Baixa umidade do solo na eficácia de herbicidas aplicados em pré-emergência

The aim of this study was to evaluate the effect of low soil moisture on the efficacy of applying herbicides ametryn + clomazone, sulfentrazone and tebuthiuron in pre-emergence application submitted to simulated rainfalls at different time intervals after application in control of B. pilosa, C. echinatus and U. plantaginea plants. The experiment was carried out in pots with a capacity of 2.5 L in green-house conditions and experimental design was completely randomized with four replications, arranged in a 3x5 factorial (three herbicides and five rains intervals). The herbicides clomazone + ametryn (Sinerge EC) 5.0 L commercial product (cp) ha(-1), sulfentrazone (Boral 500 SC) 1.2 L cp ha(-1) and tebuthiuron (combine SC) 2.0 L cp ha(-1) were applied in pre-emergence and the precipitation of 20 mm were applied under de pots in five time intervals after the herbicide application (0h, 4h, 8h, 12h and 24hours). Visual evaluations of plants control that emerged plants were realized at 14 and 21 days after treatment application and the plant emergence percentage was calculated. The application of these three herbicides in dry soil then rain within 24 hours after application provided C. echinatus plants emergence, reduced B. pilosa emergency but in the end of the experiment effectively controlled these two species and U. plantaginea plants.

A mathematical view of water table fluctuations in a shallow aquifer in Brazil

Detailed monitoring of the groundwater table can provide important data about both short- and long-term aquifer processes, including information useful for estimating recharge and facilitating groundwater modeling and remediation efforts. In this paper, we presents results of 4 years (2002 to 2005) of monitoring groundwater water levels in the Rio Claro Aquifer using observation wells drilled at the Rio Claro campus of São Paulo State University in Brazil. The data were used to follow natural periodic fluctuations in the water table, specifically those resulting from earth tides and seasonal recharge cycles. Statistical analyses included methods of time-series analysis using Fourier analysis, cross-correlation, and R/S analysis. Relationships could be established between rainfall and well recovery, as well as the persistence and degree of autocorrelation of the water table variations. We further used numerical solutions of the Richards equation to obtain estimates of the recharge rate and seasonable groundwater fluctuations. Seasonable soil moisture transit times through the vadose zone obtained with the numerical solution were very close to those obtained with the cross-correlation analysis. We also employed a little-used deep drainage boundary condition to obtain estimates of seasonable water table fluctuations, which were found to be consistent with observed transient groundwater levels during the period of study.

Influência do manejo de residuos vegetais na umidade do solo e na produtividade do feijoeiro irrigado por pivô central

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Greenhouse gas emissions and N2o mitigation in beef cattle production on tropical pasture

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação do efeito da inclinação e umidade antecedente na qualidade e quantidade das parcelas escoadas, percoladas e armazenadas em telhado verde extensivo

This study investigated the effect of slope and antecedent soil moisture on the water depth stored and percolated on extensive green roofs built in pilot scale. For this purpose, slopes of 10, 20 and 30% were investigated. Moisture was measured before and after each test in order to determine the differential moisture (∆U). The experimental runoff and percolated flow were analyzed by varying moisture and slope. Apparent color and turbidity were measured on runoff and percolated flow for each one of the modules. The results yielded that for the slopes of 10% the smaller values of runoff was obtained (average of 1,01% ± 0,7%). For the others slopes (20% and 30%), the runoffs were around 35% ± 15%. The sum of runoff and percolated water results in 77% (average) for slope of 10% and 80% for 20% and 30%. The slope and moisture have explained 87% of data for retained water and 81% for runoff. For percolated flow the inverse trend was observed. The retained water was 11,6±1,4mm for the module with 10% of slope, around 10,0±1,2 mm for the module with 20% of slope, and about 9,5±1,1 mm for the module with 30%. The results pointed out that both slope and antecedent moisture are crucial for runoff reduction and for material transportation.

Emissão de CO2 em um latossolo vermelho coberto com palha sob aplicação de efluente e lodo de esgoto

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Desenvolvimento da grama Tifton 419 submetida a distintos manejos de adubação e irrigação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Variabilidade espaço-temporal da emissão de CO2 do solo em curto período sob influência de eventos de precipitação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Lodo de esgoto compostado na produção de tapetes de grama esmeralda e na manutenção de água no solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Plataforma computacional fuzzy para avaliação nos estágios do tomateiro dos efeitos da irrigação e salinidade da água

Pós-graduação em Agronegócio e Desenvolvimento - Tupã

Desenvolvimento inicial de um reflorestamento de guanandi (Calophyllum brasiliense Cambess. Calophyllaceae) em sistema de plantio sombreado e a pleno sol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Emissão de CO2 do solo em áreas de restauração na Mata Atlântica

Pós-graduação em Geociências e Meio Ambiente - IGCE

Fisiologia, qualidade e produtividade da videira cv Syrah em diferentes estratégias de irrigação no semiárido

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

RB34-6 The Relation of Drouth to Water-Use in Nebraska

Three severe drouths have occurred in Nebraska and adjacent states within the past eighty years, and less severe ones have come at moderately regular intervals. Their influence on the agricultural development of the state is well known, but their relation to water supply in general is not so well understood. This research bulletin is a brief review of the relation of drouth to soil moisture, surface water, and groundwater supplies.

G00-1417 Site Preparation: Key to Successful Conservation Tree Planting in Western Nebraska (Revised February 2002)

Establishing a conservation tree planting can be a challenge in semiarid regions like western Nebraska, where annual precipitation of 20 inches or less is the norm. Tree planting failure commonly occurs as a result of poor site preparation coupled with inadequate weed and grass control the first three to five years after planting. Effective site preparation begins the year before planting. The results help young trees survive and grow in several ways. This NebGuide explains when and how to do site preparation for conservation tree planting in Western Nebraska.