Effect of slow release urea in sheep feed on nitrogen balance

The aim of this study was to evaluate the effect of inclusion of 0.0%, 0.4%, 0.8%, and 1.2% slow release urea (SRU) in sheep feed on nitrogen balance (intake, fecal and urinary excretion, nitrogen absorbed and retained and/or nitrogen balance). Four sheep with an average body weight (BW) of 30.8 ± 1.7 kg were distributed using a Latin square experimental design. Sheep were allocated in metabolic cages and received two meals a day. The data were subjected to analysis of variance and differences were tested using a regression equation with a 5% probability. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets did not change (p > 0.05) nitrogen intake (NI), with an average value of 20.49 g animal day-1 and 1.57 g (kg0.75)-1. The inclusion of 0.0%, 0.4%, 0.8%, and 1.2% SRU in sheep diets did not affect (p > 0.05) fecal nitrogen (FN) in g (kg0.75)-1, with an average value of 0.65 g (kg0.75)-1. However, the inclusion of SRU changed (p 0.05) the NB expressed as g animal day-1 (10.86) and g (kg0.75)-1 (0.82). However, the NB expressed as % NI or in relation to the NI responded in a quadratic manner (p < 0.05) to the inclusion of different levels of SRU in sheep food. The maximum value for NB was 59.68% NI and it was obtained at 0.68% SRU. Thus, the inclusion of 0.6% to 0.8% slow release urea in sheep diets provides the lowest fecal and urinary nitrogen losses. In addition, these levels provide the best NB values, expressed as a percentage of NI

Distiller’s dried grains with solubles (Zea mays L.) in feeding sheep on nitrogen balance

The objective of this study was to evaluate the effects of diets supplemented with 0.0, 8.0, 16.0, and 24.0% distiller’s dried grain solubles (DDGS) on nitrogen (N) intake, fecal and urinary N excretion, and N absorption and retention (N balance, NB) by feeding sheep. Four sheep of unidentified race were used, with an average body weight of 23.5 ± 1.5 kg, and housed in metabolism cages. We used a 4 × 4 Latin square design for the experimental design, and each experimental period lasted for 20 days. Data on N intake (NI), fecal N, urinary N, absorbed N, and NB were expressed in g day-1; percentage of NI and grams per kilogram of metabolic weight g (kg0.75)-1 were subjected to analysis of variance (ANOVA) and regression analysis at 5% probability. Inclusion of the different concentrations of DDGS in sheep diets had no effect on NI (mean of 15.11 g animal-1 day-1), nor on fecal and urinary N excretion (mean of 5.16 and 0.16 g animal-1 day-1, respectively). Moreover, DDGS supplementation did not alter NB or N absorption (mean of 9.79 and 9.95 g animal-1 day-1, respectively). Thus, it can be concluded that inclusion of up to 24% of DDGS in feed does not affect NI, fecal and urinary N excretion, and NB in sheep

Dinâmica dos atributos físicos e estoque de carbono de um latossolo em sistemas integrados de produção

Nas últimas décadas os sistemas agropecuários têm objetivado o aumento da produtividade de forma menos danosa ao meio ambiente, neste sentido, destacam-se os sistemas de integração lavoura-pecuária (ILP) e integração lavourapecuária- floresta (ILPF). O objetivo desta pesquisa foi avaliar atributos físicos e o teor e estoque de carbono orgânico de um Latossolo Vermelho distrófico sob sistemas integrados de produção. A pesquisa foi realizada em Campo Grande, MS, Brasil, cujos tratamentos constituíram-se de sete sistemas de uso do solo: integração lavoura-pecuária-floresta, com o cultivo de soja, eucalipto com 357 árvores ha-1 e capim Piatã pastejado com altura de 0,15 m (ILPF357-15); integração lavoura-pecuária-floresta, como cultivo de soja, eucalipto com 357 árvores ha-1 e capim Piatã pastejado com altura 0,30 m (ILPF357-30); integração lavoura-pecuáriafloresta, com o cultivo de soja, eucalipto com 227 árvores ha-1 e capim Piatã pastejado com altura de 0,15 m (ILPF227-15); integração lavoura-pecuária-floresta, com o cultivo de soja, eucalipto com 227 árvores ha-1 e capim Piatã pastejado com altura de 0,30 m (ILPF227-30); integração lavoura-pecuária com o cultivo de soja e capim Piatã pastejado com altura de 0,15 m (ILP15); integração lavoura-pecuária com o cultivo de soja e capim Piatã pastejado com altura de 0,30 m (ILP30) e vegetação nativa (VN). Nos sistemas com ação antrópica o cultivo da soja se deu nos anos 2008/2009 e 2012/2013. Em janeiro de 2011 e em outubro de 2012, em todos os sistemas de uso foram coletadas amostras de solo, nos sistemas com ILPF as amostras foram coletadas na metade do espaçamento entre os renques e a 2 m das árvores. O maior adensamento de árvores (14 x 2 m; 357 árvores hectare-1) associado com a menor altura de pastejo (0,15 m) permitiram menor proteção física ao solo e por consequência maior compactação...In last decades, agricultural systems have aimed to increase productivity in a less damaging to the environment, the integrated crop-livestock (ICL) and integrated crop-livestock-forest (ICLF) is systems that can to contribute for this. The objective of this research was to evaluate physical attributes, soil carbon and soil carbon stock of an Oxisol under integrated production systems. The study was conducted in Campo Grande, MS, Brazil. Were used seven land use systems: integrated crop-livestock-forest, with the cultivation of soybean, eucalyptus with 357 trees ha-1 and palisade grass grazed with height of 0.15 m (ICLF357-15), integrated crop-livestock-forest, with the cultivation of soybean, eucalyptus with 357 trees ha-1 and palisade grass grazed with height 0.30 m (ICLF357-30), crop- livestock-forest, with the cultivation of soybean, eucalyptus with 227 trees ha-1 and palisade grass grazed with a height of 0.15 m (ICLF227-15), integrated crop-livestock-forest, with the cultivation of soybean, eucalyptus 227 trees ha-1 and palisade grass grazed with a height of 0.30 m (ICLF227-30), integrated crop-livestock with the cultivation of soybean and palisade grass grazed with a height of 0.15 m (ICL15); integrated crop-livestock with cultivation of soybean and palisade grass grazed with a height of 0.30 m (ICL30) and native vegetation (NV). In systems with human action soybean cultivation occurred in the years 2008/2009 and 2012/2013. In January 2011 and in October 2012, were collect soil samples in all use systems, in ICLF systems the samples were collected at half the spacing between trees and in 2 m from trees. The highest density of trees (14 m x 2; 357 trees ha-1) in together with the low grazing height (0.15 m) allow smaller physical protection to the soil and thus greater compaction, although the values are not considered restrictive to development of plant species. The integrated production ..

Physical quality of an Oxisol after different periods of management systems

Os sistemas de manejo podem ocasionar a perda da qualidade do solo, em decorrência da retirada da cobertura vegetal e do excessivo uso da mecanização. A hipótese desta pesquisa foi que a estabilidade de agregados, a densidade do solo, a macro e a microporosidade do solo, o índice S e a condutividade hidraúlica saturada pudessem ser utilizados como indicadores de qualidade física do solo. Diante disso, objetivaram-se estudar os efeitos dos diferentes tempos e manejos nos atributos físicos de um Latossolo Vermelho de textura média, cultivado por dois anos agrícolas, com soja e milho e determinar quais são as camadas mais susceptíveis a variações. O delineamento experimental foi inteiramente casualizado com parcelas subdivididas (cinco tratamentos e quatro camadas), com quatro repetições. Os tratamentos em 2008/09 foram: plantio direto por cinco anos (NTS5), plantio direto por sete anos (NTS7), plantio direto por nove anos (NTS9), preparo convencional (CTS) e área adjacente de mata nativa (NF). Os tratamentos estenderam-se para o ano de 2009/10, assim identificados: NTS6, NTS8, NTS10, CTS e NF; as camadas de solo estudadas foram: 0-0,05; 0,05-0,10; 0,10-0,20; e 0,20-0,30 m. Os maiores valores do índice S foram observados no CTS nas camadas de 0-0,05 (0,106) e 0,05-0,10 m (0,099), no ano de 2008/09; e na de 0-0,05 m (0,066), em 2009/10. Esse fato pode estar associado ao revolvimento, resultando em elevadas macroporosidades do solo neste tratamento. Em contraposição, no NTS, verificou-se ocorrência de valores restritivos de macroporosidade em algumas camadas (abaixo de 0,10 m³ m-3). Constatou-se que a maior estabilidade de agregados assim como os maiores valores de condutividade hidraúlica saturada (Kθ) foram verificados na NF, em relação aos demais tratamentos; no ano de 2009/10, a Kθ na NF somente diferiu do NTS10. Pode-se afirmar com este estudo que apenas o uso do índice S não é recomendável como indicador absoluto de qualidade física do solo, mesmo tendo apresentado valores superiores a 0,035.Management systems may lead to a loss of soil physical quality as a result of removal of the plant cover and excessive agricultural mechanization. The hypothesis of this study was that the soil aggregate stability, bulk density, macro- and microporosity, and the S index and saturated hydraulic conductivity may be used as indicators of the soil physical quality. The aim was to study the effects of different periods and managements on the physical attributes of a medium-textured Red Oxisol under soybean and corn for two growing seasons, and determine which layers are most susceptible to variations. A completely randomized experimental design was used with split plots (five treatments and four layers), with four replications. The treatments in 2008/09 consisted of: five years of no-tillage (NTS5), seven years of no-tillage (NTS7), nine years of no-tillage (NTS9), conventional tillage (CTS) and an adjacent area of native forest (NF). The treatments were extended for another year, identified in 2009/10 as: NTS6, NTS8, NTS10, CTS and NF. The soil layers 0-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.30 m were sampled. The highest S index values were observed in the treatment CTS in the 0-0.05 m layer (0.106) and the 0.05-0.10 m layer (0.099) in 2008/09, and in the 0-0.05 m layer (0.066) in 2009/10. This fact may be associated with soil turnover, resulting in high macroporosity in this treatment. In contrast, in the NTS, limiting macroporosity values were observed in some layers (below 0.10 m³ m-3). Highest aggregate stability as well as the highest saturated hydraulic conductivity (Kθ) values were observed in NF in relation to the other treatments. In 2009/10, the Kθ in NF differed only from NTS10. This study showed that the use of the S index alone cannot be recommended as an absolute indicator of the soil physical quality, even at values greater than 0.035.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Compaction of an Oxisol and chemical composition of palisadegrass

Compaction is an important problem in soils under pastoral land use, and can make livestock systems unsustainable. The objective of this research was to study the impact of soil compaction on yield and quality of palisade (UROCHLOA BRIZANTHA cv. Marandu). The experiment was conducted on an Oxisol in the State of Mato Grosso, Brazil. Treatments consisted of four levels of soil compaction: no compaction (NC), slight compaction (SC), medium compaction (MC) and high compaction (HC). The following soil properties were evaluated (layers 0-0.05 and 0.05-0.10 m): aggregate size distribution, bulk density (BD), macroporosity, microporosity, total porosity (TP), relative compaction (RC), and the characteristics of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and dry matter yield (DMY) of the forage. Highly compacted soil had high BD and RC, and low TP (0-0.05 m). Both DMY and CP were affected by HC, and both were strongly related to BD. Higher DMY (6.96 Mg ha-1) and CP (7.8 %) were observed in the MC treatment (BD 1.57 Mg m-3 and RC 0.91 Mg m-3, in 0-0.05 m). A high BD of 1.57 Mg m-3 (0-0.05 m) did not inhibit plant growth. The N concentration in the palisade biomass differed significantly among compaction treatments, and was 8.72, 11.20, 12.48 and 10.98 g kg-1 in NC, SC, MC and HC treatments, respectively. Increase in DMY and CP at the MC level may be attributed to more absorption of N in this coarse-textured soil

Dispersão da fração argila de um latossolo sob diferentes sistemas de uso e dispersantes Effectiveness of distinct methods in dispersing the clay fraction of an oxisol under different use systems

Uma das condições essenciais para a realização da análise textural é a individualização completa das partículas minerais da amostra de solo. Este estudo teve por objetivo avaliar a eficiência de métodos químicos e físicos combinados na dispersão de um Latossolo Vermelho irrigado com água de poço tubular no município de Janaúba - MG (16 º 01 ' 56 '' S e 43 º 25 ' 21 '' W). Foram coletadas amostras de solo na camada de 0-0,10 m em um bananal irrigado e em área adjacente sob mata nativa para determinação da análise textural. Os tratamentos constituíram-se de cinco dispersantes químicos (NaOH 0,1 mol L-1, NaOH 1 mol L-1, calgon 0,1 mol L-1, HCl 0,1 mol L-1 + NaOH 0,1 mol L-1e HCl 1 mol L-1 + NaOH 1 mol L-1) e dois dispersantes físicos (agitação com 50 oscilações horizontais por minuto durante 720 min e agitação com 12.000 rotações por minuto durante 10 min) dispostos em esquema fatorial 2 x 5 x 2 com cinco repetições. Com exceção de HCl 1 mol L-1 + NaOH 1 mol L-1, todos os dispersantes químicos apresentaram teores de argila inferiores no solo sob irrigação, o que pode ser atribuído ao elevado teor de carbonato de Ca no solo em decorrência da água utilizada na irrigação. A utilização de HCl 1 mol L-1 + NaOH 1 mol L-1 é eficiente em dispersar a argila presente em amostras de solo com elevado teor de carbonato de Ca.One of the essential conditions for soil particle size analysis is the complete dispersion of mineral particles of the soil sample. This study aimed to evaluate the efficiency of chemical and physical methods in combination to disperse samples of an Ustox irrigated with water from a deep well in Janaúba - MG (16 º 01 ' 56 '' S, 43 º 25 ' 21 '' W) was evaluated. Soil samples were collected in the 0-0.10 m layer from an irrigated banana plantation adjacent to a native forest for particle size analysis. Five chemical dispersants were applied in the treatments (NaOH 0.1 mol L-1, NaOH 1 mol L-1, calgon 0.1 mol L-1, HCl 0.1 mol L-1 + NaOH 0.1 mol L-1and HCl 1 mol L-1 + NaOH 1 mol L-1) and two physical dispersants (50 horizontal oscillations per minute for 720 min and 12,000 revolutions per minute for 10 min.) arranged in a factorial design with five replications. All chemical dispersants except HCl 1 mol L-1 + NaOH 1 mol L-1resulted in low clay values in the soil under irrigation, which can be attributed to the high content of calcium carbonate in the soil. The use of HCl 1 mol L-1 + NaOH 1 mol L-1 is effective in dispersing soil samples with high calcium carbonate content

Atributos físicos do solo e produtividade de milho em resposta a culturas de pré-safra

O objetivo deste trabalho foi avaliar os atributos físicos de um Latossolo Vermelho distrófico argiloso e a produtividade de milho em sistemas de manejo que incluem plantas de cobertura cultivadas em pré-safra (setembro a novembro). Foram utilizadas, durante quatro anos, as seguintes plantas de cobertura: crotalária (Crotalaria juncea); milheto (Pennisetum americanum sin. tiphoydes); lab-lab (Dolichus lablab) em sistema de semeadura direta; e pousio cultivado em sistema de preparo convencional, antecedendo o cultivo de milho. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e quatro repetições. Amostras de solo indeformadas foram coletadas para determinações físicas e avaliou-se a produtividade de milho em área de 22,5 m². As plantas de cobertura no sistema de semeadura direta promoveram maior estabilidade de agregados e maior densidade do solo na camada superficial, sem alteração do conteúdo de água disponível às plantas. A utilização de lab-lab, em pré-safra, promoveu a menor produtividade de milho. A utilização de plantas de cobertura em pré-safra no sistema de semeadura direta de milho é viável no Estado de São Paulo.The objective of this work was to evaluate soil physical attributes and corn productivity of a Typic Hapludox in system including cover crops before corn. During four years the following cover crop species were used: sunn hemp (Crotalaria juncea); millet (Pennisetum americanum sin. tiphoydes); lab-lab (Dolichus lablab) in no-tillage system. An additional treatment was used with a tillage system composed of a disk plow and two harrowing. The experiment was set up in randomized block with split-plot design, with four repetitions. Undisturbed soil samples were collected for physical determinations and corn yield was evaluated in 22.5 m² areas. The cover crop treatments in no-tillage promoted bigger aggregate stability and bulk density in the superficial layer, but did not affect the available water to the plants. The lab-lab cultivated prior to corn promoted smaller corn yield. The utilization of cover crop before main cash crop in no-tillage system improve soil quality in São Paulo State, Brazil

Physical quality of an Oxisol under an integrated crop-livestock-forest system in the Brazilian Cerrado

Soil physical quality is an important factor for the sustainability of agricultural systems. Thus, the aim of this study was to evaluate soil physical properties and soil organic carbon in a Typic Acrudox under an integrated crop-livestock-forest system. The experiment was carried out in Mato Grosso do Sul, Brazil. Treatments consisted of seven systems: integrated crop-livestock-forest, with 357 trees ha-1 and pasture height of 30 cm (CLF357-30); integrated crop-livestock-forest with 357 trees ha-1 and pasture height of 45 cm (CLF357-45); integrated crop-livestock-forest with 227 trees ha-1 and pasture height of 30 cm (CLF227-30); integrated crop-livestock-forest with 227 trees ha-1 and pasture height of 45 cm (CLF227-45); integrated crop-livestock with pasture height of 30 cm (CL30); integrated crop-livestock with pasture height of 45 cm (CL45) and native vegetation (NV). Soil properties were evaluated for the depths of 0-10 and 10-20 cm. All grazing treatments increased bulk density (r b) and penetration resistance (PR), and decreased total porosity (¦t) and macroporosity (¦ma), compared to NV. The values of r b (1.18-1.47 Mg m-3), ¦ma (0.14-0.17 m³ m-3) and PR (0.62-0.81 MPa) at the 0-10 cm depth were not restrictive to plant growth. The change in land use from NV to CL or CLF decreased soil organic carbon (SOC) and the soil organic carbon pool (SOCpool). All grazing treatments had a similar SOCpool at the 0-10 cm depth and were lower than that for NV (17.58 Mg ha-1).A qualidade física do solo é um importante fator para a sustentabilidade dos sistemas agrícolas. O objetivo desta pesquisa foi avaliar as propriedades físicas do solo e o carbono orgânico em um Latossolo Vermelho distrófico, sob sistema de integração lavoura-pecuária-floresta. O experimento foi conduzido no Mato Grosso do Sul, Brasil. Os tratamentos consistiram de sete sistemas: integração lavoura-pecuária-floresta, com 357 árvores ha-1 e altura de pastejo de 30 cm (CLF357-30); integração lavoura-pecuária-floresta, com 357 árvores ha-1 e altura do pastejo de 45 cm (CLF357-45); integração lavoura-pecuária-floresta, com 227 árvores ha-1 e altura do pastejo de 30 cm (CLF227-30); integração lavoura-pecuária-floresta, com 227 árvores ha-1 e altura do pastejo de 45 cm (CLF227-45); integração lavoura-pecuária, com a altura do pastejo de 30 cm (CL30); integração lavoura-pecuária, com a altura do pastejo de 45 cm (CL45); e vegetação nativa (NV). As propriedades do solo foram avaliadas nas profundidades de 0-10 e 10-20 cm. Todos os tratamentos com pastagem aumentaram a densidade do solo (r b) e resistência à penetração (RP) e diminuíram a porosidade total (¦t) e macroporosidade (¦ma), em comparação com a NV. Os valores de r b (1,18-1,47 Mg m-3), ¦ma (0,14-0,17 m³ m-3) e PR (0,62-0,81 MPa) na profundidade de 0-10 cm não foram restritivos ao crescimento de plantas. A mudança de uso do solo a partir NV para CL ou CLF diminuiu o carbono orgânico (SOC) e o estoque de carbono orgânico (SOCpool). Todos os tratamentos com pastagem apresentaram SOCpool similar na profundidade de 0-10 cm e foram menores em comparação à NV (17,58 Mg ha-1)