A novel consensus bacterial 6-phytase variant improves the responses of laying hens fed an inorganic phosphorus-free diet with reduced energy and nutrients from 23 to 72 wk of age.

The objective of this study was to evaluate the effect of a novel consensus bacterial 6-phytase variant (PhyG) on egg productivity, eggshell quality, and body composition of laying hens fed inorganic phosphate-free diets with reduced energy and nutrients from 23 to 72 wk of age. Five treatments were randomly assigned, performing 28 replicates per treatment with 4 hens each, totaling 560 Hy-Line W80 birds. A positive control (PC) feed was formulated to contain adequate levels of energy and nutrients. A negative control (NC) feed was formulated without added inorganic phosphate (0.12% nonphytic phosphorus [nPP]) and reduced in Ca, Na, dig AA, and metabolizable energy in comparison with PC feed. Phytase was supplemented in the NC feed at 0, 300, 600, and 900 FTU/kg of feed. The responses evaluated were performance, egg quality, economic analysis, body composition, and tibia composition. Data were analyzed by a 2-factor (diet and age) repeated measure analysis. Overall, the feed intake, hen-day egg production, egg mass, and egg revenue were reduced by the complete removal of dicalcium phosphate (DCP) (P < 0.05). Supplement phytase in the NC diet elicits a positive response on each one of those variables. Laying hens consuming the NC feed with 900 FTU/kg of phytase produced more eggs per hen-housed compared with the phytase dosages of 300 and 600 FTU/kg. Body composition was not affected by dietary nPP, Ca, Na, dig AA, and energy reductions (P > 0.05). At 72-wk-old, tibia ash was reduced in hens consuming the NC diet vs. PC (P < 0.05) and no difference was observed between hens supplemented with phytase and the PC feed. Margin over feeding cost increased in a dose-dependent manner with phytase supplementation. Supplementation with 900 FTU/kg of phytase is recommended to improve the number of eggs produced per hen-housed and the number of marketable eggs produced through 23 to 72 wk of age, under this dietary setting.

Soil degradation and Cu, Cr, Ni, Pb and Zn contamination in dumpsites of humid and semiarid tropical regions in northeastern Brazil.

We investigated soil characteristics and heavy metal content changes in 12 inactive dumpsites in humid and semiarid tropical climates in Northeast Brazil. The metals Cu, Cr, Ni, Pb and Zn in soil samples were determined by atomic absorption spectrophotometry. Other parameters measured include pH, electric conductivity, soil texture, soil organic carbon, total porosity and available P. The soil contents of sand, clay, soil organic carbon, available P and heavy metals, and soil bulk density, total porosity and pH were efficient indicators of soil degradation. We found no influence of current use, soil class or climate on the soil response. The mean concentrations of heavy metals in the dumpsite soils followed the order Zn (49.96 mg kg-1) > Cu (38.48 mg kg-1) > Pb (24.64 mg kg-1) > Cr (21.94 mg kg-1) > Ni (7.77 mg kg-1). They were 6- to 36-fold higher than the background values for the region and were above the Brazilian guideline values for metals. The four dumpsite soils that showed simultaneous contamination with two or more heavy metals were located in the semiarid region. This challenges the assumption that soil impacts in the semiarid region are minimal due to lower leaching and high evaporation. Soil changes increase with time under activity, size and decommission time of the dumpsite. These data are important for local authorities to establish more effective targeting policies for closure of dumps and control of the spread of contaminants in areas impacted by the disposal of municipal waste.

Effects of long-term fertilization on phoD-harboring bacterial community in Karst soils.

Phosphorus (P) acquisition by plants from soil organic P mainly relies on microorganisms. Examining the community of functional microbes that encode phosphatases (e.g. PhoD) under different fertilization managements may provide valuable information for promoting soil organic P availability. Here, we investigated how the abundance and community diversity of phoD-harboring bacteria responded to long-term fertilization in Karst soils. Six fertilization treatments were designed as follows: non-fertilized control (CK), inorganic fertilization only (NPK), and inorganic fertilization combined with low- and high amounts of straw (LSNPK and HSNPK), or cattle manure (LMNPK and HMNPK). We found that soil available phosphorus (AP) content and the activity of alkaline phosphatase (ALP) were significantly higher in all combined inorganic/organic fertilization treatments, while the abundance of the phoD gene was only higher in the HMPNK treatment, compared to NPK. The combination of inorganic/organic fertilizations had no effect on the diversity of phoD genes compared to NPK alone, but the phoD gene richness was greater in these treatments as compared to the control. Only organic fertilization combinations with high amounts of organic matter (both HSNPK and HMNPK) significantly affected the phoD community structure. A structure equation model demonstrated that soil organic carbon (SOC), rather than P, greatly affected the phoD community structure, suggesting that organic P mineralization in soils is decoupled from C mineralization. Our results suggested that optimized combinations of inorganic/organic fertilizations could promote P availability via regulating soil phoD-harboring bacteria community diversity and ALP activity.

CARACTERIZACIÓN DE LA FERTILIDAD QUÍMICA DE LOS SUELOS EN SISTEMAS PRODUCTIVOS DE LA ALTILLANURA PLANA, META, COLOMBIA / CHEMICAL CHARACTERIZATION OF SOIL FERTILITY IN PRODUCTION SYSTEMS OF A FLAT HIGH PLATEAU, META, COLOMBIA

La Altillanura Plana de la Orinoquia de Colombia es por excelencia una despensa agropecuaria. Su fertilidad química dependerá principalmente de sistemas productivos que involucren un manejo de los suelos de manera apropiada y que incrementen los contenidos de la materia orgánica del suelo (MOS). Se aplicó un análisis de tipo multivariado con el objetivo de caracterizar la fertilidad química de los suelos en algunos sistemas productivos de la Altillanura Plana comparados con otros de Piedemonte del departamento del Meta, Oriente de Colombia. Fueron seleccionados cinco sistemas productivos en cada zona. Se encontró una alta variabilidad en las características químicas de los suelos, siendo la MOS y la acidez de los suelos las que tuvieron mayor capacidad discriminatoria entre los sistemas productivos. El análisis de clúster conformo tres grupos bien definidos: suelos de alta, mediana y baja fertilidad; y aunque no se encontró un patrón definido en cuanto a los sistemas productivos que los caracterice en cada uno de los grupos, cinco de los sistemas productivos de Piedemonte estuvieron ubicados en suelos de baja fertilidad. Las pasturas mejoradas y los sistemas silvopastoriles (SPSs) de la Altillanura Plana son una buena opción para aumentar la fertilidad química de los suelos.

The flat high plateau of the Colombian Orinoquia is, par excellence, an agricultural pantry. Its chemical soil fertility depends mainly of productive systems that involve appropriate soil management that increment soil organic matter (SOM). A multivariate analysis was applied in order to characterize the soil chemical fertility in some productive systems of the flat high plateau compared to other foothills of the Department of Meta in the western region of Colombia. Five production systems were selected for each zone. A high variability in the chemical characteristics of the soils was found, being SOM and the acidity of the soils the ones having greater discriminatory capacity among the productive systems. Cluster analysis consisted of three well-defined groups: high, medium and low fertility soils and, although a definite pattern of productive systems was not found in each of the groups, five productive foothill systems were located in low fertility soils. The improved pastures and the silvopastoral systems (SPSs) of flat high plateaus are a good option to increase the chemical fertility of the soils.

Biological Invasion Influences the Outcome of Plant-Soil Feedback in the Invasive Plant Species from the Brazilian Semi-arid.

Plant-soil feedback is recognized as the mutual interaction between plants and soil microorganisms, but its role on the biological invasion of the Brazilian tropical seasonal dry forest by invasive plants still remains unclear. Here, we analyzed and compared the arbuscular mycorrhizal fungi (AMF) communities and soil characteristics from the root zone of invasive and native plants, and tested how these AMF communities affect the development of four invasive plant species (Cryptostegia madagascariensis, Parkinsonia aculeata, Prosopis juliflora, and Sesbania virgata). Our field sampling revealed that AMF diversity and frequency of the Order Diversisporales were positively correlated with the root zone of the native plants, whereas AMF dominance and frequency of the Order Glomerales were positively correlated with the root zone of invasive plants. We grew the invasive plants in soil inoculated with AMF species from the root zone of invasive (I changed) and native (I unaltered) plant species. We also performed a third treatment with sterilized soil inoculum (control). We examined the effects of these three AMF inoculums on plant dry biomass, root colonization, plant phosphorous concentration, and plant responsiveness to mycorrhizas. We found that I unaltered and I changed promoted the growth of all invasive plants and led to a higher plant dry biomass, mycorrhizal colonization, and P uptake than control, but I changed showed better results on these variables than I unaltered. For plant responsiveness to mycorrhizas and fungal inoculum effect on plant P concentration, we found positive feedback between changed-AMF community (I changed) and three of the studied invasive plants: C. madagascariensis, P. aculeata, and S. virgata.

Adubação do milho com superfosfato triplo em Latossolo Vermelho sob efeito residual de fontes alternativas de fósforo / Corn fertilization with triple superphosphate in a Typic Hapludox soil under the residual effect of alternative phosphorus sources

O uso de fontes alternativas na adubação fosfatada em solos de carga variável pode influenciar a adubação com fosfato solúvel. O objetivo do trabalho foi avaliar a eficiência na disponibilidade de fósforo (P) para a cultura do milho em resposta a adubação com superfosfato triplo (TSP) em Latossolo Vermelho sob efeito residual de fontes alternativas de P. O experimento foi conduzido em casa de vegetação em delineamento inteiramente casualizado no esquema fatorial 2x4x5, com quatro repetições. Os tratamentos consistiram de cinco doses de TSP (0, 30, 60, 90 e 120 mg dm-3 de P) com dois cultivos sequenciais de milho com calagem e sem calagem, em solo anteriormente adubado com Fosfato precipitado-1 (PP1), Fosfato precipitado-2 (PP2), Fosfato natural reativo (NRP) e TSP na dose de 120 mg dm-3 de P e cultivado com Urochloa. A dinâmica e a eficiência do fósforo (P) no sistema solo-planta proveniente superfosfato triplo (TSP) na adubação da cultura do milho é alterado pelo efeito residual de fontes alternativas e pelo uso de corretivos no solo. Sob o efeito residual de PP2 e NRP houve maior produção de matéria seca e acúmulo de P nas plantas de milho em doses a partir de 30 mg dm-3 de P na forma de TSP, sendo os maiores incrementos no primeiro cultivo e nas condições do solo com calagem. Nos tratamentos sob o efeito residual de PP2 e NRP houveram os maiores teores de P disponível no solo após dois cultivos sequenciais de milho em ambas as condições de manejo da acidez do solo, demonstrando um maior efeito residual.(AU)

In variable-charge soils, the use of alternative phosphorus sources may influence further soluble phosphate fertilization. This study aimed to evaluate phosphorus (P) availability for corn plants in response to triple superphosphate fertilization (TSP) in a Typic Hapludox (Oxisol) soil with residual P from alternative sources. The experiment was carried out in a greenhouse under a completely randomized design and 2x4x5 factorial scheme, with four replications. Treatments consisted of five TSP doses (0, 30, 60, 90, and 120 mg dm-3 P), and two sequential corn croppings with and without liming; the area was previously grown with Urochloa spp. and fertilized with precipitated phosphate-1 (PP1), precipitated phosphate-2 (PP2), natural reactive phosphate (NRP), and TSP at 120 mg dm-3. The P from TSP has its dynamics within the soil-plant system and fertilization efficiency in corn crops altered by the residual effect of P from alternative sources and by soil acidity correctives. The residual effects of PP2 and NRP, dry matter yield and P accumulation in corn were higher for TSP doses above 30 mg dm-3, being greater in the first cropping and in limed soils. Yet for PP2 and NRP residual effects, the highest soil availability of P was registered after the two sequential cropping in both acidity conditions, thus showing an enhanced residual effect.(AU)

Adubação do milho com superfosfato triplo em Latossolo Vermelho sob efeito residual de fontes alternativas de fósforo / Corn fertilization with triple superphosphate in a Typic Hapludox soil under the residual effect of alternative phosphorus sources

O uso de fontes alternativas na adubação fosfatada em solos de carga variável pode influenciar a adubação com fosfato solúvel. O objetivo do trabalho foi avaliar a eficiência na disponibilidade de fósforo (P) para a cultura do milho em resposta a adubação com superfosfato triplo (TSP) em Latossolo Vermelho sob efeito residual de fontes alternativas de P. O experimento foi conduzido em casa de vegetação em delineamento inteiramente casualizado no esquema fatorial 2x4x5, com quatro repetições. Os tratamentos consistiram de cinco doses de TSP (0, 30, 60, 90 e 120 mg dm-3 de P) com dois cultivos sequenciais de milho com calagem e sem calagem, em solo anteriormente adubado com Fosfato precipitado-1 (PP1), Fosfato precipitado-2 (PP2), Fosfato natural reativo (NRP) e TSP na dose de 120 mg dm-3 de P e cultivado com Urochloa. A dinâmica e a eficiência do fósforo (P) no sistema solo-planta proveniente superfosfato triplo (TSP) na adubação da cultura do milho é alterado pelo efeito residual de fontes alternativas e pelo uso de corretivos no solo. Sob o efeito residual de PP2 e NRP houve maior produção de matéria seca e acúmulo de P nas plantas de milho em doses a partir de 30 mg dm-3 de P na forma de TSP, sendo os maiores incrementos no primeiro cultivo e nas condições do solo com calagem. Nos tratamentos sob o efeito residual de PP2 e NRP houveram os maiores teores de P disponível no solo após dois cultivos sequenciais de milho em ambas as condições de manejo da acidez do solo, demonstrando um maior efeito residual.

In variable-charge soils, the use of alternative phosphorus sources may influence further soluble phosphate fertilization. This study aimed to evaluate phosphorus (P) availability for corn plants in response to triple superphosphate fertilization (TSP) in a Typic Hapludox (Oxisol) soil with residual P from alternative sources. The experiment was carried out in a greenhouse under a completely randomized design and 2x4x5 factorial scheme, with four replications. Treatments consisted of five TSP doses (0, 30, 60, 90, and 120 mg dm-3 P), and two sequential corn croppings with and without liming; the area was previously grown with Urochloa spp. and fertilized with precipitated phosphate-1 (PP1), precipitated phosphate-2 (PP2), natural reactive phosphate (NRP), and TSP at 120 mg dm-3. The P from TSP has its dynamics within the soil-plant system and fertilization efficiency in corn crops altered by the residual effect of P from alternative sources and by soil acidity correctives. The residual effects of PP2 and NRP, dry matter yield and P accumulation in corn were higher for TSP doses above 30 mg dm-3, being greater in the first cropping and in limed soils. Yet for PP2 and NRP residual effects, the highest soil availability of P was registered after the two sequential cropping in both acidity conditions, thus showing an enhanced residual effect.

Eficiência de uma fitase bacteriana na liberação de fósforo fítico em dietas de frangos de corte / Efficiency of a bacterial phytase to release phytate phosphorus in broiler chicken diets

Foi avaliada a eficiência de uma fitase (FT) bacteriana na liberação de fósforo fítico utilizando-se curvas de calibração para características ósseas e de desempenho em frangos de corte. O delineamento experimental foi inteiramente ao acaso, com seis tratamentos e seis repetições até 28 dias de idade. O tratamento-controle foi uma dieta à base de milho e farelo de soja deficiente em fósforo (P). Dois tratamentos corresponderam às dietas basais acrescidas de P suplementar, 0,05 por cento e 0,10 por cento, e os outros à dieta basal com 66, 99 e 131 FTU/kg de ração. A curva padrão é definida pelo efeito da adição de P suplementar consumido sobre características ósseas e de desempenho, e os resultados dos tratamentos com fitase são confrontados com a curva para cálculo de P liberado. A adição de P suplementar influenciou o ganho de peso, o peso vivo e o consumo de ração de forma quadrática, bem como miligramas de cinzas ósseas de forma linear. A curva padrão adotada foi da variável miligramas de cinzas ósseas, pois a resposta linear melhor descreve a curva. As inclusões de 66, 99 e 131 FTU/kg liberaram, respectivamente, 0,048 por cento, 0,049 por cento e 0,062 por cento de P. A fitase bacteriana é eficiente na liberação de fósforo fítico e possui viabilidade econômica.

The objective was to determine the efficiency of a bacterial phytase to release phytate phosphorus using calibration curves for performance and bone characteristics in broiler chickens. A completely randomized design with 6 treatments and 6 replicates was used in an experiment with chickens from 1 to 28 days of age. The control treatment was a diet based on corn and soybean meal deficient in phosphorus. Two treatments consisted of the basal diet supplemented with additional phosphorus (0.05 percent and 0.10 percent), and the other treatments received 66, 99 and 131 FTU/kg of feed. The standard curves represented the effect of the levels of additional P intake on performance and bone variables. Then, the responses of the phytase treatments were compared to the standard curves to calculate the P released. The increasing levels of supplemental P had a quadratic effect on weight gain, live weight and feed intake, and linear effect on mg of bone ash. The standard curve elected was mg of bone ash because linear response better represents the curve. Inclusion of 66, 99 and 131 FTU/kg released 0.048 percent, 0.049 percent and 0.062 percent. The bacterial phytase is efficient in releasing phytate, which may be of economical significance.

Eficiência de uma fitase bacteriana na liberação de fósforo fítico em dietas de frangos de corte / Efficiency of a bacterial phytase to release phytate phosphorus in broiler chicken diets

Foi avaliada a eficiência de uma fitase (FT) bacteriana na liberação de fósforo fítico utilizando-se curvas de calibração para características ósseas e de desempenho em frangos de corte. O delineamento experimental foi inteiramente ao acaso, com seis tratamentos e seis repetições até 28 dias de idade. O tratamento-controle foi uma dieta à base de milho e farelo de soja deficiente em fósforo (P). Dois tratamentos corresponderam às dietas basais acrescidas de P suplementar, 0,05 por cento e 0,10 por cento, e os outros à dieta basal com 66, 99 e 131 FTU/kg de ração. A curva padrão é definida pelo efeito da adição de P suplementar consumido sobre características ósseas e de desempenho, e os resultados dos tratamentos com fitase são confrontados com a curva para cálculo de P liberado. A adição de P suplementar influenciou o ganho de peso, o peso vivo e o consumo de ração de forma quadrática, bem como miligramas de cinzas ósseas de forma linear. A curva padrão adotada foi da variável miligramas de cinzas ósseas, pois a resposta linear melhor descreve a curva. As inclusões de 66, 99 e 131 FTU/kg liberaram, respectivamente, 0,048 por cento, 0,049 por cento e 0,062 por cento de P. A fitase bacteriana é eficiente na liberação de fósforo fítico e possui viabilidade econômica.(AU)

The objective was to determine the efficiency of a bacterial phytase to release phytate phosphorus using calibration curves for performance and bone characteristics in broiler chickens. A completely randomized design with 6 treatments and 6 replicates was used in an experiment with chickens from 1 to 28 days of age. The control treatment was a diet based on corn and soybean meal deficient in phosphorus. Two treatments consisted of the basal diet supplemented with additional phosphorus (0.05 percent and 0.10 percent), and the other treatments received 66, 99 and 131 FTU/kg of feed. The standard curves represented the effect of the levels of additional P intake on performance and bone variables. Then, the responses of the phytase treatments were compared to the standard curves to calculate the P released. The increasing levels of supplemental P had a quadratic effect on weight gain, live weight and feed intake, and linear effect on mg of bone ash. The standard curve elected was mg of bone ash because linear response better represents the curve. Inclusion of 66, 99 and 131 FTU/kg released 0.048 percent, 0.049 percent and 0.062 percent. The bacterial phytase is efficient in releasing phytate, which may be of economical significance.(AU)

Carcass characteristics of broilers at 42 days receiving diets with phytase in different energy and crude protein levels / Características de carcaça de frangos aos 42 dias recebendo rações com fitase em diferentes níveis energéticos e de proteína bruta

The aim of this study was to evaluate carcass characteristics and quality of breast meat after the inclusion of phytase in broiler diets with different levels of apparent metabolizable energy (AMEn) corrected for nitrogen and reduced crude protein (CP) supplemented with essential amino acids following the concept of ideal protein. A total of 1,500 Cobb broilers from 22 to 42 days (initial weight of 833 ± 7 g and final weight of 2741 ± 48 g) were distributed in completely randomized design in a factorial 3x3+1 experiment (three levels of AMEn - 2,950; 3,100 and 3,250 kcal/kg - and three levels of CP - 14, 16 and 18 percent - and an additional treatment - control without phytase, with 3,100 kcal/kg EMAn, 19.2 percent PB and 0.4 percent available phosphorus), in six replications of 25 birds each. At the end of the trial, two birds of each experimental unit were slaughtered in order to measure carcass yield and yields of parts and to determine the chemical composition of the breast meat. The levels of AMEn and CP of diets with phytase influenced (P<0.05) the carcass, breast and abdominal fat yield and humidity, protein and fat percentage in the pectoralis major muscle of the birds. The levels of 3,100 kcal AMEn/kg and 18 percent CP showed higher carcass and breast yield and lower abdominal fat deposition, although with higher fat percentage in the breast meat. It was concluded that the manipulation of the energy levels of diets with reduced crude protein supplemented with amino acids and phytase influenced the yields of parts of carcass and the breast meat quality of the broilers at 42 days.

Objetivou-se, com este trabalho, estudar as características de carcaça e qualidade da carne do peito depois da inclusão de fitase em dietas para frangos de corte, com diferentes níveis de energia metabolizável aparente corrigida para nitrogênio (EMAn) e proteína bruta (PB) reduzida, suplementadas com aminoácidos essenciais seguindo o conceito de proteína ideal. Foram utilizados 1.500 frangos machos Cobb dos 22 aos 42 dias de idade com peso inicial de 833 ± 7 g e final de 2741 ± 48 g distribuídos em delineamento inteiramente casualizado em esquema fatorial 3x3+1 (três níveis de EMAn - 2950, 3100 e 3250 kcal/kg - e três de PB - 14, 16 e 18 por cento - e um tratamento adicional - controle, sem fitase, com 3100 kcal/kg EMAn, 19,2 por cento de PB e 0,4 por cento de fósforo disponível) em seis repetições com 25 aves cada. Ao final do experimento, duas aves de cada parcela foram sacrificadas para a mensuração do rendimento de carcaça e de cortes e determinação da composição química da carne do peito. Os níveis de energia e proteína em rações com fitase influenciaram (P<0,05) os rendimentos de carcaça, peito e gordura abdominal a porcentagem de umidade, proteína e lipídios no músculo pectoralis major das aves, sendo os níveis de 3100 kcal EMAn/kg e 18 por cento de PB os que proporcionaram maiores rendimentos de carcaça e de peito e menor deposição de gordura abdominal, mas em maior teor de lipídios na carne do peito. Conclui-se que a manipulação da energia em rações com reduzido teor de proteína e suplementadas com aminoácidos e fitase influencia o rendimento de cortes e a qualidade da carne do peito de frangos aos 42 dias.

Hillslope curvature, clay mineralogy, and phosphorus adsorption in an Alfisol cultivated with sugarcane

Hillslope curvatures are associated with specific environments that correlate to chemical and mineralogical attributes of soil, so determining specific management zones. Phosphorus is one of the main limiting factors to the development and longevity of sugarcane. The type and the mineralogical constitution of the clay fraction play an important role in the phosphorus (P) adsorption of soil. High proportion of gibbsite (Gb) in soil may be the major responsible for P adsorption. The relationships among spatial variability as a function of hillslope curvature, the proportion of kaolinite (Kt) and Gb, and phosphorus adsorption were evaluated in an Alfisol cultivated with sugarcane. Two plots of 1 ha of a concave and a convex hillslope area were selected and 121 samples were collected in each area. The maximum P adsorption was determined in six samples taken randomly in each area. Data were submitted to descriptive statistical and geostatistical analysis. The lowest average values of available phosphorus were found in the convex area. In this area, the proportion of gibbsite, expressed by the values of the ratio [Gb/(Gb + Ct)] and the values of maximum adsorption capacity of phosphorus were higher than in the concave area.

As curvaturas do relevo promovem pedoambientes específicos que condicionam os atributos químicos e mineralógicos do solo e podem auxiliar na definição de zonas específicas de manejo. O fósforo (P) é um dos principais elementos limitantes ao desenvolvimento e longevidade do canavial. O teor e a constituição mineralógica da fração argila assumem papel importante na disponibilidade do P, sendo que a gibbsita (Gb), quando presente em altas proporções no solo, pode ser a principal responsável pela sua adsorção e indisponibilidade. Investigaram-se as relações e a variabilidade espacial da adsorção de P e a ocorrência de caulinita (Ct) e gibbsita na fração argila de um Argissolo Vermelho-Amarelo eutrófico originado de rochas areníticas sob diferentes curvaturas do relevo em área sob cultivo de cana-de-açúcar. Duas malhas de 1 ha foram delimitadas numa área côncava e outra área convexa. Foram coletadas 121 amostras em cada área para realização das análises granulométricas, químicas e mineralógicas. A capacidade máxima de adsorção de P foi obtida em seis amostras escolhidas ao acaso em cada área. Os resultados foram submetidos às análises estatísticas descritiva e geoestatística. Os menores valores médios de P disponível encontraram-se na área convexa. Nesta área, a proporção de gibbsita, expressa pelos valores da razão [Gb/(Gb+Ct)] e os valores de capacidade máxima de adsorção de fósforo foram maiores do que na área côncava.

Calcium and available phosphorus levels for laying hens in second production cycle

This experiment studied the effect of four calcium (3.0, 3.5, 4.0, and 4.5%) and four available phosphorus levels (0.25, 0.30, 0.35, and 0.40%) in the diet of semi-heavy commercial layers after molting. Hisex Brown® layers between 90 and 108 weeks of age were distributed in a completely randomized experimental design with a 4x4 factorial arrangement with 16 treatments of five replicates of eight birds each. mortality, egg production, feed intake, egg mass, average egg weight, calcium and phosphorus intake, feed conversion ratio (per dozen eggs and per kg eggs), eggshell percentage and thickness, eggshell strength, eggshell weight per surface area (ESWSA), yolk percentage and color, albumen percentage, albumen and yolk heights, and blood and excreta calcium and phosphorus concentrations. There was no interaction (P>0.05) between dietary Ca and avP for any of the studied parameters. There were linear increases in Ca intake (P 0.01), eggshell percentage (P 0.05); ESWSA (P 0.05); yolk color (P 0.05); Ca concentration in the blood (P 0.05) and excreta (P 0.01) as dietary Ca level increased. The intake of avP linearly increased (P 0.01) with dietary avP levels. The remaining parameters were not influenced (P>0.05) by dietary Ca and avP levels. The diet containing 4.5% calcium improved feed conversion ratio per dozen eggs and eggshell quality. The lowest avP level fed (0.25%) is sufficient to maintain the performance and the egg quality of semi-heavy commercial layers after molting.

Hillslope curvature, clay mineralogy, and phosphorus adsorption in an Alfisol cultivated with sugarcane

Hillslope curvatures are associated with specific environments that correlate to chemical and mineralogical attributes of soil, so determining specific management zones. Phosphorus is one of the main limiting factors to the development and longevity of sugarcane. The type and the mineralogical constitution of the clay fraction play an important role in the phosphorus (P) adsorption of soil. High proportion of gibbsite (Gb) in soil may be the major responsible for P adsorption. The relationships among spatial variability as a function of hillslope curvature, the proportion of kaolinite (Kt) and Gb, and phosphorus adsorption were evaluated in an Alfisol cultivated with sugarcane. Two plots of 1 ha of a concave and a convex hillslope area were selected and 121 samples were collected in each area. The maximum P adsorption was determined in six samples taken randomly in each area. Data were submitted to descriptive statistical and geostatistical analysis. The lowest average values of available phosphorus were found in the convex area. In this area, the proportion of gibbsite, expressed by the values of the ratio [Gb/(Gb + Ct)] and the values of maximum adsorption capacity of phosphorus were higher than in the concave area.

As curvaturas do relevo promovem pedoambientes específicos que condicionam os atributos químicos e mineralógicos do solo e podem auxiliar na definição de zonas específicas de manejo. O fósforo (P) é um dos principais elementos limitantes ao desenvolvimento e longevidade do canavial. O teor e a constituição mineralógica da fração argila assumem papel importante na disponibilidade do P, sendo que a gibbsita (Gb), quando presente em altas proporções no solo, pode ser a principal responsável pela sua adsorção e indisponibilidade. Investigaram-se as relações e a variabilidade espacial da adsorção de P e a ocorrência de caulinita (Ct) e gibbsita na fração argila de um Argissolo Vermelho-Amarelo eutrófico originado de rochas areníticas sob diferentes curvaturas do relevo em área sob cultivo de cana-de-açúcar. Duas malhas de 1 ha foram delimitadas numa área côncava e outra área convexa. Foram coletadas 121 amostras em cada área para realização das análises granulométricas, químicas e mineralógicas. A capacidade máxima de adsorção de P foi obtida em seis amostras escolhidas ao acaso em cada área. Os resultados foram submetidos às análises estatísticas descritiva e geoestatística. Os menores valores médios de P disponível encontraram-se na área convexa. Nesta área, a proporção de gibbsita, expressa pelos valores da razão [Gb/(Gb+Ct)] e os valores de capacidade máxima de adsorção de fósforo foram maiores do que na área côncava.

Calcium and available phosphorus levels for laying hens in second production cycle

This experiment studied the effect of four calcium (3.0, 3.5, 4.0, and 4.5%) and four available phosphorus levels (0.25, 0.30, 0.35, and 0.40%) in the diet of semi-heavy commercial layers after molting. Hisex Brown® layers between 90 and 108 weeks of age were distributed in a completely randomized experimental design with a 4x4 factorial arrangement with 16 treatments of five replicates of eight birds each. mortality, egg production, feed intake, egg mass, average egg weight, calcium and phosphorus intake, feed conversion ratio (per dozen eggs and per kg eggs), eggshell percentage and thickness, eggshell strength, eggshell weight per surface area (ESWSA), yolk percentage and color, albumen percentage, albumen and yolk heights, and blood and excreta calcium and phosphorus concentrations. There was no interaction (P>0.05) between dietary Ca and avP for any of the studied parameters. There were linear increases in Ca intake (P 0.01), eggshell percentage (P 0.05); ESWSA (P 0.05); yolk color (P 0.05); Ca concentration in the blood (P 0.05) and excreta (P 0.01) as dietary Ca level increased. The intake of avP linearly increased (P 0.01) with dietary avP levels. The remaining parameters were not influenced (P>0.05) by dietary Ca and avP levels. The diet containing 4.5% calcium improved feed conversion ratio per dozen eggs and eggshell quality. The lowest avP level fed (0.25%) is sufficient to maintain the performance and the egg quality of semi-heavy commercial layers after molting.

Mineralização óssea com quatro fontes de fósforo na terminação de suínos

Four phosphorus (P) sources for bone mineralization of finishing pigs, considering their available phosphorus were studied. Thirty-two castrated male crossbred pigs, averaging 60kg live weight were used in a randomized experimental design, with four treatments, four replicates of two animals each, and a control group of six pigs that were slaughtered at the beginning of the experiment. The evaluated P souces were: bicalcium phosphate-standard (BPS), triple superphosphate (TSP), monoammonium phosphate (MAP), and the association between 20% Patos de Minas rock phosphate (PMP) plus 80% BPS. Diets were isoproteic and isocaloric and properly indicated for finishing swine. Dry matter, ash, calcium, phosphorus and fluorine deposition levels and Ca:P ratio in swine bone were evaluated. Animals that received BPS and PMP diets showed higher and lower percent of P (P 0.05), respectively, in bone ashes. Higher fluorine deposition in bone ashes was observed in swines fed PMP diet, in relation to the other treatments. In animals fed BPS and MAP diet, the fluorine deposition levels were lower (P 0.05) than TSP and PMP 20% + BPS 80% diets. P sources, in this experimental conditions, may be used in finishing swine rations, but PMP may be associated with superior patern phosphate.

Avaliou-se a inclusão de quatro fontes de fósforo (P), considerando-se seu fósforo disponível, sobre a mineralização óssea de suínos em terminação (60 a 100 kg). As fontes avaliadas foram fosfato bicálcico padrão (FBP), superfosfato supertriplo (FST), fosfato monoamônio (FMA) e consorciação de FBP (80%) com fosfato de Patos de Minas (FPM - 20%). Foram utilizados 32 leitões machos castrados, mestiços de raça tipo carne, com média de peso de 60kg. O delineamento experimental utilizado foi o inteiramente ao acaso, constituído de quatro tratamentos, com quatro repetições, cada uma com dois animais e um grupo controle de seis animais sacrificados ao início do experimento. As dietas foram isoprotéicas e isoenergéticas, adequadas para a fase de terminação. Avaliaram-se os teores de matéria seca, cinzas, cálcio, fósforo, flúor e relação Ca:P dos ossos. Os animais que receberam dietas suplementadas com FBP e FPM apresentaram maior (P 0,05) e menor porcentagem de P nas cinzas ósseas (P 0,05), respectivamente. Maior deposição de flúor nos ossos (P 0,05) ocorreu em suínos alimentados com a dieta suplementada com FPM, em relação aos demais tratamentos. Nos tratamentos com FBP e FMA, os níveis de deposição de F nos ossos foram menores (P 0,05) do que nos tratamentos que usaram FST e 20% de FPM+80% de FBP. As fontes de fósforo avaliadas, nas condições experimentais adotadas, podem ser utilizadas em rações de suínos em terminação, ressalvando-se que a indicação do fosfato de Patos de Minas deve ser em associação com outro fosfato de qualidade superior.

Comportamento de extratores em solo tratado com fontes diversas de fósforo

In order to evaluate the direct and residual effects of ordinary granulated superphosphate as compared to magnesium thermophosphate (Yoorin), supplied at four rates (0,50,100 and 200 ppm), seven successive croppings were carried out in the glasshouse. Available phosphorus was assessed after the third, fourth and seventh harvest by using Mehlich 1, Bray 1, anión exchange resin and isotopic dilution (E value). The highest correlation coefficients between available P and either total dry matter or total P content was found to occur with data provided by Mehlich 1 and resin. Phosphorus extracted by Bray 1 as well as that estimated by the E value showed lower "r" coefficients.

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.

Comportamento de extratores em solo tratado com fontes diversas de fósforo

In order to evaluate the direct and residual effects of ordinary granulated superphosphate as compared to magnesium thermophosphate (Yoorin), supplied at four rates (0,50,100 and 200 ppm), seven successive croppings were carried out in the glasshouse. Available phosphorus was assessed after the third, fourth and seventh harvest by using Mehlich 1, Bray 1, anión exchange resin and isotopic dilution (E value). The highest correlation coefficients between available P and either total dry matter or total P content was found to occur with data provided by Mehlich 1 and resin. Phosphorus extracted by Bray 1 as well as that estimated by the E value showed lower "r" coefficients.

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.