Osmar Klauberg Filho

Screening and selecting arbuscular mycorrhizal fungi for inoculating micropropagated apple rootstocks in acid soils

Santa Catarina state is the largest producer of apples in Brazil. Soils in this region have low pH and high levels of aluminum and manganese, requiring high inputs of fertilizers and amendments increasing costs of apple production. Inoculation of arbuscular mycorrhizal fungi can improve the establishment of micropropagated apple plants in such adverse soil conditions. Soil samples were collected from apple orchards in the Caçador, Fraiburgo and São Joaquim regions to develop a corn bioassay to identify mycorrhizal communities with high infectivity. Eleven fungal species were identified from one Caçador soil with the highest infectivity. Glomus etunicatum SCT110, Scutellospora pellucida SCT111, Acaulospora scrobiculata SCT112 and Scutellospora heterogama SCT113 were brought into single-species culture and used in a plant growth and nutrient uptake experiment using micropropagated apple (Malus prunifolia), cultivated at three soil pH. Colonization by fungal isolates significantly affected plant height, shoot and root dry weights, and root:shoot ratio. Soil pH also significantly affected all growth parameters except shoot dry weight. Mycorrhizal inoculation also significantly altered tissue concentrations of P, Zn, Cu, Ca, S, Na, N, K, Fe and Al. Association with mycorrhizal fungi increased P concentration and also decreased Al concentrations in the shoots. Overall, G. etunicatum and S. pellucida were the most effective isolates to promote plant growth and nutrient uptake. Inoculation of apple rootstock with selected fungal isolates during the acclimatization stage represents a useful strategy for producing micropropagated apples that can withstand acidic soil conditions.

Análise multivariada de atributos do solo em sistemas convencional e orgânico de produção de maçãs

Este estudo foi conduzido em pomares de macas nos sistemas de manejo convencional e orgânico, com o objetivo de identificar diferencas entre os dois sistemas de producao, com base em atributos microbiologicos e quimicos do solo, por meio de metodos multivariados, como a analise canonica discriminante (ACD) e a analise de correlacao canonica (ACC). Em ambos os pomares, foram feitas amostragens em 24 plantas distribuidas em uma grade de 45x54 m, em duas epocas, para a quantificacao de teores de carbono da biomassa microbiana (CBM), carbono orgânico total do solo (COT), nitrogenio da biomassa microbiana (NBM), nitrogenio total do solo (NT), relacao CBM:COT, relacao NBM:NT, respiracao basal (C-CO2) e quociente metabolico (qCO2), alem da determinacao de atributos quimicos destes solos. A ACD identificou o CBM como o atributo microbiologico mais importante pela analise multivariada, na separacao entre os pomares, seguido do qCO2 e da relacao NBM:NT. Atributos microbiologicos e quimicos relacionados ao carbono foram mais sensiveis as variacoes entre os sistemas do que os relacionados ao nitrogenio. Houve alta correlacao canonica entre os atributos microbiologicos e quimicos do solo nos pomares, com destaque para o CBM, entre os atributos biologicos, e para o pH H2O e aluminio, entre os atributos quimicos.

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.

Carbono, nitrogênio e fósforo microbiano do solo sob diferentes coberturas em pomar de produção orgânica de maçã no sul do Brasil

The use of soil mulching is an alternative in the prevention of weeds in organic orchard, which exclude the use of herbicides. However, there are few studies in southern Brazil on the impact of soil mulching in the soil microbiological quality. In this sense, the purpose of this study was to evaluate in two different seasons the effect of different types of soil mulching in the attributes of microbial carbon, nitrogen and phosphorus in a Typic Hapludox producing of organic apples in southern Brazil. The study was conducted at the Experimental Station of Embrapa in Vacaria, Rio Grande do Sul State, in a randomized block design. The mulchings were: pinus needle, wooden dust and black plastic compared to bare soil and weeds. Soil samples were collected in February (summer) and August (winter), 2006, with analysis microbial and chemical attributes related to carbon, nitrogen and phosphorus. Organic mulching (pinus needle and wooden dust) promoted higher soil moisture and higher levels of Cmic, Nmic, Corg, greater ratio Cmic/Corg, Nmic/Ntotal and microbial C/N. Black plastic mulching and bare soil promoted higher temperature, nitrate, immobilized phosphorus in biomass and metabolic quotient. Based on this study and considering soil microbial quality the best mulching were the organics.

Soil microbial biomass under mulch types in an integrated apple orchard from Southern Brazil

The use of mulching is an alternative to control weeds but there are few studies on its effect on soil quality. In this sense, this study aimed to evaluate the effect of types of mulching on the attributes of microbial carbon, nitrogen and phosphorus in a Typic Hapludox with production of integrated apples in southern Brazil. The experiment was conducted in randomized blocks in the Vacaria, state of Rio Grande do Sul, southern Brazil. The soil mulch types studied were: pine needle, sawdust, black plastic and a control. The soil samples were collected in February (summer) and August (winter) of 2006, and the attributes related to total organic and microbial carbon, nitrogen and phosphorus were determined. Organic mulchings (pine needle and sawdust) promoted lower soil temperature, and greater moisture, microbial carbon (Cmic), microbial nitrogen (Nmic), and the ratios Cmic:Corg, Nmic:Norg and microbial C:N than black plastic. Microbial phosphorus was greater in winter. Sawdust mulching promoted the best conditions to microbial biomass in winter. The mulch types increased the microbial compartment in winter as compared to the nonweeded control .

Influência de diferentes sistemas de manejo e calagem em experimento de longa duração sobre fungos micorrízicos arbusculares

Visando estudar a influencia de diferentes sistemas de manejo do solo com e sem calagem, sobre a colonizacao micorrizica radicular e a producao de micelio extrarradicular, por meio de tecnica de analise multivariada, utilizou-se um experimento implantado em 1978, no municipio de Guarapuava, PR. A analise de componentes principais comprovou a existencia de efeitos negativos do sistema de preparo convencional do solo sobre a colonizacao de fungos micorrizicos arbusculares (FMAs) do solo, principalmente em estruturas como arbusculos e vesiculas. A calagem apresentou beneficios para os parâmetros de colonizacao micorrizica e comprimento de micelio extrarradicular, sendo mais significativo nos sistemas de manejo conservacionistas, principalmente o sistema de plantio direto. Nas areas de sistemas convencionais ocorreu uma reducao na colonizacao micorrizica e, consequentemente, diminuicao dos efeitos beneficos dos FMAs para as plantas, reduzindo a qualidade do solo e a sustentabilidade.

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.