New agroclimatic approach for soybean sowing dates recommendation: A case study

Abstract

A B S T R A C TThe objective of this study was to introduce a new approach to recommend sowing dates for soybean crop in Brazil, considering the climatic conditions and crop yield. The first step was to define the periods when air temperature is smaller than 40 °C and greater than 1 °C in at least 80% of the years, and with at least 60% of relative crop evapotranspiration during the establishment phase in more than 50% of the years. The actual yield of crop was estimated by FAO Agroecological zone model for the suitable sowing dates. Based on that, when actual yield overcome the production cost in more than 80% of years and mean air temperature along the cycle is between 20 and 30 °C, the sowing date is classified as suitable, but if actual yield overcome the production cost only between 60 and 80% of the years or mean air temperature is not between 20 and 30 °C, the date is classified as marginal. Sowing dates are considered as unsuitable if actual crop yield overcome the production cost in less than 60% of the years. The new approach was applied, as case studies, for Cruz Alta, RS, Jataí, GO, and Balsas, MA, in order to compare it with the agroclimatic zoning approach presently used in Brazil. The new procedures can generate more accurate information to support sowing dates recommendation for soybean, minimizing yield losses from climatic risk.Nova abordagem para recomendação de datas de semeadura na cultura da soja: Estudo de caso R E S U M O O objetivo deste trabalho foi apresentar uma nova metodologia para a recomendação das datas de semeadura para a cultura da soja no Brasil, considerando-se as condições climáticas e a produtividade. Definem-se, primeiro, as datas de semeadura em que não há ocorrência de temperatura do ar acima de 40 °C ou abaixo de 1 °C em pelo menos 80% dos anos e com disponibilidade maior que 60% da demanda hídrica da cultura na fase de estabelecimento em mais de 50% dos anos. Para as datas aptas foi estimada a produtividade da cultura por meio do modelo da zona agroecológica FAO. Se a produtividade superar o custo de produção em mais de 80% dos anos e a temperatura média do ar durante o ciclo da cultura for entre 20 e 30 °C, a data é classificada apta e marginal quando a produtividade estimada supera o custo de produção entre 60 e 80% dos anos ou a temperatura média não está entre 20 e 30 °C. Se esses níveis probabilísticos não são alcançados a data de semeadura é classificada inapta. Como estudo de casos, a metodologia foi aplicada para as localidades de Cruz Alta (RS), Jatai (GO) e Balsas (MA) de modo a ser comparada com a metodologia do zoneamento agrícola atualmente em uso no Brasil. Com esses procedimentos propostos para recomendar as datas de semeadura da soja é possível gerar informações mais acuradas, minimizando o risco climático para a produção desta cultura.

Uncertainty assessment of soya bean yield gaps using DSSAT‐CSM‐CROPGRO‐Soybean calibrated by cultivar maturity groups

“…For a better understanding of such uncertainty for yield gap quantification, a detailed soil sampling would be required (Van Wart et al, 2013). Crop management can be considered as an important strategy for reducing YG WD in the sites where rainfall variability limits soya bean yield, like in Mamborê and Castro, which includes sowing the crop preferentially in soils with higher water-holding capacity or improving root depth by better chemical and physical soil preparation , and to choose the best sowing dates and cultivars (maturity groups) for the region (Battisti & Sentelhas, 2014Rattalino et al, 2017). Differently, in Primavera do Leste and Montividiu, where the YG WD is lower, cultivars should be selected by their potential yield, based on physiological traits (Battisti, Sentelhas, Boote, Câmara, et al, 2017;Jin et al, 2010;Keep, Schapaugh, Prasad, & Boyer, 2016;Koester, Skoneczka, Cary, Diers, & Ainsworth, 2014).…”

Sowing seasons maturity groups on quantitative traits in soybean

“…Likewise, stress conditions will cause a negative influence on the biological yield of soybeans, by damaging the final production of the plants (Siahbidi et al, 2013). The other climatic elements did not affect the studied variables, since temperatures in the range 20 to 30°C and adequate humidity are critical to the growth and development of soybean (Alcântara et al, 2012;Taiz and Zeiger, 2013;Battisti and Sentelhas, 2014) (Figures 1 and 2). Sowing season 6 was a conflicting point, which generated good results in C2 (Table 2).…”