Liquid manure applied in agricultural lands improves soil quality. However, incorrect management of manure may cause environmental problems due to sediments and nutrients losses associated to runoff. The aims of this work were to: (i) evaluate the time effect of postliquid dairy manure (LDM) application on runoff, sediment and nutrient losses; (ii) compare the effect of conventional tillage and no-till systems on runoff, sediment and nutrients losses after LDM application. A rainfall simulation experiment was conducted on intact soil blocks collected from fields that had been under conventional tillage and no-till systems. Rainfall was applied 24 hours or 7 days after LDM application. Conventional tillage without manure application resulted on higher runoff, sediment and nutrient losses (mainly the particulate fraction) than no-till without manure. The greatest runoff, sediment and nutrients losses occurred in the treatments where simulated rainfall was performed 24 hours after LDM application independent of the tillage system. An interval of 7 days between manure application and the simulated rainfall reduced mainly, sediment, particulate P, and particulate N losses in both, conventional and no-till systems. In practical terms, we would recommend a minimum of 7 days between LDM application and rainfall-runoff event to provide agronomic benefits minimizing the potential risk of water pollution.

Anibal de MORAES 7 RESUMOA grande maioria do rebanho brasileiro de bovinos é criado a pasto e apresenta baixa produtividade, dado pelo baixo suprimento e qualidade das pastagens. O objetivo foi avaliar a produtividade e composição química do Capim Mombaça (Panicum maximum) sob doses crescentes de nitrogênio. O experimento foi conduzido na Estação Experimental do Cangüiri localizada em Pinhais-PR, pertencente à Universidade Federal do Paraná. O delineamento experimental foi o de blocos ao acaso com quatro repetições e cinco tratamentos (0, 85, 170, 320 e 510 kg de N ha -1 ) aplicados a lanço em novembro de 2007. Os parâmetros avaliados foram produtividade de matéria seca (MS), teor de clorofila na folha e concentrações totais de N e C. A pastagem obteve incrementos na produção de MS, teor de clorofila e concentração total de N. A adubação nitrogenada propiciou incrementos lineares na produção de MS e PB, variando de 585 a 10.310 e de 45 a 1.279 kg ha -1 , após 85 e 161 dias da aplicação, respectivamente. Os incrementos na produtividade de matéria seca foram lineares com 19 kg de MS para cada kg de N aplicado. Cada kg de N também propiciou as seguintes variações lineares: 0,5x10 -5 mg kg -1 de N -teor de clorofila, 0,015 g kg -1 de N -concentração de N; 2,52 kg kg -1 de N -PB; 7,98 kg kg -1 de N -C total, e -0,025 -relação C/N. A adubação nitrogenada aumentou a produtividade, bem como as concentrações de PB e clorofila, além de diminuir a relação C/N. Palavras-chave: produtividade; forrageira; nitrogênio; clorofila. ABSTRACTThe majority of Brazilian livestock is raised under pasture which usually has low productivity. This is due to both low biomass offer and low quality of pastures. The objective of this study was to evaluate the Nitrogen fertilization on yield and quality of Mombaça grass (Panicum maximum cv. Mombaça). The experiment was carried out at Canguiri Experimental Station located Pinhais county-Parana state, belonging to Federal University of Paraná. An oxissol with high organic matter content, low acidic, and without limitation of available P and K was used for the study. The experimental design was a randomized complete block with four replications and five N rate treatments (0, 85, 170, 320 e 510 kg of N ha -1 ) applied broadcast in the first week of November 2007. The pasture was evaluated for yield dry matter (DM), chlorophyll leaf contents, and total concentration of nitrogen and carbon. The nitrogen fertilization resulted in great improvement on DM and protein yield, varying from 585 to 10.310 and from 45 to 1279 kg ha -1 , after 85 and 161 days fertilization application, respectively. The DM increment showed to be linear with 19 kg DM for each kg N applied. Each kg N applied also provided the following linear variation: 0,5x10 -5 mg kg -1 -chlorophyll leaf content; 0,015 g kg -1 -N concentration; 2,52 kg ha -1 -total protein yield; 7,98 kg ha -1 total C yield, and -0,025 -C/N ratio. The nitrogen fertilization enhanced productivity and forage quality for developed grass under good condition of s...

Manure application and no-till management improve soil quality, crop yields and C inputs, but little specific knowledge is available regarding the combined effect of long-term dairy liquid manure (DLM) application and no-till management on soil organic matter status and soil structure in topsoils. Here, we assess the impacts of surface-applied DLM for a 10-year period on soil total organic carbon (TOC) and nitrogen (TN) concentrations and stocks, on organic matter fractions and on soil physical-structural attributes in a no-till crop rotation system on clayey Ferralsol under no-till crop rotation management in a subtropical climate. Four rates of DLM (0, 60, 120 and 180 m 3 ha −1 year −1) were applied in a randomized block design with four replications. Soil samples were collected to calculate TOC and TN stocks to 100-cm depth and organic matter fractions in the 0-5-cm layer, and physical indicators of soil quality: bulk density, macroporosity and microporosity and aggregate stability. The largest DLM rates (120 and 180 m 3 ha −1 year −1) added 3.8-5.8 Mg C ha −1 year −1 as manure, increased crop residue input by 0.6 Mg C ha −1 year −1 , and increased TOC stock by 17% and TN stock by 27% in the top 10 cm of soil, at annual accumulation rates that averaged 0.72 Mg C ha −1 year −1 and 86 kg N ha −1 year −1. Stocks of TOC and TN in the sand-POM (particulate organic matter) fraction under the 180 m 3 ha −1 year −1 rate increased by 49 and 63%, and in the silt-MOM (mineral-associated organic matter) fraction by 30 and 47%, respectively. In the clay-MOM fraction, the change in TOC was not significant, but the TN increased by 16%. Soil physical-structural attributes (bulk density, porosity and aggregates) were improved by DLM application in the 10-cm layer and followed the soil carbon and nitrogen increments. Overall, the DLM amendment applied on the soil surface of no-till proved to be a strategy to ameliorate soil organic matter status, an important factor for agronomic and environmental benefits, besides improving crop biomass production. Highlights • Long-term application of liquid manure increased concentration and stock of SOC and TN in the 0-10-cm layer. • Increases of 0.72 Mg C ha −1 year −1 and 86 kg N ha −1 year −1 were observed in the 10-cm topsoil with manure.

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