Lucieta Guerreiro Martorano

Indicadores da condição hídrica do solo com soja em plantio direto e preparo convencional

Soil water condition indicators were assessed in a field experiment conducted in Eldorado do Sul, Brazil. The Paleudult soil of the experimental area has been managed during eight years under no-tillage and conventional tillage. Soy bean cultivar Fepagro Rs-10 was sown on November 20, 2003, with 0.40 m of row spacing and 300,000 plants ha-1, with and without irrigation. Variables of soil, plant and atmosphere were monitored with emphasis during drought periods. Variations of the matrix water potential were monitored from 0.075 to 1.20 m of soil depth. A regular delay was observed in the soil drying process in no-tilled plots, in particular during drought periods, indicating higher water storage in no-tillage than in conventional tillage. Higher matrix water potential, lower maximum temperature and smaller thermal amplitude were observed in no-tillage, in comparison to the conventional tillage. Indirect indicators, such as plant height and leaf area index, were in accordance to the higher water storage in no-tilled plots, due to reductions of water deficit in plants. This set of indicators demonstrated the importance of evaluating crop responses in a systemic approach to soil and water management.

Assessment of surface temperatures of buffalo bulls (Bubalus bubalis) raised under tropical conditions using infrared thermography

This paper aimed to evaluate the surface temperatures of buffalo bulls using infrared thermography, considering four distinct anatomical parts over time, and to correlate surface temperatures and thermal comfort indexes. The humid tropical climate (Koppens Afi) was predominant in the research station where the experiment was performed and the trial lasted from April to August. Ten bulls (n=10) were evaluated every 25 days (morning: 6:00-9:00; afternoon: 12:00-15:00) and the parameters assessed were respiratory rate (RR), rectal temperature (RT), and the thermograms of surface temperature for orbital area (ORB), right flank (RF), left flank (LF) and scrotum (SCR). Climatological data was continuously monitored and the Temperature and Humidity Index (THI) and the Index of Comfort of Benezra (ICB) were calculated. The average values of THI were ≥78, and significant differences between shifts were observed (P<0.05). The ICB ranged from 1.96 to 2.25 and significant differences were observed for shifts and throughout the months (P<0.05). The averages of surface temperatures were RT=38.2±0.5°C, ORB=36.1±0.8°C, LF=33.5±2.5°C, RF=35.4±1.7oC and SCR=33.3±1.1°C, which exhibited significant differences for shifts and throughout the months (P<0.05). Positive correlations were obtained between THI and ORB (0.72), RF (0.77), LF (0.75) and SCR (0.41) (P<0.0001). The maximum temperature of ORB showed the highest correlation with RT (0.58, P<0.0001). Therefore, the surface temperatures are subject to climatic variations and increase throughout the day, due to the variation in thermal comfort indexes, and the maximum ORB temperature was the parameter most related to rectal temperature. Lastly, the results indicate that IRT may be a useful non-invasive and accurate tool to detect the variations in ORB, LF, RF and SCR temperature in buffalo bulls.

Impact of agricultural expansion on water footprint in the Amazon under climate change scenarios

Agricultural expansion and intensification are main drivers of land-use change in Brazil. Soybean is the major crop under expansion in the area. Soybean production involves large amounts of water and fertiliser that act as sources of contamination with potentially negative impacts on adjacent water bodies. These impacts might be intensified by projected climate change in tropical areas. A Water Footprint Assessment (WFA) serves as a tool to assess environmental impacts of water and fertiliser use. The aim of this study was to understand potential impacts on environmental sustainability of agricultural intensification close to a protected forest area of the Amazon under climate change. We carried out a WFA to calculate the water footprint (WF) related to soybean production, Glycine max, to understand the sustainability of the WF in the Tapajós river basin, a region in the Brazilian Amazon with large expansion and intensification of soybean. Based on global datasets, environmental hotspots - potentially unsustainable WF areas - were identified and spatially plotted in both baseline scenario (2010) and projection into 2050 through the use of a land-use change scenario that includes climate change effects. Results show green and grey WF values in 2050 increased by 304% and 268%, respectively. More than one-third of the watersheds doubled their grey WF in 2050. Soybean production in 2010 lies within sustainability limits. However, current soybean expansion and intensification trends lead to large impacts in relation to water pollution and water use, affecting protected areas. Areas not impacted in terms of water pollution dropped by 20.6% in 2050 for the whole catchment, while unsustainability increased 8.1%. Management practices such as water consumption regulations to stimulate efficient water use, reduction of crop water use and evapotranspiration, and optimal fertiliser application control could be key factors in achieving sustainability within a river basin.

Decision Strategies for Soil Water Estimations in Soybean Crops Subjected to No-Tillage and Conventional Systems, in Brazil

Conservationist practices have been increasingly adopted in Brazil during the last thirty years, especially with the change from the conventional cropping system to the no-tillage system. The latter has been widely spread in several Brazilian regions where the soybean crop takes part in annual crop rotation (Denardin et al., 2005). In the Center-Southern region it reached nearly 80% of grain producers. Among environmental and economic gains are: increasing crop yield, soil water and carbon stocks increments, reductions of production costs, control of soil erosion, mitigation of carbon emissions and water crop deficit. According to Buarque (2006) sustainable agriculture involves several structural changes and faces social and political resistance. In order to mitigate environmental impacts on food production and ecosystem services, policies should aim to develop more resilient cropping systems and provide sustainable management of natural resources.

Testicular thermoregulation, scrotal surface temperature patterns and semen quality of water buffalo bulls reared in a tropical climate

This study evaluated the capacity of thermoregulation and its consequences on the scrotal surface temperature patterns and semen quality of buffalo bulls raised in a wet tropical climate. Eleven water buffaloes were evaluated in the rainiest, in the transitional and in the less rainy season. Air temperature and humidity were consistently high, but the animals did not show thermal stress in any season. The scrotal temperature gradient of buffalo bulls using infrared thermography was described, and three parallel and decreasing thermal bands were characterised. Sperm quality (n = 176 ejaculates) was maintained in normal parameters over the periods. Pearsons coefficients showed that sperm volume and progressive motility were negatively correlated with ocular globe, epididymal tail and minimum scrotal temperatures (p < .01). Sperm membrane integrity was negatively influenced by increases in epididymal tail and minimum scrotal temperatures (p < .01). Ocular globe temperature also showed positive correlation with rectal, spermatic cord, and epididymal tail temperatures (p < .01). Therefore, even under high temperature and humidity, the thermoregulatory system was effective in preventing heat stress and the normality of scrotal surface temperatures, spermatogenesis and sperm maturation were maintained.

Modelos não lineares mistos para descrever o teor de carbono orgânico no solo.

 RESUMO: O objetivo deste trabalho foi modelar um conjunto de dados de teores de carbono orgânico ao longo do perfil do solo, em diferentes sistemas de uso da terra, com base na teoria de modelos mistos. Os solos foram coletados nas camadas 0-10, 10-20, 20-30, 30-40, 40-60, 60-80, 80-100, 100-130 e 130-150 cm, em três áreas distintas. Uma alta variabilidade no teor de carbono foi verificada nas camadas superficiais, por conta da maior incorporação de matéria orgânica existente. Modificando a estrutura que contém o efeito fixo e a que contém o efeito aleatório foi possível gerar modelos e testados pelo método da máxima verossimilhança. Os dados de carbono no solo foram estimados com alta precisão ao longo do perfil do solo, concluise que o modelo misto foi eficiente para simular a dinâmica de carbono ao longo do perfil do solo em diferentes padrões de uso e cobertura.

Agrometeorological conditions associated with phenological responses of tucumã-do-pará (Astrocaryum vulgare Mart.)

As palmeiras estao entre as especies hiperdominantes na Amazonia e o tucuma (Astrocaryum vulgare Mart.) demanda de informacoes climaticas e fenologicas para subsidiar o planejamento estrategico e o manejo sustentavel dessa palmacea nativa da regiao. O objetivo neste trabalho foi avaliar as condicoes agrometeorologicas associadas as respostas fenologicas do tucuma por ser uma especie que apresenta alto potencial economico na producao de polpa dos frutos. Foram levantados dados meteorologicos correspondentes ao periodo em que foram realizadas as coletas de dados de fenologia no Banco de Germoplasma. Tambem, foram instalados sensores para monitorar a temperatura e a umidade relativa do ar onde eram observadas as fenofases. Foram realizadas analises para identificar respostas dos tucumanzeiros em funcao das condicoes agrometeorologicas na area de estudo. A precipitacao pluvial, amplitude termica e insolacao apresentaram correlacoes positivas principalmente quanto aos percentuais de individuos com bracteas, de individuos com inflorescencias e de individuos com inflorescencias fecundadas. Nas fenofases de frutificacao a precipitacao pluvial e a umidade relativa do ar influenciaram nos percentuais de individuos com cachos de frutos imaturos e de individuos com cachos de frutos maduros. Temperaturas maximas elevadas comprometem a expressao da porcentagem de individuos com cachos verdes do tucuma. Os tucumanzeiros estavam em plena capacidade vegetativa durante as avaliacoes a campo, pois o NDVI manteve-se, dominantemente superior a 0,41 nos tres anos analisados. As fenofases do tucuma demonstrando forte associacao positiva com insolacao, temperatura maxima e amplitude termica.