Assessing climate change effects on gladiola in Southern Brazil

Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls’ Day across the Rio Grande do Sul State. For harvesting spikes for Mother’s Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mother’s Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.

Assessing climate change effects on gladiola in Southern Brazil

Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls Day across the Rio Grande do Sul State. For harvesting spikes for Mothers Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mothers Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.(AU)

Yield potential of Cassava Crop in a function of planting date in a subtropical environment / Potencial de produtividade da mandioca em função da época de plantio em ambiente subtropical

Studies of potential and yield potential are extremely important worldwide, to identify and narrow yield potential. The objective of this study was to simulate cassava yield potential and water-limited yield potential using the Simanihot model. Cassava yield gap and the planting date effect were estimated for two locations in Rio Grande do Sul, Brazil (Santa Maria and São Luiz Gonzaga). Due to weather conditions, in Santa Maria cassava cycle was defined as annual and São Luiz Gonzaga as annual and biannual. Planting dates were set from August 1st 2017 to May 1st 2018, and harvested on Jun 15th 2018. Results showed that cassava express higher yield potential on early planting (August 10th), achieving 64.6 Mg ha-1 and 50.2 Mg ha-1 of tuber roots and 47.3 Mg ha-1 and 38.9 Mg ha-1 of aboveground biomass, in São Luiz Gonzaga and Santa Maria, respectively. Planting dates after the beginning of the climatic risk zoning, present a yield reduction of 0.364 Mg ha-1 in São Luiz Gonzaga and 0.282 Mg ha-1 in Santa Maria, for each day of delay on the planting date. These results indicate that planting cassava during the first ten days of August expresses the highest yields and reduces the gaps for both locations.

Estudos de potencial e lacuna de produtividade são de extrema importância a nível mundial, para identificar e diminuir as lacunas de produtividade. O objetivo deste estudo foi estimar o potencial produtivo através do modelo Simanihot e quantificar a lacuna de produtividade na cultura da mandioca para dois locais do Rio Grande do Sul. Foram utilizados para as simulações os municípios de Santa Maria (cultivo anual) e São Luiz Gonzaga (cultivo anual e bianual). As datas de plantio foram definidas desde primeiro de agosto de 2017 até primeiro de maio de 2018. O melhor potencial de produtividade encontrado para a cultura da mandioca neste estudo foi 64,6 Mg ha1, 50,2 Mg ha1 de raízes e 47,3 Mg ha-1, 38,9 Mg ha-1 de parte aérea, respectivamente para São Luiz Gonzaga e para Santa Maria. Os plantios a partir do zoneamento de risco climático, apresentam uma lacuna de 0,364 Mg ha-1 em São Luiz Gonzaga e 0,282 Mg ha-1 em Santa Maria a cada dia de atraso. Estes resultados apontam que a antecipação do plantio para o primeiro decêndio de agosto expressa as maiores produtividades e diminuem as lacunas para ambos os locais.

Yield potential of Cassava Crop in a function of planting date in a subtropical environment / Potencial de produtividade da mandioca em função da época de plantio em ambiente subtropical

Studies of potential and yield potential are extremely important worldwide, to identify and narrow yield potential. The objective of this study was to simulate cassava yield potential and water-limited yield potential using the Simanihot model. Cassava yield gap and the planting date effect were estimated for two locations in Rio Grande do Sul, Brazil (Santa Maria and São Luiz Gonzaga). Due to weather conditions, in Santa Maria cassava cycle was defined as annual and São Luiz Gonzaga as annual and biannual. Planting dates were set from August 1st 2017 to May 1st 2018, and harvested on Jun 15th 2018. Results showed that cassava express higher yield potential on early planting (August 10th), achieving 64.6 Mg ha-1 and 50.2 Mg ha-1 of tuber roots and 47.3 Mg ha-1 and 38.9 Mg ha-1 of aboveground biomass, in São Luiz Gonzaga and Santa Maria, respectively. Planting dates after the beginning of the climatic risk zoning, present a yield reduction of 0.364 Mg ha-1 in São Luiz Gonzaga and 0.282 Mg ha-1 in Santa Maria, for each day of delay on the planting date. These results indicate that planting cassava during the first ten days of August expresses the highest yields and reduces the gaps for both locations.(AU)

Estudos de potencial e lacuna de produtividade são de extrema importância a nível mundial, para identificar e diminuir as lacunas de produtividade. O objetivo deste estudo foi estimar o potencial produtivo através do modelo Simanihot e quantificar a lacuna de produtividade na cultura da mandioca para dois locais do Rio Grande do Sul. Foram utilizados para as simulações os municípios de Santa Maria (cultivo anual) e São Luiz Gonzaga (cultivo anual e bianual). As datas de plantio foram definidas desde primeiro de agosto de 2017 até primeiro de maio de 2018. O melhor potencial de produtividade encontrado para a cultura da mandioca neste estudo foi 64,6 Mg ha1, 50,2 Mg ha1 de raízes e 47,3 Mg ha-1, 38,9 Mg ha-1 de parte aérea, respectivamente para São Luiz Gonzaga e para Santa Maria. Os plantios a partir do zoneamento de risco climático, apresentam uma lacuna de 0,364 Mg ha-1 em São Luiz Gonzaga e 0,282 Mg ha-1 em Santa Maria a cada dia de atraso. Estes resultados apontam que a antecipação do plantio para o primeiro decêndio de agosto expressa as maiores produtividades e diminuem as lacunas para ambos os locais.(AU)