Julio Cesar Pires Santos

Análise multivariada da fauna edáfica em diferentes sistemas de preparo e cultivo do solo

The objective of this work was to evaluate the effect of different soil tillage and crop management systems on soil fauna groups, by means of multivariate analysis. In the canonical discriminant analysis the conservation soil management systems with crop succession were discriminated in relation to other treatments with crop rotation. The groups Acarina, Hymenoptera, Isopoda, and Collembola, and the Shannon index (H) showed the highest contribution for the discrimination between treatments. The correspondence analysis showed a strong association between Acarina and Hymenoptera groups with the treatment no-tillage with crop succession, and between Collembola group with the conventional tillage system.The objective of this work was to evaluate the effect of different soil tillage and crop management systems on soil fauna groups, by means of multivariate analysis. In the canonical discriminant analysis the conservation soil management systems with crop succession were discriminated in relation to other treatments with crop rotation. The groups Acarina, Hymenoptera, Isopoda, and Collembola, and the Shannon index (H) showed the highest contribution for the discrimination between treatments. The correspondence analysis showed a strong association between Acarina and Hymenoptera groups with the treatment no-tillage with crop succession, and between Collembola group with the conventional tillage system.

Seed phytate content and phosphorus uptake and distribution in dry bean genotypes

Phytic acid is the major storage form of phosphorus in seeds of legumes and cereals. Since phytate can form complexes with proteins and minerals, reducing the digestive availability of these nutrients, it is usually regarded as an antinutrient, although recent work indicates that it has important beneficial roles as an antioxidant and anticarcinogen. Therefore, there is an interest in the assessment and manipulation of phytate contents in important food grains such as beans. The objective of this work was to compare eleven dry bean genotypes with regard to grain contents of P, phytate, inorganic P and protein and to examine if differences between genotypes could be explained by differences in grain protein content or in uptake and partitioning of P. Plants were grown in a greenhouse in pots containing soil and commercial substrate amended with 7.4 and 37 mg P.dm-3. The experimental setup was a random, complete block design with five replications. Genetic variability in grain phytate contents was observed. At the higher dose of P fertilization, genotype Una presented the highest phytate content (1.48 %) and the highest fraction of P as phytate (72 %), whereas these features were lowest in Paraiso (0.70 % and 47 %, respectively). Inorganic P made up 8 % of total P in Paraiso. A correlation between phytate and protein contents among genotypes was significant (r = 0.73) only under the higher dose of P fertilization. With the exception of genotype 4AP, differences in phytate content could not be explained by differences in uptake and partitioning of P in the plant. In the case of Paraiso, it is inferred that the lower phytate contents were due to differences in the metabolism of P and dry matter accumulation in the grain.

Termite activity in relation to natural grassland soil attributes

Soil-feeding termites transport soil for mound building, and this process can affect soil characteristics. To verify the influence of soil termite activity on soil characteristics, samples were collected from top, bottom and center of termite mounds, and of the adjacent area, to assess chemical and physical properties and mineralogical composition. Four replicates of termite mounds and respective adjacent areas were randomly sampled in Lages, Capao Alto, Painel, Sao Jose do Cerrito and Coxilha Rica (State of Santa Catarina, southern Brazil). Results of chemical analyses showed a greater content of K, P, Ca, Mg and organic C in the inner part of termite mounds, accompanied by lower pH in relation to soil of the adjacent area. There were no differences regarding clay mineral composition between termite mounds and adjacent soil, however the proportion of sand and clay differed between them. It is concluded that termites modify soil characteristics due to great volume of soil transported per ascensum for mound construction (varying from 20.9 m3 ha-1 to 136.6 m3 ha-1, in this study) which promotes a strong pedo-bio-perturbation and affects nutrient cycling and soil physical properties.

Modificações nos atributos químicos de solo sob campo nativo submetido à queima

Studies done with the soil nutrient dynamics pastures on native fields burned in the South of Brazil are rare. The present work has the objective of evaluating the changes on the soil chemical attributes originated after burning native permanent pasture. The work was developed in Lages - SC, Brazil in a Haplumbrept, on a clay soil and with high percentage of organic matter . The treatments consisted of two adjacent areas, one with 5.06ha. under grazing and burned over and another with 3.5ha submitted to grazing only. The soil temperature, at 1cm of depth, of the burned area was measured by electric drilling. The soil samples, in three layers (0-2, 2-5 and 5-10cm), were taken 3 days before the burning, immediately after the burning and 30, 60, 90, 150, 220 and 350 days after the burning, for the burned treatment; and 3 days before the burning, 90 and 220 days after the burning, for the non-burned treatment. The pH in water and the percentages of total N, N-NO3-+NO2, N-NH4+, Ca+Mg, K, Al and P were determined. The soil on the superficial layer (0¾2cm) was the one which was more susceptible to the burning action, reaching the maximum temperature of 70oC, at four minutes after the burning. In this layer, the burning caused an increase in the N-NO3- percentages and decrease in the N-NH4+ percentages. Also the burning increased the K, Ca+Mg and the pH values and it decreased the Al+3. Generally, all the soil chemical attributes, which were evaluated, demonstrated a tendency to return to the original values after 90 days of the burning.

Aplicação de dejeto suíno e estrutura de um latossolo vermelho sob semeadura direta

Objetivou-se, neste trabalho, estimar o efeito da aplicacao de doses crescentes de dejetos suinos, em atributos fisicos do solo. O experimento localizado em Campos Novos, SC, foi conduzido num Latossolo Vermelho Distroferrico, no delineamento experimental em blocos casualizados, com quatro repeticoes, com os tratamentos: testemunha (0); adubo soluvel (AS); combinacao dejeto e adubo soluvel (DS); dejeto liquido suino aplicado nas doses de 50, 100 e 200 m3 ha-1. Desde 2001 foi cultivado milho e aveia preta, sob sistema de semeadura direta. A amostragem do solo foi realizada em janeiro de 2006, nas camadas de 0-5; 5-10; 10-20 cm de profundidade, para determinacao de carbono orgânico, densidade, estabilidade de agregados, macroporos, microporos e porosidade total. A aplicacao de dejeto suino nas doses de 50 e 100 m3 ha-1, reduziu a estabilidade de agregados do solo em relacao a testemunha sem adubacao. Os demais atributos fisicos do solo e o teor de C orgânico nao foram modificados pelos tratamentos, indicando que o uso agricola do dejeto suino, nas condicoes estudadas, mantem a qualidade fisica do solo.

Capacidade de cocção de grãos de feijão em função do genótipo e da temperatura da água de hidratação

Objetivou-se, neste trabalho, avaliar o efeito da temperatura da agua de embebicao sobre a capacidade de hidratacao/coccao, e se a hidratacao pode ser um indicativo do menor tempo de coccao em graos de feijao. Foram utilizadas 5 cultivares de feijao: Rubi, Uirapuru, Perola, Valente e Campeiro, produzidas em lavouras comerciais em Lages SC, no ano agricola 2005/2006. Os graos recem-colhidos foram padronizados para 12% de umidade e analisados quanto ao tempo de hidratacao, capacidade de hidratacao e tempo de coccao. O aumento da temperatura da agua de embebicao proporcionou aumento na capacidade de hidratacao diferentemente para as cultivares com temperatura superior a 25oC, Perola demorou em torno de 8 horas para atingir a maxima hidratacao, enquanto que Rubi, nessa mesma condicao, nao atingiu a maxima hidratacao. A analise de correlacao mostrou que apenas para as cultivares Campeiro e Rubi a rapida absorcao de agua pelos graos e um indicativo de maior rapidez na coccao, mas uma correlacao negativa foi observada para Uirapuru. Com base nos genotipos avaliados, e improvavel fazer uma padronizacao unica das condicoes previas ao cozimento que valha para todas as cultivares, ou seja, ha a necessidade de uma caracterizacao mais detalhada e especifica para cada genotipo em estudo.

Carbono orgânico e atributos químicos do solo em áreas florestais

The objective of this work was to evaluate organic carbon contents and soil chemical attributes in forest areas in Campo Belo do Sul, Santa Catarina, Brazil, with the following land use: native grassland (NG); 12-year-old loblolly pine (Pinus taeda) reforestation (P12); 20-year-old loblolly pine reforestation (P20); 18-year-old araucaria (Araucaria angustifolia) reforestation (A18); and native forest with araucaria (NF). The soil samples were systematically collected with eight replicates, in the layers of 0.0-0.05; 0.05-0.1; 0.1-0.2 and 0.2-0.4 m. The pinus and araucaria reforestations showed organic C stocks similar to those in native forest and grassland areas, reaching 12.5 to 14.2 kg m-2 in the layer of 0.0-0.4 m depth. Soil acidity and available P contents were highest, in the mean of the analyzed soil layers, under the P20 treatment. Soil nutrient status ranged from low to medium for available P and exchangeable K, Ca and Mg.

Effect of inoculation associated to leaf sprayed Co+Mo on the yield and grain nutrients in common bean (Phaseolus vulgaris L)

The objective of this work was to evaluate the efficiency of nitrogen fixing inoculum associated with Co + Mo leaf spray on the common bean grain yield and grain nutrients, cv. FT Nobre. Three dosages of the inoculant (0, 200 and 400 g/50 kg seeds), combined with four Co + Mo leaf spray levels (T0=0,0; T1=4.9,49; T2=7.3,73; and T3=9.7,97 g ha-1 of Co and Mo, respectively) were tested. The grain yield with the use of the inoculant (400 g / 5O kg seed-1) associated with the higher level of Co+Mo (T2 and T3) was very similar to the mineral nitrogen condition fertilizer recommended for the bean (70 kg ha-1 of N). With the increased inoculant dosage, an increase of the protein content and of P and Mg in the grain was also observed. The results indicated that the mineral nitrogen source could be replaced by inoculation of the seeds with Rhizobium tropici combined with Co + Mo leaf spray.

Crescimento de leguminosas forrageiras afetado pela adição de fósforo, calagem do solo e micorrizas, em condições de casa de vegetação

Acid soils under native pasture in Southern Brazil presents low diversity of legume species, minly due to the low availability of phosphorus and higth aluminum concentration. Four greenhouse experiments were carried out to evaluate the efect of liming, phosphorus addition and micorrhizal inoculation on three legume species. Dry Matter production was limited by phosphorus availability and aluminum concentration. Lime and phosphorus aplication increased matter production. Soil fumigation decreased Desmodium incanum productivity. Mycorrhizal inoculation of soils without fumigation did not affect the Lotus corniculatus and Trifolium riograndense grouth, which might be explained by the high natural population and colonization potential of these soils.

Rendimento de massa seca e absorção de fósforo pelo milho afetado pela aplicação de fósforo, calcário e inoculação com fungos micorrízicos

The existence of mycorrhiza in the plant roots may increase phosphorus uptake and thus crop yield. This effect, however, seems to occur only in phosphorus deficient soils. The objetive of this work was to evaluate the effect of soil pH, rates of phosphorus addition, and mycorrhiza inoculation on dry matter yield of corn and on phosphorus uptake. The experiment was run in a greenhouse, using an oxisol, with five replicates per treatment distributed in a completely randomized experimental design. The treatments, a 2x2x2 factorial, were two rates of phosphorus (25 and 100mg P/kg), two pH levels (pH 4.8 and 5.5), and without and with indigenous mycorrhiza inoculation. Forty-six days after germination, the plants were harvested, and the following determinations were done: dry matter of shoots and roots, root length, root radius, phosphorus uptake, and rate and intensity of mycorrhiza colonization. Soil inoculation with indigenous mycorrhiza increased the rates of mycorrhiza colonization in the corn roots, but had no effect on dry matter yield or on phosphorus uptake. Shoot and root dry matter of corn, root length, and phosphorus uptake all increased with the phosphorus added but especially with liming.