the soil and 10-40% more P was leached by adding superphosphate rather than coastal superphosphate. The percentage of the cumulative P lost by leaching decreased with increasing application rate of both fertilizers when expressed as a percentage of the cumulative water plus citrate-soluble P added. Addition of either fertilizer increased the amount of acid-extractable P, but coastal superphosphate had a much greater effect than superphosphate. Leaching losses of P were influenced by fertilizer solubility in the short term (< 1 year). In the long term, however, the water plus citrate-insoluble P in the fertilizers also contributed to P losses by leaching.

Low effectiveness of three rock phosphates as phosphorus fertilizers and liming materials on an acid clay-loam

The effectiveness of three finely ground rock phosphates (PRs) was compared with ordinary superphosphate (OSP) for subterranean clover growth and for increasing soil bicarbonate-extractable P levels over two successive 8-week periods on a very acid clay-loam (pH (0.01 M CaCl2) 4.3) in a glasshouse experiment. All PR sources were poorly effective compared to OSP. Maximum dry matter and P uptake of each PR source was less than that of OSP at each harvest. Relative to surface application, mixing throughout the soil reduced the effectiveness of OSP for dry matter and P uptake, but had little effect on the PR sources. Relative to OSP, the effectiveness of PR sources did not increase at the second harvest. Bicarbonate-extractable P levels for soil-incorporated Island PR plateaued below the highest rate applied. Phosphorus uptake by the herbage at harvests 1 and 2 was not well related to soil bicarbonateextractable P levels at harvest 1, and source dependency was indicated. Soil pH was markedly increased by each of PR sources at application rates within the rates required to reach maximum dry matter and P yield. Increased soil pH at high PR applications is likely to have reduced PR dissolution, and contributed to low agronomic effectiveness. Dry matter yield at both harvests was dependent on P concentration in the tops, regardless of the P source or method of P application. A higher soil buffering capacity for pH, P or Ca than was present in this soil seems necessary for sufficient PR dissolution to achieve the same agronomic effectiveness as OSP.

Competição de adubos fosfatados no algodoeiro, em ensaio de longa duração

Após quatro anos de aplicações sucessivas de misturas de adubos contendo P ou P mais S, em ensaio permanente com o algodoeiro, fez-se rotação com cultivo de mucuna-preta na entressafra do quarto para o quinto ano, seguida de calagem visando à adequada correção da acidez do solo. No qüinqüênio 1978-1983, cultivou-se a variedade IAC 18 de algodoeiro, mantendo-se a mesma adubação da primeira fase, que, através de combinações de produtos comerciais, como sulfato de amônio, Nitrocálcio, superfosfato triplo, superfosfato simples e cloreto de potássio, forneceu anualmente às plantas N e K em doses constantes e P e S em doses variáveis. Sintomas de deficiência de enxofre, representados especialmente pelo "verde-limão" das folhas de ponteiro, tornaram-se evidentes a partir do quinto ano agrícola (primeiro da segunda fase), coincidindo com tendência para aumento de produtividade do algodoeiro. Entretanto, só após a correção da acidez do solo (pH em H2O ao redor de 6,2), é que a produtividade das plantas se estabilizou em nível alto, e as diferenças a favor das misturas contendo superfosfato simples tornaram-se estatisticamente significativas. Na segunda fase, as doses de 50 e 100 kg/ha de P2O5 proporcionaram acréscimos no volume de produção, respectivamente de 37 e 40%, quando se usou superfosfato triplo na adubação, e de 55 a 67% no caso do superfosfato simples. Em termos de lucro, o superfosfato simples proporcionou acréscimos sobre o triplo da ordem de 55 a 82%, em função da dose de P2O5 usada. Peso de capulho e comprimento de fibra também foram significativamente beneficiados pelo superfosfato simples, enquanto o fornecimento suplementar de enxofre, 120 kg/ha de S, não alterou as características gerais do algodoeiro adubado com a dose básica de 60 kg/ha de S. E proposto que se reavalie a necessidade de incorporar enxofre nas formulações comerciais de adubos, diante dos resultados obtidos.

Efeitos da utilização de misturas de adubos com ou sem enxofre na precocidade e nas características do capulho e da fibra do algodoeiro

São apresentados resultados referentes à precocidade e características do capulho e da fibra do algodoeiro, obtidos em ensaio de caráter permanente, no município de Guaíra (SP), em gleba de Latossolo Roxo, durante o período 1974/75-1977/78, utilizando-se a variedade 'IAC 16'. Além da reação ao fósforo, foi planejado um estudo conjunto visando observar a resposta do algodoeiro à aplicação de misturas de adubo contendo fósforo e enxofre em quantidades variáveis. A análise e a interpretação dos resultados permitiram as seguintes conclusões: a) Adubações com superfosfato triplo ou simples, em solo deficiente em fósforo, resultaram em maior precocidade no ciclo do algodoeiro, enquanto o uso de sulfato de amônio em cobertura tendeu a prolongar esse ciclo; b) Ambas as fontes citadas de fósforo proporcionaram aumentos significativos no peso de capulho e no comprimento das fibras, enquanto apenas o superfosfato simples aumentou sensivelmente o peso de cem sementes e o índice Micronaire, que representa o complexo finura + maturidade da fibra; c) As características porcentagem de fibras, uniformidade de comprimento, resistência e maturidade das fibras, não foram alteradas significativamente pelos tratamentos estudados.

Effect of irrigation, pyrites and phosphobacteria on the efficiency of rock phosphate applied to lentils

SUMMARYA field experiment was made at the Indian Agricultural Research Institute, New Delhi, during the autumn-spring season of crop years 1979–80 and 1980–1 to study the effects of irrigation, pyrites and phosphobacteria on the efficiency of Mussoorie rock phosphate(north-western Himalayan deposits) for lentils (Lens culinaris Medic), and residual effects were studied in maize (Zea mays L.). Response to phosphate was observed only when the crop received irrigation. Mussoorie rock phosphate was only 40·5% as effective as ordinary superphosphate; its efficiency was increased to 50·4% when it was mixed with 25% (by weight) pyrites. When the lentil seeds were treated with the culture of Pseudomonas striata (phosphate solubilizing bacteria) the efficiency of rock phosphate was increased to 79·7%. Rock phosphate together with seed treatment with phosphobacteria also showed residual effects on the succeeding maize crop which were equal to those obtained with ordinary superphosphate. Our results thus show that use of phosphobacteria can considerably increase the efficiency of rock phosphate on neutral soils.

CALCIUM DEFICIENCY IN CLAYEY B HORIZONS OF SAVANNA OXISOLS

ABSTRACT The restriction of crop root growth in Cerrado (savanna) Oxisols often reduces yields because the volume of soil explored by the roots is insufficient to supply enough water during dry periods that occur in the rainy season. A recent soil survey of the 580 000 hectares of the Federal District in Central Brazil shows a number of profiles that have clayey B21 horizons within 50 centimeters of the surface with very low levels of exchangeable calcium + magnesium (0.2 milliequivalents per 100 grams or less) and no exchangeable aluminum. The hypothesis that root penetration in such subsoils is limited by lack of calcium, rather than by aluminum toxicity, is supported by the results of simple and inexpensive tests showing that the addition of 0.10 to 0.15 meq/100 g calcium as chloride, phosphate, or carbonate effectively normalized seedling root growth, which, in the absence of such additions, stopped within a few days. The addition of magnesium carbonate, however, did not improve root growth. To test whether the leaching of calcium salts might ameliorate the calcium deficiency in the subsoil, samples were taken from an experiment that had received about 2500 kg/ha calcium as limestone and ordinary superphosphate at installation 2 years previous. Compared with root growth in samples from adjacent virgin soil, these soils showed improved root growth to as deep as 75 cm, thus suggesting that fertilizer management can have a beneficial effect on subsoil rooting in such soils.

Long‐term Response to Phosphorus Fertilization on Selected Southeastern Coastal Plain Soils

AbstractSignificant response in height, diameter, basal area, and volume growth to phosphorus (P) fertilization at time of planting lasted 17 to 20 years on a variety of sites in northern and western Florida. Ground rock phosphate and the more soluble ordinary superphosphate were equally effective P sources. Comparing the residual fertilizer P in the soil to a long‐term response of slash pine (Pinus elliottii Engelm. var elliottii) helped explain lack of differences in effectiveness of P sources. The largest long‐term slash pine responses were apparent on a poorly drained Ultisol and Inceptisol while the Spodosols were more variable in their response. There were no P responses on well‐to‐excessively‐drained Entisols.

Dissolution of granulated CuZn-superphosphate in soils

Granules and pressed pellets of ordinary superphosphate and CuZn superphosphate were drilled and surface applied to two moist soils in the field. Residues were collected at intervals up to 1 year and chemically analyzed. The water-soluble P, Cu and Zn fractions dissolved within 7 days. Dissolution of S, Ca, remaining Cu and citratesoluble P was slow with approximately half the initial contents remaining in pellets and large granules after 1 year.

Relative efficiency of rock phosphate and superphosphate for forage legumes and residual effects on succeeding wheat

SummaryA field experiment was made at the Indian Agricultural Research Institute, New Delhi to compare the efficiency of Mussoorie rock phosphate with ordinary superphosphate for two forage legumes, cowpea (Vigna sinensis Savi) and cluster beans (Cyamopsis tetragononoloba L.) and residual effects were studied in wheat (Triticum aestivum L.). For both the forage legumes Mussoorie rock phosphate was only 22% as effective as ordinary superphosphate (on soil of pH 7·1) and it had no significant residual effects on wheat even when the application rates supplied three times as much P as was supplied by ordinary superphosphate.