Phosphate-Solubilizing Bacteria with Low-Solubility Fertilizer Improve Soil P Availability and Yield of Kikuyu Grass.

Inoculation with phosphate-solubilizing bacteria (PSB) and the application of phosphorus (P) sources can improve soil P availability, enhancing the sustainability and efficiency of agricultural systems. The implementation of this technology in perennial grasses, such as Kikuyu grass, for cattle feed in soils with high P retention, such as Andisols, has been little explored. The objective of this study was to evaluate the productive response of Kikuyu grass and soil P dynamics to BSF inoculation with different P sources. The experiment was conducted on a Kikuyu pasture, which was evaluated for 18 months (September 2020 to March 2022). Three P fertilizers with different solubility levels were applied: diammonium phosphate (DAP) (high-solubility), rock phosphate (RP), and compost (OM) (low-solubility). Moreover, the inoculation of a PSB consortium (Azospirillum brasilense D7, Rhizobium leguminosarum T88 and Herbaspirillum sp. AP21) was tested. Inoculation with PSB and fertilization with rock phosphate (RP) increased soil labile P and acid phosphomonoesterase activity. Increased grass yield and quality were related with higher soil inorganic P (Pi) availability. This study validated, under field conditions, the benefits of PSB inoculation for soil P availability and Kikuyu grass productivity.

Role of Rahnella aquatilis AZO16M2 in Phosphate Solubilization and Ex Vitro Acclimatization of Musa acuminata var. Valery.

Rahnella aquatilis AZO16M2, was characterized for its phosphate solubilization capacity to improve the establishment and survival of Musa acuminata var. Valery seedlings under ex-acclimation. Three phosphorus sources (Rock Phosphate (RF), Ca3(PO4)2 and K2HPO4) and two types of substrate (sand:vermiculite (1:1) and Premix N°8) were selected. The factorial analysis of variance (p < 0.05) showed that R. aquatilis AZO16M2 (OQ256130) solubilizes Ca3(PO4)2 in solid medium, with a Solubilization Index (SI) of 3.77 at 28 °C (pH 6.8). In liquid medium, it was observed that R. aquatilis produced 29.6 mg/L soluble P (pH 4.4), and synthesized organic acids (oxalic, D-gluconic, 2-ketogluconic and malic), Indole Acetic Acid (IAA) (33.90 ppm) and siderophores (+). Additionally, acid and alkaline phosphatases (2.59 and 2.56 µg pNP/mL/min) were detected. The presence of the pyrroloquinoline-quinone (PQQ) cofactor gene was confirmed. After inoculating AZO16M2 to M. acuminata in sand:vermiculite with RF, the chlorophyll content was 42.38 SPAD (Soil Plant Analysis Development). Aerial fresh weight (AFW), aerial dry weight (ADW) and root dry weight (RDW) were superior to the control by 64.15%, 60.53% and 43.48%, respectively. In Premix N°8 with RF and R. aquatilis, 8.91% longer roots were obtained, with 35.58% and 18.76% more AFW and RFW compared with the control as well as 94.45 SPAD. With Ca3(PO4)2, values exceeded the control by 14.15% RFW, with 45.45 SPAD. Rahnella aquatilis AZO16M2 favored the ex-climatization of M. acuminata through improving seedling establishment and survival.

Trichoderma strains accelerate maturation and increase available phosphorus during vermicomposting enriched with rock phosphate.

AIMS: To suggest microbial inoculation as a tool to shorten organic residues stabilization and increase rock phosphate (RP) solubilization through vermicomposting, thus increasing nutrient content in plants and making it more appealing to farmers. Two Trichoderma strains were inoculated alone or combined in a RP apatite-enriched vermicompost. Stability and plant-available phosphorus levels were monitored for 120 days. METHODS AND RESULTS: Observable higher total organic carbon reduction in the treatment with the combined Trichoderma strains, followed by the inoculation with T. asperellum and T. virens. Combined Trichoderma and inoculation with T. virens increased humic acids (HA) content in 38·2 and 25·0%, respectively; non-inoculated vermicompost with T. asperellum increased it by 15·0%. The combined Trichoderma strains and T. virens achieved the stability index based on the humic/fulvic acids (HA/FA) ratio after 120 days. T. asperellum, combined Trichoderma and T. virens increased the citric acid soluble-P content in 83·2, 62·2 and 49·5%, respectively, compared to the non-inoculated vermicompost. CONCLUSIONS: Inoculation with combined T. asperellum and T. virens efficiently accelerated vermicompost stabilization; T. asperellum increased the citric acid soluble-P in the final product. SIGNIFICANCE AND IMPACT OF THE STUDY: Combined Trichoderma inoculation and RP enrichment improves the vermicompost quality, increasing HA and citric acid soluble-P, recycling organic waste nutrients and reducing agricultural dependence on phosphate fertilizers.

Long-Term Rock Phosphate Fertilization Impacts the Microbial Communities of Maize Rhizosphere.

Phosphate fertilization is a common practice in agriculture worldwide, and several commercial products are widely used. Triple superphosphate (TSP) is an excellent soluble phosphorus (P) source. However, its high cost of production makes the long-term use of crude rock phosphate (RP) a more attractive alternative in developing countries, albeit its influence on plant-associated microbiota remains unclear. Here, we compared long-term effects of TSP and RP fertilization on the structure of maize rhizosphere microbial community using next generation sequencing. Proteobacteria were dominant in all conditions, whereas Oxalobacteraceae (mainly Massilia and Herbaspirillum) was enriched in the RP-amended soil. Klebsiella was the second most abundant taxon in the RP-treated soil. Burkholderia sp. and Bacillus sp. were enriched in the RP-amended soil when compared to the TSP-treated soil. Regarding fungi, Glomeromycota showed highest abundance in RP-amended soils, and the main genera were Scutellospora and Racocetra. These taxa are already described as important for P solubilization/acquisition in RP-fertilized soil. Maize grown on TSP and RP-treated soil presented similar productivity, and a positive correlation was detected for P content and the microbial community of the soils. The results suggest changes of the microbial community composition associated to the type of phosphate fertilization. Whilst it is not possible to establish causality relations, our data highlights a few candidate taxa that could be involved in RP solubilization and plant growth promotion. Moreover, this can represent a shorter path for further studies aiming the isolation and validation of the taxa described here concerning P release on the soil plant system and their use as bioinoculants.

Characteristics and Mechanisms of Biosolubilization of Rock Phosphate by Aspergillus japonicus

ABSTRACT Rock phosphate (RP) is traditionally solubilized by chemical process causing high cost and environmental pollution. To reduce process cost and protect environment, RP solubilization by Aspergillus japonicus was studied and its mechanisms were discussed. Results show that A. japonicus could effectively solubilize RP in NBRIP medium. RP solubilization by A. japonicus included direct and indirect actions of the strain on RP. Cells of A. japonicus attached rapidly to RP surface and the RP surface was seriously corroded by the strain. A. japonicus excreted multiple organic acids, and followed by a significant increase of titratable acidity and decrease of pH in the culture. A positive correlation between content of soluble phosphate and quantity of titratable acidity but a negative correlation between content of soluble phosphate and pH were observed. Results of abiotic solubilization of RP using organic and inorganic acids indicated that the release of soluble phosphate was significantly lower than that of inoculated with A. japonicus. Higher release of soluble phosphate and pH reduction achieved when using ammonium nitrogen rather than nitrate nitrogen.

Desempenho ponderal de bovinos Nelore suplementados com fontes alternativas de fósforo / Weight gain of Nelore cattle supplemented with different phosphorus sources

O desempenho produtivo e a possível interferência do flúor sobre a saúde dos animais foram investigados em bovinos Nelore suplementados, por 866 dias, com distintas fontes alternativas de fósforo com diferentes relações fósforo:fluor (P:F). Os tratamentos experimentais foram: Controle negativo (CONTNEG, sem qualquer suplementação com P), fosfato bicálcico (FB 120:1, FB 30:1 e FB 10:1), fosfato monobicálcico (FMBC 60:1), superfosfato triplo (SFT 30:1) e fosfato de rocha de Cajati (FR 10:1). Foram utilizados 49 novilhos, desmamados aos oito meses de idade, castrados e com 230 kg de peso médio, distribuídos em sete piquetes com água e mistura mineral formulada sem P. A dieta padrão foi feita com bagaço de cana (0,03% de P) como volumoso e um concentrado contendo 0,239 % de P oferecido na base de 1% do peso dos animais para permitir um ganho de peso aproximado de 0,50 kg/dia. Até o dia 134, não houve diferença estatística entre os diversos lotes, inclusive para o tratamento CONTNEG, que não recebeu fósforo suplementar na dieta e ganhou 71,6 kg de peso ou 0,633 kg/dia. Após 866 dias de confinamento (2,37 anos), os animais suplementados com o fosfato bicálcico padrão (120:1) ganharam menos peso que os suplementados com as fontes FMCB 60:1, FB 30:1 e SFT 30:1. Até um ano de suplementação fosfórica com fosfato bicálcico padrão (120:1) artificialmente fluoretado com NaF ou com o fosfato de rocha não se detectou danos à saúde ou ao ganho de peso dos animais. As análises de fósforo nos ossos mostraram diferença estatística apenas entre o tratamento CONTNEG e os que tinham fosfato bicálcico. As concentrações de flúor nos ossos se mostraram intimamente associadas à quantidade de flúor disponível nas fontes utilizadas. Conforme a proporção P:F na dieta foi diminuindo, características relacionadas à fluorose dentária ficaram mais evidentes, sendo que os animais que receberam fontes com relação 10:1, apresentaram, ao final do experimento, dentes incisivos permanentes mal formados, quebradiços e com manchas esbranquiçadas.(AU)

Weight gain and possible interference of fluoride on animal health was investigated in Nellore cattle supplemented during 866 days with alternative sources of phosphorus with different phosphorus:fluor (P:F) ratios. The five treatments were: (1) Negative control (NC, without any supplemental P), (2) dicalcium phosphate (DCP 120:1, DCP 30:1 and DCP 10:1), (3) monodicalcium phosphate (MDCP 60:1), (4) triple superphosphate (TSF 30:1), and (5) cajati rock phosphate (RP 10:1). We used 49 oxen weaned with 8 months of age and an average weight of 230 kg, distributed into seven paddocks with water and mineral mixture formulated without P. A standard diet consisting of sugar cane bagasse (0.03% P) as roughage and a concentrate containing 0.239% P was provided on 1% of live weight to allow a weight gain of about 0.50 kg/day. Until day 134, there was no statistical difference between the various groups, including the treatment NC which received no supplemental phosphorus in the diet and gained weight of 71.6 kg or 0.633 kg/day. After 866 days of confinement (2.37 years), the oxen supplemented with dicalcium phosphate standard (120:1) gained less weight than those supplemented with sources MDCP 60:1, DCP 30:1 and TSF 30:1. Up to one year of supplementation with dicalcium phosphate artificially fluoridated with NaF or with rock phosphate did not result in damage to health or in weight gain of the animals. Analyses of phosphorus in bones showed statistical difference between treatments, and group NC that did not receive any supplemental P showed the lowest values. The concentration of fluoride in bones proved to be closely related to the amount of fluoride available in the sources used. As the ratio P:F in the diet decreased, characteristic signs related to dental fluorosis became more evident, and the animals that received P supplies with 10:1 ratio showed at the end of the experiment permanent malformed incisor teeth, brittle and whitish stained.(AU)

Desempenho ponderal de bovinos Nelore suplementados com fontes alternativas de fósforo / Weight gain of Nelore cattle supplemented with different phosphorus sources

O desempenho produtivo e a possível interferência do flúor sobre a saúde dos animais foram investigados em bovinos Nelore suplementados, por 866 dias, com distintas fontes alternativas de fósforo com diferentes relações fósforo:fluor (P:F). Os tratamentos experimentais foram: Controle negativo (CONTNEG, sem qualquer suplementação com P), fosfato bicálcico (FB 120:1, FB 30:1 e FB 10:1), fosfato monobicálcico (FMBC 60:1), superfosfato triplo (SFT 30:1) e fosfato de rocha de Cajati (FR 10:1). Foram utilizados 49 novilhos, desmamados aos oito meses de idade, castrados e com 230 kg de peso médio, distribuídos em sete piquetes com água e mistura mineral formulada sem P. A dieta padrão foi feita com bagaço de cana (0,03% de P) como volumoso e um concentrado contendo 0,239 % de P oferecido na base de 1% do peso dos animais para permitir um ganho de peso aproximado de 0,50 kg/dia. Até o dia 134, não houve diferença estatística entre os diversos lotes, inclusive para o tratamento CONTNEG, que não recebeu fósforo suplementar na dieta e ganhou 71,6 kg de peso ou 0,633 kg/dia. Após 866 dias de confinamento (2,37 anos), os animais suplementados com o fosfato bicálcico padrão (120:1) ganharam menos peso que os suplementados com as fontes FMCB 60:1, FB 30:1 e SFT 30:1. Até um ano de suplementação fosfórica com fosfato bicálcico padrão (120:1) artificialmente fluoretado com NaF ou com o fosfato de rocha não se detectou danos à saúde ou ao ganho de peso dos animais. As análises de fósforo nos ossos mostraram diferença estatística apenas entre o tratamento CONTNEG e os que tinham fosfato bicálcico. As concentrações de flúor nos ossos se mostraram intimamente associadas à quantidade de flúor disponível nas fontes utilizadas. Conforme a proporção P:F na dieta foi diminuindo, características relacionadas à fluorose dentária ficaram mais evidentes, sendo que os animais que receberam fontes com relação 10:1, apresentaram, ao final do experimento, dentes incisivos permanentes mal formados, quebradiços e com manchas esbranquiçadas.

Weight gain and possible interference of fluoride on animal health was investigated in Nellore cattle supplemented during 866 days with alternative sources of phosphorus with different phosphorus:fluor (P:F) ratios. The five treatments were: (1) Negative control (NC, without any supplemental P), (2) dicalcium phosphate (DCP 120:1, DCP 30:1 and DCP 10:1), (3) monodicalcium phosphate (MDCP 60:1), (4) triple superphosphate (TSF 30:1), and (5) cajati rock phosphate (RP 10:1). We used 49 oxen weaned with 8 months of age and an average weight of 230 kg, distributed into seven paddocks with water and mineral mixture formulated without P. A standard diet consisting of sugar cane bagasse (0.03% P) as roughage and a concentrate containing 0.239% P was provided on 1% of live weight to allow a weight gain of about 0.50 kg/day. Until day 134, there was no statistical difference between the various groups, including the treatment NC which received no supplemental phosphorus in the diet and gained weight of 71.6 kg or 0.633 kg/day. After 866 days of confinement (2.37 years), the oxen supplemented with dicalcium phosphate standard (120:1) gained less weight than those supplemented with sources MDCP 60:1, DCP 30:1 and TSF 30:1. Up to one year of supplementation with dicalcium phosphate artificially fluoridated with NaF or with rock phosphate did not result in damage to health or in weight gain of the animals. Analyses of phosphorus in bones showed statistical difference between treatments, and group NC that did not receive any supplemental P showed the lowest values. The concentration of fluoride in bones proved to be closely related to the amount of fluoride available in the sources used. As the ratio P:F in the diet decreased, characteristic signs related to dental fluorosis became more evident, and the animals that received P supplies with 10:1 ratio showed at the end of the experiment permanent malformed incisor teeth, brittle and whitish stained.

Avaliação de indicadores de qualidade do solo sob alternativas de recuperação do solo no Nordeste Paraense / Evaluation of soil quality indicators under soil reclamation alternatives in Northeastern Pará State

Os indicadores convencionais de fertilidade de solo, mais comumente utilizados, enfatizam o balanço ácido-base e o conteúdo de elementos químicos, mas não consideram adequadamente as propriedades biológicas do solo, responsáveis por grande parte do seu funcionamento. Os indicadores biológicos, ainda pouco difundidos, levam em consideração a atividade microbiana do solo que é mais sensível à dinâmica do solo. Em Marapanim-PA, e utilizando um desenho experimental inteiramente casualizado, com quatro repetições, avaliou-se o comportamento dos indicadores do solo carbono e nitrogênio da biomassa microbiana, fosfatase ácida, matéria orgânica, carbono orgânico e fósforo disponível, em um solo com cultivo sequencial de mandioca e milho, preparo com corte-e-trituração da capoeira original. Os fatores corte-e-trituração, fosfato natural e adubação verde foram arranjados nos seguintes tratamentos: capoeira; testemunha; fosfato natural (FN); feijão-de-porco [Canavalia ensiformis (L.) DC] (FP); FN + FP; FN + guandu [Cajanus cajan (L.) Millspaugh]. (G); FN + titônia [Tithonia diversifolia (Hemsley) A. Gray] (T); FP + G; FP + T. Em quatro épocas de amostragens, foram tiradas amostras compostas do solo (0 - 10 cm) de cada parcela para análise dos indicadores. Os indicadores estudados foram influenciados pela época de amostragem do solo. Os indicadores fosfatase ácida, nitrogênio da biomassa microbiana e carbono da biomassa microbiana foram capazes de detectar os efeitos de maior número de tratamentos de recuperação do solo testados, enquanto a matéria orgânica do solo foi o menos capaz. Ao longo do tempo, a resposta dos indicadores variou em função dos fatores estudados.

The more commonly used traditional soil fertility indicators emphasize the acid-basic balance and the content of chemical elements, but do not consider adequately the biologic soil properties, largely responsible for soil functioning. The biologic indicators, not yet sufficiently used, take into consideration the microbial activity that is more sensible to soil dynamics. This study was carried out in Marapanim-PA and using a completely randomized plot design, with four replications, to evaluate the behavior of some indicators such as microbial biomass, acid phosphatase, soil organic matter, organic carbon and available phosphorus - in a soil cultivated with cassava and corn, and in which the secondary vegetation was prepared by slash-and-trituration practice. The slash-and-trituration, rock phosphate and green manure factors were arranged in the following treatments: secondary vegetation; control; rock phosphate (RP); wonderbean Canavalia ensiformis (L.) DC (W); RP + W; RP + pigeonpea Cajanus cajan (L.) Millspaugh (P); RP + tithonia Tithonia diversifolia (Hemsley) A. Gray (T); W + P; W + T. In four season of sampling, soil samples were taken from the 0 - 10 cm layer of each parcel to measure the indicator values. The indicators studied were influenced by the time of soil sampling. The acid phosphatase, microbial biomass nitrogen and microbial biomass carbon soil indicators were capable of detecting the effects of a higher number of soil reclamation treatments, while soil organic matter was the least capable. With the passing of time, the response of the indicators varied according to the factors studied.

Avaliação de indicadores de qualidade do solo sob alternativas de recuperação do solo no Nordeste Paraense

The more commonly used traditional soil fertility indicators emphasize the acid-basic balance and the content of chemical elements, but do not consider adequately the biologic soil properties, largely responsible for soil functioning. The biologic indicators, not yet sufficiently used, take into consideration the microbial activity that is more sensible to soil dynamics. This study was carried out in Marapanim-PA and using a completely randomized plot design, with four replications, to evaluate the behavior of some indicators such as microbial biomass, acid phosphatase, soil organic matter, organic carbon and available phosphorus - in a soil cultivated with cassava and corn, and in which the secondary vegetation was prepared by slash-and-trituration practice. The slash-and-trituration, rock phosphate and green manure factors were arranged in the following treatments: secondary vegetation; control; rock phosphate (RP); wonderbean Canavalia ensiformis (L.) DC (W); RP + W; RP + pigeonpea Cajanus cajan (L.) Millspaugh (P); RP + tithonia Tithonia diversifolia (Hemsley) A. Gray (T); W + P; W + T. In four season of sampling, soil samples were taken from the 0 - 10 cm layer of each parcel to measure the indicator values. The indicators studied were influenced by the time of soil sampling. The acid phosphatase, microbial biomass nitrogen and microbial biomass carbon soil indicators were capable of detecting the effects of a higher number of soil reclamation treatments, while soil organic matter was the least capable. With the passing of time, the response of the indicators varied according to the factors studied.

Os indicadores convencionais de fertilidade de solo, mais comumente utilizados, enfatizam o balanço ácido-base e o conteúdo de elementos químicos, mas não consideram adequadamente as propriedades biológicas do solo, responsáveis por grande parte do seu funcionamento. Os indicadores biológicos, ainda pouco difundidos, levam em consideração a atividade microbiana do solo que é mais sensível à dinâmica do solo. Em Marapanim-PA, e utilizando um desenho experimental inteiramente casualizado, com quatro repetições, avaliou-se o comportamento dos indicadores do solo carbono e nitrogênio da biomassa microbiana, fosfatase ácida, matéria orgânica, carbono orgânico e fósforo disponível, em um solo com cultivo sequencial de mandioca e milho, preparo com corte-e-trituração da capoeira original. Os fatores corte-e-trituração, fosfato natural e adubação verde foram arranjados nos seguintes tratamentos: capoeira; testemunha; fosfato natural (FN); feijão-de-porco [Canavalia ensiformis (L.) DC] (FP); FN + FP; FN + guandu [Cajanus cajan (L.) Millspaugh]. (G); FN + titônia [Tithonia diversifolia (Hemsley) A. Gray] (T); FP + G; FP + T. Em quatro épocas de amostragens, foram tiradas amostras compostas do solo (0 - 10 cm) de cada parcela para análise dos indicadores. Os indicadores estudados foram influenciados pela época de amostragem do solo. Os indicadores fosfatase ácida, nitrogênio da biomassa microbiana e carbono da biomassa microbiana foram capazes de detectar os efeitos de maior número de tratamentos de recuperação do solo testados, enquanto a matéria orgânica do solo foi o menos capaz. Ao longo do tempo, a resposta dos indicadores variou em função dos fatores estudados.

Rhizosphere pH and phosphorus forms in an Oxisol cultivated with soybean, brachiaria grass, millet and sorghum

Plants have shown different responses to fertilization with rock phosphate, including responses through alteration of the attributes of rhizospheric soil. The objective of this study was to evaluate soil pH alterations and alterations in the contents of forms of phosphorus in the rhizosphere of soil fertilized with rock phosphate as a result of cultivation of species of plants. An experiment was developed under greenhouse conditions to evaluate alterations in the pH and in the forms of phosphorus in the rhizosphere of an Oxisol fertilized with rock phosphate and cultivated with four species. Treatments consisted of the cultivation of four species of soybean - Glycine max (L.) Merrill, brachiaria grass - Brachiaria brizantha Hochst Stapf, millet - Pennisetum glaucum (L.) R. Brown, and sorghum - Sorghum bicolor (L.) Moench grown in PVC columns filled with soil and divided with a nylon screen (25 µm mesh) to impede root growth in part of the column. After 45 days of cultivation, the soil was divided into the layers of 0-1, 1-2, 2-3, 3-4, 4-5, 5-7, 7-9, and 9-14 mm from the rhizoplane and air dried to determine pH and P contents through Hedley fractionation. In the 1-2 and 2-3 mm layers, soybean cultivation caused an increase in pH when compared to the control treatment (without plants). In the other layers, there were no alterations in pH due to cultivation of plants. The cultivation of millet, brachiaria grass, and sorghum reduced the inorganic P content in the most labile forms only in the 0-1 mm layer from the rhizoplane.

Rhizosphere pH and phosphorus forms in an Oxisol cultivated with soybean, brachiaria grass, millet and sorghum

Plants have shown different responses to fertilization with rock phosphate, including responses through alteration of the attributes of rhizospheric soil. The objective of this study was to evaluate soil pH alterations and alterations in the contents of forms of phosphorus in the rhizosphere of soil fertilized with rock phosphate as a result of cultivation of species of plants. An experiment was developed under greenhouse conditions to evaluate alterations in the pH and in the forms of phosphorus in the rhizosphere of an Oxisol fertilized with rock phosphate and cultivated with four species. Treatments consisted of the cultivation of four species of soybean - Glycine max (L.) Merrill, brachiaria grass - Brachiaria brizantha Hochst Stapf, millet - Pennisetum glaucum (L.) R. Brown, and sorghum - Sorghum bicolor (L.) Moench grown in PVC columns filled with soil and divided with a nylon screen (25 µm mesh) to impede root growth in part of the column. After 45 days of cultivation, the soil was divided into the layers of 0-1, 1-2, 2-3, 3-4, 4-5, 5-7, 7-9, and 9-14 mm from the rhizoplane and air dried to determine pH and P contents through Hedley fractionation. In the 1-2 and 2-3 mm layers, soybean cultivation caused an increase in pH when compared to the control treatment (without plants). In the other layers, there were no alterations in pH due to cultivation of plants. The cultivation of millet, brachiaria grass, and sorghum reduced the inorganic P content in the most labile forms only in the 0-1 mm layer from the rhizoplane.

Eficiência agronômica de superfosfato triplo e fosfato natural de Arad em cultivos sucessivos de soja e milho / Agronomic efficiency of triple superphosphate and Arad rock phosphate on crop rotation of soybean and corn

Conduziu-se este estudo, com o objetivo de avaliar os efeitos de doses de adubos fosfatados sobre a cultura da soja e do milho, em cultivos sucessivos. O experimento foi realizado em casa de vegetação da UFGD, em vasos contendo amostras de 5,5 dm³ de um Latossolo Vermelho Distroférrico argiloso, sendo utilizado como fontes de fósforo (P) o superfosfato triplo (SFT) e o fosfato natural de Arad (FNA). O FNA foi utilizado sob duas formas. Em uma, considerou-se o P total (Arad T) e, em outra, apenas a fração de P solúvel em ácido cítrico a 2% (Arad SA), resultando em três fatores de estudo, cada um em seis níveis de P (0, 56, 112, 224, 336 e 560), expressos em mg dm-3. A soja foi semeada em dezembro de 2006 e ao final do ciclo, efetuou-se a colheita, avaliando-se a produtividade de grãos, teores de P na folha e no solo. Após o cultivo da soja, semeou-se o milho, cuja colheita das plantas ocorreu aos 76 dias após a semeadura, sendo avaliados a produção de massa seca da parte aérea e teores de P na folha. O índice de eficiência agronômica foi calculado para ambas as culturas. Conclui-se que, para o primeiro cultivo (soja), o SFT apresentou um melhor desempenho no que se refere à produtividade de grãos, quando comparado ao FNA. No cultivo do milho em sucessão a soja, o FNA tendeu a equiparar-se ao SFT nos atributos avaliados.

The aim of this study was to evaluate the effects of phosphate fertilizer rates on soybean and corn crops, in crop rotation. The experiment was carried out in a greenhouse at the Grande Dourados University, in pots with samples of 5.5 dm³ clayey Dystropherric Red Latosol, where the triple superphosphate (TSP) and the Arad rock phosphate (ARP) were used as P source. Two kinds of ARP were used. In one, the total P (Arad T) was considered while in the other, only the P soluble fraction in citric acid at the concentration of 2% (Arad SA) was considered, resulting in three factors of study, each with six levels of P (0, 56, 112, 224, 336, and 560 mg dm-3). The soybean was sowed in December 2006 and in the end of the cycle, the crop was harvested and evaluated for grain yield, P concentration in leaves and in the soil. After the soybean crop, it was turn for the corn sowing, which harvest occurred 76 days after sowing. The shoot dry matter and P concentrations in leaves were evaluated. The Index of Agronomic Efficiency was calculated for both crops. We concluded that the TSP caused a better soybean grain yield, when compared to the ARP. In the corn crop succeeding the soybean crop, the ARP tended to be similar to the TSP values in the attributes evaluated.

Solubilização de fosfato in vitro por microorganismos rizosféricos de Guandu / In vitro phosphate solubilization by rhizospheric microorganisms from pigeonpea

Diversos microrganismos do solo têm a capacidade de solubilizar diferentes formas de fosfatos inorgânicos, podendo contribuir para o aproveitamento de fontes menos solúveis. Seis meios de cultura sólidos foram testados para isolar microrganismos solubilizadores de fosfato (MSF). O isolamento foi feito a partir do rizoplano mais rizosfera de guandu utilizando a metodologia das diluições sucessivas e Número Mais Provável. Os critérios de seleção usados foram: número de MSF presentes, tempo de aparecimento de colônias e facilidade de distinção do halo transparente. Os meios GL (glicose e extrato de levedura) e GELP (glicose, extrato de levedura, peptona, extrato de solo e sais de base) favoreceram ao crescimento mais rápido e um maior número de MSF. Uma vez obtidos, 12 isolados de fungos e 37 de bactérias foram testados quanto à capacidade de solubilização de fosfato de Araxá em meio líquido. Estes isolados foram incubados, sob agitação, em meio líquido contendo 200 mg de fosfato de Araxá L-1, durante 7 dias a 28 ºC. No início e final do período de incubação foram determinados pH e P solúvel em meio líquido. Houve isolados que, apesar de solubilizar fosfato em meio sólido, não mantiveram esta capacidade em meio líquido. Para os que mantiveram a capacidade solubilizadora de fosfato em meio líquido, houve uma relação inversa entre pH do meio e teor de P solúvel. Os resultados sugerem que a etodologia de isolamento baseada na formação de halo em placa deve ser aliada à quantificação da solubilização de fosfato em meio líquido.

Several soil microorganisms can solubilize different inorganic P forms, contributing to the use of low reactive P sources. Six solid growth media were tested to isolate P-solubilizing microorganisms. Isolation was performed from rhizoplane plus rhizosphere of pigeonpea (Cajanus cajan L. Millsp.), using the method of successive dilutions and Most Probable Number. The criteria for choosing the most suitable solid media to isolate pigeonpea solubilizers were: number of colonies, time to colony appearing and distinction of the transparent halo. Growth media GL (glucose, yeast extract and agar) and GELP (glucose, yeast extract, peptone and agar) induced a faster colony development and a higher number of P-solubilizing microorganisms. Twelve fungi isolates and 37 bacteria were tested in relation to their ability to solubilize ?Araxá? phosphate in liquid medium. The isolates were cultivated for 7 days at 28 ºC in liquid medium on a rotary shaker. 200 mg of ?Araxá? phosphate L-1 was added to the liquid medium. pH and soluble P were determined at initial and final of the incubation time. Some isolates solubilized phosphate in solid medium but not in liquid medium. For the isolates that maintained the solubilization ability in liquid medium, an inverse relationship between pH and soluble P was verified. The results suggest that the isolation method, based on the halo formation in Petri dishes should be combined with quantification of soluble phosphate in liquid media.

Gafsa rock phosphate and triple superphosphate for dry matter production and P uptake by corn

Crops in general make poor use of phosphorous fertilizer and, as a result, recommended rates and production costs are very high. Phosphorus can be made more readily available to plants by proper management of phosphate fertilization, selecting both, type of fertilizer and application method. This study was carried out to evaluate the efficiency of the natural Gafsa rock phosphate and the triple superphosphate on dry matter production and P uptake by corn plants cultivated in a greenhouse. Fertilizers were applied localized and broadcast/incorporated on to two soils with contrasting phosphorus capacity factors (PCF). Rock phosphate broadcast application was as efficient as triple superphosphate in increasing corn plant dry matter in the Tropudult, with lower PCF. This effect was not observed on the Haplustox, owing to the lower P solubility due to the higher Ca concentration in this soil. Triple superphosphate rates increased plant P uptake in both soils and for both application forms. Rock phosphate resulted in higher P-content in plants, but only for broadcast application on the Ultisol.

Os fertilizantes fosfatados, de modo geral, apresentam baixa eficiência de utilização pelas culturas. Essa realidade faz com que as doses aplicadas sejam altas, elevando o custo de produção. O aumento da disponibilidade de fósforo para as plantas pode ser obtido mediante o manejo correto da adubação fosfatada, com ênfase na fonte utilizada e no modo de aplicação mais adequado para solos com diferentes capacidades de adsorção do elemento. Avaliou-se a eficiência do fosfato natural de Gafsa e do superfosfato triplo, em amostras de dois solos (Argissolo Amarelo e Latossolo Amarelo) com diferentes fatores capacidade de fósforo (FCP), em diferentes doses aplicadas de forma incorporada e localizada, sobre a produção de matéria seca e absorção de fósforo por plantas de milho cultivadas em casa de vegetação. No Argissolo Amarelo (menor FCP) o fosfato natural de Gafsa incorporado foi tão eficiente quanto o superfosfato triplo no aumento da produção de matéria seca da parte aérea das plantas de milho. Para o Latossolo Amarelo (maior FCP) esse efeito não foi obtido, provavelmente, devido à diminuição da solubilização do fosfato natural causada pelos maiores teores de Ca no solo. As doses de superfosfato triplo aumentaram a absorção de P pelas plantas de milho em ambos os solos e modos de aplicação. As doses de fosfato natural de Gafsa aumentaram o conteúdo de P nas plantas de milho apenas para a aplicação incorporada no Argissolo.

Gafsa rock phosphate and triple superphosphate for dry matter production and P uptake by corn

Crops in general make poor use of phosphorous fertilizer and, as a result, recommended rates and production costs are very high. Phosphorus can be made more readily available to plants by proper management of phosphate fertilization, selecting both, type of fertilizer and application method. This study was carried out to evaluate the efficiency of the natural Gafsa rock phosphate and the triple superphosphate on dry matter production and P uptake by corn plants cultivated in a greenhouse. Fertilizers were applied localized and broadcast/incorporated on to two soils with contrasting phosphorus capacity factors (PCF). Rock phosphate broadcast application was as efficient as triple superphosphate in increasing corn plant dry matter in the Tropudult, with lower PCF. This effect was not observed on the Haplustox, owing to the lower P solubility due to the higher Ca concentration in this soil. Triple superphosphate rates increased plant P uptake in both soils and for both application forms. Rock phosphate resulted in higher P-content in plants, but only for broadcast application on the Ultisol.

Os fertilizantes fosfatados, de modo geral, apresentam baixa eficiência de utilização pelas culturas. Essa realidade faz com que as doses aplicadas sejam altas, elevando o custo de produção. O aumento da disponibilidade de fósforo para as plantas pode ser obtido mediante o manejo correto da adubação fosfatada, com ênfase na fonte utilizada e no modo de aplicação mais adequado para solos com diferentes capacidades de adsorção do elemento. Avaliou-se a eficiência do fosfato natural de Gafsa e do superfosfato triplo, em amostras de dois solos (Argissolo Amarelo e Latossolo Amarelo) com diferentes fatores capacidade de fósforo (FCP), em diferentes doses aplicadas de forma incorporada e localizada, sobre a produção de matéria seca e absorção de fósforo por plantas de milho cultivadas em casa de vegetação. No Argissolo Amarelo (menor FCP) o fosfato natural de Gafsa incorporado foi tão eficiente quanto o superfosfato triplo no aumento da produção de matéria seca da parte aérea das plantas de milho. Para o Latossolo Amarelo (maior FCP) esse efeito não foi obtido, provavelmente, devido à diminuição da solubilização do fosfato natural causada pelos maiores teores de Ca no solo. As doses de superfosfato triplo aumentaram a absorção de P pelas plantas de milho em ambos os solos e modos de aplicação. As doses de fosfato natural de Gafsa aumentaram o conteúdo de P nas plantas de milho apenas para a aplicação incorporada no Argissolo.

Efeito de diferentes fontes de fósforo na dieta sobre as características dos ossos de porcas e suas proles / Effects of different sources of phosphorus on bone characteristics of sows and their offspring

The main limitation in the use of rock phosphate in swine diets is the fluorine content that may be toxic when used for long periods. The objective of this study was to evaluate the effects of monocalcium phosphate (MP) and Tapira phosphate (TP) to sows and their offspring when fed during four reproductive cycles, as compared to the traditional use of dicalcium phosphate (DP). The study involved 13, 16 and 13 sows for DP, MP and TP phosphates, respectively. The litters were also fed with the same respective phosphate treatments until they reached 95 kg of body weight. The variables analyzed were: macroscopic tooth lesions score in sows, histological evaluation of bone tissue, the thyroid and parathyroid glands, and the evaluation of bone mineral contents and bone morphometrical characteristics. The results showed that TP is toxic for sows when used continuously during 4 reproductive cycles and causes lesions of chronic fluorosis in the teeth and bone tissue. TP also affected the litters with some minor lesions of fluorosis in bone tissue at the 4th reproductive cycle. MP induced some minor inespecific lesions only in bone tissue of the sows. No deleterious effects were observed in sows and litters fed DP.(AU)

A limitação principal do uso de fosfatos naturais na alimentação de suínos é a presença de flúor que pode ser tóxico quando ingerido por longos períodos. O objetivo deste trabalho foi avaliar os eventuais efeitos deletérios dos fosfatos Monocálcico (MP) e Tapira (TP), sobre porcas e suas proles alimentadas com esses fosfatos durante quatro ciclos reprodutivos consecutivos, comparativamente com o tradicional fosfato bicálcico (DP). Foram usadas 13 porcas alimentadas com FB (testemunha) 16 com MP e 13 com TP. As leitegadas oriundas de cada ciclo também foram alimentados com os respectivos fosfatos até a idade de abate. As seguintes variáveis foram avaliadas: lesões macroscópicas nos dentes das porcas, alterações histológicas no tecido ósseo e nas glândulas tireóide e paratireóide, conteúdo de minerais no tecido ósseo e características morfométricas do osso. Os resultados obtidos mostraram que o uso de TP por 4 ciclos reprodutivos, na alimentação de suínos, provocou lesões de fluorose crônica nos dentes e tecido ósseo das porcas. As leitegadas alimentadas com este fosfato também apresentaram discretas lesões de fluorose, mas somente evidentes no 4º ciclo reprodutivo. Somente algumas alterações inespecíficas ocorreram nos ossos das porcas que receberam o MP.O DP não provocou alterações patológicas no tecido ósseo, tanto nas porcas como nas suas leitegadas.(AU)

Efeito de diferentes fontes de fósforo na dieta sobre as características dos ossos de porcas e suas proles

The main limitation in the use of rock phosphate in swine diets is the fluorine content that may be toxic when used for long periods. The objective of this study was to evaluate the effects of monocalcium phosphate (MP) and Tapira phosphate (TP) to sows and their offspring when fed during four reproductive cycles, as compared to the traditional use of dicalcium phosphate (DP). The study involved 13, 16 and 13 sows for DP, MP and TP phosphates, respectively. The litters were also fed with the same respective phosphate treatments until they reached 95 kg of body weight. The variables analyzed were: macroscopic tooth lesions score in sows, histological evaluation of bone tissue, the thyroid and parathyroid glands, and the evaluation of bone mineral contents and bone morphometrical characteristics. The results showed that TP is toxic for sows when used continuously during 4 reproductive cycles and causes lesions of chronic fluorosis in the teeth and bone tissue. TP also affected the litters with some minor lesions of fluorosis in bone tissue at the 4th reproductive cycle. MP induced some minor inespecific lesions only in bone tissue of the sows. No deleterious effects were observed in sows and litters fed DP.

A limitação principal do uso de fosfatos naturais na alimentação de suínos é a presença de flúor que pode ser tóxico quando ingerido por longos períodos. O objetivo deste trabalho foi avaliar os eventuais efeitos deletérios dos fosfatos Monocálcico (MP) e Tapira (TP), sobre porcas e suas proles alimentadas com esses fosfatos durante quatro ciclos reprodutivos consecutivos, comparativamente com o tradicional fosfato bicálcico (DP). Foram usadas 13 porcas alimentadas com FB (testemunha) 16 com MP e 13 com TP. As leitegadas oriundas de cada ciclo também foram alimentados com os respectivos fosfatos até a idade de abate. As seguintes variáveis foram avaliadas: lesões macroscópicas nos dentes das porcas, alterações histológicas no tecido ósseo e nas glândulas tireóide e paratireóide, conteúdo de minerais no tecido ósseo e características morfométricas do osso. Os resultados obtidos mostraram que o uso de TP por 4 ciclos reprodutivos, na alimentação de suínos, provocou lesões de fluorose crônica nos dentes e tecido ósseo das porcas. As leitegadas alimentadas com este fosfato também apresentaram discretas lesões de fluorose, mas somente evidentes no 4º ciclo reprodutivo. Somente algumas alterações inespecíficas ocorreram nos ossos das porcas que receberam o MP.O DP não provocou alterações patológicas no tecido ósseo, tanto nas porcas como nas suas leitegadas.

Estudos histológico-morfométricos e microrradiográficos de costelas de bovinos suplementados com fosfato de rocha

The present study was conducted to evaluate possible bone changes in cattle due to the ingestion of different levels of fluorine from rock phosphate used as a phophorus supplement. The bone material studied were ribs collected from cattle of three experiments where Tapira rock phosphate was used at different levels and during different periods as a partial or sole source of supplementary phosphorus. In the first experiment feedlot cattle ingested during a 6 month period 63 and 128g/day of Tapira rock phosphate containing 1.3% fluorine. In the second experiment cattle maintained in Brachiaria decumbens pastures during 33 months ingested several levels of Tapira rock phosphate in the mineral mixtures. In the third experiment heifers averaging 14 months of age ingested a mineral supplement with Tapira rock phosphate until the 5th lactation period. Careful examination of the rib samples by histological, morphometric and microradiographic techniques revealed no abnormalities which could be related to fluorine ingestion, neither any differences among tretaments regarding the bone structure. These findings support the conclusion that, as far as bone alterations are concerned, Tapira rock phosphate could be used as a source of phosphorus for cattle under the conditions described in the experiments, a practice which would markedly reduce the cost of phosphorus supplementation.

O objetivo do presente trabalho foi o de avaliar, através de técnicas especializadas, as possíveis alterações ósseas produzidas em bovinos em decorrência da ingestão prolongada de diferentes níveis de flúor contido no fosfato de rocha de Tapira utilizado como fonte suplementar de fósforo. No primeiro experimento bovinos confinados ingeriram, durante 6 meses, quantidades variáveis (63 e 128g/dia) de fosfato de Tapira contendo 1.3% de flúor. No segundo experimento, bovinos em pastos de Brachiaria decumbens ingeriram, durante 33 meses, misturas minerais contendo diferentes níveis de fosfato de rocha de Tapira. No terceiro experimento, novilhas com idade inicial média de 14 meses ingeriram mistura mineral com fosfato de Tapira até a quinta lactação inclusivamente. Através de exames histológicos, morfométricos e microrradiográficos das amostras de costelas, não se observaram alterações da normalidade óssea, bem como não foram registradas diferenças entre amostras provenientes de diferentes tratamentos. Tais achados permitem inferir que, do ponto de vista de alterações ósseas, o fosfato de rocha de Tapira pode ser utilizado como fonte suplementar de fósforo para bovinos, nas dosagens, períodos e manejos alimentares estudados, sem risco de produzir alterações patológicas nos esqueleto dos animais.

Estudos histológico-morfométricos e microrradiográficos de costelas de bovinos suplementados com fosfato de rocha

The present study was conducted to evaluate possible bone changes in cattle due to the ingestion of different levels of fluorine from rock phosphate used as a phophorus supplement. The bone material studied were ribs collected from cattle of three experiments where Tapira rock phosphate was used at different levels and during different periods as a partial or sole source of supplementary phosphorus. In the first experiment feedlot cattle ingested during a 6 month period 63 and 128g/day of Tapira rock phosphate containing 1.3% fluorine. In the second experiment cattle maintained in Brachiaria decumbens pastures during 33 months ingested several levels of Tapira rock phosphate in the mineral mixtures. In the third experiment heifers averaging 14 months of age ingested a mineral supplement with Tapira rock phosphate until the 5th lactation period. Careful examination of the rib samples by histological, morphometric and microradiographic techniques revealed no abnormalities which could be related to fluorine ingestion, neither any differences among tretaments regarding the bone structure. These findings support the conclusion that, as far as bone alterations are concerned, Tapira rock phosphate could be used as a source of phosphorus for cattle under the conditions described in the experiments, a practice which would markedly reduce the cost of phosphorus supplementation.

O objetivo do presente trabalho foi o de avaliar, através de técnicas especializadas, as possíveis alterações ósseas produzidas em bovinos em decorrência da ingestão prolongada de diferentes níveis de flúor contido no fosfato de rocha de Tapira utilizado como fonte suplementar de fósforo. No primeiro experimento bovinos confinados ingeriram, durante 6 meses, quantidades variáveis (63 e 128g/dia) de fosfato de Tapira contendo 1.3% de flúor. No segundo experimento, bovinos em pastos de Brachiaria decumbens ingeriram, durante 33 meses, misturas minerais contendo diferentes níveis de fosfato de rocha de Tapira. No terceiro experimento, novilhas com idade inicial média de 14 meses ingeriram mistura mineral com fosfato de Tapira até a quinta lactação inclusivamente. Através de exames histológicos, morfométricos e microrradiográficos das amostras de costelas, não se observaram alterações da normalidade óssea, bem como não foram registradas diferenças entre amostras provenientes de diferentes tratamentos. Tais achados permitem inferir que, do ponto de vista de alterações ósseas, o fosfato de rocha de Tapira pode ser utilizado como fonte suplementar de fósforo para bovinos, nas dosagens, períodos e manejos alimentares estudados, sem risco de produzir alterações patológicas nos esqueleto dos animais.

Non-conventional P sources for zebu cows in Brazil

To evaluate non-conventional phosphorus sources, a group of 400 Nellore cows mantained under pasture received a mineral mixture with different P sources (group I: superphosphate - 500 ppm P; group II: superphosphate - 340 ppm P plus rock phosphate Patos 160 ppm P; group III: superphosphate 340 ppm P plus dicalcium phosphate 160 ppm P; group IV - dicalcium phosphate 500 ppm P). There were no differences in pregnancy rate, calving rate and calving interval. A fluorine deposition in bone was observed for the treatments with superphosphate and rock phosphate (66.92 ± 15.53; 69.97 ± 6.5 and 64.05 ± 3.35% respectively for group I, II and III). Superphosphate was almost as good dicalcium phosphate to provide phosphorus for grazing cows and there was a potentially significant economic advantage over dicalcium phosphate.

Quatrocentas vacas Nelore, mantidas em pastagem, receberam mistura mineral contendo fontes não convencionais de fósforo (grupo I - 500 ppm P-superfosfato triplo; grupo II - 340 ppm P como superfosfato e 160 ppm P como rocha Patos; grupo III - 340 ppm P como superfosfato e 160 ppm P como fosfato bicálcico; grupo IV -500 ppm P como fosfato bicálcico). Não se verificou diferenças na taxa de prenhez, porcentagem de nascimento e intervalo entre partos. Observou-se que houve maior concentração de flúor nos ossos para o tratamento com fosfato de rocha. O superfosfato triplo apresentou-se como fonte adequada de P e mostrou vantagem econômica em relação ao bicálcico.