Claudir José Basso

Dejeto líquido de suínos: I - perdas de nitrogênio e fósforo na solução escoada na superfície do solo, sob plantio direto

The application of pig slurry in crop land and/or pasture areas, besides being an additional source of nutrients to plants is also an alternative for manure disposal. However, nitrogen and phosphorus losses by surface run off in no tillage can decrease the efficiency of organic fertilizers and also be a potential pollutant, threatening the quality of water bodies. This work aimed at evaluating the importance of surface run off as a nitrogen and phosphorus loss phenomenon applied via pig slurry. The work was carried out at the Federal University of Santa Maria, RS, from May, 2002, in a Typic Hapludalf soil. Black oat (Avena strigosa), corn (Zea mays) and oilseed radish (Raphanus sativus), in a succession were fertilized with increasing doses of pig slurry (0, 20, 40 and 80m3 ha-1). The pig slurry was distributed on soil surface before the sowing of each species of the succession for two consecutive years. The concentrations of reative phosphorus and mineral nitrogen concentrations in the surface run off water were directly related to the doses of applied pig slurry. Phosphorus and nitrogen concentrations in the surface run off solution as well as the predominance of ammonium or nitrate are directly related to the interval between the waste application and the first superficial flow, with in turn depended on the rainfall event. Nitrogen and phosphorus losses by superficial flow, expressed in kg ha-1, are small, but their concentrations at some periods are high enough to cause concerns of eutrophication of water bodies.

PRODUÇÃO E DECOMPOSIÇÃO DE FITOMASSA DE PLANTAS INVERNAIS DE COBERTURA DE SOLO E MILHO, SOB DIFERENTES MANEJOS DA ADUBAÇÃO NITROGENADA

Mestrando do Programa de Pos-graduacao em Agronomia, UFSM.RESUMOA qualidade do residuo vegetal e a disponibilidadede nitrogenio (N) mineral sao fatores que afetam adecomposicao de residuos vegetais. O presente trabalho teve porobjetivo avaliar a producao de materia seca, o acumulo denitrogenio de tres plantas para cobertura de solo no inverno e ainfluencia de diferentes epocas de aplicacao da adubacaonitrogenada na cultura do milho sobre a decomposicao doresiduo vegetal mantido na superficie. O experimento foidesenvolvido na Universidade Federal de Santa Maria (RS), nosanos agricolas de 1996/97 e 1997/98, em solo ARGISSOLOVERMELHO Distrofico arenico (Hapludalf), sendo que aavaliacao da taxa de decomposicao do residuo superficial foifeita somente no ano agricola de 1997/98. O delineamentoexperimental foi de blocos ao acaso com parcelas subdivididas etres repeticoes. Nas parcelas principais (25 x 5m), durante oinverno foram utilizadas tres coberturas de solo: aveia preta(Avena strigosa Schieb), aveia+ervilhaca ( Vicia sativa L.) e naboforrageiro (Raphanus sativus). Nas subparcelas (5 x 5m),diferentes epocas de aplicacao de N no milho: (i)00-00-00,(ii)00-30-90, (iii)30-30-60, (iv)60-30-30 e (v)90-30-00, quecorresponde a quantidade de N em kg ha

Dejeto líquido de suínos: II - perdas de nitrogênio e fósforo por percolação no solo sob plantio direto

Swine production has great social and economical relevance in Southern Brazil. However, the use of wastes resulted from the production process, as a plant nutrient source may not be sufficient solution to treat pig slurry production. Application of pig slurry to crop fields may result in nitrogen and phosphorus losses, decreasing the plant uptake efficiency and increasing the risk of water contamination. The present work objective is to evaluate the percolation of nitrogen and phosphorus in soil after slurry application. The field work was developed at the Federal University of Santa Maria, from May 2000 to May 2002, in crop rotation using of black oat (Avena strigosa), corn (Zea mays) and oilseed radish (Raphanus sativus) were grown in plots amended with 0, 20, 40, and 80 m3 ha -1 pig slurry, spread onto soil surface before each seeding operation. Increase in nitrate in soil solution increases with the amount of slurry applied, mainly right after application, which coincides with the initial crop development. In spite of that, it was not detected increase on available phosphorus in soil solution. Losses of nitrogen and phosphorus are negligible as compared with the amount applied, although the nitrate concentration in soil solution at the loss peaks was above the recommended levels for water quality.

Formas de fósforo no solo após sucessivas adições de dejeto líquido de suínos em pastagem natural

The swine industry generates large amounts of pig slurry (PS), which is reused as agricultural fertilizer. However, if applied at excessive rates, pig slurry becomes a severe environmental pollutant. The objective of this study was to evaluate forms of soil phosphorus accumulation after successive swine manure applications. The experiment was installed in 1995, in an area of native pasture. Rates of 0, 20 and 40 m3 ha-1 of PS were applied periodically (at 45 to 60 days intervals) during five years. In 1999, after 28 PS applications totaling 0, 560 and 1.120 m3 ha-1 of PS, soil samples were collected from the layers 0-2.5, 2.5-5.0, 5-10, 10-15, and 15-20 cm. Soil phosphorus in the samples was fractionated using Hedleys fractionation scheme (Hedley et al., 1982). The maximum phosphorus adsorption capacity (MPAC) was determined in soil samples without PS application using the Langmuir model. Results showed that phosphorus added as PS is accumulated essentially in inorganic forms, mainly those extractable by anion exchange resin, NaHCO3 0.5 mol L-1, NaOH 0.1 mol L-1 and HCl 1.0 mol L-1.

Manejo da adubação nitrogenada na sucessão aveia preta/milho, no sistema plantio direto

The objectives of this study were to evaluate, in the succession black oat/corn, the dry matter production and N accumulation by black oat and their corn productivity, the influence of applied N on soil N content and the best application time of mineral N for corn production. The treatments were: 15-0-20-55, 30-0-20-40, 45-0-20-25, 0-35-20-35, 0-70-20-0, 0-0-20-70 and 0-0-0-0, corresponding, respectively, to the amounts of N (kg ha -1 ) applied at black oat tillering, before corn seeding, at corn seeding and corn sidedress. The increase in the dry matter production and of N accumulated in the black oat, with the applications of N in the black oat tillering, did not affect corn grain productivity. Although the application of N before corn seeding provided greater soil N content at the beginning of corn development, the application of N as sidedress provided the highest corn grain yield.

Produção de forragem em pastagem natural com o uso de esterco líquido de suínos

Forage dry matter production of native pastures in southern Brazil is usually low due to the restricted soil nutrient availability - a limitation that can be compensated by application of liquid swine manure. In an experiment carried out from November 1995 to November 1999, in an area near a swine farm in Paraiso do Sul County, Rio Grande do Sul State, the efficiency and frequency of liquid swine manure application in relation to dry matter production and nutrient uptake by native grass pasture were evaluated. Liquid swine manure (0, 20 and 40 m3 ha-1) was applied every 45 to 60 days. Before each manure application, the pasture dry matter was measured and the plots mowed. A dose of 20 m3 ha-1, applied at intervals of 45 to 60 days, was most efficient to supply nutrients for the native grass pasture. Phosphorus amounts introduced by the liquid swine manure were much greater than what was taken up by the pasture. Potassium and Mg contents in the liquid swine manure should be carefully considered, due to their high extraction rates by the native pasture. During the low temperature periods of fall and winter, when the dry matter production of the native pasture is restricted, a reduction in manure application rates becomes necessary.

Perdas de nitrogênio de dejeto líquido de suínos por volatilização de amônia

Ammonia volatilization is one of the main mechanisms of soil nitrogen loss, especially associated with application of pig slurry on soil surface. The objectives of this study were to determine the ammonia volatilization after soil application of pig slurry in soil surface, at different times of the year and hour of application. The pig slurry was spread over the soil surface in February, May, October and December. In February and December the ammonia volatilization was also evaluated for application at 10:00 AM and 6:00 PM. The rates tested were 0, 20, 40 and 80m3 ha-1 and the determination of ammonia loss were made at 3, 6, 12, 24, 30, 36, 42, 48, 60, 72, 96, 120, and 144 hours after the slurry application, adding up to six days of loss evaluation. Minimum ammonia volatilization was achieved with small amount of pig slurry application. The largest losses peaks were observed in the few hours following application indicating that, whenever possible, its soil incorporation would be an option to decrease N loss. The application time was not a consistent solution to the ammonia volatilization problem.

Manejo da adubação nitrogenada na sucessão aveia-preta/milho no sistema plantio direto

Os objetivos deste trabalho foram determinar, na sucessao aveiapreta/milho, a producao de materia seca e o acumulo de N pela aveiapreta e sua relacao com a produtividade do milho em sucessao; a influencia de epocas de aplicacao de N sobre os teores de N no solo e a produtividade de graos do milho. Os tratamentos foram: 15-0-20-55, 30-0-20-40, 45-0-20-25, 0-35-20-35, 0-70-20-0, 0-0-20-70 e 0-0-0-0, correspondendo, respectivamente, as quantidades de N (kg ha1), aplicadas no perfilhamento da aveiapreta, na pre-semeadura, na semeadura e na cobertura do milho. O aumento na producao de materia seca e de N acumulado pela aveiapreta, com as aplicacoes de N no seu perfilhamento, nao alteraram a produtividade de graos de milho. Apesar da aplicacao de N em pre-semeadura do milho ter proporcionado maior teor de N no solo no inicio do desenvolvimento, a aplicacao de N em cobertura propicia a obtencao de maiores produtividades de graos.

Produtividade de grãos de milho, produção de matéria seca e acúmulo de nitrogênio, fósforo e potássio na rotação aveia preta/milho/nabo forrageiro com aplicação de dejeto líquido de suínos

Os dejetos liquidos de suinos sao largamente utilizados em cultivos comerciais ou de plantas de cobertura de solo e a definicao da quantidade a ser utilizada depende da eficiencia de uso dos nutrientes pelas plantas. O trabalho teve por objetivo avaliar a eficiencia de uso de nutrientes aplicados via dejeto liquido de suinos a nutricao de plantas, considerando o acumulo de nutrientes nas plantas, em uma rotacao de culturas representativa de regioes suinicolas. Foram aplicados 0, 20, 40 e 80m3 ha-1 de dejeto liquido de suinos antes da semeadura de cada especie na rotacao. A maior eficiencia tecnica para a produtividade de graos de milho e para producao de materia seca de aveia preta ocorreu com doses muito altas de dejeto liquido de suinos, ou seja, em torno de 85m3 ha-1, que somado ao incremento linear no acumulo de N, P e K na maioria dos casos, evidencia que na tomada de decisao sobre doses de dejeto deve ser levado em consideracao tambem aspectos operacionais, economicos e ambientais. O nabo forrageiro foi a cultura que se destacou na ciclagem dos nutrientes aplicados via dejeto liquido de suinos. Os porcentuais de recuperacao aparente de nutrientes pelo milho, que foram na ordem K>N>P, mostram que devem ser tomadas medidas para a conservacao do solo visando maior aproveitamento do efeito residual, diminuindo o potencial de perdas.

Sucessões de culturas com plantas de cobertura e milho em plantio direto e sua influência sobre o nitrogênio no solo

Em condicoes naturais, o solo encontra-se em equilibrio, mas o manejo inadequado causa degradacao, principalmente da fracao orgânica, comprometendo a sustentabilidade de sistemas agricolas. Este trabalho, realizado num experimento de seis anos em Argissolo Vermelho-Amarelo (Hapludalf), localizado na area experimental do Departamento de Solos da Universidade Federal de Santa Maria (RS), teve como objetivo avaliar a influencia de cinco sucessoes de culturas no nitrogenio do solo, sob plantio direto. Foram implantadas as sucessoes de culturas ervilhaca comum (Vicia sativa )/milho (Zea mays), tremoco azul (Lupinus angustifolius)/milho, ervilha forrageira (Pisum arvense)/milho, aveia-preta (Avena strigosa)/milho e pousio/milho, associadas a duas doses de N aplicadas no milho (0 e 80 kg ha-1). O solo foi manejado em plantio direto e foram feitas avaliacoes dos teores de N das plantas de cobertura e dos residuos vegetais superficiais, bem como do nitrogenio do solo (total, mineral e orgânico), em tres profundidades (0-2,5; 2,5-7,5 e 7,5-17,5 cm). As avaliacoes das plantas de cobertura de solo no inverno foram realizadas nas subparcelas sem aplicacao de N mineral. Os resultados mostraram que a introducao de plantas de cobertura de solo, sob plantio direto, durante seis anos, promoveu acumulos significativos de nitrogenio mineral, orgânico e total no solo e apresentaram diferencas entre as sucessoes de culturas, apenas na camada de 0-2,5 cm. A sucessao tremoco azul/milho destacou-se pela capacidade de promover acrescimos de nitrogenio no solo.