Cleber Maus Alberto

Estudo numérico do impacto da mudança climática sobre o rendimento de trigo, soja e milho

The objective of this work was to evaluate through a numerical study the impact of a possible climate change on the yield of wheat, soybean and maize, in Santa Maria, RS. Climate change scenarios were created by doubling CO2, with different increases in air temperature, and with increases and without increases in rainfall. Yield of the three crops was simulated with models available in the literature. It was concluded that projected climate change will affect wheat, soybean and maize yield in Santa Maria, RS, Brazil. The increase of 2, 3 and 6oC may cancel the benefits of increasing CO2 on yield of wheat, soybean and maize, respectively.

Simulação do impacto da mudança climática sobre a água disponível do solo em agroecossistemas de trigo, soja e milho em Santa Maria, RS

The impact of the projected climate change on soil water is an important and relevant issue for planning rural activities. The objective of this study was to simulate the fraction of transpirable soil water (FTSW) in wheat, soybean and maize agroecosystems under climate change scenarios in Santa Maria, RS. Air temperature and rainfall were modified to generate climate change scenarios. FTSW was simulated with models available in the literature. The results showed that an increase in air temperature decreases FTSW and this decrease is more evident in soybean and maize than in wheat agroecosystems.

Simulação do desenvolvimento da batata cultivar asterix em cinco cenários de mudanças climáticas em Santa Maria, RS

SIMULATION OF POTATO CULTIVAR ASTERIX DEVELOPMENT UNDER FIVE CLIMATE CHANGE SCENARIOS IN SANTA MARIA In studies of the impact of climate change on agroecosystems, it is important to quantify the effect of global warming on crop development. The objective of this study was to simulate the impact of increasing air temperature scenarios on the potato (Solanum tuberosum L.) development in Santa Maria,

Água no solo e rendimento do trigo, soja e milho associados ao El Niño Oscilação Sul

The objective of this study was to simulate soil water content, and wheat, soybean and maize yields, in Santa Maria, RS, Brazil, and link their interannual variability to El Nino Southern Oscillation (ENSO). The period studied was 1969 to 2003. Soil water content and the yields of wheat, soybean and maize were simulated with models available in the literature. Soil water content was represented by the fraction of transpirable soil water. The results showed that the lowest soil water content in Santa Maria is associated to neutral years and the highest soil water is associated to El Nino events. La Nina years were more favorable to high wheat yield, whereas El Nino years were more favorable to high soybean and maize yields. It was evident that years classified as neutral years in respect to ENSO are riskier to grain yields of soybean and maize crops, which is an important information for planning strategies in agribusiness considering ENSO forecast.

Épocas de semeadura do milho com menor risco de ocorrência de deficiência hídrica no município de Santa Maria, RS, Brasil

The aim of this work was to determine the corn sowing date (ES) with the least and the highest risk of water deficit in Santa Maria, RS, Brazil. Daily data during 34 years collected at a meteorological station in Santa Maria were used to calculate the daily water balance (BH), based on the Thornthwaite and Mather adapted model. Forty two ES were simulated, from August to February, for three corn maturation groups. The duration of the subperiods and cycle was estimated by residual growing degreedays with 10oC as base temperature for development. The BH was calculated considering the fraction of available water in the soil, a threshold below which water deficit starts. Reference evapotranspiration (ETo) was estimated with the adjusted Penman model. It was concluded that the water deficiency occurrence probability are great in October, November and the first half of December sowing dates, considering all the crop cycle. December and the beginning January sowing dates present the least risk of water stress during the most critic period, assuming enough soil moisture at sowing and emergence.

Produtividade simulada de tubérculos de batata em cenários de mudanças climáticas

O objetivo deste trabalho foi simular a produtividade de tuberculos de batata (Solanum tuberosum) em diferentes cenarios climaticos de aumento da concentracao de dioxido de carbono [CO2] e da temperatura do ar, considerando aumentos simetricos e assimetricos nas temperaturas minimas e maximas diarias do ar. Utilizou-se o modelo de Spitters para simular a produtividade de tuberculos da cultivar Asterix, em duas epocas de cultivo (primavera e outono), recomendadas para a regiao de Santa Maria, RS. Em cada epoca, cinco datas de plantio foram avaliadas, em cenarios climaticos de cem anos sem aumentos na [CO2] e na temperatura (cenario atual), e em cenarios com o dobro da [CO2] atual e aumentos de 0, 1, 2, 3, 4, 5 e 6oC na temperatura. No cultivo de primavera, o aumento simetrico de 4oC, nas temperaturas minimas e maximas diarias do ar, e assimetrico de 5oC e suficiente para anular o efeito benefico na produtividade do aumento da [CO2]. No cultivo de outono, o aumento da temperatura, praticamente, nao afeta a produtividade de tuberculos de batata. A antecipacao da data de plantio, no cultivo de primavera, e o atraso, no de outono, diminuem o impacto negativo do aumento da temperatura do ar sobre a produtividade de tuberculos de batata.

Vernalization response of brazilian wheat cultivars

Vernalizacao e o processo pelo qual as plantas sao induzidas a florescer atraves da exposicao a temperaturas baixas nao congelantes. Funcoes de resposta a vernalizacao foram ajustadas para caracterizar trigos de inverno, mas ainda nao as foram para trigos brasileiros. Os objetivos deste trabalho foram determinar a sensibilidade a vernalizacao de algumas cultivares de trigo do sul do Brasil e ajustar uma funcao nao linear de reposta a vernalizacao para estas cultivares. Foram aplicados oito tratamentos de vernalizacao (0, 7, 14, 21, 28, 35, 42 e 49 dias de vernalizacao) em seis cultivares de trigo (BRS Louro, BRS 177, BRS Taruma, CEP 51, CEP 52 e Nova Era). A cultivar BRS Louro nao foi responsiva aos tratamentos de vernalizacao, na cultivar BRS Taruma ocorreu forte sensibilidade a vernalizacao, similar a trigos de inverno, e nas cultivares BRS 177, CEP 51, CEP 52 e Nova Era a resposta a vernalizacao foi intermediaria. Para as cultivares responsivas a vernalizacao foram ajustadas funcoes nao lineares que podem ser usadas em modelos de simulacao do desenvolvimento de cultivares sul brasileiras de trigo com distintos requerimentos em vernalizacao.

Simulação do balanço de água no solo cultivado com trigo com modificação de dois modelos

Wheat is the main winter crop in Rio Grande do Sul State, Brazil, and the calculation of soil water balance is an important element in simulation models for crop growth, development and yield. The objective of this study was to improve the water balance estimation in soil under wheat by two modified models. The soil water content was measured by the gravimetric method during the growing season of two wheat cultivars sown on three dates in Santa Maria, RS, Brazil. Soil water for crop was represented as the fraction of plant-available soil water (FASW). The performance of the original and the modified version of two water balance models, namely the Campbell & Diaz model and the Amir & Sinclair model, was evaluated by the root of the mean square error (RMSE). The modified Campbell & Diaz model is more realistic and has a greater potential for performing well in regions other than where it was developed, while the modified Amir & Sinclair model simulated the available soil water for a wheat crop better in the study region. A maximum root depth of 0.3 m is most appropriate to simulate the fraction of plant-available water in the Sao Pedro soil unit.