The impact of cow dung augmentation on soil restoration and bio-accumulation of metals (Lead and Cadmium) in Pheretima posthuma (Annelida: Clitellata) / O impacto do aumento de esterco de vaca na restauração do solo e bioacumulação de metais (chumbo e cádmio) em Pheretima posthuma (Annelida: Clitellata)

To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T¹ of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma.

Para investigar o papel do esterco de vaca na recuperação do solo e bioassimilação, juntamente com a bioacumulação de metais pesados em minhocas (P. posthuma) (N = 900), minhocas foram usadas e grupos de tratamento de mistura CD-solo de diferentes proporções de esterco de vaca foram projetados. Doses não letais de acetato de chumbo e cloreto de cádmio foram adicionadas aos grupos de tratamento. P. posthuma maduros foram liberados em cada vaso experimental, mantendo as condições favoráveis. Foram avaliados o pH, carbono, nitrogênio, fósforo, cátions trocáveis e nível de metais pesados de cada mistura. Os resultados indicaram que a bioassimilação de Pb e Cd por P. posthuma foi significativamente (P ˂ 0,01) maior em diferentes tratamentos de solo-CD em relação ao controle. A maior bioassimilação de ambos os metais foi observada em T1 de ambos os grupos (Pb = 563,8 mg / kg e Cd = 42,95 mg / kg). O conteúdo de ambos os metais foi significativamente (P ˂ 0,05) reduzido na fundição. A concentração de nutrientes nas fundições finais de todos os tratamentos de solo-CD também foi igualmente transformada de menos ou insolúvel para mais solúvel e disponível para as plantas, exceto o nível de carbono que aumenta com a proporção de CD. Conclui-se que o esterco de vaca como matéria orgânica tem um efeito positivo na recuperação do solo e na bioassimilação de metais por P. posthuma.

Chemical Recovery of Degraded Soil and Consequence in the Cost of Corn Production

Abstract Improper management degrades the soil, decreases corn productivity and is reflected in the cost of production. The objective of this research was to evaluate the soil recovery in non-conservationist treatments after the change of management and cultivation to the conservation condition direct sowing, and compare these systems to consolidated direct seeding; This evaluation was based on the soil responsiveness to crop production and water erosion control, and based on the financial cost of soil recovery and corn production when soil management was converted from non-conservationist (tillage rotation - RT, minimum tillage - MT, conventional tillage - CT and bare soil - BS) to no-tillage (NT) condition, in a Humic Cambisol. The transition from managements to no-tillage occurred in 2015 year, after 27 years of conducting the preexisting managements. The chemical recovery was carried out with the application of limestone, phosphorus, and potassium. At the end of the research the yield of the corn crop, the cost of recovering the soil fertility and the cost of crop production were evaluated. Previous soil management influenced the cost of soil chemical recovery. The cost of production showed a financial loss for the previous treatments CT and BS, on the average of the three corn crops.

Calagem e adubação orgânica na produção de biomassa e óleo essencial em Lippia citriodora (Kunth) / Liming and organic fertilization on Lippia citriodora (Kunth) phytomass and essential oil production

O presente trabalho objetivou avaliar a calagem e adubação orgânica na produção de biomassa e óleo essencial em Lippia citriodora Kunth. O delineamento experimental utilizado constou de fatorial 7 x 2, sendo sete tratamentos (testemunha; adição de sulfato de Ca e Mg; calcário dolomítico; silicato de Ca e Mg; sulfato de Ca e Mg + esterco de curral; calcário dolomítico + esterco de curral; silicato de Ca e Mg + esterco de curral) e duas épocas de colheita, com quatro repetições, inteiramente casualizado (DIC). Verificou-se que a correção do solo mostrou-se prática necessária para o desenvolvimento da Lippia citriodora. Independentemente da época de colheita, a produção de massa fresca e seca foi maior com a aplicação do esterco de curral (32 t ha-1), no entanto, isso não refletiu em maior rendimento de óleo essencial.

The present work aimed to evaluate the effect of liming and bovine fertilization on Lippia citriodora Kunth phytomass and essential oil production. The experimental design was completely randomized with seven treatments (control; Ca and Mg sulfate; limestone; Ca and Mg silicate; Ca and Mg sulfate + manure; limestone + manure; Ca and Mg silicate + manure) and two harvest seasons, with four replicates. Soil adjustment showed to be a necessary procedure for Lippia citriodora development. Independently of the harvest season, fresh and dry matter yields were higher under treatments with bovine manure (32 t ha-1); however, no effect of treatments was observed on essential oil concentration.

Respostas do capim-Tifton 85 à aplicação de nitrogênio: cobertura do solo, índice de área foliar e interceptação da radiação solar / Responses of the grass Tifton 85 to the application of nitrogen: soil cover, leaf area index, and solar radiation interception

Estudaram-se os efeitos da adubação nitrogenada sobre o crescimento do capim Tifton 85 (Cynodon spp. cv. Tifton 85), em termos de ocorrência de plantas e altura do dossel, índice de área foliar e interceptação de radiação fotossinteticamente ativa. O estudo foi desenvolvido sobre um planossolo de ocorrência em campo experimental. Os tratamentos consistiram de níveis de N (0; 150; 300; 450 e 600kg/ha de N-ureia, aplicados em duas vezes), arranjados em um desenho experimental de blocos inteiramente ao acaso, com quatro repetições. As avaliações foram realizadas semanalmente, entre 10 e 40 dias após o corte. Tanto a ocorrência de plantas como a altura do dossel responderam à adubação nitrogenada, conforme um padrão de resposta que variou, sazonalmente, em função das doses de N em interação com as condições ambientais. A expansão da área foliar e a interceptação da radiação fotossinteticamente ativa associada, também foram controladas direta e proporcionalmente pelas doses de N aplicadas, sendo maximizadas a valores de índice de área foliar em torno de 4,0.

The effects of nitrogen (N) fertilization levels on the growth patterns of the grass Tifton 85 (Cynodon spp. cv.Tifton 85) were studied in terms of occurrence of plants, sward height, leaf area index, and photosynthetically active radiation interception (PARint). The field trial was made in an experimental area. Treatments consisted of N levels (0; 150; 300; 450; and 600kg/ha N-urea, split in two applications) arranged in an experimental design of entirely randomized blocks with four repetitions. Plots were weekly sampled, from the day 10th to 40th after cutting. Both occurrence of plants as well as sward height were responsive to nitrogen fertilization according to a response pattern that seasonally varied, depending on N rates and environmental conditions; thus, demonstrating their sensitivity as indicators of growth conditions and canopy structure. Leaf expansion and its associated PAR interception were also directly and proportionately controlled by N rates, being maximized to values of leaf area index around 4.0.

Doses e fontes de nitrogênio na recuperação de pastagens do capim-marandu / Nitrogen doses and sources on pasture recuperation of grass marandu

Avaliaram-se o efeito de doses e fontes de nitrogênio na recuperação do capim-marandu, por um período de três anos, em pastagem estabelecida há mais de 10 anos, com baixa produção de forragem. O delineamento experimental foi em blocos completos ao acaso, com três repetições. Nas parcelas foi utilizado o fatorial 2 x 4, sendo duas fontes de nitrogênio (sulfato de amônio e uréia) e quatro doses de nitrogênio (0, 100, 200 e 300kg ha-1 ano-1). Nas subparcelas, foram alocados os três anos (2004, 2005 e 2006), referentes ao tempo de recuperação da pastagem. A aplicação de nitrogênio foi determinante para a recuperação do capim-marandu. A maior produção de massa seca foi observada no segundo ano e o maior teor de proteína bruta no terceiro ano de recuperação da pastagem. As maiores doses de nitrogênio promoveram acréscimos lineares na produção de massa seca e redução nos teores de fibra em detergente neutro e fibra em detergente ácido. O sulfato de amônio promoveu maior produção de massa seca do que a ureia, em todas as doses e anos avaliados.

The effects of nitrogen doses and sources were evaluated on pasture recuperation of grass marandu, in a three-year period. The pasture was established for more than ten years and it was presenting low herbage production being considered in moderate degradation phase. The experiment was arranged in a randomized complete block design with split-plots and three replications, in a 2x4 factorial, being two sources of N (ammonium sulphate and urea) and four doses of N (0, 100, 200, and 300kg ha-1 yr-1). The time of pasture evaluation was represented by the years 2004, 2005, and 2006. The highest dry matter production was observed in the second year and the highest crude protein in the third one. The highest nitrogen doses promoted linear increase on dry mass production and decrease in fiber concentration and in neutral and acid detergents. Ammonium sulphate resulted in higher dry mass production than urea in all doses applied and evaluated years.

Biocontrol capacity of wild and mutant Trichoderma harzianum (Rifai) strains on Rhizoctonia solani 618: effect of temperature and soil type during storage

Wild (Th11, Th12 and Th650) and mutant (Th11A80.1, Th12A40.1, Th12C40.1 and Th650-NG7) Trichoderma harzianum strains were stored for 180 days at 5ºC or at 22ºC, in two types of soils. Strains recovered at 90, 120 and 180 days from the two types of soils, retained their full capacity to biocontrol Rhizoctonia solani 618, that produces crown and root rot of tomatoes. Recovery, estimated as colony forming units (cfu) of the wild and mutant strains, showed that all increased their cfu after storage independently of the type of soil and temperature, although kinetic behavior differed among strains. Ratios of recovery after storage in type B soil/ type A soil or at 22ºC/5ºC, higher or lower than one respectively, allowed to establish that Th11 and Th12 were the most appropriate strains for the biocontrol of R. solani in conditions where growth of the phytopathogen is optimal.