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Rainfall variability and soybean production: comparative analysis between producing regions of Brazil, the United States and India

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Vinicius Carmello
Total Authors: 1
Document type: Doctoral Thesis
Press: Presidente Prudente. 2018-11-13.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências e Tecnologia. Presidente Prudente
Defense date:
Advisor: João Lima Sant'Anna Neto

This research main goal is to analyze the rainfall variability and soybean yield in producing regions in Brazil, India and United States. The study sought to understand the specific regional arrangements based on a comparative study supported by climatological analyzes involving statistical and cartographic techniques. Configured and considered under different and unequal technique access forms and required management to minimize variability’ positive/negative adverse effects, the research considers this heterogeneity gives greater or lesser susceptibility to agricultural breaks or deficits. Different regional arrangements are produced differently according to history and global connection international politics. Theoretical basis was elaborated dealing with contemporary geopolitics issues such as globalization, concept of region and comparative study. 4-regions soybean yield, precipitation and temperature data were collected. The first region corresponds to Southern Brazil, specifically Rio Grande do Sul northwest, and the second is placed on Brazil’s Middle-West, at northern Mato Grosso state. The third region is located at United States, in northwest Ohio state, and the fourth one represents the most agricultural region of India: western Madhya Pradesh state. Strong annual soybean yield variability was found in Rio Grande do Sul, Ohio and Madhya Pradesh, with less variation and strong homogeneity in Mato Grosso. Also, Mato Grosso and Ohio are the largest producers, with annual values reaching 3,800kg/ha, followed by Rio Grande do Sul, affected by seasonality. The Indian region shows the lowest values although has a strong data homogeneity (less variation). Annual rainfall variability was well marked in Rio Grande do Sul and Ohio, with less intensity in Madhya Pradesh and northern Mato Grosso state. However, monthly data allows to reach better correlations between soybean yield and rainfall. 90% of 42 correlation tests showed statistical significance (p-value between 0.001 and 0.03) for southern Brazil, principally in January and February. For Ohio, positive correlations (p-value between 0,028 and 0.042) were found in July and August, and negative correlations were found in May. The first result corresponds to main soybean development period in Brazil, with more water needs: January and February correspond to flowering and pods’ filling and development period, that requires a satisfactory precipitation distribution (which explains the substantial number of positive correlations). At the same time, in United States the results indicate more dependence between soybean yield and July and August rainfall, most important months to phenological development at this region. The results increase climatological research related to climate at global scale, and the climate change regional impacts. Also contributes to geopolitics issues at current context (strategies), related to food production. The thesis presents correlation between the geographical-climatic reality (rainfall and agricultural vulnerability) from regional context of each selected point. (AU)

FAPESP's process: 14/01071-1 - The rainfall variability and the social-environmental vulnerability of soybeans territory in Brazil, India and USA, from the food security perspective
Grantee:Vinicius Carmello
Support Opportunities: Scholarships in Brazil - Doctorate