Agregados em um Latossolo sob sistema plantio direto e rotação de culturas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Propriedades físicas do solo em sistemas de rotação de culturas conforme o uso de corretivos da acidez

O objetivo deste trabalho foi avaliar o efeito de sistemas de rotação de culturas e de corretivos da acidez nas propriedades físicas do solo. O experimento foi realizado entre outubro de 2006 e julho de 2008, em Botucatu, SP, em blocos ao acaso, com parcelas subdivididas e oito repetições. As parcelas foram constituídas por quatro sistemas de rotação: soja/pousio/milho/pousio, soja/aveia-branca/milho/feijão, soja/milheto/milho/guandu e soja/braquiária/milho/braquiária. As subparcelas consistiram do tratamento testemunha, sem correção, e da aplicação de 3,8 Mg ha-1 de calcário dolomítico (PRNT = 90%) ou de 4,1 Mg ha-1 de silicato de cálcio e magnésio (PRNT = 80%), na superfície de um Latossolo Vermelho argiloso. Foram determinadas: estabilidade de agregados, densidade do solo, porosidade total, macro e microporosidade, resistência do solo à penetração e umidade do solo. A aplicação dos corretivos de acidez em superfície não reduz a agregação do solo e aumenta a macroporosidade até 0,20 m de profundidade, após aplicação de silicato, e até 0,10 m, após aplicação de calcário. A manutenção do solo em pousio, na entressafra, prejudica a estruturação do solo, reduz a estabilidade de agregados e aumenta a resistência à penetração nas camadas superficiais. A semeadura de braquiária, entre as safras de verão, aumenta a estabilidade de agregados até 0,10 m de profundidade.

Atributos químicos, produção e qualidade do capim braquiária em solos corrigidos com calcário e escória silicatada

As pastagens constituem a base dos sistemas de produção de bovinos, o que evidencia sua importância e a necessidade de outras práticas de manejo que resultem em maior eficiência desses sistemas. Assim, este trabalho teve como objetivo avaliar os atributos químicos do solo (pH, Ca, Mg e H+Al), o potencial produtivo e a composição química do capim braquiária (Brachiaria decumbens Stapf) em solo corrigido com diferentes doses de calcário e escória silicatada. O experimento foi conduzido em ambiente protegido no período de 2006/2007, na UNESP de Ilha Solteira. Foram testadas cinco doses de calcário e escória silicatada, 0,0; 0,5; 1,0; 1,5; 2,0 vezes a dose recomendada. O delineamento experimental foi inteiramente casualizado, com quatro repetições. Avaliou-se a composição química do solo após incubação dos corretivos, o perfilhamento, a matéria seca, proteína, FDN (fibra em detergente neutro) e FDA (fibra em detergente ácido). Ambos os corretivos proporcionaram ao solo efeito positivo em relação ao pH e teores de cálcio e magnésio. As variáveis matéria seca e FDA não foram influenciadas significativamente pelos tipos e doses de corretivos.

Estabilidade de agregados de um latossolo vermelho degradado em recuperação com adubos verdes, calcário e gesso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos da amonização sobre o valor nutritivo do feno de capim-braquiária

This work was conducted to determine the effects of ammoniation and supplementation on the nutritive value of signal grass (Brachiaria decumbens Stapf) hay. The hay was treated with anhydrous ammonia (3.0% DM) and introduced into the rations for sheep with 12.00% of CP, identified as T1 grass hay without NH3 + cotton seed meal; T2 = treated hay (3.0% de NH3); T3 = treated hay (3.0% de NH3) + com grain meal; T4 = hay + cotton seed meal + corn grain meal. nit: following coefficients of digestibility were determined for T1, T2, T3 e T4, respectively: DM (54.90; 55.50); 54.50; and 56.12%); NI)I: (51.36; 60.20; 55.30; and 48.35%); ADF (47.36; 58.66; 56.03; and 47.07%); hemicellulose (58.80; 63.32; 56.00; and 49.70%); cellulose (55.58; 71.80; 68.07; and 58.21%); lignin (10.10; 32.18; 31.74; and 0.72%) and protein (64.6; 59.36; 56.16; and 70. 15%). nle N balances for T1, T2, T3 and T4 were 5.69; 3.88; 3.90; and 8,82 g N/day. It was concluded that the ammoniation was equivalent to the vegetable protein supplementation in the rations. Furthermore, this treatment showed a greater potential to increase fiber digestion, particulary for ADF and cellulose.

Effect of grazing system on fetal development in Nellore cattle

Intensive grazing systems for beef females, based on abundant availability of high quality forages and supplementary concentrates, may affect fetal development. The objective of this study was to determine the effect of grazing system on length of gestation, fetal development, and characteristics of the calf at birth. Twenty-four pregnant (bred to Nellore bulls) Nellore females were allocated into two groups. The control group (G1) grazed Brachiaria decumbens (signal grass) in a traditional (extensive) grazing system and the second group (G2) were managed on Panicum maximumcv. Tanzania 1 (Tanzania grass) in an intensive grazing system. Fetal development was evaluated by ultrasonography on days 31, 45, 59, 94, 122, 220, and 255 of gestation. The diameter of the amniotic and allantoic cavities, crown-rump length, circumference, and diameter of the head and ocular orbit were determined. At birth, calves were weighed and height, length, thoracic circumference, and ocular orbit and bi-parietal diameters were measured. There were no differences (P > 0.05) in fetal development. The G1 cows had a longer gestation period (4.5 days; P < 0.05) and their calves had greater (P < 0.05) weight, height, length, and thoracic circumference at birth. In conclusion, Nellore females raised under intensive pasture management conditions, had significantly shorter gestation and smaller calves at birth than those raised under extensive pasture management conditions. Therefore, adoption of new management practices (e.g. intensive pasture management), should take into consideration animal behavior and productivity. (C) 2003 Elsevier B.V. All rights reserved.

Densidades de plantas de Urochloa decumbens em convivência com Corymbia citriodora

This study aimed to evaluate the effects of plant densities of Urochloa decumbens on the early growth of Corymbia citriodora. The experimental design was completely randomized design with four replications, each plot consisted of a of 60 L capacity vase. The signal grass densities were 0, 20, 40, 80 and 160 plants m(-2), along with one eucalyptus plant. At the end of eight months of living together increase in height and in diameter and plant dry mass of eucalyptus and signal grass were carried out. The eucalyptus characteristics were influenced by all the weed populations, the effect being more pronounced with the increasing of grass density.

Produção de matéria seca da braquiária de acordo com os atributos químicos de um Latossolo em Selvíria, Mato Grosso do Sul

Rustic forages as the signal-grass are predominant in areas of Cerrado in extensive livestock systems that favor soil degradation. However, with time, not even these forages can have a good development in those areas. The objective of this study was to analyze the variability of plant and soil attributes; to define the linear and spatial correlations between signal-grass yield and the chemical attributes of the studied soil, and to evaluate, among the chemical attributes of the soil, which one that best explain the variability in this forage yield. The experiment was conducted in an area that had been under pasture for more than 30 years, belonging to UNESP - Ilha Solteira Campus, located in Selvíria - MS. A geostatistical grid was installed in an oxisol, for soil and plant data collection, with 121 sampling stations, consisted of eleven transections with 160 m width in the direction of the Cartesian axes. The dry mass yield of signal-grass was low, presenting high variation. The attributes MSr, N, PB, MO1, MO2, pHa1, pHa2, pHk1 and pHk2 did not vary at random. They presented data variability from low to high and followed clearly defined spatial patterns, ranging between 17.7-162.9 m. There was significant linear correlation at 1% between MSr and N leaf, and between MSr and PB. The cross semivariograms MSr=f(N) and MSr=f(PB) confirmed that the dry matter can be estimated from data of nitrogen leaf and crude protein content of this forage.

Cover crop termination timing on rice crop production in a no-till system

Measuring shikimic acid accumulation in response to glyphosate applications can be a rapid and accurate way to quantify and predict glyphosate-induced damage to sensitive plants. The objective of this paper was to evaluate the effect of cover crop termination timing by glyphosate application on rice (Oryza sativa L.) yield in a no-till system. A factorial experiment, arranged in a split-plot design, was conducted for 2 yr. Treatments consisted of cover crops (main plots) and timed herbicide applications (subplots) to these cover crops (30, 20, 10, and 0 d before rice planting). There was a decrease in rice yield from 2866 kg ha-1 to 2322 kg ha-1 when the herbicide was applied closer to the rice planting day. Glyphosate application on cover crops increased shikimate concentrations in rice seedlings cultivated under palisade grass (Brachiaria brizantha), signal grass (B. ruziziensis), guinea grass (Panicum maximum), and weedy fallow (spontaneous vegetation) but not under millet (Pennisetum glaucum), which behaved similarly to the control (clean fallow, no glyphosate application). Glyphosate applications in the timing intervals used were associated with stress in the rice plants, and this association increased if cover crops took longer to completely dry and if higher amounts of biomass were produced. Millet, as a cover crop, allowed the highest seedling dry matter for upland rice and the highest rice yield. Our results suggest that using millet as a cover crop, with glyphosate application far from upland rice planting day (10 d or more), was the best option for upland rice under a no-tillage system. © Crop Science Society of America.

Características anatômicas foliares e controle químico em pós-emergência de Brachiaria decumbens e Brachiaria plantaginea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dietas e conteúdo alimentar de alguns Carabidae (Coleoptera) observados na região nordeste do Estado de São Paulo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Produção de silagem de milho em consórcio com braquiárias e sobressemeadura de aveia para terminação de cordeiros

Pós-graduação em Zootecnia - FMVZ

Body Composition and Net Energy Requirements for Maintenance of Non-Castrated Water Buffaloes (Bubalus bubalis)

The research aimed to estimate body contents of protein and energy and net requirements of energy for maintenance of buffaloes, slaughtered at different stages of maturity. There were used 14 Mediterranean intact males with initial average body weight of 352.2 +/- 24.3 kg and average age of 24 months. The animais were randomly divided into four experimental groups. One group was designed to slaughter at the beginning of the experimental period (IS). The animals of another group were restricting fed, receiving, individually, levels of protein and energy 15% above maintenance (RF). The animals of the two remaining groups were individually fed ad libitum (SW450 and SW500) to reach weights corresponding to 100 and 110 percent of the mature weight of the buffalo cows (respectively 450 and 550 kg). The ration contained ground-corn cobs, soybean meal, urea, minerals, and signal-grass (Brachiaria decumbens) hay, with a concentrate: roughage ratio of 50: 50 and 13% of crude protein on a dry matter basis. To estimate changes in body composition inside the range of weights included in the trial, linear regression equations of log protein (kg), fat (kg) and energy (Mcal) as a function of log empty-body-weight (EBW), in kg, were fitted. Energy requirements for maintenance were obtained as estimated heat production at zero level of energy intake. Buffaloes submitted to fattening in feedlot presented early body fat deposition, and had with the same live weight lower protein content and higher fat content and energy per unit weight than european-zebu crossbred cattle.

Effect of brushwood transposition on the leaf litter arthropod fauna in a cerrado area

The results of ecological restoration techniques can be monitored through biological indicators of soil quality such as the leaf litter arthropod fauna. This study aimed to determine the immediate effect of brushwood transposition transferred from an area of native vegetation to a disturbed area, on the leaf litter arthropod fauna in a degraded cerrado area. The arthropod fauna of four areas was compared: a degraded area with signal grass, two experimental brushwood transposition areas, with and without castor oil plants, and an area of native cerrado. In total, 7,660 individuals belonging to 23 taxa were sampled. Acari and Collembola were the most abundant taxa in all studied areas, followed by Coleoptera, Diptera, Hemiptera, Hymenoptera, and Symphyla. The brushwood transposition area without castor oil plants had the lowest abundance and dominance and the highest diversity of all areas, providing evidence of changes in the soil community. Conversely, the results showed that the presence of castor oil plants hampered early succession, negatively affecting ecological restoration in this area.

Atributos químicos do solo, reservas orgânicas e sistema radicular de pastos degradados associada à introdução de leguminosa

The aim was to study the recovery of degraded pasture with the introduction of Stylosanthes macrocephala e capitata cv. Campo Grande on Brachiaria decumbens cv. Basilisk evaluating the levels N-total in roots, biomass, area, and length, diameter and root levels of macro and micronutrients in the soil. The experiment was conducted in the municipality of Andradina, Sao Paulo State, Brazil. The experimental design was a randomized block design in a split-plot (with and without phosphorus), with four replicates, forming the following treatments: control Brachiaria decumbens (CB), partial desiccation with 1.5 L ha(-1) of glyphosate (DP), total desiccation with 3.0 L ha(-1) of glyphosate (TD); tillage (T), soil scarification (S); harrowing rome (H) and plowing + disking (PD). Treatments H and PD were sown by broadcasting and the other in the form of direct seeding. Recovery strategies of grazing signal grass showed significant differences between treatments only for the content of N-total, there were no differences in geometric characteristics of roots and root biomass. The contents of macro and micronutrients in the soil showed no significant differences between the strategies of recovery. Fertilization had a significant effect for P. The introduction of estilosantes Campo Grande accompanied by techniques such as drying and plowing + disking contributed to increases in the N-total levels in the root system. Forms of introduction of legumes did not change the soil chemical properties.