Southeastern Brazil inland tropicalization: Köppen system applied for detecting climate change throughout 100 years of meteorological observed data.

Many regions around the world are facing climate changes, with substantial increase in air temperature over the past decades, which is mainly related to continental and global warming forced by the higher greenhouse gas (GHG) emissions. The objectives of this study were to use the Köppen climate classification to detect local climate change based on a historical series of 100 years and to assess if such change is related to those that are occurring in other spatial scales as a likely consequence of increasing GHG. This paper brings a content full of innovative results. The study area presented an average annual air temperature increase by 0.9 °C between 1917 and 2016, rising from 21.4 °C for the first climatological normal (1917-1946) to 22.3 °C for the last one (1987-2016). Furthermore, in the summer months, the temperature rose from 24.5 to 25.3 °C, and in the winter months, such increase was from 17.1 (1917-1946) to 18.3 °C (1987-2016). Our findings showed the subtropical conditions (Cfa in Köppen's classification) in the study area persisted from the beginning of the analysis (1917-1946) until the climatological normal of 1979-2008, with a clear tendency of tropicalization after that with a change in the climate type of Piracicaba from subtropical to tropical, which can now be classified as tropical with dry winter (Aw climate type). The local average air temperature showed concordances with the long-term air temperature anomalies from regional, continental, and global scales, indicating that all of them may be linked with increasing GHG emissions, since well-defined long-term linear relationships (r 2 = 0.99) were observed between continental and global average air temperature anomalies and atmospheric CO2 concentration observed at the NOAA Lab in Mauna Loa in the last 59 years. While the local and regional forcing effects remain to be fully unraveled, our study provided a valid and strong scientific sound evidence that climate change occurred in Piracicaba, southeastern Brazil, in the last 100 years.

Microclimate of grass canopies and biomass accumulation are influenced by the use of caged exclosures in grazing research.

Exclosure cages are often used for estimating biomass accumulation on continuously stocked pastures in grazing experiments. The microclimate inside the cages may affect the estimates of biomass accumulation, but this has not been previously identified or quantified. We evaluated how the exclusion from grazing for 21 days in Mulato II brachiariagrass (Brachiaria brizantha × Brachiaria decumbens × Brachiaria ruziziensis) pastures affected canopy air temperature (T) and relative humidity (RH) and how this related to biomass accumulation. We also evaluated the effect of the exclosure cage on wind speed (WS) and incoming solar radiation (SR), and how these impacted evapotranspiration (ET) and estimates of biomass accumulation on grazed canopies maintained at 20- and 30-cm height under continuous stocking. Regardless of canopy height, changes in canopy structure during the exclusion period up to 21 days did not affect T and RH (averages of 24.3 °C and 88.7%, respectively), indicating that the air circulation was not affected by the exclusion. The cage structure reduced SR by 5%, although there were times during clear days when SR was slightly greater inside the cage than outside. The cage also reduced WS by 4.4%. Smaller SR and WS resulted in less ET inside the cages than outside, although with close values (2.9 vs. 3.0 mm day-1; P = 0.0494). The biomass accumulation rate was greater inside than outside the cages for both canopy heights. This overestimation would be 5.8 and 9.7% greater if the structure of the cage did not reduce the SR, WS, and ET.

Assessing the performance of two gridded weather data for sugarcane crop simulations with a process-based model in Center-South Brazil.

High-quality measured weather data (MWD) are essential for long-term and in-season crop model applications. When MWD is not available, one alternative for crop simulations is to employ gridded weather data (GWD), which needs to be evaluated a priori. Therefore, this study aimed to evaluate the impact of weather data from two GWD sources (NASA and XAVIER), in the way that they are available for end users, on simulating sugarcane crop performance within the APSIM-Sugar model at traditional sites where sugarcane is grown in Center-South Brazil, compared to simulations with MWD. Besides, this study also evaluated the impact of replacing GWD rainfall by the site-specific measured data on such simulations. A common sugarcane cropping system was repeatedly simulated between 1997 and 2015 for different combinations of climate input. Both NASA and XAVIER appear to be interesting for applications that only require temperature and solar radiation for predictions, such as crop phenology and potential yield. Nonetheless, GWD should be used with caution for crop model applications that rely on accurate estimation of crop water balance, canopy development, and biomass accumulation, at least with crop models that run at a daily time-step. The replacement of gridded rainfall with measured rainfall was pivotal for improving sugarcane simulations, as observed for cane yield, by increasing both agreement (NASA d index from 0.67 to 0.90; XAVIER d from 0.73 to 0.93) and R2 (NASA from 0.35 to 0.76; XAVIER from 0.43 to 0.79) and reducing root mean square errors (RMSE) from 32.8 to 16.3 t/ha when simulated with other variables of NASA data and from 27.9 to 12.7 t/ha when having XAVIER data as input. Therefore, while using both GWD sets without any correction, it is recommended to replace gridded rainfall by measured values, whenever possible, to improve sugarcane simulations in Center-South Brazil.

On-farm assessment of eucalypt yield gaps - a case study for the producing areas of the state of Minas Gerais, Brazil.

The concept of yield gaps provides a basis for identifying the main sources of production losses, caused by water or management deficiencies, which may help foresters and forest companies to better plan and make decisions in their areas. Thus, the aim of this study was to identify the magnitude and the major causes of yield gaps of eucalypts, being this the most planted forest genus in Brazil, in different producing regions of the state of Minas Gerais that has the largest planted area. To these ends, potential (Yp) and attainable (Ya) yields were simulated using the agroecological zone model (AEZ-FAO) adapted and calibrated for Brazilian eucalypt clones. Actual yield (Yr) data were obtained from 22 sites located in the state of Minas Gerais from 2009 to 2016, considering an average forest rotation of 6.7 years and plantings occurring between 2002 and 2010. From this, the total yield gap (YGtot), yield gap by water deficit (YGwd), and yield gap by sub-optimal management (YGman) were determined. The YGwd ranged from 37 to 69 m3 ha-1 year-1 across the 22 sites assessed, with an average value of 55 m3 ha-1 year-1. On the other hand, the YGman ranged from zero (optimal management) to 31 m3 ha-1 year-1. The eucalypt yield gap in commercial areas of Minas Gerais state was mainly caused by water deficit, which represented 77% of the total yield gap. On the other hand, the deficiencies in forest management accounted for 23% of the total yield gap.

Silvopastoral system with Eucalyptus as a strategy for mitigating the effects of climate change on Brazilian pasturelands.

The aim of the present study was to assess the effect of Eucalyptus trees in a silvopastoral system on the microclimate and the capacity of that to mitigate the effects of climate change on pasturelands. This study included an open pasture of Piatã palisadegrass and an adjacent pasture that contained both palisadegrass and East-to-West rows of Eucalyptus trees, with 15 m between rows, 2 m between trees within rows. The micrometeorological measurements were collected at several distances from the tree rows and in the open pasture. The silvopastoral system was associated with greater between-row shading when solar declination was high and greater near-tree shading when solar declination was around -22°. Both soil heat flux and temperature were influenced by solar radiation, wind speed, and the ability of tree canopies to reduce radiation losses. Wind speed was consistently lower in the silvopastoral system, owing to the windbreak effect of the Eucalyptus trees. The present study demonstrated that silvopastoral systems can be used to attenuate the effects of climate change, as trees can protect pastureland from intense solar radiation and wind, thereby reducing evapotranspiration and, consequently, improving soil water availability for the understory crop.

Biology at Different Temperatures, Thermal Requirements, and Ecological Zoning of Opogona sacchari (Lepidoptera: Tineidae).

The banana moth, Opogona sacchari (Bojer, 1856), is a polyphagous pest that causes serious damage to different crops around the world, particularly to bananas in southern Brazil. The insect is designated a quarantine pest in several countries including Argentina, the main consumer market for bananas produced in southern Brazil. To provide support for the management of O. sacchari, the present study investigated the biology and thermal requirements at eight temperatures (18, 22, 25, 28, 30, 32, 33, and 34 ± 1°C) and constructed a fertility life table at five temperatures (18, 22, 25, 28, and 30 ± 1°C). Above 30°C, the mortality of all life stages was 100%; the best temperature for development was 25°C. Based on this information, an ecological zoning of the pest was developed for Brazil. The lower temperature threshold was 8.6°C. The zoning indicated that the pest does not occur in regions with warmer climates, corresponding to the actual distribution of this pest in Brazil.

Weather-based coffee leaf rust apparent infection rate modeling.

Brazil is the major coffee producer in the world, with 2 million hectares cropped, with 75% of this area with Coffea arabica and 25% with Coffea canephora. Coffee leaf rust (CLR) is one of the main diseases that cause yield losses by reducing healthy leaf area. As CLR is highly influenced by weather conditions, this study aimed to determine the best linearization model to estimate the CLR apparent infection rate, to correlate CLR infection rates with weather variables, and to develop and assess the performance of weather-based infection rate models to be used as a disease warning system. The CLR epidemic was analyzed for 88 site-seasons, while progress curves were assessed by linear, monomolecular, logistic, Gompertz, and exponential linearization models for apparent infection rate determination. Correlations between CLR infection rates and weather variables were conducted at different periods. From these correlations, multiple linear regressions were developed to estimate CLR infection rates, using the most weather-correlated variables. The Gompertz growth model had the best fit with CLR progress curves. Minimum temperature and relative humidity were the weather variables most correlated to infection rate and, therefore, chosen to compose a CLR forecast system. Among the models developed, the one for the condition of high coffee yield at a narrow row spacing was the best, with only 9.4% of false negative occurrences for all the months assessed.

Sugarcane yield gap analysis in Brazil - A multi-model approach for determining magnitudes and causes.

Brazil is the largest sugarcane producer in the world playing a pivotal role on global ethanol production. The sugarcane yield levels across the producing regions of the country vary substantially, resulting in yield gaps of different magnitudes, which represent a huge opportunity for increasing sugarcane and ethanol production. According to that, the present study aimed to investigate the sugarcane yield gap in Brazil, their magnitude and causes (water deficit or crop management), considering a multi-model approach. Three different sugarcane simulation models, FAO-Agroecological Zone, DSSAT/CANEGRO and APSIM-Sugarcane, properly calibrated and validated for sugarcane in Brazil, were used to estimate potential and water-limited yields and yield gaps for 30 locations across the country. The average of total yield gap for the 30 locations was 124 t ha-1. The main proportion of the total yield gap was caused by water deficit (about 89 t ha-1, representing 73% of the total), followed by sub-optimal crop management (about 35 t ha-1, representing 27% of the total). The highest yield gap by water deficit was found in the Northeastern region, whereas São Paulo State showed the lowest yield gap by crop management. The main causes of yield gap by crop management are possibly related to the production system based on long-term monoculture and soil compaction due to intense crop mechanization in recent years. Reducing sugarcane yield gap caused by crop management by 20 to 100% would allow to diminish the cultivated area with this crop, respectively, from 9 to 32%. Possible solutions to mitigate the yield gaps, such as use of irrigation, adoption of drought tolerant cultivars, better traffic control, periodical crop rotation, among others, were also discussed.

Vineyard microclimate and yield under different plastic covers.

The use of plastic cover in vineyards minimizes effects of adverse weather conditions. The northwest of São Paulo State is one of the largest grape producing regions in Brazil; however, few studies investigate the effects of different plastic covers on vineyards in this region. This study compared the effect of black shading screen (BSS) and braided polypropylene film (BPF) on BRS Morena vineyard microclimate, grown on an overhead trellis system in the northwestern São Paulo. The experiments were carried out during three growing seasons (2012-2014). BSS allowed superior incoming solar radiation (SR) transmissivity, resulting in higher net radiation (Rn), and higher ratio between photosynthetically active (PAR) and SR. No differences were observed between the average air temperatures (T) and relative humidity (RH) of covered environments (BPF and BSS) and outside condition (automatic weather station-AWS), due to high air circulation, despite wind speed (WS) reduction caused by plastic covers. BPF provided better conditions for vineyard growth with higher fruit yield than vineyard under BSS regarding the number of shoots with bunches per plant, bunch and stem weights, longitudinal diameter of berries, quantity of fertile buds per shoot, and yield per shoot and per plant. BPF covers also influenced leaf size and growth speed of plants in vineyards.

Cherry tomato yield in greenhouses with different plastic covers / Produção de tomate cereja em ambientes protegidos com diferentes coberturas plásticas

ABSTRACT: The objective of the present study was to evaluate the influence of different plastic covers on microclimate and cherry tomato yield in greenhouses. The experiments were carried out in Piracicaba, state of São Paulo (Brazil), during three growing periods (2008/2009/2010). A greenhouse was divided in: Environment I (EI) - covered with plastic film anti-UV and thermo-reflective shading screen, and Environment II (EII) - covered with diffusive plastic film; monitored with automatic weather sensors; and cultivated with cherry tomato ('Sweet Grape' and 'Sweet Million'). Use of diffusive plastic in greenhouses provides a better inside distribution of solar energy without causing major changes in air temperature and relative humidity, resulting in higher yield (kg plant-1), fruits quantity (number plant-1) and fruits average weight than those obtained under thermo-reflective shading screen.

RESUMO: O objetivo do presente estudo foi avaliar a influência de diferentes coberturas plásticas no microclima e rendimento do tomate cereja em casa-de-vegetação. Os experimentos foram realizados em Piracicaba, Estado de São Paulo, durante três períodos de produção (2008/2009/2010). A casa-de-vegetação foi dividida em Ambiente I (EI) - coberto com filme plástico anti-UV e tela de sombreamento termo-refletora, e Ambiente II (EII) - coberto com filme plástico difusor; monitorados com sensores meteorológicos automáticos; e cultivados com tomate cereja ('Sweet Grape' e 'Sweet Million'). O uso do plástico difusor em casas-de-vegetação proporcionou melhor distribuição da energia solar sem causar grandes mudanças na temperatura e umidade relativa do ar, resultando em maiores rendimento (kg planta-1), quantidade de frutos (número planta-1) e peso médio dos frutos do tomateiro, em comparação ao ambiente coberto com tela termo-refletora.

Incidence and severity of white mold for soybean under different cultural practices and local meteorological conditions / Incidência e severidade de mofo-branco em soja sob diferentes práticas culturais e condições meteorológicas locais

The Sclerotinia sclerotiorum (Lib.) de Bary fungus is a necrotrophic and polyphagous pathogen with soybean crop as one of its most important hosts. However in order to occur epidemics caused by such a pathogen it is necessary that the climatic conditions, mainly air temperature and relative humidity be favorable to the occurrence and development of the disease. The current research aimed to assess the incidence and severity of S. sclerotiorum in soybean plants grown in Arapoti, PR, Brazil, as a function of different plant populations, row spacing, and microclimate. The experiment was conducted in a naturally infested area. The experimental design adopted was a randomized block in a factorial combination with 4 row spacing (0.35, 0.45, 0.60, 0.75 m) and 4 plant populations (150, 200, 250; 300 thousand plants per hectare), totaling 16 treatments and 4 replications. Throughout the current study we performed 4 assessments of incidence and severity. Local climatic conditions were favorable for the incidence and severity of the pathogen. Mean air temperature, rainfall, relative humidity and leaf wetness duration, monitored during all experimental period, favored the development of the pathogen in the experimental field. Yield and 100 seed weight did not show fluctuations as a function of variations on the incidence and severity of white mold in soybean crop fields. Nevertheless, crop yield was higher under a reduced spacing, whereas the 100 seed weight showed the highest values under the lowest plant population treatment.

O fungo Sclerotinia sclerotiorum (Lib.) de Bary é um patógeno necrotrófico, polífago que tem a planta da soja como um dos seus principais hospedeiros. Porém, para que ocorram epidemias em decorrência desse patógeno é necessário que as condições climáticas, principalmente de umidade e temperatura do ar, sejam favoráveis para a ocorrência e o desenvolvimento da doença. O presente trabalho teve como objetivo avaliar a incidência e severidade de S. sclerotiorum em plantas de soja cultivadas em Arapoti, PR, Brasil, em função de diferentes densidades populacionais, espaçamentos entrelinhas e microclima. O experimento foi conduzido em área naturalmente infestada. O delineamento experimental adotado foi o de blocos casualizados em esquema fatorial, combinando 4 espaçamentos entrelinhas (0,35; 0,45; 0,60; 0,75 metros) e 4 densidades populacionais (150, 200, 250, 300 mil plantas ha-1), totalizando 16 tratamentos e 4 repetições. Ao longo do experimento foram efetuadas 4 avaliações de incidência e severidade. A temperatura média do ar, precipitação, umidade relativa do ar e a duração do molhamento foliar, monitoradas durante todo o período experimental, foram favoráveis para o desenvolvimento do patógeno na área experimental. A produção e a massa de 1000 grãos não apresentaram oscilações em função das variações nos níveis de incidência e severidade de mofo-branco na cultura da soja cultivada na condição climática estudada. Contudo, a produtividade da cultura foi maior nos tratamentos com espaçamentos reduzidos. Já a massa de 1000 grãos apresentou maiores valores em tratamentos com reduzida densidade populacional.

Eficiência climática para as culturas da soja e do trigo no estado do Rio Grande do Sul em diferentes datas de semeadura / Climatic efficiency for soybean and wheat crops in the state of Rio Grande do Sul, Brazil, in different sowing date

Eficiência climática (EC) é um índice que demonstra em termos quantitativos a redução produtiva ocasionada pelo déficit hídrico. Assim, este trabalho teve como objetivo avaliar a EC das culturas da soja e do trigo para o estado do Rio Grande do Sul, considerando-se diferentes locais e datas de semeaduras. A EC foi obtida pela relação entre as produtividades atingível (PA) e potencial (PPf), estimadas por meio de modelos de simulação. A PA foi obtida pela estimativa da PPf, a qual foi determinada pelo método de Zona Agroecológica da FAO, deflacionada pelo déficit hídrico em cada uma das fases das culturas para cada data de semeadura, entre os anos de 1979 e 2008. Os resultados evidenciaram que as datas de semeadura influenciam a EC para a cultura da soja, a qual variou de 0,31 a 0,61. Com base nos resultados de EC e PA, há um ganho de produtividade com o atraso da semeadura de 01/10 para 21/12. Para a cultura do trigo, a EC média foi superior a 0,81, o que leva a concluir que se deve optar por datas de semeadura em que há maior PPf. As maiores PPf para o trigo são obtidas nas semeaduras a partir de meados do mês de junho ao final do mês de julho.

Climatic efficiency (EC) is an index that shows the yield loss caused by water deficiency. The objective of this study was to evaluate the EC of soybean and wheat crops for the state of Rio Grande do Sul, Brazil. The EC was obtained by the ratio between the attainable yield (PA) and potential yield (PPf) of these crops, estimated by crop simulation models. The PA was obtained by estimating the potential yield (PPf), which was determined by the FAO Agroecological Zone method, depreciated by the water deficit in each crop phenological phase for each sowing date, between 1979 and 2008. The results showed that sowing dates influenced the EC for the soybean crop, ranging from 0.31 to 0.61. Based on the results from EC and PA, there is an increase of crop yield when sowings are delayed from 01/10 to 21/12. For the wheat crop, the average EC was greater than 0.81, which allows to conclude that the best sowing dates should be chosen considering the highest PPf. The highest potential yields for the wheat crop were obtained for sowings from mid-June to end July.

Eficiência agrícola da produção de soja, milho e trigo no estado do Rio Grande do Sul entre 1980 e 2008 / Agricultural efficiency of soybean, corn and wheat production in the state of Rio Grande do Sul, Brazil, between 1980 and 2008

Eficiência agrícola (EA) é utilizada como indicador do nível de desenvolvimento agrícola regional, expressando, por meio da relação entre as produtividades real e atingível, o nível tecnológico empregado nas culturas. Com base nisso, o objetivo deste estudo foi avaliar a EA das culturas da soja, do milho e do trigo para o estado do Rio Grande do Sul, entre os anos de 1980 e 2008, identificando os principais fatores que as condicionaram. A EA foi obtida pela relação entre a produtividade atingível (PA) e a real (PR). A PR foi obtida junto ao banco de dados do Instituto Brasileiro de Geografia e Estatística (IBGE). A PA foi obtida pela estimativa da produtividade potencial (PPf), pelo método de Zona Agroecológica da FAO, deflacionada pelo déficit hídrico em cada uma das fases da cultura. Verificou-se que as EAs médias para as culturas do milho, da soja e do trigo para o RS foram iguais a 54, 61 e 43 por cento, respectivamente. Nas localidades de Santa Rosa, São Borja e Veranópolis, a EA para a soja foi, ao contrário das demais localidades, negativa. Os principais fatores que contribuíram para o aumento da EA, na maioria das localidades, foram: mudanças no uso e fertilidade do solo; uso de mecanização agrícola; preços pagos pelas commodities; investimentos em pesquisa e desenvolvimento; adoção do zoneamento de risco climático; e melhoramento genético.

Agricultural efficiency (EA) is used as an indicator of the level of regional agricultural development, reflecting, by mean of the ratio between actual and achievable yields, the crop technology level. Based on that, the objective of this study was to evaluate the EA for soybean, corn and wheat crops in the state of Rio Grande do Sul, Brazil, between 1980 and 2008, identifying the main factors which conditioned it. EA was obtained by the relationship between the achievable yield (PA) and actual crop yield (PR). PR was obtained from the Brazilian Institute of Geography and Statistics (IBGE) data base. PA was obtained by estimating the potential yield (PPf) with the FAO Agroecological Zone method, penalized by the water deficit for each crop phase. Average EAs for corn, soybean and wheat crops were 54, 61 and 43 percent, respectively. On the contrary of the majority of location, in Santa Rosa, São Borja and Veranópolis EA values were negative for soybean crop. The main factors that contributed to the increase of EA, in the majority of the locations, were: change on the soil use and fertility; use of agricultural machinery; prices paid for commodities; investments in research and development; climatic risk zoning; and plant breeding.